Ceci est le fichier Info bison.info, produit par Makeinfo version 4.0b à partir bison.texinfo. START-INFO-DIR-ENTRY * bison: (bison). GNU Project parser generator (yacc replacement). END-INFO-DIR-ENTRY This file documents the Bison parser generator. Copyright (C) 1988, 1989, 1990, 1991, 1992, 1993, 1995, 1998, 1999, 2000, 2001 Free Software Foundation, Inc. Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided also that the sections entitled "GNU General Public License" and "Conditions for Using Bison" are included exactly as in the original, and provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Permission is granted to copy and distribute translations of this manual into another language, under the above conditions for modified versions, except that the sections entitled "GNU General Public License", "Conditions for Using Bison" and this permission notice may be included in translations approved by the Free Software Foundation instead of in the original English.  File: bison.info, Node: Table of Symbols, Next: Glossary, Prev: Invocation, Up: Top Bison Symbols ************* `error' A token name reserved for error recovery. This token may be used in grammar rules so as to allow the Bison parser to recognize an error in the grammar without halting the process. In effect, a sentence containing an error may be recognized as valid. On a parse error, the token `error' becomes the current look-ahead token. Actions corresponding to `error' are then executed, and the look-ahead token is reset to the token that originally caused the violation. *Note Error Recovery::. `YYABORT' Macro to pretend that an unrecoverable syntax error has occurred, by making `yyparse' return 1 immediately. The error reporting function `yyerror' is not called. *Note The Parser Function `yyparse': Parser Function. `YYACCEPT' Macro to pretend that a complete utterance of the language has been read, by making `yyparse' return 0 immediately. *Note The Parser Function `yyparse': Parser Function. `YYBACKUP' Macro to discard a value from the parser stack and fake a look-ahead token. *Note Special Features for Use in Actions: Action Features. `YYERROR' Macro to pretend that a syntax error has just been detected: call `yyerror' and then perform normal error recovery if possible (*note Error Recovery::), or (if recovery is impossible) make `yyparse' return 1. *Note Error Recovery::. `YYERROR_VERBOSE' Macro that you define with `#define' in the Bison declarations section to request verbose, specific error message strings when `yyerror' is called. `YYINITDEPTH' Macro for specifying the initial size of the parser stack. *Note Stack Overflow::. `YYLEX_PARAM' Macro for specifying an extra argument (or list of extra arguments) for `yyparse' to pass to `yylex'. *Note Calling Conventions for Pure Parsers: Pure Calling. `YYLTYPE' Macro for the data type of `yylloc'; a structure with four members. *Note Data Types of Locations: Location Type. `yyltype' Default value for YYLTYPE. `YYMAXDEPTH' Macro for specifying the maximum size of the parser stack. *Note Stack Overflow::. `YYPARSE_PARAM' Macro for specifying the name of a parameter that `yyparse' should accept. *Note Calling Conventions for Pure Parsers: Pure Calling. `YYRECOVERING' Macro whose value indicates whether the parser is recovering from a syntax error. *Note Special Features for Use in Actions: Action Features. `YYSTACK_USE_ALLOCA' Macro used to control the use of `alloca'. If defined to `0', the parser will not use `alloca' but `malloc' when trying to grow its internal stacks. Do _not_ define `YYSTACK_USE_ALLOCA' to anything else. `YYSTYPE' Macro for the data type of semantic values; `int' by default. *Note Data Types of Semantic Values: Value Type. `yychar' External integer variable that contains the integer value of the current look-ahead token. (In a pure parser, it is a local variable within `yyparse'.) Error-recovery rule actions may examine this variable. *Note Special Features for Use in Actions: Action Features. `yyclearin' Macro used in error-recovery rule actions. It clears the previous look-ahead token. *Note Error Recovery::. `yydebug' External integer variable set to zero by default. If `yydebug' is given a nonzero value, the parser will output information on input symbols and parser action. *Note Debugging Your Parser: Debugging. `yyerrok' Macro to cause parser to recover immediately to its normal mode after a parse error. *Note Error Recovery::. `yyerror' User-supplied function to be called by `yyparse' on error. The function receives one argument, a pointer to a character string containing an error message. *Note The Error Reporting Function `yyerror': Error Reporting. `yylex' User-supplied lexical analyzer function, called with no arguments to get the next token. *Note The Lexical Analyzer Function `yylex': Lexical. `yylval' External variable in which `yylex' should place the semantic