Lines Matching full:ahead
213 * Look-Ahead:: Parser looks one token ahead when deciding what to do.
768 input string with just a single token of look-ahead. Strictly
778 (called a "look-ahead") of the remaining input. A context-free grammar
781 "nondeterministic", meaning that no fixed look-ahead always suffices to
1030 require more than one symbol of look-ahead, or (in rare cases) fall
1059 normal LALR(1) one-token look-ahead it is not possible to decide
1094 look-ahead than the underlying LALR(1) algorithm actually allows for.
1318 type of the look-ahead token present at the time of the associated
1321 look-ahead token's semantic value and location, if any. In a
1323 to influence syntax analysis. *Note Look-Ahead Tokens: Look-Ahead.
3182 It is also possible to access the semantic value of the look-ahead
3335 the "look-ahead" token at this time, since the parser is still deciding
3336 what to do about it. *Note Look-Ahead Tokens: Look-Ahead.)
3480 It is also possible to access the location of the look-ahead token,
3773 initial value and location of the look-ahead -- and the
3832 * the current look-ahead and the entire stack (except the current
4111 parser states and what is done for each type of look-ahead token in
4588 a single value, and only when there is no look-ahead token. It is
4589 also disallowed in GLR parsers. It installs a look-ahead token
4594 look-ahead token already, then it reports a syntax error with a
4600 Value stored in `yychar' when there is no look-ahead token.
4603 Value stored in `yychar' when the look-ahead is the end of the
4620 Variable containing either the look-ahead token, or `YYEOF' when
4621 the look-ahead is the end of the input stream, or `YYEMPTY' when
4622 no look-ahead has been performed so the next token is not yet
4624 (*note GLR Semantic Actions::). *Note Look-Ahead Tokens:
4625 Look-Ahead.
4628 Discard the current look-ahead token. This is useful primarily in
4638 Variable containing the look-ahead token location when `yychar' is
4644 Variable containing the look-ahead token semantic value when
4766 * Look-Ahead:: Parser looks one token ahead when deciding what to do.
4777 File: bison.info, Node: Look-Ahead, Next: Shift/Reduce, Up: Algorithm
4779 5.1 Look-Ahead Tokens
4785 reduction is possible, the parser sometimes "looks ahead" at the next
4789 becomes the "look-ahead token", which is not on the stack. Now the
4791 the stack, while the look-ahead token remains off to the side. When no
4792 more reductions should take place, the look-ahead token is shifted onto
4794 done; depending on the token type of the look-ahead token, some rules
4797 Here is a simple case where look-ahead is needed. These three rules
4823 The look-ahead token is stored in the variable `yychar'. Its
4829 File: bison.info, Node: Shift/Reduce, Next: Precedence, Prev: Look-Ahead, Up: Algorithm
4845 When the `ELSE' token is read and becomes the look-ahead token, the
4963 to shift or reduce when the stack contains `1 - 2' and the look-ahead
5024 precedence of the rule being considered with that of the look-ahead
5032 rule or the look-ahead token has no precedence, then the default is to
5096 Each time a look-ahead token is read, the current parser state
5097 together with the type of look-ahead token are looked up in a table.
5098 This table entry can say, "Shift the look-ahead token." In this case,
5106 look-ahead token is erroneous in the current state. This causes error
5246 token of look-ahead: when a `param_spec' is being read, an `ID' is a
5257 require different look-ahead tokens in the two contexts, so it makes a
5309 Computation of LALR(1) Look-Ahead Sets, `ACM Transactions on
5321 input and on one extra token of look-ahead. As a result, normal Bison
5326 look-ahead, since the parser lacks the information necessary to make a
5489 the old look-ahead token is not acceptable to be shifted next, the
5535 The previous look-ahead token is reanalyzed immediately after an
5544 lexical scanner is probably correct. The previous look-ahead token
5896 symbol, and the look-ahead is a `NUM', then this token is shifted on
5898 look-ahead triggers a syntax error."
5901 report lists `NUM' as a look-ahead token because `NUM' can be at the
5928 the rule 5, `exp: NUM;', is completed. Whatever the look-ahead token
5948 because of the item `exp -> exp . '+' exp', if the look-ahead if `+',
6017 Indeed, there are two actions associated to the look-ahead `/':
6035 look-ahead is required to select the action. State 8 is one such
6036 state: if the look-ahead is `*' or `/' then the action is shifting,
6038 items, corresponding to rule 1, are not eligible when the look-ahead
6041 possible look-ahead tokens. When run with `--report=look-ahead', Bison
6042 specifies these look-ahead tokens:
6359 `look-ahead'
6361 with each rule's look-ahead set.
7497 syntax error, the token `error' becomes the current look-ahead
7499 the look-ahead token is reset to the token that originally caused
7609 look-ahead token. *Note Special Features for Use in Actions:
7614 look-ahead token. (In a pure parser, it is a local variable within
7620 look-ahead token. *Note Error Recovery::.
7674 look-ahead token. *Note Actions and Locations: Actions and
7686 actions, it stores the semantic value of the look-ahead token.
7821 Look-ahead token
7822 A token already read but not yet shifted. *Note Look-Ahead
7823 Tokens: Look-Ahead.
7832 look-ahead is needed to disambiguate the parsing of any piece of
8656 * look-ahead token: Look-Ahead. (line 6)
8794 * yychar <2>: Look-Ahead. (line 47)
8830 * yylloc <2>: Look-Ahead. (line 47)
8842 * yylval <2>: Look-Ahead. (line 47)
8951 Node: Look-Ahead195105
