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, 92 insertions, 0 deletions

diff --git a/lib/Parser/ParserFile.cc b/lib/Parser/ParserFile.cc
new file mode 100644
index 0000000..6fd368c
--- /dev/null
+++ b/lib/Parser/ParserFile.cc
@@ -0,0 +1,92 @@
+#include "cps/Parser.h"
+#include "cps/FileAST.h"
+#include <cstdio>
+
+using namespace cps;
+
+// OPENFILE <expr> FOR READ|WRITE|APPEND
+std::unique_ptr<StmtAST> Parser::ParseOpenFile() {
+    int Line = Lex.getLine();
+    getNextToken(); // eat OPENFILE
+
+    auto FileName = ParseExpression();
+    if (!FileName) return nullptr;
+
+    if (CurTok != tok_for) {
+        fprintf(stderr, "Error: Expected FOR after OPENFILE filename at line %d\n", Lex.getLine());
+        return nullptr;
+    }
+    getNextToken(); // eat FOR
+
+    FileMode Mode;
+    switch (CurTok) {
+    case tok_read:   Mode = FileMode::Read;   break;
+    case tok_write:  Mode = FileMode::Write;  break;
+    case tok_append: Mode = FileMode::Append; break;
+    case tok_random:
+        fprintf(stderr, "Error: File mode RANDOM is not implemented (text files only) at line %d\n",
+                Lex.getLine());
+        return nullptr;
+    default:
+        fprintf(stderr, "Error: Expected file mode READ, WRITE or APPEND at line %d\n", Lex.getLine());
+        return nullptr;
+    }
+    getNextToken(); // eat the mode keyword
+
+    return std::make_unique<OpenFileStmtAST>(std::move(FileName), Mode, Line);
+}
+
+// READFILE <expr>, <identifier>
+std::unique_ptr<StmtAST> Parser::ParseReadFile() {
+    int Line = Lex.getLine();
+    getNextToken(); // eat READFILE
+
+    auto FileName = ParseExpression();
+    if (!FileName) return nullptr;
+
+    if (CurTok != ',') {
+        fprintf(stderr, "Error: Expected ',' after READFILE filename at line %d\n", Lex.getLine());
+        return nullptr;
+    }
+    getNextToken(); // eat ','
+
+    if (CurTok != tok_identifier) {
+        fprintf(stderr, "Error: Expected variable name after ',' in READFILE at line %d\n", Lex.getLine());
+        return nullptr;
+    }
+    std::string VarName = Lex.IdentifierStr;
+    getNextToken(); // eat the variable name
+
+    return std::make_unique<ReadFileStmtAST>(std::move(FileName), VarName, Line);
+}
+
+// WRITEFILE <expr>, <expr>
+std::unique_ptr<StmtAST> Parser::ParseWriteFile() {
+    int Line = Lex.getLine();
+    getNextToken(); // eat WRITEFILE
+
+    auto FileName = ParseExpression();
+    if (!FileName) return nullptr;
+
+    if (CurTok != ',') {
+        fprintf(stderr, "Error: Expected ',' after WRITEFILE filename at line %d\n", Lex.getLine());
+        return nullptr;
+    }
+    getNextToken(); // eat ','
+
+    auto Data = ParseExpression();
+    if (!Data) return nullptr;
+
+    return std::make_unique<WriteFileStmtAST>(std::move(FileName), std::move(Data), Line);
+}
+
+// CLOSEFILE <expr>
+std::unique_ptr<StmtAST> Parser::ParseCloseFile() {
+    int Line = Lex.getLine();
+    getNextToken(); // eat CLOSEFILE
+
+    auto FileName = ParseExpression();
+    if (!FileName) return nullptr;
+
+    return std::make_unique<CloseFileStmtAST>(std::move(FileName), Line);
+}