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, 63 insertions, 0 deletions

diff --git a/include/cps/FileAST.h b/include/cps/FileAST.h
new file mode 100644
index 0000000..04bd06a
--- /dev/null
+++ b/include/cps/FileAST.h
@@ -0,0 +1,63 @@
+#pragma once
+#include "cps/AST.h"
+#include "cps/FileMode.h"
+#include <memory>
+#include <string>
+
+namespace cps {
+
+class OpenFileStmtAST : public StmtAST {
+    std::unique_ptr<ExprAST> FileName;
+    FileMode Mode;
+    int Line;
+
+public:
+    OpenFileStmtAST(std::unique_ptr<ExprAST> FileName, FileMode Mode, int Line)
+        : FileName(std::move(FileName)), Mode(Mode), Line(Line) {}
+
+    ExprAST *getFileName() const { return FileName.get(); }
+    FileMode getMode() const { return Mode; }
+    int getLine() const { return Line; }
+};
+
+class ReadFileStmtAST : public StmtAST {
+    std::unique_ptr<ExprAST> FileName;
+    std::string VarName;
+    int Line;
+
+public:
+    ReadFileStmtAST(std::unique_ptr<ExprAST> FileName, const std::string &VarName, int Line)
+        : FileName(std::move(FileName)), VarName(VarName), Line(Line) {}
+
+    ExprAST *getFileName() const { return FileName.get(); }
+    const std::string &getVarName() const { return VarName; }
+    int getLine() const { return Line; }
+};
+
+class WriteFileStmtAST : public StmtAST {
+    std::unique_ptr<ExprAST> FileName;
+    std::unique_ptr<ExprAST> Data;
+    int Line;
+
+public:
+    WriteFileStmtAST(std::unique_ptr<ExprAST> FileName, std::unique_ptr<ExprAST> Data, int Line)
+        : FileName(std::move(FileName)), Data(std::move(Data)), Line(Line) {}
+
+    ExprAST *getFileName() const { return FileName.get(); }
+    ExprAST *getData() const { return Data.get(); }
+    int getLine() const { return Line; }
+};
+
+class CloseFileStmtAST : public StmtAST {
+    std::unique_ptr<ExprAST> FileName;
+    int Line;
+
+public:
+    CloseFileStmtAST(std::unique_ptr<ExprAST> FileName, int Line)
+        : FileName(std::move(FileName)), Line(Line) {}
+
+    ExprAST *getFileName() const { return FileName.get(); }
+    int getLine() const { return Line; }
+};
+
+} // namespace cps