Better error report.

language/interpreter.cc

@@ -1,5 +1,6 @@
 #include "interpreter.hpp"
 #include "parser.hpp"
+#include <sstream>
 
 using namespace peglib;
 using namespace std;
@@ -187,11 +188,20 @@ std::ostream& operator<<(std::ostream& os, const Value& val)
     return val.out(os);
 }
 
-bool run(Env& env, const char* expr, size_t len, Value& val, std::string& msg, bool print_ast)
+bool run(const string& path, Env& env, const char* expr, size_t len, Value& val, std::string& msg, bool print_ast)
 {
     try {
         shared_ptr<Ast> ast;        
-        if (get_parser().parse_n(expr, len, ast)) {
+
+        auto& parser = get_parser();
+
+        parser.log = [&](size_t ln, size_t col, const string& err_msg) {
+            stringstream ss;
+            ss << path << ":" << ln << ":" << col << ": " << err_msg << endl;
+            msg = ss.str();
+        };
+
+        if (parser.parse_n(expr, len, ast)) {
             if (print_ast) {
                 ast->print();
             }
@@ -199,7 +209,7 @@ bool run(Env& env, const char* expr, size_t len, Value& val, std::string& msg, b
             val = Eval::eval(*ast, env);
             return true;
         }
-    } catch (exception& e) {
+    } catch (runtime_error& e) {
         msg = e.what();
     }
 

language/interpreter.hpp

@@ -193,4 +193,4 @@ private:
     std::map<std::string, Value> dic_;
 };
 
-bool run(Env& env, const char* expr, size_t len, Value& val, std::string& msg, bool print_ast);
+bool run(const std::string& path, Env& env, const char* expr, size_t len, Value& val, std::string& msg, bool print_ast);

language/main.cc

@@ -44,6 +44,7 @@ int main(int argc, const char** argv)
         shell = path_list.empty();
     }
 
+    try {
         Env env;
         env.setup_built_in_functions();
 
@@ -56,9 +57,8 @@ int main(int argc, const char** argv)
 
             Value val;
             string msg;
-        if (!run(env, buff.data(), buff.size(), val, msg, print_ast)) {
+            if (!run(path, env, buff.data(), buff.size(), val, msg, print_ast)) {
-            cerr << "error in '" << path << "'." << endl;
+                cerr << msg;
-            cerr << msg.c_str() << endl;
                 return -1;
             }
         }
@@ -66,6 +66,10 @@ int main(int argc, const char** argv)
         if (shell) {
             repl(env, print_ast);
         }
+    } catch (exception& e) {
+        cerr << e.what() << endl;
+        return -1;
+    }
 
     return 0;
 }

language/parser.cc

@@ -40,7 +40,24 @@ static auto g_grammar = R"(
     Comment             <-  '/*' (!'*/' .)* '*/' /  ('#' / '//') (!(EndOfLine / EndOfFile) .)* (EndOfLine / EndOfFile)
 )";
 
-static auto g_parser = peg(g_grammar)
+peglib::peg& get_parser()
+{
+    static peg parser;
+
+    static bool initialized = false;
+
+    if (!initialized) {
+        initialized = true;
+
+        parser.log = [&](size_t ln, size_t col, const string& msg) {
+            cerr << ln << ":" << col << ": " << msg << endl;
+        };
+
+        if (!parser.load_grammar(g_grammar)) {
+            throw logic_error("invalid peg grammar");
+        }
+
+        parser
             .ast_node_optimizable("STATEMENTS", Statements)
             .ast_node("WHILE", While)
             .ast_node("ASSIGNMENT", Assignment)
@@ -59,14 +76,10 @@ static auto g_parser = peg(g_grammar)
             .ast_token("BOOLEAN", Boolean)
             .ast_token("STRING")
             .ast_token("IDENTIFIER", Identifier)
-    .ast_end()
+            .ast_end();
-    .set_logger([&](size_t ln, size_t col, const string& msg) {
+    }
-        cerr << ln << ":" << col << ": " << msg << endl;
-    });
 
-const peglib::peg& get_parser()
+    return parser;
-{
-    return g_parser;
 }
 
 // vim: et ts=4 sw=4 cin cino={1s ff=unix

language/parser.hpp

@@ -6,6 +6,6 @@ enum AstType
    Identifier, Number, Boolean, Function
 };
 
-const peglib::peg& get_parser();
+peglib::peg& get_parser();
 
 // vim: et ts=4 sw=4 cin cino={1s ff=unix

language/repl.cc

@@ -16,11 +16,11 @@ int repl(Env& env, bool print_ast)
         if (!line.empty()) {
             Value val;
             string msg;
-            if (run(env, line.c_str(), line.size(), val, msg, print_ast)) {
+            if (run("(repl)", env, line.c_str(), line.size(), val, msg, print_ast)) {
                 cout << val << endl;
                 linenoise::AddHistory(line.c_str());
             } else if (!msg.empty()) {
-                cout << msg << endl;
+                cout << msg;
             }
         }
     }