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ceed8467b7
* src/machine.h: Remove, leaving its contents in... * src/system.h: here. Include stdio.h. Adjust all dependencies on stdio.h and machine.h. * src/getargs.h: New file. Let all `extern' declarations about getargs.c be replaced with inclusion of `getargs.h'. * src/Makefile.am (noinst_HEADERS): Adjust. * tests/calc.m4 (yyin): Be initialized in main, not on the global scope. (yyerror): Returns void, not int. * doc/bison.texinfo: Formatting changes.
174 lines
3.5 KiB
Plaintext
174 lines
3.5 KiB
Plaintext
# -*- Autoconf -*-
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cat <<EOF
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Simple Calculator.
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EOF
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## ---------------------------------------------------- ##
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## Compile the grammar described in the documentation. ##
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## ---------------------------------------------------- ##
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# We use integers to avoid dependencies upon the precision of doubles.
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AT_SETUP(Compiling a grammar)
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AT_DATA([calc.y],
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[[/* Infix notation calculator--calc */
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%{
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#include <stdio.h>
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#include <stdlib.h>
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#include <ctype.h>
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#define YYSTYPE int
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static int power (int base, int exponent);
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static int read_signed_integer (FILE *stream);
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static void yyerror (const char *s);
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extern void perror (const char *s);
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%}
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/* BISON Declarations */
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%token NUM
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%left '-' '+'
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%left '*' '/'
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%left NEG /* negation--unary minus */
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%right '^' /* exponentiation */
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/* Grammar follows */
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%%
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input: /* empty string */
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| input line
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;
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line: '\n'
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| exp '\n' { printf ("%d", $1); }
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;
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exp: NUM { $$ = $1; }
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| exp '+' exp { $$ = $1 + $3; }
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| exp '-' exp { $$ = $1 - $3; }
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| exp '*' exp { $$ = $1 * $3; }
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| exp '/' exp { $$ = $1 / $3; }
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| '-' exp %prec NEG { $$ = -$2; }
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| exp '^' exp { $$ = power ($1, $3); }
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| '(' exp ')' { $$ = $2; }
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;
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%%
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/* The input. */
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FILE *yyin;
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static void
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yyerror (const char *s)
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{
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fprintf (stderr, "%s\n", s);
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}
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static int
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read_signed_integer (FILE *stream)
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{
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int c = getc (stream);
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int sign = 1;
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int n = 0;
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if (c == '-')
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{
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c = getc (stream);
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sign = -1;
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}
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while (isdigit (c))
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{
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n = 10 * n + (c - '0');
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c = getc (stream);
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}
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ungetc (c, stream);
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return sign * n;
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}
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/*---------------------------------------------------------------.
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| Lexical analyzer returns an integer on the stack and the token |
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| NUM, or the ASCII character read if not a number. Skips all |
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| blanks and tabs, returns 0 for EOF. |
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`---------------------------------------------------------------*/
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int
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yylex ()
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{
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int c;
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/* Skip white space. */
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while ((c = getc (yyin)) == ' ' || c == '\t')
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;
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/* process numbers */
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if (c == '.' || isdigit (c))
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{
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ungetc (c, yyin);
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yylval = read_signed_integer (yyin);
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return NUM;
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}
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/* Return end-of-file. */
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if (c == EOF)
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return 0;
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/* Return single chars. */
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return c;
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}
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static int
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power (int base, int exponent)
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{
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int res = 1;
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if (exponent < 0)
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exit (1);
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for (/* Niente */; exponent; --exponent)
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res *= base;
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return res;
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}
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int
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main (int argn, const char **argv)
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{
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if (argn == 2)
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yyin = fopen (argv[1], "r");
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else
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yyin = stdin;
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if (!stdin)
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{
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perror (argv[1]);
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exit (1);
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}
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yyparse ();
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return 0;
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}
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]])
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# Specify the output files to avoid problems on different file systems.
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AT_CHECK([bison calc.y -o calc.c], 0, [], [])
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AT_CHECK([$CC $CFLAGS calc.c -o calc], 0, [], [])
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# AT_CHECK_CALC(INPUT, OUTPUT)
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# ----------------------------
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# Run `calc' on INPUT, and expect OUTPUT.
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AT_DEFINE([AT_CHECK_CALC],
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[AT_CHECK([echo "$1" | calc], 0, [$2], [])])
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# Test the priorities.
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AT_CHECK_CALC([1 + 2 * 3], [7])
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AT_CHECK_CALC([1 + 2 * -3], [-5])
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AT_CHECK_CALC([-1^2], [-1])
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AT_CHECK_CALC([(-1)^2], [1])
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AT_CHECK_CALC([---1], [-1])
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AT_CHECK_CALC([1 - 2 - 3], [-4])
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AT_CHECK_CALC([1 - (2 - 3)], [2])
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AT_CHECK_CALC([2^2^3], [256])
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AT_CHECK_CALC([(2^2)^3], [64])
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AT_CLEANUP(calc calc.c)
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