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The Core Systems (Frontend → Semantics → Types → MLIR)

This chapter is the “where things live” chapter.

Lane A: You mainly need this when you’re writing tests/diagnostics.
Lane B: You will use this daily.

5.1 Frontend: Lexer + Parser + AST​

Lexer​

Responsibilities:

  • tokenization
  • keyword recognition
  • literal scanning
  • span tracking
  • recovery (keep going after errors)

Key locations:

  • src/lexer.zig
  • src/lexer/scanners/

Parser​

Responsibilities:

  • build AST nodes
  • attach spans
  • basic structural validation
  • error recovery

Key locations:

  • src/parser.zig and src/parser/*

AST​

Responsibilities:

  • define node types
  • arena allocation
  • serialization/debug prints

Key locations:

  • src/ast/ (including arena + serializer)

5.2 Semantics: symbol tables and scopes​

Responsibilities:

  • collect declarations
  • build symbol table
  • manage scoping rules
  • prepare for type resolution

Key locations:

  • src/semantics.zig
  • src/semantics/*

5.3 Types: TypeInfo + type resolver​

Responsibilities:

  • annotate AST nodes with TypeInfo
  • enforce typing rules
  • enforce rules around refinements and error unions
  • produce precise diagnostics when typing fails

Key locations:

  • src/ast/type_resolver/
  • (and related structures in AST/type modules)

Practical note:

  • if MLIR lowering “mysteriously” fails, check whether TypeInfo is missing or wrong

5.4 MLIR lowering: typed AST → Ora IR​

Responsibilities:

  • translate typed nodes to MLIR ops
  • attach attributes and types
  • produce structured lowering errors
  • produce IR that can be verified + transformed

Key locations:

  • src/mlir/
  • src/mlir/lower.zig

5.5 Verification, passes, and conversion: MLIR → MLIR​

Responsibilities:

  • verify dialect invariants
  • canonicalize/optimize
  • convert Ora → SIR as a legality boundary
  • optionally run SMT verification passes

Key locations:

  • src/mlir/verification.zig
  • src/mlir/pass_manager.zig
  • src/mlir/ora/lowering/OraToSIR/
  • src/z3/*

If you’re new:

  1. CLI entrypoints in src/main.zig
  2. lexer + parser to understand artifacts
  3. type resolver (TypeInfo flow)
  4. lowering (how typed nodes become ops)

That order matches how you’ll debug in real life.