value associated with a token. (In a pure parser, it is a local variable within `yyparse', and its address is passed to `yylex'.) *Note Semantic Values of Tokens: Token Values. `yylloc' External variable in which `yylex' should place the line and column numbers associated with a token. (In a pure parser, it is a local variable within `yyparse', and its address is passed to `yylex'.) You can ignore this variable if you don't use the `@' feature in the grammar actions. *Note Textual Positions of Tokens: Token Positions. `yynerrs' Global variable which Bison increments each time there is a parse error. (In a pure parser, it is a local variable within `yyparse'.) *Note The Error Reporting Function `yyerror': Error Reporting. `yyparse' The parser function produced by Bison; call this function to start parsing. *Note The Parser Function `yyparse': Parser Function. `%debug' Equip the parser for debugging. *Note Decl Summary::. `%defines' Bison declaration to create a header file meant for the scanner. *Note Decl Summary::. `%left' Bison declaration to assign left associativity to token(s). *Note Operator Precedence: Precedence Decl. `%no_lines' Bison declaration to avoid generating `#line' directives in the parser file. *Note Decl Summary::. `%nonassoc' Bison declaration to assign non-associativity to token(s). *Note Operator Precedence: Precedence Decl. `%prec' Bison declaration to assign a precedence to a specific rule. *Note Context-Dependent Precedence: Contextual Precedence. `%pure_parser' Bison declaration to request a pure (reentrant) parser. *Note A Pure (Reentrant) Parser: Pure Decl. `%right' Bison declaration to assign right associativity to token(s). *Note Operator Precedence: Precedence Decl. `%start' Bison declaration to specify the start symbol. *Note The Start-Symbol: Start Decl. `%token' Bison declaration to declare token(s) without specifying precedence. *Note Token Type Names: Token Decl. `%token_table' Bison declaration to include a token name table in the parser file. *Note Decl Summary::. `%type' Bison declaration to declare nonterminals. *Note Nonterminal Symbols: Type Decl. `%union' Bison declaration to specify several possible data types for semantic values. *Note The Collection of Value Types: Union Decl. These are the punctuation and delimiters used in Bison input: `%%' Delimiter used to separate the grammar rule section from the Bison declarations section or the additional C code section. *Note The Overall Layout of a Bison Grammar: Grammar Layout. `%{ %}' All code listed between `%{' and `%}' is copied directly to the output file uninterpreted. Such code forms the "C declarations" section of the input file. *Note Outline of a Bison Grammar: Grammar Outline. `/*...*/' Comment delimiters, as in C. `:' Separates a rule's result from its components. *Note Syntax of Grammar Rules: Rules. `;' Terminates a rule. *Note Syntax of Grammar Rules: Rules. `|' Separates alternate rules for the same result nonterminal. *Note Syntax of Grammar Rules: Rules.  File: bison.info, Node: Glossary, Next: Copying This Manual, Prev: Table of Symbols, Up: Top Glossary ******** Backus-Naur Form (BNF) Formal method of specifying context-free grammars. BNF was first used in the `ALGOL-60' report, 1963. *Note Languages and Context-Free Grammars: Language and Grammar. Context-free grammars Grammars specified as rules that can be applied regardless of context. Thus, if there is a rule which says that an integer can be used as an expression, integers are allowed _anywhere_ an expression is permitted. *Note Languages and Context-Free Grammars: Language and Grammar. Dynamic allocation Allocation of memory that occurs during execution, rather than at compile time or on entry to a function. Empty string Analogous to the empty set in set theory, the empty string is a character string of length zero. Finite-state stack machine A "machine" that has discrete states in which it is said to exist at each instant in time. As input to the machine is processed, the machine moves from state to state as specified by the logic of the machine. In the case of the parser, the input is the language being parsed, and the states correspond to various stages in the grammar rules. *Note The Bison Parser Algorithm: Algorithm. Grouping A language construct that is (in general) grammatically divisible; for example, `expression' or `declaration' in C. *Note Languages and Context-Free Grammars: Language and Grammar. Infix operator An arithmetic operator that is placed between the operands on which it performs some operation. Input stream A continuous flow of data between devices or programs. Language construct One of the typical usage schemas of the language. For example, one of the constructs of the C language is the `if' statement. *Note Languages and Context-Free Grammars: Language and Grammar. Left associativity Operators having left associativity are analyzed from