Archived DTCS 1.0 Specification Snapshot¶

Historical snapshot—not the current DTCS specification

DTCS 3.0.0 and the dtcs 0.14.0 toolkit are published. The canonical current specification is DTCS SPEC.md. This local 1.0.0-draft copy is retained only for historical comparison.

Status: Draft\ Version: 1.0.0-draft

Chapter 1 --- Introduction¶

1. Purpose¶

The Data Transformation Contract Standard (DTCS) defines a vendor-neutral, implementation-independent specification for expressing the semantics of data transformations.

A DTCS Transformation Contract describes what a transformation means. It does not prescribe how that transformation is implemented, optimized, compiled, or executed.

Unless explicitly identified as informative, every requirement in this specification is normative.

2. Design Goals¶

DTCS is designed to:

Standardize transformation semantics.
Preserve semantic meaning across heterogeneous execution environments.
Enable deterministic validation, analysis, planning, and compilation.
Support portable execution through multiple backend runtimes.
Promote interoperability among independent implementations.
Enable long-term ecosystem evolution through stable contracts.

3. Scope¶

This specification defines:

Transformation Contracts
The Canonical Object Model
Transformation Plans
Execution Plans
Semantic Actions
Expressions
Functions
Rules
Validation
Diagnostics
Lineage
Compatibility
Runtime Conformance
Extensibility
Governance

This specification SHALL NOT define:

Programming languages
SQL dialects
Storage technologies
Execution engine internals
Workflow orchestration
User interface behavior

4. Architectural Overview¶

The DTCS processing model consists of five logical stages.

Transformation Contract
        │
        ▼
Canonical Object Model
        │
        ▼
Transformation Plan
        │
        ▼
Execution Plan
        │
        ▼
Runtime

Each stage SHALL preserve the semantic meaning established by the originating Transformation Contract.

5. Foundational Principles¶

5.1 Contract-First¶

Every transformation SHALL be represented by a Transformation Contract before execution.

5.2 Semantic-First¶

Semantic meaning SHALL take precedence over implementation details.

5.3 Implementation Independence¶

A conforming Transformation Contract SHALL remain portable across conforming implementations.

5.4 Determinism¶

Equivalent Transformation Contracts SHALL represent equivalent semantics.

5.5 Interoperability¶

Conforming implementations SHOULD exchange DTCS artifacts without semantic loss.

5.6 Extensibility¶

Implementations MAY extend DTCS through the standardized extensibility model without redefining standardized semantics.

6. Intended Audience¶

This specification is intended for:

Data engineers
Platform engineers
Compiler authors
Runtime implementers
Tool vendors
Standards organizations
Open-source contributors

7. Relationship to Other Standards¶

DTCS complements standards governing datasets, data quality, lineage, orchestration, and governance.

DTCS standardizes transformation semantics rather than execution technologies.

8. Normative Language¶

The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL are to be interpreted as described in RFC 2119 and RFC 8174 when, and only when, they appear in all capital letters.

9. Terminology¶

For the purposes of this specification:

Transformation Contract --- A declarative specification describing the intended semantics of a data transformation.
Canonical Object Model --- The implementation-independent representation reconstructed from a DTCS document.
Transformation Plan --- The canonical semantic intermediate representation derived from a validated Transformation Contract.
Execution Plan --- A backend-specific representation generated from a Transformation Plan.
Semantic Action --- A standardized operation that transforms datasets.
Expression --- A computation that produces a value.
Function --- A reusable computation invoked by an Expression.
Rule --- A declarative invariant evaluated before, during, or after execution.
Runtime --- A component responsible for executing an Execution Plan while preserving DTCS semantics.

These definitions are normative.

10. Conformance¶

Conformance requirements are specified in Chapter 23.

Software claiming DTCS conformance SHALL satisfy all mandatory requirements applicable to its declared conformance profile.

11. Summary¶

DTCS establishes a contract-first, semantic foundation for portable data transformation.

The remainder of this specification defines the Canonical Object Model, semantic model, validation framework, planning architecture, compiler interfaces, runtime requirements, extensibility mechanisms, conformance model, security considerations, and governance processes required to build interoperable DTCS implementations.

Chapter 2 --- Core Concepts¶

1. Purpose¶

This chapter defines the fundamental concepts that form the conceptual foundation of the Data Transformation Contract Standard (DTCS).

These concepts establish the normative vocabulary used throughout this specification. Every conforming implementation SHALL interpret these concepts consistently.

2. Design Goals¶

The DTCS conceptual model is designed to be:

Semantic-first
Contract-first
Deterministic
Implementation-independent
Extensible
Composable

Core concepts SHALL remain stable across compatible revisions of the specification.

3. Transformation Contract¶

A Transformation Contract is the authoritative declaration of the intended semantics of a data transformation.

A Transformation Contract SHALL define:

transformation identity
inputs
outputs
semantic actions
expressions
rules
guarantees
metadata

A Transformation Contract SHALL NOT prescribe implementation details.

4. Canonical Object Model¶

The Canonical Object Model is the implementation-independent representation of a Transformation Contract.

All supported document formats SHALL deserialize into an equivalent Canonical Object Model.

The Canonical Object Model is the authoritative representation for validation, analysis, planning, and compilation.

5. Transformation Plan¶

A Transformation Plan is the canonical semantic intermediate representation (IR) derived from a validated Transformation Contract.

A Transformation Plan SHALL:

preserve semantic meaning
preserve lineage
preserve logical types
remain independent of execution engines

Transformation Plans are defined in detail in Chapter 13.

6. Execution Plan¶

An Execution Plan is a backend-specific representation produced from a Transformation Plan.

Execution Plans MAY target different execution engines while preserving identical observable semantics.

Generation of Execution Plans is implementation specific.

7. Runtime¶

A Runtime executes an Execution Plan.

A conforming Runtime SHALL preserve:

transformation semantics
logical types
contractual guarantees
lineage
deterministic behavior for deterministic transformations

Runtime requirements are specified in Chapter 16.

8. Semantic Actions¶

A Semantic Action is an implementation-independent operation that changes the logical state of a dataset.

Semantic Actions define what changes.

They SHALL NOT define how the change is implemented.

The normative Semantic Action Library is defined in Chapter 17.

9. Expressions¶

An Expression computes a value.

Expressions MAY invoke Functions and Operators.

Expressions SHALL NOT directly modify datasets.

10. Functions¶

A Function is a reusable computation invoked by an Expression.

Functions SHALL:

declare parameter types
declare return types
define null behavior
define determinism

The Standard Function Library is defined in Chapter 18.

11. Rules¶

A Rule is a declarative invariant evaluated before, during, or after execution.

Rules express truth conditions.

Rules SHALL NOT modify datasets.

The Standard Rule Library is defined in Chapter 19.

12. Diagnostics¶

A Diagnostic is structured information produced during processing.

Diagnostics MAY be generated by:

readers
validators
analyzers
planners
optimizers
compilers
runtimes

Diagnostics SHALL NOT alter transformation semantics.

13. Conceptual Relationships¶

The DTCS conceptual model is illustrated below.

Transformation Contract
        │
        ▼
Canonical Object Model
        │
        ▼
Transformation Plan
        │
        ▼
Execution Plan
        │
        ▼
Runtime

Semantic Actions
        │
        ▼
Expressions
        │
        ▼
Functions

Rules ─────────────► Validation
Diagnostics ◄────── All Processing Stages

This conceptual model is normative.

14. Conformance¶

Implementations claiming DTCS conformance SHALL interpret the concepts defined in this chapter consistently with the remainder of this specification.

Implementations SHALL NOT redefine the semantics of these core concepts.

15. Summary¶

The concepts defined in this chapter establish the common vocabulary and architectural foundation of DTCS.

Subsequent chapters refine these concepts into formal object models, semantic definitions, planning rules, compilation interfaces, runtime requirements, and conformance obligations while preserving the conceptual relationships established herein.

Chapter 3 --- Canonical Object Model¶

1. Purpose¶

This chapter defines the Canonical Object Model (COM) of the Data Transformation Contract Standard (DTCS).

The Canonical Object Model is the authoritative, implementation-independent representation of a DTCS Transformation Contract. All normative processing defined by this specification SHALL operate on the Canonical Object Model rather than on any serialized document format.

2. Design Goals¶

The Canonical Object Model SHALL be:

implementation independent
deterministic
serialization independent
machine readable
extensible
stable across conforming implementations

The Canonical Object Model SHALL preserve the complete semantic meaning of a Transformation Contract.

3. Architectural Role¶

The Canonical Object Model occupies the architectural boundary between document parsing and semantic analysis.

Transformation Contract
        │
        ▼
Canonical Object Model
        │
        ▼
Validation
        │
        ▼
Transformation Plan

All subsequent processing SHALL consume the Canonical Object Model.

4. Canonical Representation¶

A conforming implementation SHALL reconstruct an equivalent Canonical Object Model from every supported serialization.

Equivalent serialized documents SHALL produce semantically equivalent Canonical Object Models.

Differences in formatting, whitespace, comments, or key ordering SHALL NOT change the resulting object model.

5. Object Identity¶

Every identifiable object MAY possess a stable identifier.

Identifiers SHALL:

uniquely identify the object within its scope
remain stable during processing
preserve referential integrity

Identifiers SHALL NOT derive semantic meaning solely from serialization order.

6. Object Composition¶

The Canonical Object Model SHALL support hierarchical composition.

Objects MAY contain:

child objects
references to other objects
collections
metadata

Composition SHALL preserve semantic meaning.

7. References¶

Relationships between objects SHALL use stable references rather than positional information.

Reference resolution SHALL be deterministic.

Invalid references SHALL produce diagnostics.

8. Metadata¶

Every object MAY contain metadata.

Metadata SHALL supplement object semantics and SHALL NOT redefine standardized behavior.

Unknown metadata MAY be preserved according to Chapter 22.

9. Logical Components¶

A Transformation Contract SHALL be representable using the following logical components:

Metadata
Inputs
Outputs
Semantic Actions
Expressions
Rules
Lineage
Compatibility
Extensions

Additional logical components MAY be introduced through future revisions or standardized extensions.

10. Object Integrity¶

A valid Canonical Object Model SHALL satisfy:

structural integrity
valid references
unique identities where required
type consistency
semantic completeness

Integrity validation SHALL precede planning.

11. Immutability¶

The Canonical Object Model SHOULD be treated as immutable after successful validation.

Implementations MAY create derived representations provided semantic equivalence is preserved.

12. Serialization Independence¶

The Canonical Object Model is normative.

