Change an error case in cmd_parse.py to throw exceptions.

Catch exception when parsing 'trap' code.

Addresses issues #27 and #103.

core/cmd_exec.py

@@ -219,13 +219,23 @@ def ParseTrapCode(self, code_str):

    source_name = '<trap string>'
    self.arena.PushSource(source_name)

    try:
      node = c_parser.ParseWholeFile()
      if not node:
      # TODO: Get rid of duplicate error handling:
      err = None
      try:
        node = c_parser.ParseWholeFile()
      except util.ParseError as e:
        err = e
      else:
        if not node:
          err = c_parser.Error()

      if err:
        util.error('Parse error in %r:', source_name)
        err = c_parser.Error()
        ui.PrintErrorStack(err, self.arena, sys.stderr)
        return None

    finally:
      self.arena.PopSource()

osh/cmd_parse.py

@@ -21,6 +21,7 @@
from osh.bool_parse import BoolParser

log = util.log
p_die = util.p_die
command_e = ast.command_e
word_e = ast.word_e
assign_op_e = ast.assign_op_e
@@ -267,9 +268,7 @@ def ParseRedirect(self):

      if not self._Peek(): return None
      if self.c_kind != Kind.Word:
        self.AddErrorContext(
            'Expected word after redirect operator', word=self.cur_word)
        return None
        p_die('Invalid token after redirect operator', word=self.cur_word)

      new_word = word.TildeDetect(self.cur_word)
      node.arg_word = new_word or self.cur_word