Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/* Simple expression parser */
2%{
3#define YYDEBUG 1
4#include <stdio.h>
5#include "util.h"
6#include "util/debug.h"
7#include <stdlib.h> // strtod()
8#define IN_EXPR_Y 1
9#include "expr.h"
10#include "smt.h"
11#include <string.h>
12
13%}
14
15%define api.pure full
16
17%parse-param { double *final_val }
18%parse-param { struct parse_ctx *ctx }
19%parse-param {void *scanner}
20%lex-param {void* scanner}
21
22%union {
23 double num;
24 char *str;
25}
26
27%token EXPR_PARSE EXPR_OTHER EXPR_ERROR
28%token <num> NUMBER
29%token <str> ID
30%token MIN MAX IF ELSE SMT_ON
31%left MIN MAX IF
32%left '|'
33%left '^'
34%left '&'
35%left '-' '+'
36%left '*' '/' '%'
37%left NEG NOT
38%type <num> expr if_expr
39
40%{
41static void expr_error(double *final_val __maybe_unused,
42 struct parse_ctx *ctx __maybe_unused,
43 void *scanner,
44 const char *s)
45{
46 pr_debug("%s\n", s);
47}
48
49static int lookup_id(struct parse_ctx *ctx, char *id, double *val)
50{
51 int i;
52
53 for (i = 0; i < ctx->num_ids; i++) {
54 if (!strcasecmp(ctx->ids[i].name, id)) {
55 *val = ctx->ids[i].val;
56 return 0;
57 }
58 }
59 return -1;
60}
61
62%}
63%%
64
65start:
66EXPR_PARSE all_expr
67|
68EXPR_OTHER all_other
69
70all_other: all_other other
71|
72
73other: ID
74{
75 if (ctx->num_ids + 1 >= EXPR_MAX_OTHER) {
76 pr_err("failed: way too many variables");
77 YYABORT;
78 }
79
80 ctx->ids[ctx->num_ids++].name = $1;
81}
82|
83MIN | MAX | IF | ELSE | SMT_ON | NUMBER | '|' | '^' | '&' | '-' | '+' | '*' | '/' | '%' | '(' | ')'
84
85
86all_expr: if_expr { *final_val = $1; }
87 ;
88
89if_expr:
90 expr IF expr ELSE expr { $$ = $3 ? $1 : $5; }
91 | expr
92 ;
93
94expr: NUMBER
95 | ID { if (lookup_id(ctx, $1, &$$) < 0) {
96 pr_debug("%s not found\n", $1);
97 YYABORT;
98 }
99 }
100 | expr '|' expr { $$ = (long)$1 | (long)$3; }
101 | expr '&' expr { $$ = (long)$1 & (long)$3; }
102 | expr '^' expr { $$ = (long)$1 ^ (long)$3; }
103 | expr '+' expr { $$ = $1 + $3; }
104 | expr '-' expr { $$ = $1 - $3; }
105 | expr '*' expr { $$ = $1 * $3; }
106 | expr '/' expr { if ($3 == 0) YYABORT; $$ = $1 / $3; }
107 | expr '%' expr { if ((long)$3 == 0) YYABORT; $$ = (long)$1 % (long)$3; }
108 | '-' expr %prec NEG { $$ = -$2; }
109 | '(' if_expr ')' { $$ = $2; }
110 | MIN '(' expr ',' expr ')' { $$ = $3 < $5 ? $3 : $5; }
111 | MAX '(' expr ',' expr ')' { $$ = $3 > $5 ? $3 : $5; }
112 | SMT_ON { $$ = smt_on() > 0; }
113 ;
114
115%%