Improve parsing error message a little (this is associated with #29)

mochi/core/builtins.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python
 import sys
-import traceback
 from types import FunctionType
 from functools import reduce, partial
 from itertools import chain
@@ -10,11 +9,11 @@
 
 from pyrsistent import pmap
 
+from mochi.parser import lex
 from .utils import issequence, issequence_except_str, is_tuple_or_list
 from .constants import *
 from .exceptions import UnquoteSplicingError, DuplicatedDefError, ReadError
 from .global_env import global_env
-from mochi.parser import lex
 from .translation import binding_name_set_stack, translator, Keyword, parse
 
 
@@ -996,21 +995,17 @@ def tuple_it(obj):
 
 
 def eval_tokens(tokens):
-    try:
-        sexps = parse(tokens.__iter__())
-        for sexp in sexps:
-            if isinstance(sexp, MutableSequence):
-                sexp = tuple_it(sexp)
-            if sexp is COMMENT:
-                continue
-            py_ast = translator.translate_sexp_to_interact(sexp)
-            if py_ast is not None:
-                code = compile(py_ast, '<string>', 'exec')
-                if code is not None:
-                    exec(code, global_env)
-                # print(file=current_output_port)
-    except Exception:
-        traceback.print_exc(file=current_error_port)
+    sexps = parse(tokens.__iter__())
+    for sexp in sexps:
+        if isinstance(sexp, MutableSequence):
+            sexp = tuple_it(sexp)
+        if sexp is COMMENT:
+            continue
+        py_ast = translator.translate_sexp_to_interact(sexp)
+        if py_ast is not None:
+            code = compile(py_ast, '<string>', 'exec')
+            if code is not None:
+                exec(code, global_env)
 
 
 @builtin_rename('eval')

mochi/core/constants.py

@@ -1,7 +1,7 @@
 import ast
 
 from .global_env import global_env
-from mochi.parser.parser import Symbol
+from mochi.parser import Symbol
 
 
 # -----------------------------------------------

mochi/core/main.py

@@ -1,13 +1,13 @@
 import argparse
-import traceback
 from pathlib import Path
 import sys
 import os
 from platform import platform
+import traceback
 
 from mochi import __version__, IS_PYPY, GE_PYTHON_34, GE_PYTHON_33
+from mochi.parser import lex, REPL_CONTINUE, ParsingError
 from .builtins import current_error_port, eval_sexp_str, eval_tokens
-from mochi.parser import lex, REPL_CONTINUE
 from .global_env import global_env
 from .translation import syntax_table, global_scope, translator
 
@@ -104,7 +104,12 @@ def interact(show_tokens=False):
                 continuation_flag = False
                 buffer = ''
                 continue
-        eval_tokens(tokens)
+        try:
+            eval_tokens(tokens)
+        except ParsingError as e:
+            print(e, file=current_error_port)
+        except Exception:
+            traceback.print_exc(file=current_error_port)
 
 
 def init():
@@ -183,16 +188,21 @@ def parse_args():
 def main():
     args = parse_args()
     if args.file:
-        if args.compile:
-            output_code(compile_file(args.file, optimize=2, show_tokens=args.tokens))
-        elif args.execute_compiled_file:
-            execute_compiled_file(args.file)
-        elif args.pyc_compile:
-            pyc_compile_monkeypatch(in_file_name=args.file, show_tokens=args.tokens)
-        elif args.pyc_compile_no_monkeypatch:
-            pyc_compile_no_monkeypatch(in_file_name=args.file, show_tokens=args.tokens)
-        else:
-            load_file(args.file, global_env)
+        try:
+            if args.compile:
+                output_code(compile_file(args.file, optimize=2, show_tokens=args.tokens))
+            elif args.execute_compiled_file:
+                execute_compiled_file(args.file)
+            elif args.pyc_compile:
+                pyc_compile_monkeypatch(in_file_name=args.file, show_tokens=args.tokens)
+            elif args.pyc_compile_no_monkeypatch:
+                pyc_compile_no_monkeypatch(in_file_name=args.file, show_tokens=args.tokens)
+            else:
+                load_file(args.file, global_env)
+        except ParsingError as e:
+                print(e, file=sys.stderr)
+        except Exception:
+                traceback.print_exc(file=sys.stderr)
         sys.exit(0)
     else:
         interact(args.tokens)

mochi/core/translation.py

@@ -5,12 +5,12 @@
 from os import chdir
 from os.path import normpath, abspath
 
+from mochi import GE_PYTHON_34, IS_PYPY
+from mochi.parser import Symbol, Keyword, parse, lex, get_temp_name
 from .utils import issequence_except_str
 from .constants import *
 from .exceptions import MochiSyntaxError, DuplicatedDefError
 from .global_env import global_env
-from mochi import GE_PYTHON_34, IS_PYPY
-from mochi.parser import Symbol, Keyword, parse, lex, get_temp_name
 
 
 if GE_PYTHON_34:
@@ -104,7 +104,7 @@ def translate_file(self, filename, show_tokens=False):
         body = []
         self.filename = filename
         with open(filename, 'r') as f:
-            sexps = parse(lex(f.read(), debug=show_tokens))
+            sexps = parse(lex(f.read(), debug=show_tokens), filename)
             chdir(normpath(str(Path(filename).parent)))
             for sexp in sexps:
                 if isinstance(sexp, MutableSequence):
@@ -120,7 +120,7 @@ def translate_loaded_file(self, filename, show_tokens=False):
         body = []
         self.filename = filename
         with open(filename, 'r') as f:
-            sexps = parse(lex(f.read(), debug=show_tokens))
+            sexps = parse(lex(f.read(), debug=show_tokens), filename)
             for sexp in sexps:
                 if isinstance(sexp, MutableSequence):
                     sexp = tuple_it(sexp)

mochi/parser/__init__.py

@@ -1,2 +1,2 @@
-from mochi.parser.lexer import lex, REPL_CONTINUE
-from mochi.parser.parser import parse, Symbol, Keyword, get_temp_name
+from .lexer import lex, REPL_CONTINUE
+from .parser import parse, Symbol, Keyword, get_temp_name, ParsingError

mochi/parser/parser.py

@@ -1,34 +1,49 @@
 import warnings
 from collections import Sequence
 
-from rply import ParserGenerator, ParsingError
+import rply
+from rply import ParserGenerator
 
 from mochi import __version__
-from mochi.parser.lexer import lg, klg
 
 name_seq = 0
 
+
 def get_temp_name():
     global name_seq
     name_seq += 1
     name_symbol = Symbol('_gs%s' % name_seq)
     return name_symbol
 
 
-def parse(lexer):
+class ParsingError(Exception):
+    def __init__(self, file_path, lineno=1, colno=1):
+        self.file_path = file_path
+        self.lineno = lineno
+        self.colno = colno
+
+    def __str__(self):
+        return 'ParsingError: file=' \
+               + self.file_path\
+               + ' lineno='\
+               + str(self.lineno)\
+               + ' colno='\
+               + str(self.colno)
+
+
+def parse(lexer, filename="<string>"):
     try:
         with warnings.catch_warnings():
             warnings.simplefilter('ignore')
             return pg.build().parse(lexer)
-    except ParsingError as e:
+    except rply.errors.ParsingError as e:
         source_pos = e.getsourcepos()
         if source_pos is None:
-            print('')
+            raise ParsingError(filename)
         else:
-            print('ParsingError: lineno='
-                  + str(source_pos.lineno)
-                  + ' colno='
-                  + str(source_pos.colno))
+            raise ParsingError(filename,
+                               source_pos.lineno,
+                               source_pos.colno)
 
 
 class Symbol(object):