handle compiler errors using an exception

Author: ghewgill

main.cpp

@@ -38,20 +38,30 @@ int main(int argc, char *argv[])
     std::stringstream buf;
     buf << inf.rdbuf();
 
-    auto tokens = tokenize(buf.str());
-    if (dump_tokens) {
-        dump(tokens);
-    }
+    try {
+        auto tokens = tokenize(buf.str());
+        if (dump_tokens) {
+            dump(tokens);
+        }
 
-    auto ast = parse(tokens);
-    if (dump_ast) {
-        dump(ast);
-    }
+        auto ast = parse(tokens);
+        if (dump_ast) {
+            dump(ast);
+        }
 
-    auto bytecode = compile(ast);
-    if (dump_bytecode) {
-        disassemble(bytecode, std::cerr);
-    }
+        auto bytecode = compile(ast);
+        if (dump_bytecode) {
+            disassemble(bytecode, std::cerr);
+        }
 
-    exec(bytecode);
+        exec(bytecode);
+
+    } catch (SourceError &error) {
+        fprintf(stderr, "%s\n", error.token.source.c_str());
+        fprintf(stderr, "%*s\n", error.token.column, "^");
+        fprintf(stderr, "Error S%d: %d:%d %s %s (%s:%d)\n", error.number, error.token.line, error.token.column, error.token.tostring().c_str(), error.message.c_str(), error.file.c_str(), error.line);
+        exit(1);
+    } catch (InternalError &error) {
+        fprintf(stderr, "Compiler Internal Error: %s (%s:%d)\n", error.message.c_str(), error.file.c_str(), error.line);
+    }
 }

util.cpp

@@ -2,18 +2,12 @@
 
 #include <stdlib.h>
 
-#include "lexer.h"
-
 void abort_error(const char *file, int line, int number, const Token &token, const std::string &message)
 {
-    fprintf(stderr, "%s\n", token.source.c_str());
-    fprintf(stderr, "%*s\n", token.column, "^");
-    fprintf(stderr, "Error S%d: %d:%d %s %s (%s:%d)\n", number, token.line, token.column, token.tostring().c_str(), message.c_str(), file, line);
-    exit(1);
+    throw SourceError(file, line, number, token, message);
 }
 
 void abort_internal_error(const char *file, int line, const std::string &message)
 {
-    fprintf(stderr, "Compiler Internal Error: %s (%s:%d)\n", message.c_str(), file, line);
-    exit(1);
+    throw InternalError(file, line, message);
 }

util.h

@@ -3,7 +3,30 @@
 
 #include <string>
 
-class Token;
+#include "lexer.h"
+
+class CompilerError {
+public:
+    CompilerError(const std::string &file, int line, const std::string &message): file(file), line(line), message(message) {}
+    virtual ~CompilerError() {}
+    const std::string file;
+    const int line;
+    const std::string message;
+private:
+    CompilerError &operator=(const CompilerError &);
+};
+
+class InternalError: public CompilerError {
+public:
+    InternalError(const std::string &file, int line, const std::string &message): CompilerError(file, line, message) {}
+};
+
+class SourceError: public CompilerError {
+public:
+    SourceError(const std::string &file, int line, int number, const Token &token, const std::string &message): CompilerError(file, line, message), number(number), token(token) {}
+    const int number;
+    const Token token;
+};
 
 #define error(number, token, message) abort_error(__FILE__, __LINE__, number, token, message)
 #define internal_error(message) abort_internal_error(__FILE__, __LINE__, message)