X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/3a414bbfa049a2f6e0f497a230bd86fe96a87884..348f56088399476429207812ded8d164c714f2f3:/NEWS diff --git a/NEWS b/NEWS index 3dab543c..b2727cfa 100644 --- a/NEWS +++ b/NEWS @@ -3,6 +3,31 @@ Bison News * Changes in version 2.5 (????-??-??): +** Named References Support + + Historically, Yacc and Bison have supported positional references + ($n, $$) to allow access to symbol values from inside of semantic + actions code. + + Starting from this version, Bison can also accept named references. + When no ambiguity is possible, original symbol names may be used + as named references: + + if_stmt : 'if' cond_expr 'then' then_stmt ';' + { $if_stmt = mk_if_stmt($cond_expr, $then_stmt); } + + In the more common case, explicit names may be declared: + + stmt[res] : 'if' expr[cond] 'then' stmt[then] 'else' stmt[else] ';' + { $res = mk_if_stmt($cond, $then, $else); } + + Location information is also accessible using @name syntax. When + accessing symbol names containing dots or dashes, explicit bracketing + ($[sym.1]) must be used. + + These features are experimental in this version. More user feedback + will help to stabilize them. + ** IELR(1) and Canonical LR(1) Support IELR(1) is a minimal LR(1) parser table generation algorithm. That @@ -20,9 +45,9 @@ Bison News default. You can specify the type of parser tables in the grammar file with these directives: - %define lr.type "lalr" - %define lr.type "ielr" - %define lr.type "canonical-lr" + %define lr.type lalr + %define lr.type ielr + %define lr.type canonical-lr The default reduction optimization in the parser tables can also be adjusted using `%define lr.default-reductions'. See the documentation @@ -33,9 +58,15 @@ Bison News These features are experimental. More user feedback will help to stabilize them. -** Multiple %define's for any variable is now an error not a warning. +** Unrecognized %code qualifiers are now an error not a warning. + +** %define improvements. -** %define can now be invoked via the command line. +*** Unrecognized variables are now an error not a warning. + +*** Multiple invocations for any variable is now an error not a warning. + +*** Can now be invoked via the command line. Each of these command-line options @@ -54,7 +85,7 @@ Bison News quietly override %define, but -D and --define do not. For further details, see the section "Bison Options" in the Bison manual. -** %define variables renamed. +*** Variables renamed. The following %define variables @@ -69,7 +100,18 @@ Bison News The old names are now deprecated but will be maintained indefinitely for backward compatibility. -** Symbols names +*** Values no longer need to be quoted in grammar file. + + If a %define value is an identifier, it no longer needs to be placed + within quotations marks. For example, + + %define api.push-pull "push" + + can be rewritten as + + %define api.push-pull push + +** Symbol names. Consistently with directives (such as %error-verbose) and variables (e.g. push-pull), symbol names may include dashes in any position, @@ -147,6 +189,12 @@ Bison News Bison's Java feature as a whole including its current usage of %code is still considered experimental. +** Internationalization. + + Fix a regression introduced in Bison 2.4: Under some circumstances, + message translations were not installed although supported by the + host system. + * Changes in version 2.4.1 (2008-12-11): ** In the GLR defines file, unexpanded M4 macros in the yylval and yylloc