1 files changed, 112 insertions, 0 deletions

diff --git a/12/main.y b/12/main.y
new file mode 100644
index 0000000..5431c55
--- /dev/null
+++ b/12/main.y
@@ -0,0 +1,112 @@
+%{
+#include <stdio.h>
+#include <stdlib.h>
+int yylex();
+int yyerror(char *);
+%}
+
+%token ADD SUB MUL DIV INC DEC
+%token LT GT LTE GTE EQ NEQ ASSIGN
+%token VOID INT DOUBLE FLOAT CHAR
+%token LONG UNSIGNED
+%token COMMA LPAREN RPAREN LBRACE RBRACE
+%token ENDL
+%token FOR RET IF ELSE WHILE
+%token NUM ID
+
+%start function_definition
+
+%%
+type_modifier: LONG
+             | UNSIGNED
+             ;
+
+type_specifier: VOID
+              | CHAR
+              | INT
+              | FLOAT
+              | DOUBLE
+              | type_modifier type_specifier
+              ;
+
+argument: type_specifier ID
+        ;
+
+argument_list: argument
+             | argument COMMA argument_list
+             ;
+
+primary_expr: NUM
+            | ID
+            ;
+
+postfix_expr: postfix_expr INC
+            | postfix_expr DEC
+            | primary_expr
+            ;
+
+unary_expr: INC unary_expr
+          | DEC unary_expr
+          | postfix_expr
+          ;
+
+boolean_expr: unary_expr LT unary_expr
+            | unary_expr GT unary_expr
+            | unary_expr LTE unary_expr
+            | unary_expr GTE unary_expr
+            | unary_expr EQ unary_expr
+            | unary_expr NEQ unary_expr
+            ;
+
+assignment_expr: unary_expr ASSIGN unary_expr
+               | unary_expr ASSIGN boolean_expr
+               ;
+
+expression: unary_expr
+          | boolean_expr
+          | assignment_expr
+          ;
+
+for_expr: FOR LPAREN statement statement expression RPAREN statement
+        | FOR LPAREN statement statement RPAREN statement
+        ;
+
+while_expr: WHILE LPAREN expression RPAREN block
+          | WHILE LPAREN RPAREN block
+          ;
+
+if_expr: IF LPAREN expression RPAREN block
+       | IF LPAREN expression RPAREN block ELSE block
+       | IF LPAREN expression RPAREN block ELSE if_expr
+       ;
+
+block: LBRACE statement block_cont
+     ;
+
+block_cont: statement block_cont
+          | RBRACE
+          ;
+
+statement: RET expression ENDL
+         | expression ENDL
+         | block
+         | for_expr
+         | if_expr
+         | while_expr
+         | ENDL
+         ;
+
+function_definition: argument LPAREN argument_list RPAREN block
+                   | argument LPAREN RPAREN block
+                   ;
+%%
+
+int main() {
+    yyparse();
+    printf("valid expression");
+}
+
+int yyerror(char *s) {
+    printf("error: %s", s);
+    exit(0);
+}