it does addition

1 files changed, 64 insertions, 0 deletions

diff --git a/expr.y b/expr.y
new file mode 100644
index 0000000..950a772
--- /dev/null
+++ b/expr.y
@@ -0,0 +1,64 @@
+%{
+#include <stdio.h>
+
+#include "expr.h"
+
+extern int yylex(void);
+extern int yyerror(const char *s);
+
+static void breakpoint(void) { }
+%}
+
+%token INTEGER
+%token STRING
+%token '(' ')'
+%left MATCH MULTIPLICATION 
+%left '+' '-'
+%left COMPARISON AND OR
+
+%start expr
+
+%%
+
+expr	: STRING {
+		printf("string\n");
+	}
+
+	| INTEGER {
+		printf("integer %d\n", $1.u.i);
+	}
+	
+	| '(' expr ')' {
+		printf("a parenthesized expression\n");
+	}
+
+	| expr MATCH expr {
+		printf("match two\n");
+	}
+
+	| expr MULTIPLICATION expr {
+		printf("multiplicationish\n");
+	}
+
+	| expr '+' expr {
+		printf("plus\n");
+		$$.u.i = $1.u.i + $3.u.i;
+		printf("%d\n", $$.u.i);
+	}
+
+	| expr '-' expr {
+		printf("minus\n");
+	}
+
+	| expr COMPARISON expr {
+		printf("compare\n");
+	}
+
+	| expr AND expr {
+		printf("and\n");
+	}
+
+	| expr OR expr {
+		printf("or\n");
+	}
+	;