Tests here doc parse errors.

Also add some tests for assignments.

Addresses issue #27 and #103.

core/ui.py

@@ -125,9 +125,9 @@ def PrettyPrintError(parse_error, arena, f=sys.stderr):
  if span_id == const.NO_INTEGER:  # Any clause above might return this.
    # This is usually a bug.
    print('*** Error has no source location info ***', file=f)
    return
  else:
    PrintFilenameAndLine(span_id, arena, f=f)

  PrintFilenameAndLine(span_id, arena, f=f)
  print(parse_error.UserErrorString(), file=f)

osh/cmd_parse.py

@@ -121,6 +121,8 @@ def _MaybeReadHereDocs(self):

        from osh import parse_lib  # Avoid circular import
        w_parser = parse_lib.MakeWordParserForHereDoc(lines, self.arena)

        # NOTE: There can be different kinds of parse errors in here docs.
        word = w_parser.ReadHereDocBody()
        if not word:
          self.AddErrorContext(

test/parse-errors.sh

@@ -205,6 +205,35 @@ simple-command() {
  _error-case 'PYTHONPATH+=1 python'
}

assign() {
  set +o errexit
  _error-case 'local "ab"'
  _error-case 'local a.b'
}

# I can't think of any other here doc error conditions except arith/var/command
# substitution, and unterminated.
here-doc() {
  set +o errexit

  # Arith in here doc
  _error-case 'cat <<EOF
$(( 1 * ))  
EOF
'

  # Varsub in here doc
  _error-case 'cat <<EOF
invalid: ${a!}
EOF
'

  _error-case 'cat <<EOF
$(for x in )
EOF
'
}

cases-in-strings() {
  set +o errexit