diff options
Diffstat (limited to 'doc/bison.texinfo')
| -rw-r--r-- | doc/bison.texinfo | 32 |
1 files changed, 19 insertions, 13 deletions
diff --git a/doc/bison.texinfo b/doc/bison.texinfo index 62471f46..0f5dbbb3 100644 --- a/doc/bison.texinfo +++ b/doc/bison.texinfo @@ -163,9 +163,9 @@ Reverse Polish Notation Calculator Grammar Rules for @code{rpcalc} -* Rpcalc Input:: -* Rpcalc Line:: -* Rpcalc Expr:: +* Rpcalc Input:: Explanation of the @code{input} nonterminal +* Rpcalc Line:: Explanation of the @code{line} nonterminal +* Rpcalc Expr:: Explanation of the @code{expr} nonterminal Location Tracking Calculator: @code{ltcalc} @@ -1517,11 +1517,13 @@ The source code for this calculator is named @file{rpcalc.y}. The Here are the C and Bison declarations for the reverse polish notation calculator. As in C, comments are placed between @samp{/*@dots{}*/}. +@comment file: rpcalc.y @example /* Reverse polish notation calculator. */ %@{ #define YYSTYPE double + #include <stdio.h> #include <math.h> int yylex (void); void yyerror (char const *); @@ -1566,13 +1568,14 @@ type for numeric constants. Here are the grammar rules for the reverse polish notation calculator. +@comment file: rpcalc.y @example input: /* empty */ | input line ; line: '\n' - | exp '\n' @{ printf ("\t%.10g\n", $1); @} + | exp '\n' @{ printf ("%.10g\n", $1); @} ; exp: NUM @{ $$ = $1; @} @@ -1607,9 +1610,9 @@ main job of most actions. The semantic values of the components of the rule are referred to as @code{$1}, @code{$2}, and so on. @menu -* Rpcalc Input:: -* Rpcalc Line:: -* Rpcalc Expr:: +* Rpcalc Input:: Explanation of the @code{input} nonterminal +* Rpcalc Line:: Explanation of the @code{line} nonterminal +* Rpcalc Expr:: Explanation of the @code{expr} nonterminal @end menu @node Rpcalc Input @@ -1653,7 +1656,7 @@ Now consider the definition of @code{line}: @example line: '\n' - | exp '\n' @{ printf ("\t%.10g\n", $1); @} + | exp '\n' @{ printf ("%.10g\n", $1); @} ; @end example @@ -1769,6 +1772,7 @@ A token type code of zero is returned if the end-of-input is encountered. Here is the code for the lexical analyzer: +@comment file: rpcalc.y @example @group /* The lexical analyzer returns a double floating point @@ -1817,6 +1821,7 @@ In keeping with the spirit of this example, the controlling function is kept to the bare minimum. The only requirement is that it call @code{yyparse} to start the process of parsing. +@comment file: rpcalc.y @example @group int @@ -1837,6 +1842,7 @@ always @code{"syntax error"}). It is up to the programmer to supply @code{yyerror} (@pxref{Interface, ,Parser C-Language Interface}), so here is the definition we will use: +@comment file: rpcalc.y @example @group #include <stdio.h> @@ -1919,15 +1925,15 @@ example session using @code{rpcalc}. @example $ @kbd{rpcalc} @kbd{4 9 +} -13 +@result{} 13 @kbd{3 7 + 3 4 5 *+-} --13 +@result{} -13 @kbd{3 7 + 3 4 5 * + - n} @r{Note the unary minus, @samp{n}} -13 +@result{} 13 @kbd{5 6 / 4 n +} --3.166666667 +@result{} -3.166666667 @kbd{3 4 ^} @r{Exponentiation} -81 +@result{} 81 @kbd{^D} @r{End-of-file indicator} $ @end example |