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