YAML, JSON, TOML, XML, Protocol Buffers, and future encodings are representations of the same underlying model.

Serialization SHALL NOT introduce or remove semantics.

13. Transformation Plan Relationship¶

The Transformation Plan SHALL be derived from a validated Canonical Object Model.

A Transformation Plan SHALL preserve:

semantic actions
expressions
rules
lineage
logical types
guarantees

14. Extensibility¶

The Canonical Object Model MAY be extended through the DTCS Extensibility Model.

Extensions SHALL:

use namespaced identifiers
preserve standardized semantics
remain machine readable

Extensions SHALL NOT redefine standardized object semantics.

15. Conformance¶

A conforming DTCS implementation SHALL:

reconstruct a Canonical Object Model from every supported document format
preserve semantic equivalence during parsing
preserve object identity and references
reject invalid object structures through standardized diagnostics

16. Summary¶

The Canonical Object Model is the normative foundation of DTCS processing.

By separating semantic representation from document serialization, DTCS enables consistent validation, analysis, planning, optimization, compilation, and execution across heterogeneous implementations while preserving identical observable semantics.

Chapter 4 --- Type System¶

1. Purpose¶

This chapter defines the normative DTCS Type System.

The Type System establishes the logical value domains used by Transformation Contracts. It provides a stable, implementation-independent type model that SHALL be preserved throughout validation, planning, compilation, and execution.

2. Design Goals¶

The DTCS Type System SHALL be:

implementation independent
deterministic
portable
extensible
machine readable
semantically stable

Logical types SHALL describe data semantics rather than storage or programming language representations.

3. Type Model¶

A logical type defines the set of values and operations permitted for a field or expression.

Implementations MAY use different native representations internally, provided the observable logical type remains unchanged.

4. Primitive Types¶

DTCS defines the following primitive logical types:

boolean
integer
decimal
string
binary
date
time
datetime
duration

Future versions MAY introduce additional primitive types through additive changes.

5. Composite Types¶

DTCS defines the following composite types:

list
map
object
tuple

Composite types SHALL declare the logical types of their contained values.

6. Nullability¶

Nullability SHALL be explicit.

A nullable type and a non-nullable type are distinct logical types.

Implementations SHALL preserve nullability throughout processing.

7. Type Identity¶

Logical type identity SHALL be determined by:

type kind
parameters
nullability
constraints where applicable

Equivalent native types SHALL map to the same logical type when semantics are identical.

8. Type Compatibility¶

Type compatibility SHALL be evaluated using logical semantics rather than implementation-specific representations.

Compatibility analysis SHALL distinguish:

identical types
compatible types
incompatible types

Compatibility requirements are further defined in Chapter 11.

9. Type Conversion¶

Conversions MAY be explicit or implicit where permitted by this specification.

Conversions SHALL preserve semantic correctness.

Lossy conversions SHALL be explicitly identified.

10. Type Inference¶

Implementations MAY infer logical types.

Inferred types SHALL be semantically equivalent to explicitly declared types.

Inference SHALL NOT weaken contractual guarantees.

11. Expression Typing¶

Every Expression SHALL have a well-defined logical type.

Function parameter types, return types, and operator behavior SHALL be type-consistent.

Type errors SHALL produce diagnostics.

12. Collection Typing¶

Collections SHALL declare their element or member types.

Nested collections SHALL recursively preserve logical typing.

13. Extension Types¶

Extensions MAY define additional logical types.

Extension types SHALL:

use namespaced identifiers where required
define compatibility behavior
define conversion behavior
preserve interoperability

14. Conformance¶

A conforming implementation SHALL:

preserve logical types
preserve nullability
perform type validation
reject invalid type usage through standardized diagnostics

15. Summary¶

The DTCS Type System provides a stable semantic foundation for expressing values independently of programming languages and execution engines. By standardizing logical types, nullability, compatibility, and conversion behavior, DTCS enables portable validation, planning, compilation, and execution while preserving consistent transformation semantics.

Chapter 5 --- Metadata¶

1. Purpose¶

This chapter defines the normative metadata model for the Data Transformation Contract Standard (DTCS).

Metadata provides descriptive information about a Transformation Contract and its constituent objects. Metadata enriches understanding, governance, discovery, and interoperability while preserving the semantic behavior of the contract.

Unless explicitly stated otherwise, metadata SHALL NOT alter transformation semantics.

2. Design Goals¶

The DTCS metadata model SHALL be:

implementation independent
machine readable
extensible
deterministic
portable
semantically neutral

Metadata SHALL supplement, but SHALL NOT redefine, standardized DTCS semantics.

3. Metadata Model¶

Metadata MAY be associated with:

Transformation Contracts
inputs
outputs
Semantic Actions
Expressions
Functions
Rules
other identifiable objects

Metadata associations SHALL preserve object identity.

4. Standard Metadata¶

DTCS defines the following standard metadata categories:

identity
descriptive information
ownership
lifecycle
documentation
governance
provenance
classification

Additional categories MAY be introduced through future specification revisions.

5. Identity Metadata¶

Identity metadata SHOULD include, where applicable:

identifier
name
version
description

Identifiers SHALL remain stable for the lifetime of the object they identify.

6. Documentation Metadata¶

Documentation metadata MAY include:

summary
detailed description
examples
references
external documentation

Documentation metadata is informative.

7. Governance Metadata¶

Governance metadata MAY include:

owner
steward
approval status
review date
policy references

Governance metadata SHALL NOT modify execution behavior.

8. Provenance Metadata¶

Metadata MAY describe provenance, including:

author
creation timestamp
modification timestamp
originating system

Operational provenance supplements, but does not replace, contractual lineage defined elsewhere in this specification.

9. Classification Metadata¶

Implementations MAY classify objects for governance purposes.

Examples include:

public
internal
confidential
restricted

Classification metadata SHALL be treated as descriptive unless another specification explicitly defines behavioral requirements.

10. Custom Metadata¶

Organizations MAY define additional metadata.

Custom metadata SHALL:

use namespaced identifiers where appropriate
avoid redefining standard metadata
preserve interoperability

11. Serialization¶

Metadata SHALL be preserved across supported DTCS serializations.

Serialization format SHALL NOT change metadata meaning.

12. Validation¶

Metadata SHALL be validated for:

structural correctness
identifier consistency
reference integrity

Unknown metadata MAY be preserved in accordance with Chapter 22.

13. Conformance¶

A conforming DTCS implementation SHALL:

preserve standardized metadata
preserve metadata identity
reject invalid standardized metadata through diagnostics
avoid assigning semantic meaning to descriptive metadata unless explicitly defined by this specification

14. Summary¶

The DTCS metadata model provides a consistent mechanism for describing Transformation Contracts and related objects without altering their semantics. By separating descriptive information from behavioral definitions, DTCS supports governance, documentation, discovery, and interoperability while maintaining a clear contract-first semantic architecture.

Chapter 6 --- Inputs and Outputs¶

1. Purpose¶

This chapter defines the normative model for declaring inputs and outputs within a DTCS Transformation Contract.

Inputs and outputs establish the observable interface of a transformation. They define the datasets consumed and produced by a transformation without prescribing storage technologies, execution engines, or transport mechanisms.

Unless explicitly stated otherwise, declarations in this chapter are normative.

2. Design Goals¶

The DTCS input and output model SHALL be:

implementation independent
deterministic
machine readable
portable
extensible
semantically complete

Input and output declarations SHALL describe contractual interfaces rather than implementation details.

3. Input Model¶

Every Transformation Contract SHALL declare its required inputs.

Each input SHALL represent a logical dataset or data stream consumed by the transformation.

Input declarations SHALL be independent of physical storage location.

4. Output Model¶

Every Transformation Contract SHALL declare its outputs.

Each output SHALL represent a logical dataset or data stream produced by the transformation.

Output declarations SHALL describe the contractual result of execution.

5. Dataset Identity¶

Each declared input and output SHALL possess a stable logical identity.

Logical identities SHALL remain stable across document serializations, validation, planning, compilation, and execution.

Identifiers SHALL NOT depend upon ordering within a document.

6. Schema Association¶

Inputs and outputs SHOULD declare their logical schema.

Schemas SHALL use the DTCS Type System defined in Chapter 4.

Schema declarations SHALL describe logical structure rather than native implementation types.

7. Preconditions¶

Inputs MAY define preconditions.

Preconditions express assumptions that SHALL hold before execution.

Examples include:

required fields
minimum record counts
required Rules
schema compatibility

Preconditions SHALL be evaluated before execution when possible.

8. Postconditions¶

Outputs MAY define postconditions.

Postconditions express guarantees provided by the Transformation Contract.

Examples include:

schema conformance
uniqueness guarantees
required Rules
expected logical types

Postconditions SHALL be verifiable.

9. Lineage¶

Every output SHALL be traceable to one or more declared inputs.

Lineage SHALL preserve logical provenance independent of execution technology.

Lineage behavior is further specified in Chapter 10.

10. Multiplicity¶

Transformation Contracts MAY declare multiple inputs and multiple outputs.

Input and output ordering SHALL NOT imply semantic meaning unless explicitly defined by the contract.

11. Optional Inputs¶

Inputs MAY be declared optional.

Optionality SHALL be explicit.

Implementations SHALL distinguish between omitted optional inputs and invalid required inputs.

12. Streaming Interfaces¶

Inputs and outputs MAY represent bounded or unbounded datasets.

Streaming behavior SHALL be explicitly declared.

Streaming declarations SHALL preserve the same logical interface model used for bounded datasets.

13. Extensibility¶

Input and output declarations MAY be extended using the DTCS Extensibility Model.

Extensions SHALL:

preserve standardized semantics
use stable identifiers
remain machine readable

Extensions SHALL NOT redefine the meaning of standardized properties.

14. Validation¶

Implementations SHALL validate:

required inputs
required outputs
identifier uniqueness
schema consistency
reference integrity
declared preconditions and postconditions where applicable

Validation failures SHALL produce standardized Diagnostics.

15. Conformance¶

A conforming DTCS implementation SHALL:

preserve declared inputs and outputs
preserve logical identities
preserve associated schemas
preserve contractual preconditions and postconditions
reject invalid interface definitions through standardized Diagnostics

16. Summary¶

The DTCS input and output model defines the contractual interface of a Transformation Contract.

By expressing logical datasets, schemas, preconditions, postconditions, and lineage independently of implementation technologies, DTCS establishes a stable interface for validation, planning, compilation, and execution while preserving consistent transformation semantics across heterogeneous environments.

