Lines Matching full:look
213 * Look-Ahead:: Parser looks one token ahead when deciding what to do.
219 * Mystery Conflicts:: Reduce/reduce conflicts that look unjustified.
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
1058 These two declarations look identical until the `..' token. With
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.
1830 global variable `yylval', which is where the Bison parser will look for
2511 Two important functions allow look-up and installation of symbols in
2515 function `getsym' is passed the name of the symbol to look up. If
2548 The string is passed to `getsym' for look up in the symbol table. If
2955 digraph. Bison does not look for trigraphs, so if braced code uses
3182 It is also possible to access the semantic value of the look-ahead
3316 the open-brace token and look at what follows before deciding whether
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
4371 then the code in `yylex' might look like this:
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.
4772 * Mystery Conflicts:: Reduce/reduce conflicts that look unjustified.
4777 File: bison.info, Node: Look-Ahead, Next: Shift/Reduce, Up: Algorithm
4779 5.1 Look-Ahead Tokens
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
5220 Sometimes reduce/reduce conflicts can occur that don't look warranted.
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
5270 look distinct. In the above example, adding one rule to `return_spec'
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
