From 2c0f97066e7de981ff5a43ff5912fcadaab75b59 Mon Sep 17 00:00:00 2001 From: Akim Demaille Date: Thu, 15 Mar 2012 15:36:20 +0100 Subject: [PATCH] doc: style changes. * doc/bison.texinfo: Avoid line width issues with TeX. Upgrade ancient messages. Move some comments to better looking places. Add more @group. (Mfcalc Symbol Table): Reduce variable scopes. Prefer size_t for sizes. Prefer declarations with an initial value. Fix a @group environment. (cherry picked from commit aaaa2aaef40eed197ebbd0bd45d8a66606cdb19c) Conflicts: doc/bison.texinfo --- doc/bison.texinfo | 79 ++++++++++++++++++++++++++++------------------- 1 file changed, 47 insertions(+), 32 deletions(-) diff --git a/doc/bison.texinfo b/doc/bison.texinfo index 1902e432..aa82db97 100644 --- a/doc/bison.texinfo +++ b/doc/bison.texinfo @@ -1199,8 +1199,9 @@ will suffice. Otherwise, we suggest @example %@{ - #if __STDC_VERSION__ < 199901 && ! defined __GNUC__ && ! defined inline - #define inline + #if (__STDC_VERSION__ < 199901 && ! defined __GNUC__ \ + && ! defined inline) + # define inline #endif %@} @end example @@ -1389,11 +1390,11 @@ simple program, all the rest of the program can go here. @cindex simple examples @cindex examples, simple -Now we show and explain three sample programs written using Bison: a +Now we show and explain several sample programs written using Bison: a reverse polish notation calculator, an algebraic (infix) notation -calculator, and a multi-function calculator. All three have been tested -under BSD Unix 4.3; each produces a usable, though limited, interactive -desk-top calculator. +calculator --- later extended to track ``locations'' --- +and a multi-function calculator. All +produce usable, though limited, interactive desk-top calculators. These examples are simple, but Bison grammars for real programming languages are written the same way. You can copy these examples into a @@ -1492,24 +1493,28 @@ type for numeric constants. Here are the grammar rules for the reverse polish notation calculator. @example +@group input: /* empty */ | input line ; +@end group +@group line: '\n' | exp '\n' @{ printf ("\t%.10g\n", $1); @} ; +@end group +@group exp: NUM @{ $$ = $1; @} | exp exp '+' @{ $$ = $1 + $2; @} | exp exp '-' @{ $$ = $1 - $2; @} | exp exp '*' @{ $$ = $1 * $2; @} | exp exp '/' @{ $$ = $1 / $2; @} - /* Exponentiation */ - | exp exp '^' @{ $$ = pow ($1, $2); @} - /* Unary minus */ - | exp 'n' @{ $$ = -$1; @} + | exp exp '^' @{ $$ = pow ($1, $2); @} /* Exponentiation */ + | exp 'n' @{ $$ = -$1; @} /* Unary minus */ ; +@end group %% @end example @@ -1765,7 +1770,9 @@ here is the definition we will use: @example @group #include +@end group +@group /* Called by yyparse on error. */ void yyerror (char const *s) @@ -1871,6 +1878,7 @@ parentheses nested to arbitrary depth. Here is the Bison code for @example /* Infix notation calculator. */ +@group %@{ #define YYSTYPE double #include @@ -1878,32 +1886,41 @@ parentheses nested to arbitrary depth. Here is the Bison code for int yylex (void); void yyerror (char const *); %@} +@end group +@group /* Bison declarations. */ %token NUM %left '-' '+' %left '*' '/' %left NEG /* negation--unary minus */ %right '^' /* exponentiation */ +@end group %% /* The grammar follows. */ +@group input: /* empty */ | input line ; +@end group +@group line: '\n' | exp '\n' @{ printf ("\t%.10g\n", $1); @} ; +@end group -exp: NUM @{ $$ = $1; @} - | exp '+' exp @{ $$ = $1 + $3; @} - | exp '-' exp @{ $$ = $1 - $3; @} - | exp '*' exp @{ $$ = $1 * $3; @} - | exp '/' exp @{ $$ = $1 / $3; @} - | '-' exp %prec NEG @{ $$ = -$2; @} +@group +exp: NUM @{ $$ = $1; @} + | exp '+' exp @{ $$ = $1 + $3; @} + | exp '-' exp @{ $$ = $1 - $3; @} + | exp '*' exp @{ $$ = $1 * $3; @} + | exp '/' exp @{ $$ = $1 / $3; @} + | '-' exp %prec NEG @{ $$ = -$2; @} | exp '^' exp @{ $$ = pow ($1, $3); @} - | '(' exp ')' @{ $$ = $2; @} + | '(' exp ')' @{ $$ = $2; @} ; +@end group %% @end example @@ -2439,10 +2456,9 @@ void init_table (void) @{ int i; - symrec *ptr; for (i = 0; arith_fncts[i].fname != 0; i++) @{ - ptr = putsym (arith_fncts[i].fname, FNCT); + symrec *ptr = putsym (arith_fncts[i].fname, FNCT); ptr->value.fnctptr = arith_fncts[i].fnct; @} @} @@ -2476,8 +2492,7 @@ found, a pointer to that symbol is returned; otherwise zero is returned. symrec * putsym (char const *sym_name, int sym_type) @{ - symrec *ptr; - ptr = (symrec *) malloc (sizeof (symrec)); + symrec *ptr = (symrec *) malloc (sizeof (symrec)); ptr->name = (char *) malloc (strlen (sym_name) + 1); strcpy (ptr->name,sym_name); ptr->type = sym_type; @@ -2550,21 +2565,20 @@ yylex (void) /* Char starts an identifier => read the name. */ if (isalpha (c)) @{ - symrec *s; + /* Initially make the buffer long enough + for a 40-character symbol name. */ + static size_t length = 40; static char *symbuf = 0; - static int length = 0; + symrec *s; int i; @end group @group - /* Initially make the buffer long enough - for a 40-character symbol name. */ - if (length == 0) - length = 40, symbuf = (char *)malloc (length + 1); + if (!symbuf) + symbuf = (char *) malloc (length + 1); i = 0; do -@end group @group @{ /* If buffer is full, make it bigger. */ @@ -4027,6 +4041,7 @@ By default, @code{YYLLOC_DEFAULT} is defined this way: @end group @end smallexample +@noindent where @code{YYRHSLOC (rhs, k)} is the location of the @var{k}th symbol in @var{rhs} when @var{k} is positive, and the location of the symbol just before the reduction when @var{k} and @var{n} are both zero. @@ -8906,9 +8921,9 @@ The types for semantics value and locations. @end defcv @defcv {Type} {parser} {token} -A structure that contains (only) the definition of the tokens as the -@code{yytokentype} enumeration. To refer to the token @code{FOO}, the -scanner should use @code{yy::parser::token::FOO}. The scanner can use +A structure that contains (only) the @code{yytokentype} enumeration, which +defines the tokens. To refer to the token @code{FOO}, +use @code{yy::parser::token::FOO}. The scanner can use @samp{typedef yy::parser::token token;} to ``import'' the token enumeration (@pxref{Calc++ Scanner}). @end defcv @@ -9430,7 +9445,7 @@ calcxx_driver::scan_begin () yyin = stdin; else if (!(yyin = fopen (file.c_str (), "r"))) @{ - error (std::string ("cannot open ") + file + ": " + strerror(errno)); + error ("cannot open " + file + ": " + strerror(errno)); exit (EXIT_FAILURE); @} @} -- 2.45.2