Chapter 7 --- Transformation Semantics¶

1. Purpose¶

This chapter defines the normative semantic model for transformations in the Data Transformation Contract Standard (DTCS).

Transformation semantics describe the logical meaning of a transformation independently of any execution engine, programming language, storage technology, or optimization strategy.

The semantic meaning defined by a Transformation Contract SHALL remain invariant throughout validation, planning, compilation, and execution.

2. Design Goals¶

Transformation semantics SHALL be:

implementation independent
deterministic
composable
analyzable
portable
extensible

Semantics SHALL define observable behavior rather than implementation strategy.

3. Transformation Definition¶

A transformation is a declarative description of how one or more logical inputs are converted into one or more logical outputs.

A transformation SHALL be represented by a Transformation Contract.

Transformation behavior SHALL be expressed using Semantic Actions, Expressions, Functions, and Rules.

4. Semantic Identity¶

Every Transformation Contract SHALL define exactly one semantic meaning.

Equivalent implementations MAY differ internally but SHALL preserve identical observable behavior.

5. Observable Behavior¶

Observable behavior consists of:

logical outputs
logical types
contractual guarantees
declared lineage
declared Rules

Execution performance, optimization strategy, and internal data structures are not part of observable behavior unless explicitly declared by a DTCS profile.

6. Semantic Composition¶

Transformations MAY be composed from multiple Semantic Actions.

Composition SHALL preserve the semantics of each constituent action.

The resulting Transformation Plan SHALL represent the composed semantics as a single canonical intermediate representation.

7. Determinism¶

A Transformation Contract MAY declare whether it is deterministic.

For deterministic transformations, identical inputs and identical execution context SHALL produce semantically equivalent outputs.

8. Purity¶

A transformation MAY be declared pure.

Pure transformations SHALL NOT produce externally observable side effects beyond their declared outputs.

Impure transformations SHALL explicitly declare any externally observable side effects.

9. Preconditions¶

Transformations MAY declare preconditions.

Preconditions express assumptions that SHALL hold before execution.

Violation of a mandatory precondition SHALL produce a standardized Diagnostic.

10. Postconditions¶

Transformations MAY declare postconditions.

Postconditions define guarantees that SHALL hold after successful execution.

Postconditions SHALL be objectively verifiable.

11. Information Preservation¶

Semantic Actions MAY preserve, derive, aggregate, or discard information.

Information loss SHALL be explicit.

Lineage SHALL accurately describe the effect of each transformation on source information.

12. Ordering¶

Logical ordering SHALL NOT be assumed unless explicitly declared by the Transformation Contract.

Implementations SHALL NOT infer semantic ordering from document structure.

13. Semantic Equivalence¶

Two transformations are semantically equivalent when they produce identical observable behavior for all valid inputs under equivalent execution contexts.

Semantic equivalence SHALL be independent of execution technology.

14. Validation¶

Implementations SHALL validate that transformation semantics are:

internally consistent
type correct
reference complete
compatible with declared Rules
compatible with declared inputs and outputs

Validation failures SHALL produce standardized Diagnostics.

15. Conformance¶

A conforming DTCS implementation SHALL:

preserve transformation semantics
preserve declared guarantees
preserve lineage
preserve logical types
reject semantically invalid Transformation Contracts

Implementations SHALL NOT alter semantic meaning during planning, optimization, compilation, or execution.

16. Summary¶

The DTCS semantic model establishes the implementation-independent meaning of a Transformation Contract.

By defining transformations in terms of observable behavior rather than execution strategy, DTCS enables consistent validation, optimization, compilation, and execution across heterogeneous platforms while preserving identical semantic results.

Chapter 8 --- Expression Language¶

1. Purpose¶

This chapter defines the normative expression model of the Data Transformation Contract Standard (DTCS).

Expressions compute values. Expressions SHALL NOT directly modify datasets. Dataset modification SHALL occur only through Semantic Actions defined by this specification.

2. Design Goals¶

The DTCS Expression Language SHALL be:

implementation independent
deterministic by default
strongly typed
composable
machine readable
portable

Expression semantics SHALL be preserved across all conforming implementations.

3. Expression Model¶

An Expression is a declarative computation that evaluates to exactly one logical value.

Expressions MAY reference:

literals
fields
parameters
Functions
Operators
other Expressions

Expressions SHALL NOT directly produce side effects.

4. Evaluation Context¶

Expression evaluation SHALL occur within an explicit evaluation context.

The evaluation context MAY include:

current record
current dataset
transformation parameters
execution context (where explicitly permitted)

Hidden implementation state SHALL NOT influence expression semantics.

5. Expression Identity¶

Every Expression SHALL have:

a logical type
deterministic semantics unless explicitly declared otherwise
well-defined null behavior

6. Type System Integration¶

Expression typing SHALL conform to Chapter 4.

Every Expression SHALL evaluate to a single logical type.

Type violations SHALL produce standardized Diagnostics.

7. Functions¶

Expressions MAY invoke standard or extension Functions.

Function invocation SHALL preserve:

parameter ordering
declared type rules
null behavior
determinism

Function semantics are defined in Chapter 18.

8. Operators¶

Operators provide primitive computations used by Expressions.

Standard operator categories include:

arithmetic
comparison
logical
string
collection

Operator behavior SHALL be deterministic for identical operands.

9. Null Semantics¶

Every Expression SHALL define null behavior explicitly.

Implementations SHALL distinguish between:

null values
missing values
invalid values

Implicit null handling is prohibited.

10. Composition¶

Expressions MAY be nested.

Nested Expressions SHALL preserve the semantics of each constituent Expression.

Evaluation order SHALL NOT alter observable semantics except where explicitly defined.

11. Determinism¶

Expressions are deterministic unless explicitly documented otherwise.

Non-deterministic Expressions SHALL declare the source of non-determinism.

12. Constant Expressions¶

Implementations MAY evaluate constant Expressions during planning or compilation.

Constant evaluation SHALL preserve semantic equivalence.

13. Validation¶

Implementations SHALL validate:

type correctness
reference resolution
function signatures
operator compatibility
null semantics

Validation failures SHALL produce standardized Diagnostics.

14. Optimization¶

Implementations MAY optimize Expressions through semantics-preserving rewrites.

Examples include:

constant folding
algebraic simplification
dead expression elimination

Optimization SHALL NOT alter observable behavior.

15. Conformance¶

A conforming DTCS implementation SHALL:

preserve expression semantics
preserve logical types
preserve null semantics
preserve determinism
reject invalid Expressions through standardized Diagnostics

16. Summary¶

The DTCS Expression Language provides the implementation-independent mechanism for computing values within a Transformation Contract.

By separating value computation from dataset transformation, DTCS enables portable validation, optimization, planning, compilation, and execution while preserving identical observable semantics across heterogeneous execution environments.

Chapter 9 --- Validation¶

1. Purpose¶

This chapter defines the normative validation model for the Data Transformation Contract Standard (DTCS).

Validation determines whether a Transformation Contract conforms to the requirements of this specification before planning, compilation, or execution. Validation SHALL operate on the Canonical Object Model.

2. Design Goals¶

Validation SHALL be:

deterministic
implementation independent
repeatable
machine readable
comprehensive
extensible

Validation SHALL detect specification violations without altering transformation semantics.

3. Validation Model¶

Validation is the process of evaluating a Transformation Contract against the normative requirements of DTCS.

A conforming implementation SHALL perform validation before constructing a Transformation Plan.

4. Validation Phases¶

Validation SHALL be performed in the following logical phases:

Document Validation
Canonical Object Model Validation
Structural Validation
Type Validation
Reference Validation
Semantic Validation
Extension Validation

Implementations MAY combine phases internally provided the observable results remain equivalent.

5. Document Validation¶

Document Validation SHALL verify:

supported serialization
document well-formedness
specification version
required top-level elements

6. Structural Validation¶

Structural Validation SHALL verify:

required objects
required properties
identifier uniqueness
object composition
cardinality constraints

7. Type Validation¶

Type Validation SHALL verify:

logical type correctness
nullability
function signatures
expression typing
collection typing

Type evaluation SHALL conform to Chapter 4.

8. Reference Validation¶

Reference Validation SHALL verify:

object references
identifier resolution
dependency integrity
extension references

Unresolved references SHALL produce standardized Diagnostics.

9. Semantic Validation¶

Semantic Validation SHALL verify:

Transformation semantics
Semantic Actions
Expressions
Rules
Preconditions
Postconditions
Lineage consistency

Semantic Validation SHALL preserve the meaning of the Transformation Contract.

10. Extension Validation¶

Extensions SHALL be validated according to Chapter 22.

Unsupported mandatory extensions SHALL prevent successful validation.

Unsupported optional extensions MAY generate Diagnostics while allowing validation to continue.

11. Validation Results¶

Successful validation SHALL indicate that a Transformation Contract satisfies the applicable normative requirements of this specification.

Successful validation SHALL NOT imply successful execution.

12. Diagnostics¶

Validation failures SHALL produce standardized Diagnostics as defined in Chapter 20.

Diagnostics SHOULD identify:

violated requirement
affected object
validation phase
severity
suggested remediation where practical

13. Failure Handling¶

Implementations MAY continue validation after non-fatal failures in order to report additional Diagnostics.

Fatal validation failures MAY terminate further processing.

14. Conformance¶

A conforming DTCS implementation SHALL:

validate every Transformation Contract before planning
evaluate all mandatory validation phases
preserve semantic meaning during validation
report validation failures through standardized Diagnostics

15. Summary¶

The DTCS Validation Model provides a deterministic, implementation-independent process for verifying that a Transformation Contract satisfies the requirements of this specification.

By validating structure, types, references, semantics, and extensions before planning and execution, DTCS enables reliable analysis, optimization, compilation, and runtime behavior while preserving the contract-first semantic architecture.

Chapter 10 --- Lineage¶

1. Purpose¶

This chapter defines the normative lineage model for the Data Transformation Contract Standard (DTCS).

Lineage describes the semantic relationships between declared inputs, intermediate transformations, and declared outputs. Lineage SHALL be represented independently of execution technology and SHALL preserve the logical provenance established by a Transformation Contract.

2. Design Goals¶

The DTCS lineage model SHALL be:

implementation independent
deterministic
machine readable
analyzable
portable
extensible

Lineage SHALL describe semantic provenance rather than physical execution history.

3. Lineage Model¶

Lineage is the directed graph of relationships that explains how output data is derived from input data.

A Transformation Contract SHALL define lineage sufficient to describe the provenance of every declared output.