left to right: `a+b+c' first computes `a+b' and then combines with `c'. *Note Operator Precedence: Precedence. Left recursion A rule whose result symbol is also its first component symbol; for example, `expseq1 : expseq1 ',' exp;'. *Note Recursive Rules: Recursion. Left-to-right parsing Parsing a sentence of a language by analyzing it token by token from left to right. *Note The Bison Parser Algorithm: Algorithm. Lexical analyzer (scanner) A function that reads an input stream and returns tokens one by one. *Note The Lexical Analyzer Function `yylex': Lexical. Lexical tie-in A flag, set by actions in the grammar rules, which alters the way tokens are parsed. *Note Lexical Tie-ins::. Literal string token A token which consists of two or more fixed characters. *Note Symbols::. Look-ahead token A token already read but not yet shifted. *Note Look-Ahead Tokens: Look-Ahead. LALR(1) The class of context-free grammars that Bison (like most other parser generators) can handle; a subset of LR(1). *Note Mysterious Reduce/Reduce Conflicts: Mystery Conflicts. LR(1) The class of context-free grammars in which at most one token of look-ahead is needed to disambiguate the parsing of any piece of input. Nonterminal symbol A grammar symbol standing for a grammatical construct that can be expressed through rules in terms of smaller constructs; in other words, a construct that is not a token. *Note Symbols::. Parse error An error encountered during parsing of an input stream due to invalid syntax. *Note Error Recovery::. Parser A function that recognizes valid sentences of a language by analyzing the syntax structure of a set of tokens passed to it from a lexical analyzer. Postfix operator An arithmetic operator that is placed after the operands upon which it performs some operation. Reduction Replacing a string of nonterminals and/or terminals with a single nonterminal, according to a grammar rule. *Note The Bison Parser Algorithm: Algorithm. Reentrant A reentrant subprogram is a subprogram which can be in invoked any number of times in parallel, without interference between the various invocations. *Note A Pure (Reentrant) Parser: Pure Decl. Reverse polish notation A language in which all operators are postfix operators. Right recursion A rule whose result symbol is also its last component symbol; for example, `expseq1: exp ',' expseq1;'. *Note Recursive Rules: Recursion. Semantics In computer languages, the semantics are specified by the actions taken for each instance of the language, i.e., the meaning of each statement. *Note Defining Language Semantics: Semantics. Shift A parser is said to shift when it makes the choice of analyzing further input from the stream rather than reducing immediately some already-recognized rule. *Note The Bison Parser Algorithm: Algorithm. Single-character literal A single character that is recognized and interpreted as is. *Note From Formal Rules to Bison Input: Grammar in Bison. Start symbol The nonterminal symbol that stands for a complete valid utterance in the language being parsed. The start symbol is usually listed as the first nonterminal symbol in a language specification. *Note The Start-Symbol: Start Decl. Symbol table A data structure where symbol names and associated data are stored during parsing to allow for recognition and use of existing information in repeated uses of a symbol. *Note Multi-function Calc::. Token A basic, grammatically indivisible unit of a language. The symbol that describes a token in the grammar is a terminal symbol. The input of the Bison parser is a stream of tokens which comes from the lexical analyzer. *Note Symbols::. Terminal symbol A grammar symbol that has no rules in the grammar and therefore is grammatically indivisible. The piece of text it represents is a token. *Note Languages and Context-Free Grammars: Language and Grammar.  File: bison.info, Node: Copying This Manual, Next: Index, Prev: Glossary, Up: Top Copying This Manual ******************* * Menu: * GNU Free Documentation License:: License for copying this manual.  File: bison.info, Node: GNU Free Documentation License, Up: Copying This Manual GNU Free Documentation License ============================== Version 1.1, March 2000 Copyright (C) 2000 Free Software Foundation, Inc. 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed. 0. PREAMBLE The purpose of this License is to make a manual, textbook, or other written document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others. This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software. We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference. 