feat: TYPE-system front end — tokens, designators, ParamDecl grammar

- Reserve TYPE/ENDTYPE/SET/DEFINE (-600 token block); SET/DEFINE parse to
  dedicated not-implemented errors (RANDOM precedent).
- New TypeAST.h: enum/pointer/record decl nodes, designator chain
  (DesignatorExprAST + Index/Field/Deref accessors), AddrOfExprAST,
  DesignatorAssignStmtAST. Bare-name and single-index shapes degrade to
  their legacy nodes, so existing programs produce identical ASTs.
- ParserType.cc: TYPE declarations (top-level only, enforced via a
  ParseBlock depth counter), DECLARE-only record bodies with local
  field-level error recovery.
- Postfix [ ] . ^ chain in ParseIdentifierExpr; prefix ^ (address-of,
  designator operand only) in ParseUnary; assignment targets rebuilt on
  the same suffix parser.
- Parameters: ParamDecl{name, type, mode, array rank/bounds} replaces the
  (name, type, byref) tuple. Pass mode is sticky across parameters and
  BYREF is rejected in FUNCTIONs, both per guide §8.3 (the old per-param
  reset made the guide's own SWAP example pass Y by value). ARRAY OF T /
  ARRAY[l:u,...] OF T parameter syntax parses; codegen rejects it until
  the parameter-passing phase lands.
- CodeGen stubs report clear not-implemented errors for the new nodes so
  nothing is silently ignored.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Lexer/Lexer.cc b/lib/Lexer/Lexer.cc
index 3c56271..4b5acae 100644
--- a/lib/Lexer/Lexer.cc
+++ b/lib/Lexer/Lexer.cc
@@ -130,6 +130,11 @@ int Lexer::gettok() {
         if (IdentifierStr == "APPEND") return tok_append;
         if (IdentifierStr == "RANDOM") return tok_random;
 
+        if (IdentifierStr == "TYPE") return tok_type;
+        if (IdentifierStr == "ENDTYPE") return tok_endtype;
+        if (IdentifierStr == "SET") return tok_set;
+        if (IdentifierStr == "DEFINE") return tok_define;
+
         return tok_identifier;
     }