4. Scope¶

Lineage MAY describe relationships between:

inputs
outputs
Semantic Actions
Expressions
Rules
Transformation Plans

Physical storage locations, execution nodes, and runtime scheduling are outside the scope of DTCS lineage.

5. Lineage Identity¶

Every lineage relationship SHOULD possess a stable logical identity.

Lineage identities SHALL remain stable across validation, planning, compilation, and execution.

6. Provenance Relationships¶

A lineage relationship SHALL identify:

one or more source objects
one or more destination objects
the semantic operation relating them

Relationship semantics SHALL be preserved throughout processing.

7. Information Flow¶

Lineage SHALL represent the logical flow of information through a transformation.

Information MAY be:

preserved
derived
aggregated
filtered
partitioned
discarded

Information loss SHALL be explicit where it affects contractual guarantees.

8. Semantic Preservation¶

Planning, optimization, compilation, and execution SHALL preserve declared lineage.

Equivalent implementations MAY represent lineage differently internally provided observable lineage remains equivalent.

9. Granularity¶

Implementations MAY support lineage at multiple logical levels, including:

dataset
object
field
expression

Supported lineage granularity SHOULD be declared through implementation capabilities.

10. Validation¶

Implementations SHALL validate:

lineage references
lineage completeness
reference integrity
semantic consistency

Invalid lineage SHALL produce standardized Diagnostics.

11. Analysis¶

Lineage MAY be analyzed to support:

impact analysis
dependency analysis
compatibility analysis
governance
documentation

Analytical results SHALL NOT modify declared lineage.

12. Extensions¶

Extensions MAY introduce additional lineage metadata or relationship types.

Extensions SHALL preserve standardized lineage semantics and SHALL NOT redefine the meaning of existing lineage relationships.

13. Conformance¶

A conforming DTCS implementation SHALL:

preserve declared lineage
preserve provenance relationships
validate lineage integrity
report lineage violations through standardized Diagnostics

Implementations SHALL NOT alter declared lineage semantics during planning, optimization, compilation, or execution.

14. Summary¶

The DTCS lineage model provides an implementation-independent representation of the logical provenance of data throughout a Transformation Contract.

By standardizing semantic lineage independently of execution technologies, DTCS enables consistent governance, impact analysis, compatibility analysis, planning, and execution while preserving the contract-first architecture established by this specification.

Chapter 11 --- Compatibility¶

1. Purpose¶

This chapter defines the normative compatibility model for the Data Transformation Contract Standard (DTCS).

Compatibility determines whether two Transformation Contracts, or revisions of the same Transformation Contract, can interoperate without violating declared semantics or contractual guarantees.

Compatibility analysis SHALL operate on the Canonical Object Model.

2. Design Goals¶

The DTCS compatibility model SHALL be:

implementation independent
deterministic
machine readable
analyzable
extensible
version aware

Compatibility SHALL be evaluated using semantic meaning rather than document structure.

3. Compatibility Model¶

Compatibility evaluates the relationship between a source Transformation Contract and a target Transformation Contract.

The outcome of compatibility analysis SHALL be based on observable semantics, not implementation details.

4. Compatibility Levels¶

DTCS defines the following compatibility classifications:

Identical
Backward Compatible
Forward Compatible
Conditionally Compatible
Incompatible

Every compatibility result SHALL resolve to exactly one classification.

5. Compatibility Scope¶

Compatibility analysis MAY evaluate:

inputs
outputs
logical types
Semantic Actions
Expressions
Rules
lineage
metadata with defined behavioral semantics
extensions

Each evaluated aspect SHALL contribute to the overall compatibility result.

6. Semantic Compatibility¶

Two Transformation Contracts are semantically compatible when all required observable behavior is preserved.

Observable behavior includes:

logical outputs
logical types
contractual guarantees
declared lineage
Rule behavior

7. Type Compatibility¶

Logical type compatibility SHALL conform to Chapter 4.

Type compatibility SHALL be evaluated independently of native implementation types.

8. Interface Compatibility¶

Input and output compatibility SHALL evaluate:

required interfaces
optional interfaces
schema compatibility
contractual preconditions
contractual postconditions

Interface compatibility SHALL preserve contractual obligations.

9. Behavioral Compatibility¶

Behavioral compatibility SHALL evaluate changes to:

Semantic Actions
Expressions
Functions
Rules

Equivalent implementations SHALL produce equivalent observable behavior.

10. Extension Compatibility¶

Extensions SHALL declare their compatibility requirements.

Unsupported mandatory extensions SHALL produce an incompatible result unless explicitly accommodated by the implementation.

11. Version Compatibility¶

Specification version compatibility SHALL be evaluated independently from contract compatibility.

Support for a DTCS specification version SHALL NOT imply compatibility between arbitrary Transformation Contracts.

12. Compatibility Analysis¶

Compatibility analysis SHALL be deterministic.

Equivalent inputs to the analysis process SHALL produce equivalent compatibility results.

Analysis SHALL NOT modify either Transformation Contract.

13. Diagnostics¶

Compatibility violations SHALL produce standardized Diagnostics.

Diagnostics SHOULD identify:

affected object
violated compatibility rule
compatibility classification
suggested remediation where practical

14. Conformance¶

A conforming DTCS implementation SHALL:

evaluate compatibility using the Canonical Object Model
preserve semantic meaning during analysis
classify compatibility using the standardized model
report incompatibilities through standardized Diagnostics

15. Summary¶

The DTCS compatibility model provides an implementation-independent framework for evaluating whether Transformation Contracts can interoperate while preserving semantics and contractual guarantees.

By standardizing compatibility analysis independently of execution technologies, DTCS enables reliable contract evolution, impact analysis, governance, planning, and deployment across heterogeneous implementations.

Chapter 12 --- Evolution¶

1. Purpose¶

This chapter defines the normative evolution model for the Data Transformation Contract Standard (DTCS).

Evolution describes how a Transformation Contract MAY change over time while preserving interoperability, semantic integrity, and compatibility where applicable. Evolution SHALL be evaluated independently of any specific implementation or deployment environment.

2. Design Goals¶

The DTCS evolution model SHALL be:

implementation independent
deterministic
version aware
analyzable
backward-compatible where practical
extensible

Evolution SHALL preserve semantic intent unless an incompatible change is explicitly introduced.

3. Evolution Model¶

A Transformation Contract MAY evolve through one or more revisions.

Each revision SHALL represent a complete and internally consistent Transformation Contract.

Evolution SHALL NOT rely upon undocumented behavioral changes.

4. Contract Identity¶

A Transformation Contract SHALL possess a stable logical identity.

Revisions SHALL retain the same logical identity unless a new contract is intentionally created.

Identity SHALL be independent of document serialization.

5. Versioning¶

Each revision SHOULD declare version information.

Version identifiers SHALL uniquely distinguish revisions of the same Transformation Contract.

Version identifiers SHALL NOT be used as the sole basis for compatibility decisions.

6. Change Categories¶

Contract changes MAY include:

metadata changes
interface changes
type changes
semantic changes
rule changes
lineage changes
extension changes

Each change category SHALL be evaluated independently during compatibility analysis.

7. Compatible Evolution¶

Compatible evolution preserves required observable behavior.

Examples MAY include:

documentation improvements
additional optional metadata
additive optional interfaces
backward-compatible extensions

Compatibility SHALL be determined according to Chapter 11.

8. Incompatible Evolution¶

Incompatible evolution changes observable behavior or contractual guarantees.

Examples MAY include:

removing required inputs
changing required logical types
altering mandatory Semantic Actions
weakening declared guarantees

Such changes SHALL be classified as incompatible unless explicitly accommodated by a profile.

9. Migration Guidance¶

Implementations SHOULD provide migration guidance when incompatible revisions are detected.

Migration guidance is informative and SHALL NOT modify contract semantics.

10. Deprecation¶

Objects MAY be deprecated prior to removal.

Deprecation SHOULD identify:

the deprecated object
recommended replacement
anticipated removal

Deprecated objects remain valid until removed by a subsequent revision.

11. Evolution Analysis¶

Evolution analysis SHALL compare revisions using the Canonical Object Model.

Analysis SHALL preserve semantic meaning and SHALL NOT modify either revision.

12. Diagnostics¶

Evolution analysis SHALL produce standardized Diagnostics for:

incompatible revisions
deprecated features
unsupported changes
invalid version metadata

Diagnostics SHOULD identify affected objects and recommended remediation where practical.

13. Conformance¶

A conforming DTCS implementation SHALL:

preserve contract identity across revisions
distinguish revisions from distinct contracts
evaluate evolution independently of serialization
report evolution issues through standardized Diagnostics

14. Summary¶

The DTCS evolution model provides a deterministic framework for managing the lifecycle of Transformation Contracts.

By separating revision management from compatibility analysis while preserving semantic intent, DTCS enables controlled contract evolution, governance, migration planning, and long-term interoperability across independent implementations.

Chapter 13 --- Transformation Plan¶

1. Purpose¶

This chapter defines the normative Transformation Plan model for the Data Transformation Contract Standard (DTCS).

A Transformation Plan is the canonical semantic intermediate representation (IR) derived from a validated Canonical Object Model. It is the authoritative representation consumed by optimizers and compilers.

The Transformation Plan SHALL preserve the complete semantic meaning of the originating Transformation Contract.

2. Design Goals¶

The Transformation Plan SHALL be:

implementation independent
deterministic
semantically complete
machine readable
analyzable
optimizable
portable

3. Architectural Role¶

The Transformation Plan occupies the boundary between semantic analysis and backend compilation.

Transformation Contract
        │
        ▼
Canonical Object Model
        │
        ▼
Validation
        │
        ▼
Transformation Plan
        │
        ▼
Optimization
        │
        ▼
Execution Plan

All backend compilation SHALL begin from a Transformation Plan.

4. Plan Model¶

A Transformation Plan SHALL represent the complete semantic intent of a Transformation Contract.

The plan SHALL include, directly or by reference:

declared inputs
declared outputs
Semantic Actions
Expressions
Rules
logical types
lineage
contractual guarantees

No required semantic information SHALL be omitted.

5. Semantic Preservation¶

Construction of a Transformation Plan SHALL preserve:

observable behavior
logical types
lineage
preconditions
postconditions
determinism

Plan construction SHALL NOT introduce or remove semantics.

6. Canonical Representation¶

Equivalent Transformation Contracts SHALL produce semantically equivalent Transformation Plans.

Internal implementation details MAY differ provided observable semantics remain identical.

