X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/9af3fbce7c5f893ab9cd72b924e154d01f1f9190..5c16c6b13abde53223e256a351401570c2da3b5e:/NEWS diff --git a/NEWS b/NEWS index 64258f23..681a2bde 100644 --- a/NEWS +++ b/NEWS @@ -1,22 +1,83 @@ Bison News ---------- -Changes in version 1.49b: +Changes in version 1.75a, 2002-10-24: + +* Bison can no longer be built by a K&R C compiler; it requires C89 or + later to be built. This change originally took place a few versions + ago, but nobody noticed until we recently asked someone to try + building Bison with a K&R C compiler. + +Changes in version 1.75, 2002-10-14: + +* Bison should now work on 64-bit hosts. + +* Indonesian translation thanks to Tedi Heriyanto. + +* GLR parsers + Fix spurious parse errors. + +* Pure parsers + Some people redefine yyerror to steal yyparse' private variables. + Reenable this trick until an official feature replaces it. + +* Type Clashes + In agreement with POSIX and with other Yaccs, leaving a default + action is valid when $$ is untyped, and $1 typed: + + untyped: ... typed; + + but the converse remains an error: + + typed: ... untyped; + +* Values of mid-rule actions + The following code: + + foo: { ... } { $$ = $1; } ... + + was incorrectly rejected: $1 is defined in the second mid-rule + action, and is equal to the $$ of the first mid-rule action. + +Changes in version 1.50, 2002-10-04: + +* GLR parsing + The declaration + %glr-parser + causes Bison to produce a Generalized LR (GLR) parser, capable of handling + almost any context-free grammar, ambiguous or not. The new declarations + %dprec and %merge on grammar rules allow parse-time resolution of + ambiguities. Contributed by Paul Hilfinger. + + Unfortunately Bison 1.50 does not work properly on 64-bit hosts + like the Alpha, so please stick to 32-bit hosts for now. + +* Output Directory + When not in Yacc compatibility mode, when the output file was not + specified, running `bison foo/bar.y' created `foo/bar.c'. It + now creates `bar.c'. * Undefined token The undefined token was systematically mapped to 2 which prevented - the use of 2 from the user. This is no longer the case. + the use of 2 by the user. This is no longer the case. * Unknown token numbers - If yylex returned a code out of range, yyparse could die. This is + If yylex returned an out of range value, yyparse could die. This is no longer the case. * Error token - According to POSIX, the error token should be numbered as 256. + According to POSIX, the error token must be 256. Bison extends this requirement by making it a preference: *if* the user specified that one of her tokens is numbered 256, then error will be mapped onto another number. +* Verbose error messages + They no longer report `..., expecting error or...' for states where + error recovery is possible. + +* End token + Defaults to `$end' instead of `$'. + * Error recovery now conforms to documentation and to POSIX When a Bison-generated parser encounters a syntax error, it now pops the stack until it finds a state that allows shifting the error @@ -29,9 +90,11 @@ Changes in version 1.49b: * Traces Popped tokens and nonterminals are now reported. -* Large grammars - Large grammars are now supported (large token numbers, large grammar - size (= sum of the LHS and RHS lengths), large LALR tables). +* Larger grammars + Larger grammars are now supported (larger token numbers, larger grammar + size (= sum of the LHS and RHS lengths), larger LALR tables). + Formerly, many of these numbers ran afoul of 16-bit limits; + now these limits are 32 bits on most hosts. * Explicit initial rule Bison used to play hacks with the initial rule, which the user does @@ -42,6 +105,13 @@ Changes in version 1.49b: Before, Bison reported the useless rules, but, although not used, included them in the parsers. They are now actually removed. +* Useless rules, useless nonterminals + They are now reported, as a warning, with their locations. + +* Rules never reduced + Rules that can never be reduced because of conflicts are now + reported. + * Incorrect `Token not used' On a grammar such as @@ -64,7 +134,7 @@ Changes in version 1.49b: * Token end-of-file The token end of file may be specified by the user, in which case, the user symbol is used in the reports, the graphs, and the verbose - error messages instead of `$', which remains being the defaults. + error messages instead of `$end', which remains being the default. For instance %token YYEOF 0 or @@ -73,16 +143,17 @@ Changes in version 1.49b: * Semantic parser This old option, which has been broken for ages, is removed. -* New translation +* New translations + Brazilian Portuguese, thanks to Alexandre Folle de Menezes. Croatian, thanks to Denis Lackovic. * Incorrect token definitions - When fed with `%token 'a' "A"', Bison used to output `#define 'a' 65'. + When given `%token 'a' "A"', Bison used to output `#define 'a' 65'. * Token definitions as enums Tokens are output both as the traditional #define's, and, provided the compiler supports ANSI C or is a C++ compiler, as enums. - This helps debuggers producing symbols instead of values. + This lets debuggers display names instead of integers. * Reports In addition to --verbose, bison supports --report=THINGS, which @@ -105,6 +176,8 @@ Changes in version 1.49b: bar: '0' {} '0'; This is fixed. + +* GNU M4 is now required when using Bison. Changes in version 1.35, 2002-03-25: @@ -120,7 +193,6 @@ Changes in version 1.35, 2002-03-25: This kludge also addresses some C++ problems when the stack was extended. - Changes in version 1.34, 2002-03-12: