feat: implement CIE 9.1 text file handling (OPENFILE/READFILE/WRITEFILE/CLOSEFILE/EOF)

Front end: OPENFILE/READFILE/WRITEFILE/CLOSEFILE plus reserved mode
keywords READ/WRITE/APPEND (RANDOM reserved with a dedicated
not-implemented error); statement nodes in new FileAST.h, parsing in new
ParserFile.cc; EOF joins the Builtins table as the 12th builtin and
CallExprAST now carries a line number for its runtime diagnostics.

Runtime: new FileHandler (StringHandler-shaped leaf) lazily synthesizes
internal __cps_file_* helper functions and a 16-slot open-file table
keyed by filename content (strcmp — STRING '=' is pointer identity).
EOF is an fgetc/ungetc peek; READFILE grows a malloc/realloc line buffer
and strips a trailing CR; fopen uses text modes so mingw-w64 line
translation works. File-free programs get byte-identical IR. All misuse
(not open, wrong mode, reopen, fopen failure, read past EOF, table full)
dies with the existing "[Fatal] line N:" pattern via a new
RuntimeCheck::emitErrorAndExit overload taking runtime printf args.

Also fixes a pre-existing ArithmeticHandler hole surfaced by adversarial
review: mixed-width integer operands (i1 BOOLEAN / i8 CHAR vs i64) now
widen via ZExt instead of emitting invalid IR, and remaining type
mismatches get a clean diagnostic; -EOF(f) and -IS_NUM(x) compile.

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

1 files changed, 7 insertions, 0 deletions

diff --git a/include/cps/RuntimeCheck.h b/include/cps/RuntimeCheck.h
index 3c31f41..97f4765 100644
--- a/include/cps/RuntimeCheck.h
+++ b/include/cps/RuntimeCheck.h
@@ -23,6 +23,13 @@ public:
 
     void emitDivZeroCheck(llvm::Value *Divisor, int Line);
     void emitIndexCheck(llvm::Value *Index, llvm::Value *Lower, llvm::Value *Upper, int Line);
+
+    // Runtime-computed variant: FmtArgs are the printf varargs after Msg
+    // (e.g. {i32 line, ptr filename}). Needed when the failure site is inside
+    // a synthesized helper function, where the line number is an argument
+    // rather than a compile-time constant.
+    void emitErrorAndExit(llvm::Value *Condition, llvm::Value *Msg,
+                          llvm::ArrayRef<llvm::Value *> FmtArgs);
 };
 
 }