7. Plan Identity¶

A Transformation Plan MAY possess a stable logical identifier.

Plan identity SHALL remain associated with the originating Transformation Contract.

8. Dependency Graph¶

A Transformation Plan SHALL define the logical dependency relationships required for semantic evaluation.

Dependency relationships SHALL be acyclic unless explicitly permitted by a DTCS profile.

9. Optimization Boundary¶

The Transformation Plan is the input to optimization.

Optimizations SHALL transform a Transformation Plan into a semantically equivalent Transformation Plan.

Optimization SHALL NOT directly generate an Execution Plan.

10. Compiler Boundary¶

Compilers SHALL consume a Transformation Plan and produce one or more Execution Plans.

Compilation SHALL preserve all declared semantics and contractual guarantees.

11. Validation¶

Implementations SHALL validate that a Transformation Plan:

is semantically complete
preserves contract semantics
contains valid dependencies
preserves logical types
preserves lineage

Validation failures SHALL produce standardized Diagnostics.

12. Serialization¶

Implementations MAY serialize Transformation Plans.

Serialized plans SHALL preserve semantic equivalence with the in-memory representation.

Serialization format is implementation specific unless defined by a DTCS profile.

13. Extensibility¶

Transformation Plans MAY be extended through the DTCS Extensibility Model.

Extensions SHALL preserve standardized semantics and SHALL NOT redefine the meaning of existing plan constructs.

14. Conformance¶

A conforming DTCS implementation SHALL:

construct a Transformation Plan from a validated Canonical Object Model
preserve semantic meaning
preserve logical types
preserve lineage
preserve contractual guarantees
reject invalid plans through standardized Diagnostics

15. Summary¶

The Transformation Plan is the canonical semantic intermediate representation of DTCS.

By separating semantic planning from backend compilation, DTCS enables multiple optimizers, compilers, and execution engines to interoperate while preserving identical observable behavior and contractual guarantees across heterogeneous platforms.

Chapter 14 --- Engine Capability Model¶

1. Purpose¶

This chapter defines the normative Engine Capability Model for the Data Transformation Contract Standard (DTCS).

The Engine Capability Model describes the features, constraints, and execution characteristics supported by an execution engine. Capability declarations enable deterministic planning and compilation without embedding engine-specific behavior into a Transformation Contract.

Capability declarations SHALL describe execution capabilities and SHALL NOT modify the semantics of a Transformation Contract.

2. Design Goals¶

The Engine Capability Model SHALL be:

implementation independent
machine readable
deterministic
extensible
version aware
analyzable

3. Capability Model¶

An engine capability declaration identifies the semantic features an execution engine supports.

Capabilities MAY describe:

logical types
Semantic Actions
Functions
operators
optimization features
execution characteristics
extension support

4. Capability Identity¶

Each capability declaration SHALL identify:

engine identifier
engine version
capability version

Capability identifiers SHALL be stable.

5. Capability Categories¶

Capabilities SHOULD be grouped into categories including:

language features
type support
function support
Semantic Action support
optimization support
runtime features
extension support

Additional categories MAY be introduced by future revisions.

6. Capability Matching¶

Compilers SHALL compare Transformation Plan requirements against engine capabilities.

Unsupported mandatory capabilities SHALL prevent successful compilation unless an applicable profile explicitly permits an alternative.

7. Capability Profiles¶

Implementations MAY publish capability profiles.

Profiles SHALL provide a machine-readable summary of supported capabilities.

8. Versioning¶

Capability declarations SHOULD include version information.

Version identifiers SHALL supplement, but SHALL NOT replace, capability analysis.

9. Capability Discovery¶

Implementations SHOULD expose capability declarations programmatically.

Discovery mechanisms are implementation specific.

10. Extensions¶

Extensions MAY define additional capabilities.

Extension capabilities SHALL use namespaced identifiers and SHALL preserve standardized semantics.

11. Validation¶

Implementations SHALL validate:

declaration structure
identifier consistency
version metadata
capability references

Validation failures SHALL produce standardized Diagnostics.

12. Conformance¶

A conforming implementation SHALL:

publish an accurate capability declaration
preserve declared capability semantics
reject invalid capability declarations through standardized Diagnostics

13. Summary¶

The Engine Capability Model provides a standardized mechanism for describing execution engine features independently of any specific runtime.

By separating capability declarations from transformation semantics, DTCS enables planners and compilers to target multiple execution engines while preserving identical observable behavior and contractual guarantees.

Chapter 15 --- Compilation¶

1. Purpose¶

This chapter defines the normative compilation model for the Data Transformation Contract Standard (DTCS).

Compilation transforms a validated Transformation Plan into one or more backend-specific Execution Plans. Compilation SHALL preserve the semantic meaning, contractual guarantees, logical types, and lineage defined by the originating Transformation Contract.

2. Design Goals¶

The compilation model SHALL be:

implementation independent
deterministic
capability aware
semantically preserving
extensible
portable

Compilation SHALL target execution engines without modifying transformation semantics.

3. Compilation Model¶

Compilation consumes:

a validated Transformation Plan
an Engine Capability Model
applicable profiles and extensions

Compilation produces one or more Execution Plans suitable for a specific execution engine.

4. Compiler Responsibilities¶

A conforming compiler SHALL:

evaluate engine capabilities
preserve observable behavior
preserve logical types
preserve lineage
preserve contractual guarantees
generate standardized Diagnostics

5. Execution Plan¶

An Execution Plan is a backend-specific representation of a Transformation Plan.

Execution Plans MAY differ structurally across engines but SHALL remain semantically equivalent.

Execution Plans SHALL NOT become the normative representation of a transformation.

6. Capability Evaluation¶

Compilers SHALL evaluate required Transformation Plan features against the selected Engine Capability Model.

Unsupported mandatory capabilities SHALL prevent successful compilation unless otherwise permitted by a DTCS profile.

7. Semantic Preservation¶

Compilation SHALL preserve:

Semantic Actions
Expressions
Rules
Preconditions
Postconditions
Lineage
Determinism where declared

Backend optimizations SHALL NOT alter observable semantics.

8. Multiple Targets¶

A Transformation Plan MAY be compiled for multiple execution engines.

Each generated Execution Plan SHALL preserve equivalent observable behavior.

9. Optimization Boundary¶

Optimization MAY occur before, during, or after compilation provided semantic equivalence is maintained.

Compilation SHALL NOT depend upon a particular optimization strategy.

10. Diagnostics¶

Compilation failures SHALL produce standardized Diagnostics.

Diagnostics SHOULD identify:

unsupported capabilities
invalid plans
extension incompatibilities
compilation failures

11. Validation¶

Compilers SHALL validate generated Execution Plans for structural completeness and engine compatibility before execution.

12. Extensibility¶

Compilation MAY be extended through compiler plugins and standardized extensions.

Extensions SHALL preserve standardized DTCS semantics.

13. Conformance¶

A conforming DTCS compiler SHALL:

consume validated Transformation Plans
produce valid Execution Plans
preserve semantic meaning
preserve contractual guarantees
reject un-compilable plans through standardized Diagnostics

14. Summary¶

The DTCS compilation model defines the standardized process for lowering a Transformation Plan into backend-specific Execution Plans.

By separating semantic planning from engine-specific compilation, DTCS enables independent compiler implementations to target diverse execution environments while preserving identical observable behavior, lineage, logical types, and contractual guarantees.

Chapter 16 --- Runtime¶

1. Purpose¶

This chapter defines the normative Runtime Model for the Data Transformation Contract Standard (DTCS).

A Runtime executes one or more Execution Plans produced from a validated Transformation Plan. Execution SHALL preserve the semantic meaning, contractual guarantees, logical types, and lineage defined by the originating Transformation Contract.

2. Design Goals¶

The Runtime Model SHALL be:

implementation independent
deterministic where declared
capability aware
observable
extensible
semantically preserving

The Runtime SHALL execute transformations without redefining DTCS semantics.

3. Runtime Model¶

A Runtime consumes:

one or more validated Execution Plans
declared inputs
runtime parameters
implementation-specific resources

A Runtime produces the declared outputs and any standardized Diagnostics.

Execution SHALL operate within the semantic boundaries established by the Transformation Contract.

4. Runtime Responsibilities¶

A conforming Runtime SHALL:

execute valid Execution Plans
preserve observable behavior
preserve logical types
preserve lineage
enforce preconditions and postconditions
generate standardized Diagnostics

5. Execution Semantics¶

Execution SHALL preserve:

Semantic Actions
Expressions
Rules
contractual guarantees
declared determinism
declared interfaces

Execution SHALL NOT introduce observable semantic changes.

6. Runtime Context¶

The Runtime MAY maintain implementation-specific execution state.

Implementation-specific state SHALL NOT alter the semantic meaning of a Transformation Contract unless explicitly permitted by a DTCS profile.

7. Inputs and Outputs¶

The Runtime SHALL validate required inputs before execution.

Upon successful completion, the Runtime SHALL produce outputs that satisfy all declared postconditions.

8. Failure Handling¶

Execution failures SHALL produce standardized Diagnostics.

Failures MAY include:

precondition violations
runtime resource failures
unsupported capabilities
execution errors

Failure reporting SHALL preserve diagnostic information without altering contract semantics.

9. Determinism¶

When a Transformation Contract declares deterministic execution, identical valid inputs under equivalent execution contexts SHALL produce semantically equivalent outputs.

Implementations SHALL identify declared sources of non-determinism where applicable.

10. Observability¶

Implementations MAY expose runtime metrics, tracing, logging, and execution statistics.

Observability data is informative unless otherwise standardized by a DTCS profile.

Observability SHALL NOT redefine transformation semantics.

11. Runtime Validation¶

The Runtime SHALL verify:

Execution Plan integrity
input availability
precondition satisfaction
required runtime capabilities

Validation failures SHALL prevent execution.

12. Extensions¶

Runtime behavior MAY be extended through the DTCS Extensibility Model.

Extensions SHALL preserve standardized semantics and SHALL NOT redefine mandatory Runtime behavior.

13. Conformance¶

A conforming DTCS Runtime SHALL:

execute valid Execution Plans
preserve semantic meaning
preserve contractual guarantees
preserve logical types
preserve lineage
report runtime failures through standardized Diagnostics

14. Summary¶

The DTCS Runtime Model defines the standardized execution behavior for Transformation Contracts.

By separating execution from planning, optimization, and compilation, DTCS enables multiple independent runtimes to execute equivalent Execution Plans while preserving identical observable behavior, contractual guarantees, logical types, and lineage across heterogeneous execution environments.

