1 files changed, 84 insertions, 0 deletions
diff --git a/usr.bin/m4/parser.y b/usr.bin/m4/parser.y
new file mode 100644
index 0000000..fedded1
--- /dev/null
+++ b/usr.bin/m4/parser.y
@@ -0,0 +1,84 @@
+%{
+/* $OpenBSD: parser.y,v 1.7 2012/04/12 17:00:11 espie Exp $ */
+/*
+ * Copyright (c) 2004 Marc Espie <espie@cvs.openbsd.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <math.h>
+#include <stdint.h>
+#include <stdlib.h>
+#define YYSTYPE	int32_t
+extern int32_t end_result;
+extern int yylex(void);
+extern int yyerror(const char *);
+%}
+%token NUMBER
+%token ERROR
+%left LOR
+%left LAND
+%left '|'
+%left '^'
+%left '&'
+%left EQ NE
+%left '<' LE '>' GE
+%left LSHIFT RSHIFT
+%left '+' '-'
+%left '*' '/' '%'
+%right EXPONENT
+%right UMINUS UPLUS '!' '~'
+
+%%
+
+top	: expr { end_result = $1; }
+	;
+expr 	: expr '+' expr { $$ = $1 + $3; }
+     	| expr '-' expr { $$ = $1 - $3; }
+	| expr EXPONENT expr { $$ = pow($1, $3); }
+     	| expr '*' expr { $$ = $1 * $3; }
+	| expr '/' expr {
+		if ($3 == 0) {
+			yyerror("division by zero");
+			exit(1);
+		}
+		$$ = $1 / $3;
+	}
+	| expr '%' expr { 
+		if ($3 == 0) {
+			yyerror("modulo zero");
+			exit(1);
+		}
+		$$ = $1 % $3;
+	}
+	| expr LSHIFT expr { $$ = $1 << $3; }
+	| expr RSHIFT expr { $$ = $1 >> $3; }
+	| expr '<' expr { $$ = $1 < $3; }
+	| expr '>' expr { $$ = $1 > $3; }
+	| expr LE expr { $$ = $1 <= $3; }
+	| expr GE expr { $$ = $1 >= $3; }
+	| expr EQ expr { $$ = $1 == $3; }
+	| expr NE expr { $$ = $1 != $3; }
+	| expr '&' expr { $$ = $1 & $3; }
+	| expr '^' expr { $$ = $1 ^ $3; }
+	| expr '|' expr { $$ = $1 | $3; }
+	| expr LAND expr { $$ = $1 && $3; }
+	| expr LOR expr { $$ = $1 || $3; }
+	| '(' expr ')' { $$ = $2; }
+	| '-' expr %prec UMINUS { $$ = -$2; }
+	| '+' expr %prec UPLUS  { $$ = $2; }
+	| '!' expr { $$ = !$2; }
+	| '~' expr { $$ = ~$2; }
+	| NUMBER
+	;
+%%
+