1. APPLICABILITY AND DEFINITIONS This License applies to any manual or other work that contains a notice placed by the copyright holder saying it can be distributed under the terms of this License. The "Document", below, refers to any such manual or work. Any member of the public is a licensee, and is addressed as "you". A "Modified Version" of the Document means any work containing the Document or a portion of it, either copied verbatim, or with modifications and/or translated into another language. A "Secondary Section" is a named appendix or a front-matter section of the Document that deals exclusively with the relationship of the publishers or authors of the Document to the Document's overall subject (or to related matters) and contains nothing that could fall directly within that overall subject. (For example, if the Document is in part a textbook of mathematics, a Secondary Section may not explain any mathematics.) The relationship could be a matter of historical connection with the subject or with related matters, or of legal, commercial, philosophical, ethical or political position regarding them. The "Invariant Sections" are certain Secondary Sections whose titles are designated, as being those of Invariant Sections, in the notice that says that the Document is released under this License. The "Cover Texts" are certain short passages of text that are listed, as Front-Cover Texts or Back-Cover Texts, in the notice that says that the Document is released under this License. A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, whose contents can be viewed and edited directly and straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup has been designed to thwart or discourage subsequent modification by readers is not Transparent. A copy that is not "Transparent" is called "Opaque". Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML designed for human modification. Opaque formats include PostScript, PDF, proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML produced by some word processors for output purposes only. The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text. 2. VERBATIM COPYING You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3. You may also lend copies, under the same conditions stated above, and you may publicly display copies. 3. COPYING IN QUANTITY If you publish printed copies of the Document numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects. If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages. If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a publicly-accessible computer-network location containing a complete Transparent copy of the Document, free of added material, which the general network-using public has access to download anonymously at no charge using public-standard network protocols. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public. It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document. 4. MODIFICATIONS You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version: A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission. B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has less than five). C. State on the Title page the name of the publisher of the Modified Version, as the publisher. D. Preserve all the copyright notices of the Document. E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices. F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below. G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice. H. Include an unaltered copy of this License. I. Preserve the section entitled "History", and its title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence. J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission. K. In any section entitled "Acknowledgments" or "Dedications", preserve the section's title, and preserve in the section all the substance and tone of each of the contributor acknowledgments and/or dedications given therein. L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles. M. Delete any section entitled "Endorsements". Such a section may not be included in the Modified Version. N. Do not retitle any existing section as "Endorsements" or to conflict in title with any Invariant Section. If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles. You may add a section entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard. You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one. The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version. 5. COMBINING DOCUMENTS You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice. The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work. In the combination, you must combine any sections entitled "History" in the various original documents, forming one section entitled "History"; likewise combine any sections entitled "Acknowledgments", and any sections entitled "Dedications". You must delete all sections entitled "Endorsements." 6. COLLECTIONS OF DOCUMENTS You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects. You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document. 