Chapter 17 --- Semantic Actions¶

1. Purpose¶

This chapter defines the normative Semantic Action model for the Data Transformation Contract Standard (DTCS).

Semantic Actions are the fundamental operations that modify the logical state of data within a Transformation Contract. They define what transformation occurs, independent of how an implementation performs that transformation.

Semantic Actions SHALL be the only standardized mechanism for modifying datasets within DTCS.

2. Design Goals¶

The Semantic Action model SHALL be:

implementation independent
deterministic where declared
composable
machine readable
analyzable
extensible

Semantic Actions SHALL define behavior through semantics rather than algorithms.

3. Semantic Action Model¶

A Semantic Action is a declarative operation with well-defined semantic meaning.

Each Semantic Action SHALL define:

identifier
semantic definition
input requirements
output behavior
logical type behavior
lineage behavior
determinism characteristics
validation requirements

4. Action Identity¶

Every standardized Semantic Action SHALL possess a stable identifier.

Standard identifiers SHALL use the dtcs: namespace.

Vendor-defined Semantic Actions SHALL use namespaced identifiers as defined in Chapter 22.

Identifiers SHALL remain stable across compatible specification revisions.

5. Standard Semantic Actions¶

DTCS defines a standard library of Semantic Actions.

Representative categories include:

projection
selection
transformation
aggregation
grouping
joining
sorting
union
partitioning
filtering

Future versions MAY add Semantic Actions through backward-compatible revisions.

6. Composition¶

Transformation Contracts MAY compose multiple Semantic Actions.

Composition SHALL preserve the semantics of each constituent action.

The resulting Transformation Plan SHALL represent the composed semantics without semantic loss.

7. Type Semantics¶

Each Semantic Action SHALL define its effect on logical types.

Semantic Actions SHALL preserve or transform logical types only as explicitly defined.

Implicit type changes are prohibited.

8. Lineage Semantics¶

Each Semantic Action SHALL define its effect on lineage.

Lineage behavior SHALL describe how information flows from inputs to outputs.

Lineage semantics SHALL be preserved throughout planning, compilation, and execution.

9. Determinism¶

Each Semantic Action SHALL declare whether it is deterministic.

Deterministic Semantic Actions SHALL produce semantically equivalent outputs for equivalent inputs under equivalent execution contexts.

10. Validation¶

Implementations SHALL validate:

Semantic Action identity
required parameters
logical type compatibility
composition rules
extension compatibility

Validation failures SHALL produce standardized Diagnostics.

11. Optimization¶

Implementations MAY optimize Semantic Actions.

Optimization SHALL preserve:

observable behavior
logical types
lineage
contractual guarantees

Optimization SHALL NOT redefine Semantic Action semantics.

12. Extensions¶

Organizations MAY define additional Semantic Actions.

Extension Semantic Actions SHALL:

use namespaced identifiers
define complete semantic behavior
define lineage behavior
define type behavior
preserve interoperability

Extensions SHALL NOT redefine standardized Semantic Actions.

13. Conformance¶

A conforming DTCS implementation SHALL:

recognize standardized Semantic Actions
preserve Semantic Action semantics
preserve declared lineage behavior
preserve logical type behavior
reject invalid Semantic Actions through standardized Diagnostics

14. Summary¶

Semantic Actions are the fundamental semantic building blocks of DTCS.

By defining dataset transformations in terms of standardized, implementation-independent operations, DTCS enables planners, optimizers, compilers, and runtimes to preserve identical observable behavior while supporting diverse execution technologies and independent implementations.

Chapter 18 --- Function Model¶

1. Purpose¶

This chapter defines the normative Function Model for the Data Transformation Contract Standard (DTCS).

Functions provide reusable computations that MAY be invoked by Expressions. Functions compute values but SHALL NOT directly modify datasets. Dataset modification SHALL occur only through Semantic Actions.

2. Design Goals¶

The Function Model SHALL be:

implementation independent
strongly typed
machine readable
composable
deterministic where declared
extensible

Function semantics SHALL be preserved across all conforming implementations.

3. Function Model¶

A Function is a named computation with a well-defined semantic meaning.

Every Function SHALL define:

identifier
parameters
return type
null behavior
determinism characteristics
semantic definition

Functions SHALL evaluate to exactly one logical value.

4. Function Identity¶

Every standardized Function SHALL possess a stable identifier.

Standard identifiers SHALL use the dtcs: namespace.

Vendor-defined Functions SHALL use namespaced identifiers as defined in Chapter 22.

Identifiers SHALL remain stable across compatible DTCS revisions.

5. Parameters¶

Every Function SHALL declare:

parameter order
parameter types
cardinality
optional parameters, where applicable

Argument validation SHALL occur before evaluation.

6. Return Types¶

Every Function SHALL declare exactly one logical return type.

Return types SHALL conform to the DTCS Type System defined in Chapter 4.

7. Null Semantics¶

Every Function SHALL explicitly define its behavior when one or more arguments are null.

Implementations SHALL preserve declared null semantics.

Implicit null handling is prohibited.

8. Determinism¶

Every Function SHALL declare whether it is deterministic.

Deterministic Functions SHALL produce semantically equivalent results for equivalent inputs.

9. Evaluation¶

Functions SHALL be evaluated within the Expression evaluation model defined in Chapter 8.

Function evaluation SHALL NOT modify datasets or observable transformation state.

10. Validation¶

Implementations SHALL validate:

Function identity
parameter count
parameter types
return type consistency
null behavior

Validation failures SHALL produce standardized Diagnostics.

11. Optimization¶

Implementations MAY optimize Function evaluation.

Optimization SHALL preserve:

semantic meaning
return values
null behavior
determinism

12. Extensions¶

Organizations MAY define additional Functions.

Extension Functions SHALL:

use namespaced identifiers
define complete semantic behavior
define parameter and return types
define null semantics
preserve interoperability

Extensions SHALL NOT redefine standardized Functions.

13. Conformance¶

A conforming DTCS implementation SHALL:

recognize standardized Functions
preserve Function semantics
preserve declared type behavior
preserve null semantics
reject invalid Function invocations through standardized Diagnostics

14. Summary¶

The DTCS Function Model defines reusable, implementation-independent computations for use within Expressions.

By separating value computation from dataset transformation, DTCS enables planners, analyzers, optimizers, compilers, and runtimes to preserve consistent semantic behavior while supporting multiple execution technologies.

Chapter 19 --- Rule Model¶

1. Purpose¶

This chapter defines the normative Rule Model for the Data Transformation Contract Standard (DTCS).

Rules express declarative invariants that SHALL be evaluated before, during, or after transformation execution. Rules define conditions that MUST hold for a Transformation Contract without prescribing implementation algorithms.

Rules SHALL validate or constrain behavior. Rules SHALL NOT directly modify datasets.

2. Design Goals¶

The Rule Model SHALL be:

implementation independent
declarative
deterministic
machine readable
analyzable
extensible

Rule semantics SHALL be preserved across all conforming implementations.

3. Rule Model¶

A Rule is a declarative assertion that evaluates to either satisfied or violated.

Every Rule SHALL define:

identifier
semantic definition
evaluation phase
evaluation scope
failure behavior
diagnostic behavior

Rule evaluation SHALL NOT alter transformation semantics.

4. Rule Identity¶

Every standardized Rule SHALL possess a stable identifier.

Standard Rule identifiers SHALL use the dtcs: namespace.

Vendor-defined Rules SHALL use namespaced identifiers as defined in Chapter 22.

Identifiers SHALL remain stable across compatible DTCS revisions.

5. Evaluation Phases¶

Rules MAY be evaluated:

before execution (preconditions)
during execution
after execution (postconditions)

The evaluation phase SHALL be explicitly defined.

6. Evaluation Scope¶

Rules MAY apply to:

Transformation Contracts
inputs
outputs
Expressions
Semantic Actions
Transformation Plans
Execution Plans

The scope of every Rule SHALL be explicitly declared.

7. Rule Outcomes¶

Rule evaluation SHALL produce one of the following outcomes:

satisfied
violated
indeterminate (where explicitly permitted)

Violation of a mandatory Rule SHALL produce a standardized Diagnostic.

8. Type Integration¶

Rules SHALL evaluate values according to the DTCS Type System defined in Chapter 4.

Implementations SHALL preserve logical type semantics during Rule evaluation.

9. Determinism¶

Every Rule SHALL declare whether it is deterministic.

Deterministic Rules SHALL produce semantically equivalent results for equivalent inputs under equivalent evaluation contexts.

10. Validation¶

Implementations SHALL validate:

Rule identity
evaluation scope
evaluation phase
referenced objects
type consistency

Validation failures SHALL produce standardized Diagnostics.

11. Optimization¶

Implementations MAY optimize Rule evaluation.

Optimization SHALL preserve:

Rule semantics
evaluation outcomes
diagnostic behavior

Optimization SHALL NOT redefine Rule meaning.

12. Extensions¶

Organizations MAY define additional Rules.

Extension Rules SHALL:

use namespaced identifiers
define complete semantic behavior
define evaluation scope
define evaluation phase
preserve interoperability

Extensions SHALL NOT redefine standardized Rules.

13. Conformance¶

A conforming DTCS implementation SHALL:

recognize standardized Rules
preserve Rule semantics
preserve declared evaluation behavior
reject invalid Rule definitions through standardized Diagnostics

14. Summary¶

The DTCS Rule Model provides a standardized, declarative mechanism for expressing contractual invariants independently of implementation technologies.

By separating validation logic from transformation logic, DTCS enables consistent governance, analysis, planning, compilation, and runtime enforcement while preserving identical observable semantics across conforming implementations.

Chapter 20 --- Diagnostics¶

1. Purpose¶

This chapter defines the normative Diagnostics Model for the Data Transformation Contract Standard (DTCS).

Diagnostics communicate errors, warnings, informational messages, and other standardized observations produced during DTCS processing. Diagnostics provide implementation-independent reporting and SHALL NOT alter the semantic meaning of a Transformation Contract.

Unless explicitly stated otherwise, the requirements in this chapter are normative.

2. Design Goals¶

The Diagnostics Model SHALL be:

implementation independent
deterministic
machine readable
actionable
extensible
semantically neutral

Diagnostics SHALL report processing outcomes without changing processing behavior.

3. Diagnostic Model¶

A Diagnostic is a structured record describing an observation produced during parsing, validation, analysis, planning, optimization, compilation, or execution.

