From 9edcd89542cbc475e2e17606166ca7e0d541917a Mon Sep 17 00:00:00 2001 From: Akim Demaille Date: Mon, 12 Nov 2001 09:36:31 +0000 Subject: [PATCH] * doc/bison.texinfo: Use `$' as shell prompt, not `%'. Use @kbd to denote user input. (Language and Grammar): ANSIfy the example. Adjust its layout for info/notinfo. (Location Tracking Calc): Output error messages to stderr. Output locations in a more GNUtically correct way. Fix a couple of Englishos. Adjust @group/@end group pairs. --- ChangeLog | 11 ++++ configure.in | 4 +- doc/bison.texinfo | 165 ++++++++++++++++++++++++---------------------- 3 files changed, 101 insertions(+), 79 deletions(-) diff --git a/ChangeLog b/ChangeLog index 2ecb707e..d0f701f6 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,14 @@ +2001-11-12 Akim Demaille + + * doc/bison.texinfo: Use `$' as shell prompt, not `%'. + Use @kbd to denote user input. + (Language and Grammar): ANSIfy the example. + Adjust its layout for info/notinfo. + (Location Tracking Calc): Output error messages to stderr. + Output locations in a more GNUtically correct way. + Fix a couple of Englishos. + Adjust @group/@end group pairs. + 2001-11-12 Akim Demaille %expext was not functioning at all. diff --git a/configure.in b/configure.in index 19070af9..c23fe691 100644 --- a/configure.in +++ b/configure.in @@ -99,8 +99,8 @@ AM_GNU_GETTEXT(, need-ngettext) # This is necessary so that .o files in LIBOBJS are also built via # the ANSI2KNR-filtering rules. -LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'` -AC_SUBST(LIBOBJS) +LIB@&t@OBJS=`echo $LIB@&t@OBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'` +AC_SUBST(LIB@&t@OBJS) AC_OUTPUT([Makefile config/Makefile diff --git a/doc/bison.texinfo b/doc/bison.texinfo index 9f769460..bf0f790b 100644 --- a/doc/bison.texinfo +++ b/doc/bison.texinfo @@ -447,16 +447,26 @@ lexicography, not grammar.) Here is a simple C function subdivided into tokens: +@ifinfo @example int /* @r{keyword `int'} */ -square (x) /* @r{identifier, open-paren,} */ - /* @r{identifier, close-paren} */ - int x; /* @r{keyword `int', identifier, semicolon} */ +square (int x) /* @r{identifier, open-paren, identifier,} + @r{identifier, close-paren} */ @{ /* @r{open-brace} */ - return x * x; /* @r{keyword `return', identifier,} */ - /* @r{asterisk, identifier, semicolon} */ + return x * x; /* @r{keyword `return', identifier, asterisk, + identifier, semicolon} */ @} /* @r{close-brace} */ @end example +@end ifinfo +@ifnotinfo +@example +int /* @r{keyword `int'} */ +square (int x) /* @r{identifier, open-paren, identifier, identifier, close-paren} */ +@{ /* @r{open-brace} */ + return x * x; /* @r{keyword `return', identifier, asterisk, identifier, semicolon} */ +@} /* @r{close-brace} */ +@end example +@end ifnotinfo The syntactic groupings of C include the expression, the statement, the declaration, and the function definition. These are represented in the @@ -1204,19 +1214,19 @@ Here is how to compile and run the parser file: @example @group # @r{List files in current directory.} -% ls +$ @kbd{ls} rpcalc.tab.c rpcalc.y @end group @group # @r{Compile the Bison parser.} # @r{@samp{-lm} tells compiler to search math library for @code{pow}.} -% cc rpcalc.tab.c -lm -o rpcalc +$ @kbd{cc rpcalc.tab.c -lm -o rpcalc} @end group @group # @r{List files again.} -% ls +$ @kbd{ls} rpcalc rpcalc.tab.c rpcalc.y @end group @end example @@ -1225,19 +1235,19 @@ The file @file{rpcalc} now contains the executable code. Here is an example session using @code{rpcalc}. @example -% rpcalc -4 9 + +$ @kbd{rpcalc} +@kbd{4 9 +} 13 -3 7 + 3 4 5 *+- +@kbd{3 7 + 3 4 5 *+-} -13 -3 7 + 3 4 5 * + - n @r{Note the unary minus, @samp{n}} +@kbd{3 7 + 3 4 5 * + - n} @r{Note the unary minus, @samp{n}} 13 -5 6 / 4 n + +@kbd{5 6 / 4 n +} -3.166666667 -3 4 ^ @r{Exponentiation} +@kbd{3 4 ^} @r{Exponentiation} 81 -^D @r{End-of-file indicator} -% +@kbd{^D} @r{End-of-file indicator} +$ @end example @node Infix Calc @@ -1317,12 +1327,12 @@ Here is a sample run of @file{calc.y}: @need 500 @example -% calc -4 + 4.5 - (34/(8*3+-3)) +$ @kbd{calc} +@kbd{4 + 4.5 - (34/(8*3+-3))} 6.880952381 --56 + 2 +@kbd{-56 + 2} -54 -3 ^ 2 +@kbd{3 ^ 2} 9 @end example @@ -1374,13 +1384,11 @@ Bison programs. @cindex @code{ltcalc} @cindex calculator, location tracking -This example extends the infix notation calculator with location tracking. -This feature will be used to improve error reporting, and provide better -error messages. - -For the sake of clarity, we will switch for this example to an integer -calculator, since most of the work needed to use locations will be done -in the lexical analyser. +This example extends the infix notation calculator with location +tracking. This feature will be used to improve the error messages. For +the sake of clarity, this example is a simple integer calculator, since +most of the work needed to use locations will be done in the lexical +analyser. @menu * Decls: Ltcalc Decls. Bison and C declarations for ltcalc. @@ -1391,8 +1399,8 @@ in the lexical analyser. @node Ltcalc Decls @subsection Declarations for @code{ltcalc} -The C and Bison declarations for the location tracking calculator are the same -as the declarations for the infix notation calculator. +The C and Bison declarations for the location tracking calculator are +the same as the declarations for the infix notation calculator. @example /* Location tracking calculator. */ @@ -1413,22 +1421,24 @@ as the declarations for the infix notation calculator. %% /* Grammar follows */ @end example -In the code above, there are no declarations specific to locations. Defining -a data type for storing locations is not needed: we will use the type provided -by default (@pxref{Location Type, ,Data Types of Locations}), which is a four -member structure with the following integer fields: @code{first_line}, -@code{first_column}, @code{last_line} and @code{last_column}. +@noindent +Note there are no declarations specific to locations. Defining a data +type for storing locations is not needed: we will use the type provided +by default (@pxref{Location Type, ,Data Types of Locations}), which is a +four member structure with the following integer fields: +@code{first_line}, @code{first_column}, @code{last_line} and +@code{last_column}. @node Ltcalc Rules @subsection Grammar Rules for @code{ltcalc} -Whether you choose to handle locations or not has no effect on the syntax of -your language. Therefore, grammar rules for this example will be very close to -those of the previous example: we will only modify them to benefit from the new -informations we will have. +Whether handling locations or not has no effect on the syntax of your +language. Therefore, grammar rules for this example will be very close +to those of the previous example: we will only modify them to benefit +from the new information. -Here, we will use locations to report divisions by zero, and locate the wrong -expressions or subexpressions. +Here, we will use locations to report divisions by zero, and locate the +wrong expressions or subexpressions. @example @group @@ -1449,17 +1459,17 @@ exp : NUM @{ $$ = $1; @} | exp '-' exp @{ $$ = $1 - $3; @} | exp '*' exp @{ $$ = $1 * $3; @} @end group - | exp '/' exp @group + | exp '/' exp @{ if ($3) $$ = $1 / $3; else @{ $$ = 1; - printf("Division by zero, l%d,c%d-l%d,c%d", - @@3.first_line, @@3.first_column, - @@3.last_line, @@3.last_column); + fprintf (stderr, "%d.%d-%d.