[antlr-interest] zero or more vs. optional one or more
Christian
chwchw at gmx.de
Sun Jan 22 02:08:36 PST 2012
Hello everybody,
I wonder why the following lexer rules do not show equivalent behavior:
fragment Verbatim_string_literal
: '@' DOUBLE_QUOTE Verbatim_string_literal_characters? DOUBLE_QUOTE
;
fragment Verbatim_string_literal_characters
: Verbatim_string_literal_character+
;
versus
fragment Verbatim_string_literal
: '@' DOUBLE_QUOTE Verbatim_string_literal_character* DOUBLE_QUOTE
;
The first one does not parse @"Hello World!", the second however does.
Regards,
Christian
P.S.
fragment Verbatim_string_literal_character
: c=Single_verbatim_string_literal_character
| c=Quote_escape_sequence
;
fragment Single_verbatim_string_literal_character
: ~DOUBLE_QUOTE //<any Character Except ">
;
fragment Quote_escape_sequence
: DOUBLE_QUOTE DOUBLE_QUOTE
;
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