Every Diagnostic SHALL define:

diagnostic identifier
severity
processing stage
message
affected object
diagnostic category

Diagnostics MAY include remediation guidance and implementation-specific context.

4. Diagnostic Identity¶

Every standardized Diagnostic SHALL possess a stable identifier.

Standard identifiers SHALL use the dtcs: namespace.

Vendor-defined Diagnostics SHALL use namespaced identifiers as defined in Chapter 22.

Identifiers SHALL remain stable across compatible DTCS revisions.

5. Severity Levels¶

DTCS defines the following standardized severity levels:

Error
Warning
Information

Profiles MAY define additional severity levels provided interoperability is preserved.

Severity SHALL NOT change the semantic meaning of a Transformation Contract.

6. Processing Stages¶

Diagnostics MAY be produced during:

document parsing
Canonical Object Model construction
validation
analysis
planning
optimization
compilation
execution

The originating processing stage SHALL be identified.

7. Diagnostic Categories¶

Standard categories include:

syntax
structure
type
reference
semantic
compatibility
capability
runtime
extension

Future revisions MAY introduce additional categories.

8. Reporting Requirements¶

Implementations SHALL report every mandatory processing failure through one or more Diagnostics.

Implementations MAY continue processing after non-fatal failures to report additional Diagnostics.

9. Determinism¶

Equivalent processing performed on equivalent Transformation Contracts SHALL produce semantically equivalent Diagnostics.

Implementations MAY vary message wording provided the standardized identifier, severity, and meaning are preserved.

10. Validation¶

Diagnostic definitions SHALL be validated for:

identifier uniqueness
required fields
severity correctness
processing stage consistency

Invalid diagnostic definitions SHALL produce standardized Diagnostics.

11. Extensions¶

Organizations MAY define additional Diagnostics.

Extension Diagnostics SHALL:

use namespaced identifiers
preserve standardized severity semantics
preserve interoperability

Extensions SHALL NOT redefine standardized Diagnostic identifiers.

12. Conformance¶

A conforming DTCS implementation SHALL:

generate standardized Diagnostics for mandatory failures
preserve Diagnostic identifiers and severity
identify the originating processing stage
reject invalid Diagnostic definitions through standardized Diagnostics

13. Summary¶

The DTCS Diagnostics Model provides a standardized mechanism for communicating processing outcomes throughout the DTCS lifecycle.

By separating diagnostic reporting from transformation semantics, DTCS enables consistent tooling, automated validation, conformance testing, and interoperable implementations while preserving the contract-first architecture of the specification.

Chapter 21 --- Extensibility¶

1. Purpose¶

This chapter defines the normative Extensibility Model for the Data Transformation Contract Standard (DTCS).

The Extensibility Model enables organizations to introduce new capabilities while preserving interoperability with conforming DTCS implementations. Extensions SHALL augment standardized behavior and SHALL NOT redefine the semantics established by this specification.

Unless explicitly identified as informative, the requirements in this chapter are normative.

2. Design Goals¶

The Extensibility Model SHALL be:

implementation independent
deterministic
machine readable
interoperable
version aware
forward extensible

Extensions SHALL preserve the contract-first and semantic-first principles of DTCS.

3. Extension Model¶

An extension is a standardized or vendor-defined addition to the DTCS object model.

Extensions MAY introduce:

metadata
logical types
Semantic Actions
Functions
Rules
engine capabilities
profiles
registries

Extensions SHALL define complete semantic behavior for every construct they introduce.

4. Namespace Requirements¶

Every extension SHALL use a stable namespace identifier.

The dtcs: namespace is reserved for standardized extensions.

Vendor-defined extensions SHALL use globally unique namespaced identifiers.

Namespace identifiers SHALL remain stable across compatible revisions.

5. Extension Identity¶

Every extension SHALL define:

extension identifier
namespace
version
compatibility requirements
semantic definition

Extension identity SHALL be independent of serialization format.

6. Extension Categories¶

Standard extension categories MAY include:

semantic
type
function
rule
runtime
compiler
capability
metadata

Future revisions MAY define additional categories.

7. Compatibility¶

Extensions SHALL declare compatibility requirements.

Mandatory extensions unsupported by an implementation SHALL prevent successful processing.

Optional extensions MAY be ignored only when doing so does not change observable semantics.

8. Processing Requirements¶

Implementations SHALL preserve recognized extension semantics.

Unknown optional extensions MAY be preserved without interpretation.

Unknown mandatory extensions SHALL produce standardized Diagnostics.

9. Validation¶

Implementations SHALL validate:

namespace correctness
identifier uniqueness
version metadata
semantic completeness
compatibility declarations

Validation failures SHALL produce standardized Diagnostics.

10. Registry Integration¶

Standardized extensions SHOULD be registered through the DTCS registry process.

Registry identifiers SHALL remain stable.

Registration procedures are defined by DTCS governance.

11. Evolution¶

Extensions MAY evolve independently of the core specification.

Evolution SHALL preserve published compatibility guarantees.

Breaking changes SHALL require a new major extension version.

12. Conformance¶

A conforming DTCS implementation SHALL:

recognize standardized extension metadata
preserve supported extension semantics
report unsupported mandatory extensions through standardized Diagnostics
preserve extension identity and namespace information

13. Summary¶

The DTCS Extensibility Model provides a standardized framework for evolving the DTCS ecosystem without compromising interoperability.

By defining stable namespaces, explicit compatibility requirements, deterministic processing rules, and standardized extension metadata, DTCS enables independent innovation while preserving the semantic integrity of Transformation Contracts across implementations.

Chapter 22 --- Registries¶

1. Purpose¶

This chapter defines the normative Registry Model for the Data Transformation Contract Standard (DTCS).

Registries provide authoritative, versioned catalogs of standardized identifiers used throughout DTCS. Registries SHALL enable independent implementations to interpret standardized constructs consistently without redefining their semantics.

Unless explicitly identified as informative, every requirement in this chapter is normative.

2. Design Goals¶

The Registry Model SHALL be:

implementation independent
machine readable
deterministic
versioned
extensible
interoperable

Registries SHALL preserve long-term identifier stability.

3. Registry Model¶

A registry is an authoritative collection of standardized entries governed by DTCS.

Registry entries MAY define:

Semantic Actions
Functions
Rules
Logical Types
Diagnostics
Engine Capabilities
Profiles
Extension Namespaces
Other standardized identifiers

Each registry SHALL define the semantic meaning of every registered entry.

4. Registry Identity¶

Every registry SHALL possess:

registry identifier
registry version
governing specification
publication status

Registry identifiers SHALL remain stable across compatible revisions.

5. Registry Entries¶

Every registry entry SHALL define:

stable identifier
human-readable name
semantic definition
version
status
compatibility information
normative references

Registry entries MAY include informative examples.

6. Identifier Stability¶

Published standardized identifiers SHALL NOT be reassigned.

Deprecated identifiers SHALL remain reserved.

Removed identifiers SHALL NOT be reused for different semantics.

7. Versioning¶

Registries SHALL evolve through versioned publications.

Additive entries SHOULD preserve backward compatibility.

Breaking changes SHALL require an appropriate registry version increment.

8. Processing Requirements¶

Implementations SHALL recognize the standardized identifiers they claim to support.

Unknown standardized identifiers SHALL generate standardized Diagnostics when required for processing.

Implementations MAY preserve unknown optional identifiers without interpretation.

9. Validation¶

Registry processing SHALL validate:

identifier uniqueness
namespace correctness
semantic completeness
version consistency
status consistency

Validation failures SHALL produce standardized Diagnostics.

10. Publication Status¶

Registry entries SHOULD declare one of the following statuses:

Draft
Experimental
Standard
Deprecated
Obsolete

Status values SHALL NOT modify semantic meaning.

11. Governance¶

The DTCS governance process SHALL define:

registry publication
identifier allocation
review procedures
deprecation procedures
retirement procedures

Governance procedures are specified in Chapter 26.

12. Conformance¶

A conforming DTCS implementation SHALL:

preserve standardized registry identifiers
interpret supported registry entries consistently
reject invalid registry definitions through standardized Diagnostics
preserve registry version information where applicable

13. Summary¶

The DTCS Registry Model provides the authoritative mechanism for managing standardized identifiers across the DTCS ecosystem.

By separating identifier governance from transformation semantics, DTCS enables independent implementations to evolve while preserving interoperability, long-term stability, and consistent interpretation of standardized constructs.

Chapter 23 --- Conformance¶

1. Purpose¶

This chapter defines the normative conformance model for the Data Transformation Contract Standard (DTCS).

Conformance specifies the minimum requirements an implementation SHALL satisfy to claim support for DTCS. Conformance requirements are objective, testable, and implementation independent.

Unless explicitly identified as informative, all requirements in this chapter are normative.

2. Design Goals¶

The conformance model SHALL be:

objective
deterministic
implementation independent
testable
extensible
profile aware

Conformance SHALL evaluate observable behavior rather than implementation strategy.

3. Conformance Model¶

A DTCS implementation claims conformance by satisfying the mandatory requirements applicable to its declared conformance profile.

An implementation SHALL NOT claim conformance if mandatory requirements are knowingly omitted.

4. Conformance Units¶

The following implementation classes MAY claim conformance:

Parser
Validator
Analyzer
Planner
Optimizer
Compiler
Runtime
Integrated Platform

Each class SHALL identify its supported capabilities.

5. Conformance Profiles¶

A conformance profile defines a coherent set of DTCS capabilities.

Profiles SHALL identify:

supported specification version
supported registries
supported extensions
implementation class
optional capabilities

Profiles SHALL be machine readable.

6. Mandatory Requirements¶

A conforming implementation SHALL:

preserve Transformation Contract semantics
preserve logical types
preserve lineage
preserve contractual guarantees
generate standardized Diagnostics for mandatory failures
process supported standardized identifiers consistently

7. Optional Capabilities¶

Implementations MAY support optional capabilities.

Unsupported optional capabilities SHALL NOT invalidate conformance unless required by the declared profile.

Optional capability support SHALL be accurately declared.

8. Conformance Testing¶

Conformance SHALL be verified using objective test procedures.

Test suites SHOULD verify:

semantic preservation
validation behavior
compatibility analysis
planning
compilation
runtime behavior
diagnostic generation

Equivalent observable behavior constitutes a successful result.

9. Capability Declaration¶

Every conforming implementation SHALL publish a machine-readable capability declaration.

Capability declarations SHALL accurately describe supported DTCS functionality.

False capability claims invalidate conformance.

10. Version Conformance¶

An implementation SHALL identify the DTCS specification version to which it conforms.