%d: division by zero", + @@3.first_line, @@3.first_column, + @@3.last_line, @@3.last_column); @} @} @end group @@ -1474,25 +1484,24 @@ This code shows how to reach locations inside of semantic actions, by using the pseudo-variables @code{@@@var{n}} for rule components, and the pseudo-variable @code{@@$} for groupings. -In this example, we never assign a value to @code{@@$}, because the -output parser can do this automatically. By default, before executing -the C code of each action, @code{@@$} is set to range from the beginning -of @code{@@1} to the end of @code{@@@var{n}}, for a rule with @var{n} -components. - -Of course, this behavior can be redefined (@pxref{Location Default -Action, , Default Action for Locations}), and for very specific rules, -@code{@@$} can be computed by hand. +We don't need to assign a value to @code{@@$}: the output parser does it +automatically. By default, before executing the C code of each action, +@code{@@$} is set to range from the beginning of @code{@@1} to the end +of @code{@@@var{n}}, for a rule with @var{n} components. This behavior +can be redefined (@pxref{Location Default Action, , Default Action for +Locations}), and for very specific rules, @code{@@$} can be computed by +hand. @node Ltcalc Lexer @subsection The @code{ltcalc} Lexical Analyzer. -Until now, we relied on Bison's defaults to enable location tracking. The next -step is to rewrite the lexical analyser, and make it able to feed the parser -with locations of tokens, as he already does for semantic values. +Until now, we relied on Bison's defaults to enable location +tracking. The next step is to rewrite the lexical analyser, and make it +able to feed the parser with the token locations, as it already does for +semantic values. -To do so, we must take into account every single character of the input text, -to avoid the computed locations of being fuzzy or wrong: +To this end, we must take into account every single character of the +input text, to avoid the computed locations of being fuzzy or wrong: @example @group @@ -1542,17 +1551,18 @@ yylex (void) @} @end example -Basically, the lexical analyzer does the same processing as before: it skips -blanks and tabs, and reads numbers or single-character tokens. In addition -to this, it updates the @code{yylloc} global variable (of type @code{YYLTYPE}), -where the location of tokens is stored. +Basically, the lexical analyzer performs the same processing as before: +it skips blanks and tabs, and reads numbers or single-character tokens. +In addition, it updates @code{yylloc}, the global variable (of type +@code{YYLTYPE}) containing the token's location. -Now, each time this function returns a token, the parser has it's number as -well as it's semantic value, and it's position in the text. The last needed -change is to initialize @code{yylloc}, for example in the controlling -function: +Now, each time this function returns a token, the parser has its number +as well as its semantic value, and its location in the text. The last +needed change is to initialize @code{yylloc}, for example in the +controlling function: @example +@group int main (void) @{ @@ -1560,11 +1570,12 @@ main (void) yylloc.first_column = yylloc.last_column = 0; return yyparse (); @} +@end group @end example -Remember that computing locations is not a matter of syntax. Every character -must be associated to a location update, whether it is in valid input, in -comments, in literal strings, and so on... +Remember that computing locations is not a matter of syntax. Every +character must be associated to a location update, whether it is in +valid input, in comments, in literal strings, and so on. @node Multi-function Calc @section Multi-Function Calculator: @code{mfcalc} @@ -1594,20 +1605,20 @@ to create named variables, store values in them, and use them later. Here is a sample session with the multi-function calculator: @example -% mfcalc -pi = 3.141592653589 +$ @kbd{mfcalc} +@kbd{pi = 3.141592653589} 3.1415926536 -sin(pi) +@kbd{sin(pi)} 0.0000000000 -alpha = beta1 = 2.3 +@kbd{alpha = beta1 = 2.3} 2.3000000000 -alpha +@kbd{alpha} 2.3000000000 -ln(alpha) +@kbd{ln(alpha)} 0.8329091229 -exp(ln(beta1)) +@kbd{exp(ln(beta1))} 2.3000000000 -% +$ @end example Note that multiple assignment and nested function calls are permitted. -- 2.45.2