def _ReadArithExpr(self, do_next=True):
"""Read and parse an arithmetic expression in various contexts.
$(( 1+2 ))
(( a=1+2 ))
${a[ 1+2 ]}
${a : 1+2 : 1+2}
See tests/arith-context.test.sh for ambiguous cases.
${a[a[0]]} is valid # VS_RBRACKET vs Id.Arith_RBracket
${s : a<b?0:1 : 1} # VS_COLON vs Id.Arith_Colon
TODO: Instead of having an eof_type. I think we should use just run the
arith parser until it's done. That will take care of both : and ]. We
switch the state back.
See the assertion in ArithParser.Parse() -- unexpected extra input.
"""
if do_next:
self._Next(lex_mode_e.ARITH)
# calls self.ReadWord(lex_mode_e.ARITH)
a_parser = tdop.TdopParser(arith_parse.SPEC, self)
anode = a_parser.Parse()
if not anode:
error_stack = a_parser.Error()
self.error_stack.extend(error_stack)
return anode # could be None
def MakeArithParser(self, code_str, arena):
"""
NOTE: We want to add tokens to a different arena, so we don't mess up the
translation.
"""
line_reader = reader.StringLineReader(code_str, arena)
line_lexer = lexer.LineLexer(match.MATCHER, '', arena)
lx = lexer.Lexer(line_lexer, line_reader)
w_parser = word_parse.WordParser(self,
lx,
line_reader,
lex_mode=lex_mode_e.ARITH)
a_parser = tdop.TdopParser(arith_parse.SPEC, w_parser)
return a_parser