Conformance to one specification version SHALL NOT imply conformance to another version.

11. Extensions¶

Supported extensions SHALL be declared.

Unsupported mandatory extensions SHALL be reported through standardized Diagnostics.

Extensions SHALL NOT redefine mandatory DTCS semantics.

12. Conformance Reporting¶

Implementations SHOULD provide conformance reports suitable for automated verification.

Reports MAY include:

implementation identity
supported profiles
capability declarations
test results
supported extensions

13. Governance Relationship¶

The DTCS governance process defines publication and maintenance of conformance profiles, test suites, and reference implementations.

14. Conformance¶

An implementation SHALL claim DTCS conformance only if it satisfies all mandatory requirements applicable to its declared implementation class and conformance profile.

15. Summary¶

The DTCS Conformance Model establishes an objective, implementation-independent framework for verifying interoperability across the DTCS ecosystem.

By standardizing implementation classes, profiles, capability declarations, and testable requirements, DTCS enables independent implementations to demonstrate interoperable behavior while preserving the semantic integrity of Transformation Contracts.

Chapter 24 --- Security Considerations¶

1. Purpose¶

This chapter defines the normative security model for the Data Transformation Contract Standard (DTCS).

DTCS specifies the semantics of data transformations. It does not prescribe a complete security architecture. This chapter identifies the security requirements that SHALL be preserved by conforming implementations and distinguishes them from implementation-specific security controls.

Unless explicitly identified as informative, all requirements in this chapter are normative.

2. Design Goals¶

The DTCS security model SHALL be:

implementation independent
risk aware
deterministic
interoperable
extensible
semantically neutral

Security mechanisms SHALL protect DTCS processing without redefining Transformation Contract semantics.

3. Security Model¶

DTCS defines security requirements for processing Transformation Contracts.

Implementations remain responsible for selecting authentication, authorization, encryption, networking, infrastructure, and operational controls appropriate to their environments.

Security controls SHALL NOT change the semantic meaning of a Transformation Contract.

4. Security Scope¶

This specification addresses:

contract integrity
processing integrity
extension trust
registry authenticity
capability declaration integrity
diagnostic confidentiality where applicable

This specification does not mandate specific cryptographic algorithms or identity systems.

5. Contract Integrity¶

Implementations SHOULD verify that Transformation Contracts have not been modified unexpectedly.

Integrity verification mechanisms are implementation specific.

Failed integrity verification SHALL prevent trusted processing where required by policy.

6. Trusted Extensions¶

Implementations SHALL distinguish standardized extensions from vendor-defined extensions.

Organizations SHOULD establish trust policies governing extension acceptance.

Unsupported or untrusted mandatory extensions SHALL produce standardized Diagnostics.

7. Registry Trust¶

Implementations SHOULD obtain standardized registry information from trusted sources.

Registry authenticity mechanisms are implementation specific.

Compromised registry data SHALL NOT be treated as authoritative.

8. Execution Isolation¶

Execution environments SHOULD isolate Transformation Contract execution from unrelated workloads where practical.

Isolation mechanisms are outside the scope of this specification.

9. Sensitive Information¶

Transformation Contracts SHOULD avoid embedding sensitive credentials or secrets.

Implementations SHOULD provide secure mechanisms for supplying runtime secrets independently of the contract.

10. Diagnostics¶

Diagnostics SHALL avoid exposing sensitive implementation details unless explicitly authorized by local policy.

Diagnostic reporting SHALL preserve interoperability while minimizing unnecessary disclosure.

11. Extensions¶

Security-related extensions MAY introduce additional controls.

Extensions SHALL preserve standardized DTCS semantics and SHALL NOT redefine mandatory security requirements established by this specification.

12. Conformance¶

A conforming DTCS implementation SHALL:

preserve Transformation Contract semantics when applying security controls
preserve registry and extension identity
report mandatory security-related processing failures through standardized Diagnostics
distinguish standardized behavior from implementation-specific security mechanisms

13. Summary¶

The DTCS Security Model establishes implementation-independent security requirements while deliberately avoiding dependence on specific security technologies.

By separating semantic requirements from operational security controls, DTCS enables secure processing across diverse environments while preserving interoperability, portability, and the contract-first architecture defined by this specification.

Chapter 25 --- Versioning¶

1. Purpose¶

This chapter defines the normative Versioning Model for the Data Transformation Contract Standard (DTCS).

The Versioning Model establishes how DTCS specifications, Transformation Contracts, registries, profiles, extensions, and related artifacts identify revisions over time. Version identifiers enable interoperable evolution while remaining distinct from compatibility analysis.

Unless explicitly identified as informative, all requirements in this chapter are normative.

2. Design Goals¶

The Versioning Model SHALL be:

implementation independent
deterministic
machine readable
interoperable
extensible
stable

Version identifiers SHALL communicate revision identity without altering the semantic meaning of a Transformation Contract.

3. Versioning Scope¶

DTCS versioning applies to:

DTCS specifications
Transformation Contracts
registries
profiles
extensions
capability declarations
implementation conformance profiles

Each artifact SHALL identify its version independently.

4. Version Identity¶

A version identifier uniquely identifies a published revision of an artifact.

A version identifier SHALL:

uniquely identify a revision
remain stable after publication
be treated as immutable

Published version identifiers SHALL NOT be reused.

5. Specification Versions¶

Every DTCS specification SHALL declare its specification version.

Implementations claiming conformance SHALL identify the specification version they implement.

Conformance to one specification version SHALL NOT imply conformance to another.

6. Contract Versions¶

A Transformation Contract MAY define a contract version.

Contract version identifiers SHALL distinguish revisions of the same logical contract.

Contract versions SHALL NOT be used as the sole basis for compatibility decisions.

Compatibility SHALL be evaluated according to Chapter 11.

7. Registry and Extension Versions¶

Registries and extensions SHALL define independent version identifiers.

A registry or extension MAY evolve without requiring a new DTCS specification version, provided normative compatibility requirements are satisfied.

8. Version Evolution¶

Version identifiers SHOULD reflect meaningful published revisions.

Editorial revisions, additive revisions, and breaking revisions SHOULD be distinguishable according to DTCS governance policies.

Specific version numbering conventions are implementation or governance decisions unless standardized by a DTCS profile.

9. Version Resolution¶

Implementations SHALL preserve declared version identifiers during parsing, validation, planning, compilation, and execution.

Version resolution SHALL be deterministic.

Version resolution SHALL NOT modify Transformation Contract semantics.

10. Validation¶

Implementations SHALL validate:

version identifier presence where required
version identifier format
version consistency
conflicting version declarations

Validation failures SHALL produce standardized Diagnostics.

11. Relationship to Compatibility¶

Version identity and compatibility are distinct concepts.

Two artifacts MAY share the same version while remaining incompatible under Chapter 11.

Two artifacts MAY possess different version identifiers while remaining fully compatible.

Implementations SHALL evaluate compatibility independently of version identifiers.

12. Extensions¶

Extensions SHALL declare their own version identifiers.

Extension versioning SHALL preserve namespace identity and published compatibility guarantees.

13. Conformance¶

A conforming DTCS implementation SHALL:

preserve declared version identifiers
distinguish version identity from compatibility
validate required version metadata
report invalid version information through standardized Diagnostics

14. Summary¶

The DTCS Versioning Model provides a stable, implementation-independent framework for identifying revisions of DTCS artifacts.

By separating revision identity from semantic compatibility, DTCS enables controlled evolution of specifications, Transformation Contracts, registries, extensions, and implementations while preserving interoperability and long-term architectural stability.

Chapter 26 --- Governance¶

1. Purpose¶

This chapter defines the normative Governance Model for the Data Transformation Contract Standard (DTCS).

The Governance Model establishes the processes by which the DTCS specification, registries, profiles, extensions, and related standards evolve over time. Governance SHALL preserve interoperability, semantic stability, transparency, and long-term sustainability.

Unless explicitly identified as informative, all requirements in this chapter are normative.

2. Design Goals¶

The Governance Model SHALL be:

transparent
implementation independent
deterministic
community driven
extensible
accountable

Governance SHALL preserve the contract-first and semantic-first principles established by this specification.

3. Governance Scope¶

Governance applies to:

the DTCS specification
normative companion specifications
registries
conformance profiles
extension namespaces
reference implementations
conformance test suites

Each governed artifact SHALL define a responsible authority and a published lifecycle.

4. Governance Principles¶

The DTCS project SHALL be guided by the following principles:

semantic stability
backward compatibility where practical
open participation
documented decision making
objective technical evaluation
long-term identifier stability

5. Change Management¶

All normative changes SHALL be proposed through a documented change process.

Each proposal SHALL include:

problem statement
proposed solution
compatibility impact
migration considerations
affected artifacts

Normative changes SHALL undergo technical review before adoption.

6. Specification Lifecycle¶

Every specification revision SHOULD progress through defined publication states, including:

Draft
Candidate
Stable
Deprecated
Obsolete

Publication state SHALL be explicitly identified.

7. Registry Governance¶

Registry publication SHALL follow documented review procedures.

Registry authorities SHALL preserve identifier stability and SHALL NOT reuse published standardized identifiers for different semantics.

8. Extension Governance¶

Standardized extensions SHOULD undergo technical review before publication.

Extension namespaces SHALL be managed to prevent identifier conflicts.

Mandatory extensions SHALL publish compatibility requirements.

9. Conformance Governance¶

Governance SHALL maintain:

conformance profiles
conformance test suites
reference test vectors
implementation guidance

Conformance criteria SHALL remain objective and publicly documented.

10. Deprecation and Retirement¶

Governance SHALL define documented procedures for:

deprecation
retirement
replacement
migration

Deprecated artifacts SHOULD remain available for historical reference where practical.

11. Appeals and Review¶

Governance SHOULD provide a documented mechanism for requesting technical review of published decisions.

Review procedures SHALL be transparent and publicly documented.

12. Publication¶

Normative publications SHALL identify:

publication date
version
publication status
governing authority
applicable editorial baseline

Published documents SHALL be immutable.

13. Conformance¶

A DTCS-governed artifact SHALL comply with the governance procedures applicable to its artifact type before being represented as an official DTCS publication.

14. Summary¶

The DTCS Governance Model provides the institutional framework required to evolve the DTCS ecosystem while preserving semantic integrity, interoperability, and long-term stability.

By standardizing change management, publication, registry administration, extension review, conformance maintenance, and lifecycle management, DTCS enables an open, sustainable standards ecosystem capable of supporting independent implementations for many years.