Remove the last vestiges of error code handling.

Get rid of Error() and error_stack.  We're using exceptions now.

- Remove old comments
- Rename back to VirtualLineReader

core/reader.py

@@ -95,8 +95,12 @@ def StringLineReader(s, arena):
# internally.


class HereDocLineReader(_Reader):
  """Used for here docs."""
class VirtualLineReader(_Reader):
  """Read from lines we already read from the OS.
  
  Used for here docs and aliases.
  """

  def __init__(self, lines, arena):
    """
    Args:

core/reader_test.py

@@ -35,7 +35,7 @@ def testLineReadersAreEquivalent(self):

    a3 = self.pool.NewArena()
    lines = [(0, 'one\n', 0), (1, 'two', 0)]
    r3 = reader.HereDocLineReader(lines, a3)
    r3 = reader.VirtualLineReader(lines, a3)

    for a in [a1, a2, a3]:
      a.PushSource('reader_test.py')

core/tdop.py

@@ -221,11 +221,6 @@ def __init__(self, spec, w_parser):
    self.cur_word = None  # current token
    self.op_id = Id.Undefined_Tok

    self.error_stack = []

  def Error(self):
    return self.error_stack

  def _Led(self, token):
    return self.spec.LookupLed(token)

@@ -245,10 +240,7 @@ def Eat(self, token_type):
  def Next(self):
    """Preferred over Eat()? """
    self.cur_word = self.w_parser.ReadWord(lex_mode_e.ARITH)
    if self.cur_word is None:
      error_stack = self.w_parser.Error()
      self.error_stack.extend(error_stack)
      p_die('Error reading arith word in ArithParser')
    assert self.cur_word is not None
    self.op_id = word.ArithId(self.cur_word)
    return True

osh/cmd_parse.py

@@ -99,7 +99,7 @@ def _ParseHereDocBody(parse_ctx, h, line_reader, arena):
    # LiteralPart for each line.
    h.stdin_parts = _MakeLiteralHereLines(here_lines, arena)
  else:
    line_reader = reader.HereDocLineReader(here_lines, arena)
    line_reader = reader.VirtualLineReader(here_lines, arena)
    w_parser = parse_ctx.MakeWordParserForHereDoc(line_reader)
    w_parser.ReadHereDocBody(h.stdin_parts)  # fills this in

@@ -523,7 +523,6 @@ def _ExpandAliases(self, words, cur_aliases):
      expanded.append(alias_exp)
      i += 1


      if not alias_exp.endswith(' '):
        # alias e='echo [ ' is the same expansion as
        # alias e='echo ['
@@ -571,7 +570,7 @@ def _ExpandAliases(self, words, cur_aliases):
      self.arena.PopSource()

    # TODO: Change name back to VirtualLineReader?
    line_reader = reader.HereDocLineReader(line_info, self.arena)
    line_reader = reader.VirtualLineReader(line_info, self.arena)
    _, cp = self.parse_ctx.MakeParser(line_reader)

    try:

osh/parse_lib.py

@@ -19,22 +19,6 @@ def InitLexer(s, arena):
  return line_reader, lx


# When does line_reader change?
# - here docs
# - aliases
#
# WordParser gets the line_reader from either parse_state OR an explicit
# argument!
#
# self.parse_state.MakeParser(...)
#
# instead of CommandParser and WordParser holding the arena.
# NOTE: arith parser and bool parser never need to instantiate parsers
# only word/command parser have this dependency.
#
# common thing: word parser does not use arena OR aliases.  But it needs to
# create a command parser.

class ParseContext(object):
  """Context shared between the mutually recursive Command and Word parsers.

osh/word_parse.py

@@ -87,8 +87,6 @@ def Reset(self, lex_mode=lex_mode_e.OUTER):
    self.cursor = None
    self.cursor_was_newline = False

    self.error_stack = []

  def _Peek(self):
    """Helper method."""
    if self.next_lex_mode is not None:
@@ -107,9 +105,6 @@ def _Next(self, lex_mode):
    """
    self.next_lex_mode = lex_mode

  def Error(self):
    return self.error_stack

  def PrevToken(self):
    """Inspect state.  Used by completion.

@@ -1095,13 +1090,7 @@ def ReadWord(self, lex_mode):
      if not need_more:
        break

    # TODO: Change the interface of _ReadArithWord and _ReadWord.
    # Error cases should raise ParseError.
    # Then they should return either the word, or None to try again?
    if not w:
      error_stack = self.Error()
      p_die('ReadWord: %s', error_stack[-1])

    assert w is not None, w
    self.cursor = w

    # TODO: Do consolidation of newlines in the lexer?

osh/word_parse_test.py

@@ -46,11 +46,8 @@ def _assertReadWordWithArena(test, word_str):
  print('\n---', word_str)
  arena, w_parser = _InitWordParserWithArena(word_str)
  w = w_parser.ReadWord(lex_mode_e.OUTER)
  if w:
    ast_lib.PrettyPrint(w)
  else:
    err = w_parser.Error()
    test.fail("Couldn't parse %r: %s" % (word_str, err))
  assert w is not None
  ast_lib.PrettyPrint(w)

  # Next word must be Eof_Real
  w2 = w_parser.ReadWord(lex_mode_e.OUTER)
@@ -353,10 +350,7 @@ def testRead(self):

      while True:
        w = w_parser.ReadWord(lex_mode_e.OUTER)
        if w is None:
          e = w_parser.Error()
          print('Error in word parser: %s' % e)
          self.fail(e)
        assert w is not None

        ast_lib.PrettyPrint(w)

@@ -455,11 +449,7 @@ def testReadArith(self):

      while True:
        w = w_parser.ReadWord(lex_mode_e.ARITH)
        if not w:
          err = w_parser.Error()
          print('ERROR', err)
          self.fail(err)
          break
        assert w is not None
        ast_lib.PrettyPrint(w)
        if word.CommandId(w) in (Id.Eof_Real, Id.Unknown_Tok):
          break