7. AGGREGATION WITH INDEPENDENT WORKS A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, does not as a whole count as a Modified Version of the Document, provided no compilation copyright is claimed for the compilation. Such a compilation is called an "aggregate", and this License does not apply to the other self-contained works thus compiled with the Document, on account of their being thus compiled, if they are not themselves derivative works of the Document. If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one quarter of the entire aggregate, the Document's Cover Texts may be placed on covers that surround only the Document within the aggregate. Otherwise they must appear on covers around the whole aggregate. 8. TRANSLATION Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License provided that you also include the original English version of this License. In case of a disagreement between the translation and the original English version of this License, the original English version will prevail. 9. TERMINATION You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance. 10. FUTURE REVISIONS OF THIS LICENSE The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See `http://www.gnu.org/copyleft/'. Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation. ADDENDUM: How to use this License for your documents ---------------------------------------------------- To use this License in a document you have written, include a copy of the License in the document and put the following copyright and license notices just after the title page: Copyright (C) YEAR YOUR NAME. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.1 or any later version published by the Free Software Foundation; with the Invariant Sections being LIST THEIR TITLES, with the Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST. A copy of the license is included in the section entitled ``GNU Free Documentation License''. If you have no Invariant Sections, write "with no Invariant Sections" instead of saying which ones are invariant. If you have no Front-Cover Texts, write "no Front-Cover Texts" instead of "Front-Cover Texts being LIST"; likewise for Back-Cover Texts. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software.  File: bison.info, Node: Index, Prev: Copying This Manual, Up: Top Index ***** * Menu: * $$: Actions. * $N: Actions. * %expect: Expect Decl. * %left: Using Precedence. * %nonassoc: Using Precedence. * %prec: Contextual Precedence. * %pure_parser: Pure Decl. * %right: Using Precedence. * %start: Start Decl. * %token: Token Decl. * %type: Type Decl. * %union: Union Decl. * @$ <1>: Action Features. * @$: Actions and Locations. * @N <1>: Action Features. * @N: Actions and Locations. * action: Actions. * action data types: Action Types. * action features summary: Action Features. * actions in mid-rule: Mid-Rule Actions. * actions, location: Actions and Locations. * actions, semantic: Semantic Actions. * additional C code section: C Code. * algorithm of parser: Algorithm. * associativity: Why Precedence. * Backus-Naur form: Language and Grammar. * Bison declaration summary: Decl Summary. * Bison declarations: Declarations. * Bison declarations (introduction): Bison Declarations. * Bison grammar: Grammar in Bison. * Bison invocation: Invocation. * Bison parser: Bison Parser. * Bison parser algorithm: Algorithm. * Bison symbols, table of: Table of Symbols. * Bison utility: Bison Parser. * BISON_HAIRY: Environment Variables. * BISON_SIMPLE: Environment Variables. * BNF: Language and Grammar. * C code, section for additional: C Code. * C declarations section: C Declarations. * C-language interface: Interface. * calc: Infix Calc. * calculator, infix notation: Infix Calc. * calculator, multi-function: Multi-function Calc. * calculator, simple: RPN Calc. * character token: Symbols. * compiling the parser: Rpcalc Compile. * conflicts: Shift/Reduce. * conflicts, reduce/reduce: Reduce/Reduce. * conflicts, suppressing warnings of: Expect Decl. * context-dependent precedence: Contextual Precedence. * context-free grammar: Language and Grammar. * controlling function: Rpcalc Main. * dangling else: Shift/Reduce. * data type of locations: Location Type. * data types in actions: Action Types. * data types of semantic values: Value Type. * debugging: Debugging. * declaration summary: Decl Summary. * declarations, Bison: Declarations. * declarations, Bison (introduction): Bison Declarations. * declarations, C: C Declarations. * declaring literal string tokens: Token Decl. * declaring operator precedence: Precedence Decl. * declaring the start symbol: Start Decl. * declaring token type names: Token Decl. * declaring value types: Union Decl. * declaring value types, nonterminals: Type Decl. * default action: Actions. * default data type: Value Type. * default location type: Location Type. * default stack limit: Stack Overflow. * default start symbol: Start Decl. * defining language semantics: Semantics. * else, dangling: Shift/Reduce. * environment variables: Environment Variables. * error: Error Recovery. * error recovery: Error Recovery. * error recovery, simple: Simple Error Recovery. * error reporting function: Error Reporting. * error reporting routine: Rpcalc Error. * examples, simple: Examples. * exercises: Exercises. * FDL, GNU Free Documentation License: GNU Free Documentation License. * file format: Grammar Layout. * finite-state machine: Parser States. * formal grammar: Grammar in Bison. * format of grammar file: Grammar Layout. * glossary: Glossary. * grammar file: Grammar Layout. * grammar rule syntax: Rules. * grammar rules section: Grammar Rules. * grammar, Bison: Grammar in Bison. * grammar, context-free: Language and Grammar. * grouping, syntactic: Language and Grammar. * infix notation calculator: Infix Calc. * interface: Interface. * introduction: Introduction. * invoking Bison: Invocation. * invoking Bison under VMS: VMS Invocation. * LALR(1): Mystery Conflicts. * language semantics, defining: Semantics. * layout of Bison grammar: Grammar Layout. * left recursion: Recursion. * lexical analyzer: Lexical. * lexical analyzer, purpose: Bison Parser. * lexical analyzer, writing: Rpcalc Lexer. * lexical tie-in: Lexical Tie-ins. * literal string token: Symbols. * literal token: Symbols. * location <1>: Locations. * location: Locations Overview. * location actions: Actions and Locations. * look-ahead token: Look-Ahead. * LR(1): Mystery Conflicts. * main function in simple example: Rpcalc Main. * mfcalc: Multi-function Calc. * mid-rule actions: Mid-Rule Actions. * multi-function calculator: Multi-function Calc. * multicharacter literal: Symbols. * mutual recursion: Recursion. * nonterminal symbol: Symbols. * operator precedence: Precedence. * operator precedence, declaring: Precedence Decl. * options for invoking Bison: Invocation. * overflow of parser stack: Stack Overflow. * parse error: Error Reporting. * parser: Bison Parser. * parser stack: Algorithm. * parser stack overflow: Stack Overflow. * parser state: Parser States. * polish notation calculator: RPN Calc. * position, textual <1>: Locations. * position, textual: Locations Overview. * precedence declarations: Precedence Decl. * precedence of operators: Precedence. * precedence, context-dependent: Contextual Precedence. * precedence, unary operator: Contextual Precedence. * preventing warnings about conflicts: Expect Decl. * pure parser: Pure Decl. * recovery from errors: Error Recovery. * recursive rule: Recursion. * reduce/reduce conflict: Reduce/Reduce. * reduction: Algorithm. * reentrant parser: Pure Decl. * reverse polish notation: RPN Calc. * right recursion: Recursion. * rpcalc: RPN Calc. * rule syntax: Rules. * rules section for grammar: Grammar Rules. * running Bison (introduction): Rpcalc Gen. * semantic actions: Semantic Actions. * semantic value: Semantic Values. * semantic value type: Value Type. * shift/reduce conflicts: Shift/Reduce. * shifting: Algorithm. * simple examples: Examples. * single-character literal: Symbols. * stack overflow: Stack Overflow. * stack, parser: Algorithm. * stages in using Bison: Stages. * start symbol: Language and Grammar. * start symbol, declaring: Start Decl. * state (of parser): Parser States. * string token: Symbols. * summary, action features: Action Features. * summary, Bison declaration: Decl Summary. * suppressing conflict warnings: Expect Decl. * symbol: Symbols. * symbol table example: Mfcalc Symtab. * symbols (abstract): Language and Grammar. * symbols in Bison, table of: Table of Symbols. * syntactic grouping: Language and Grammar. * syntax error: Error Reporting. * syntax of grammar rules: Rules. * terminal symbol: Symbols. * textual position <1>: Locations. * textual position: Locations Overview. * token: Language and Grammar. * token type: Symbols. * token type names, declaring: Token Decl. * tracing the parser: Debugging. * unary operator precedence: Contextual Precedence. * using Bison: Stages. * value type, semantic: Value Type. * value types, declaring: Union Decl. * value types, nonterminals, declaring: Type Decl. * value, semantic: Semantic Values. * VMS: VMS Invocation. * warnings, preventing: Expect Decl. * writing a lexical analyzer: Rpcalc Lexer. * YYABORT: Parser Function. * YYACCEPT: Parser Function. * YYBACKUP: Action Features. * yychar: Look-Ahead. * yyclearin: Error Recovery. * yydebug: Debugging. * YYDEBUG: Debugging. * YYEMPTY: Action Features. * yyerrok: Error Recovery. * YYERROR: Action Features. * yyerror: Error Reporting. * YYERROR_VERBOSE: Error Reporting. * YYINITDEPTH: Stack Overflow. * yylex: Lexical. * YYLEX_PARAM: Pure Calling. * yylloc: Token Positions. * YYLLOC_DEFAULT: Location Default Action. * YYLTYPE: Token Positions. * yylval: Token Values. * YYMAXDEPTH: Stack Overflow. * yynerrs: Error Reporting. * yyparse: Parser Function. * YYPARSE_PARAM: Pure Calling. * YYPRINT: Debugging. * YYRECOVERING: Error Recovery. * |: Rules.