Turn more errors to exceptions in cmd_parse.py.

Addresses issues #27 and #103.

core/expr_eval.py

@@ -510,7 +510,7 @@ def Eval(self, node):
          mode = os.stat(s).st_mode
        except OSError:
          # TODO: Signal extra debug information?
          #self._AddErrorContext("Error from stat(%r): %s" % (s, e))
          #log("Error from stat(%r): %s" % (s, e))
          return False

        if op_id in (Id.BoolUnary_e, Id.BoolUnary_a):  # -a is alias for -e

core/tdop.py

@@ -223,10 +223,6 @@ def __init__(self, spec, w_parser):

    self.error_stack = []

  def AddErrorContext(self, msg, *args, **kwargs):
    err = util.ParseError(msg, *args, **kwargs)
    self.error_stack.append(err)

  def Error(self):
    return self.error_stack

osh/cmd_parse.py

@@ -593,8 +593,7 @@ def ParseSimpleCommand(self):

    elif kind == Kind.ControlFlow:
      if redirects:
        self.AddErrorContext('Got redirects in control flow: %s', redirects)
        return None
        p_die("Control flow shouldn't have redirects", token=kw_token)

      if prefix_bindings:  # FOO=bar local spam=eggs not allowed
        # TODO: Change location as above
@@ -676,8 +675,7 @@ def ParseForWords(self):
        break
      if self.cur_word.tag != word_e.CompoundWord:
        # TODO: Can we also show a pointer to the 'for' keyword?
        self.AddErrorContext('Invalid word in for loop', word=self.cur_word)
        return None
        p_die('Invalid word in for loop', word=self.cur_word)

      words.append(self.cur_word)
      self._Next()
@@ -704,10 +702,7 @@ def _ParseForExprLoop(self):
    elif self.c_id == Id.KW_Do:  # missing semicolon/newline allowed
      pass
    else:
      self.AddErrorContext(
          'Unexpected token after for expression: %s', self.cur_word,
          word=self.cur_word)
      return None
      p_die('Invalid word after for expression', word=self.cur_word)

    body_node = self.ParseDoGroup()
    if not body_node: return None
@@ -721,13 +716,9 @@ def _ParseForEachLoop(self):

    ok, iter_name, quoted = word.StaticEval(self.cur_word)
    if not ok or quoted:
      self.AddErrorContext(
          "Invalid for loop variable", word=self.cur_word)
      return None
      p_die("Loop variable name should be a constant", word=self.cur_word)
    if not match.IsValidVarName(iter_name):
      self.AddErrorContext(
          "Invalid for loop variable name", word=self.cur_word)
      return None
      p_die("Invalid loop variable name", word=self.cur_word)
    node.iter_name = iter_name
    self._Next()  # skip past name

@@ -761,8 +752,9 @@ def _ParseForEachLoop(self):
      # do not advance

    else:
      # Hm I think these never happens?
      self.AddErrorContext("Unexpected word in for loop: %s", self.cur_word,
          word=self.cur_word)
                           word=self.cur_word)
      return None

    node.spids.extend((in_spid, semi_spid))
@@ -859,8 +851,9 @@ def ParseCaseItem(self):
      dsemi_spid = word.LeftMostSpanForWord(self.cur_word)
      self._Next()
    else:
      # This never happens?
      self.AddErrorContext('Expected DSEMI or ESAC, got %s', self.cur_word,
          word=self.cur_word)
                           word=self.cur_word)
      return None

    if not self._NewlineOk(): return None
@@ -910,7 +903,6 @@ def ParseCase(self):

    if self.c_id != Id.KW_Esac:  # empty case list
      if not self.ParseCaseList(case_node.arms):
        self.AddErrorContext("ParseCase: error parsing case list")
        return None
      # TODO: should it return a list of nodes, and extend?
      if not self._Peek(): return None
@@ -1044,6 +1036,7 @@ def ParseCompoundCommand(self):
    if self.c_id == Id.Op_DLeftParen:
      return self.ParseDParen()

    # This never happens?
    self.AddErrorContext(
        "Expected a compound command (e.g. for while if case), got %s",
        self.cur_word, word=self.cur_word)
@@ -1082,8 +1075,8 @@ def ParseFunctionDef(self):

    ok, name = word.AsFuncName(self.cur_word)
    if not ok:
      self.AddErrorContext('Invalid function name', word=self.cur_word)
      return None
      p_die('Invalid function name', word=self.cur_word)

    self._Next()  # skip function name

    # Must be true beacuse of lookahead
@@ -1119,8 +1112,8 @@ def ParseKshFunctionDef(self):
    if not self._Peek(): return None
    ok, name = word.AsFuncName(self.cur_word)
    if not ok:
      self.AddErrorContext("Invalid function name: %r", self.cur_word)
      return None
      p_die('Invalid KSH-style function name', word=self.cur_word)

    after_name_spid = word.LeftMostSpanForWord(self.cur_word) + 1
    self._Next()  # skip past 'function name

@@ -1233,8 +1226,7 @@ def ParseCommand(self):

    # TODO: KW_Do is also invalid here.
    if self.c_id == Id.Lit_RBrace:
      self.AddErrorContext('Unexpected }', word=self.cur_word)
      return None
      p_die('Unexpected right brace', word=self.cur_word)

    if self.c_kind == Kind.Redir:  # Leading redirect
      return self.ParseSimpleCommand()
@@ -1249,6 +1241,7 @@ def ParseCommand(self):

      return self.ParseSimpleCommand()  # echo foo

    # Does this ever happen?
    self.AddErrorContext(
        "ParseCommand: Expected to parse a command, got %s", self.cur_word,
        word=self.cur_word)

test/parse-errors.sh

@@ -194,6 +194,21 @@ cmd-parse() {

  _error-case 'FOO=1 break'
  _error-case 'break 1 2'
  _error-case 'break >out'

  _error-case 'for x in &'

  _error-case 'for (( i=0; i<10; i++ )) ls'

  _error-case 'for $x in 1 2 3; do echo $i; done'
  _error-case 'for x.y in 1 2 3; do echo $i; done'
  _error-case 'for x in 1 2 3; &'

  _error-case 'x"y"() { echo hi; }'

  _error-case 'function x"y" { echo hi; }'

  _error-case '}'
}

redirect() {