Engineering Compiler

The Abstract Syntax Tree, or AST, is the normalized structural representation of parsed BDL source.

The AST shall represent the language constructs expressed by the source while removing serialization details that do not affect formal syntax.

AST nodes may represent:

declarations;

identifiers;

values;

expressions;

imports;

modules;

relationships;

constraints;

profiles;

states;

annotations;

The AST shall preserve distinctions between explicit declarations, omitted information, default references, placeholders, alternatives, and unknown values.

The AST shall not contain silently resolved engineering assumptions. Name binding, type resolution, unit conversion, profile application, configuration selection, and engineering validation occur in later stages.

Generated or transformed AST content shall identify the process that created it and the original source structures from which it was derived.

AST structures may be cached for incremental compilation when the compiler verifies that their source identity, content, language version, and parser configuration remain unchanged.

The AST is a source-oriented representation and shall not be treated as the authoritative final engineering model.