Engineering Compiler

The Compiler Front End receives source information and converts it into structured representations suitable for semantic processing.

It shall be responsible for:

identifying source formats;

verifying declared language and schema versions;

decoding source content;

lexical analysis;

parsing;

preliminary structural validation;

source-location preservation;

import and module discovery;

basic diagnostic generation;

construction of the Abstract Syntax Tree.

The Front End shall support the authorized human-readable and machine-readable serializations of BDL without treating serialization-specific formatting as engineering meaning.

Equivalent source expressions shall produce equivalent syntactic structures when their formal BDL meaning is the same. Comments, annotations, formatting, and documentation may be preserved for authoring and traceability even when they do not affect compiled engineering meaning.

The Front End shall treat every external source as untrusted until its format, identity, integrity, declared version, and permitted features have been evaluated.

Malformed syntax, unsupported language features, invalid character sequences, duplicate declarations, unsafe references, and prohibited extensions shall produce explicit diagnostics.

Controlled error recovery may allow the Front End to identify multiple source errors during one compilation. Recovered content shall not be treated as fully valid, and no safety-significant output shall be generated from an ambiguously recovered source structure.

The Front End shall preserve a source map linking every parsed declaration to its originating document, module, location, revision, and import path.

Successful front-end processing establishes only that information can be structurally interpreted. It does not establish semantic completeness, engineering validity, compatibility, evidence sufficiency, or approval.