fix branching

lab-5/Makefile

@@ -42,5 +42,5 @@ parser.c parser.h: parser.bison
 # clean causes all intermediate files to be deleted.
 
 clean:
-	rm -f parser.c parser.output parser.h scanner.c *.o interpreter.out interpreter_test.out test_evaluate.txt test_print.txt
+	rm -f parser.c parser.output parser.h scanner.c *.o interpreter.out interpreter_test.out test_evaluate.txt test_print.txt parser_test.out scanner_test.out
 

lab-5/expr.c

@@ -191,13 +191,15 @@ void expr_print(struct expr *e) {
     close = "]";
   } else if (e->kind != EXPR_NAME && e->kind != EXPR_SUBSCRIPT &&
              e->kind != EXPR_INTEGER_LITERAL && e->kind != EXPR_FLOAT_LITERAL &&
-             e->kind != EXPR_STRING_LITERAL && e->kind != EXPR_CUSTOM_FUNCTION) {
+             e->kind != EXPR_STRING_LITERAL && e->kind != EXPR_CUSTOM_FUNCTION &&
+             e->kind != EXPR_VALUE) {
     printf("(");
     close = ")";
   } else if (e->kind == EXPR_CUSTOM_FUNCTION) {
     printf("FUNCTION ");
   }
 
+
   expr_print(e->left);
 
   switch (e->kind) {
@@ -246,6 +248,7 @@ void expr_print(struct expr *e) {
   case EXPR_LESS_THAN_OR_EQUAL:
     printf("<=");
     break;
+  case EXPR_VALUE:
   case EXPR_INTEGER_LITERAL:
     printf("%d", e->integer_value);
     break;
@@ -288,6 +291,10 @@ void stmt_evaluate(struct stmt *s) {
   case STMT_IF:
     if (expr_evaluate(s->expr)) {
       stmt_evaluate(s->body);
+    } else {
+      if (s->else_body) {
+        stmt_evaluate(s->else_body);
+      }
     }
     break;
   case STMT_PRINT:
@@ -409,6 +416,8 @@ const char *expr_string_evaluate(struct expr *e) {
   case EXPR_LESS_THAN:
   case EXPR_LESS_THAN_OR_EQUAL:
   case EXPR_INTEGER_LITERAL:
+  case EXPR_VALUE:
+  case EXPR_OCCURS:
   case EXPR_FLOAT_LITERAL:
     printf("runtime error: not a string expression\n");
     exit(1);
@@ -482,6 +491,7 @@ float expr_evaluate(struct expr *e) {
   float r = expr_evaluate(e->right);
   float result;
 
+
   switch (e->kind) {
   case EXPR_NAME:
     // Get the variable expression and then evaluate it.

lab-5/parser.bison

@@ -225,7 +225,7 @@ else_parts      : else_branch
 else_branch     : TOKEN_ELSE_IF booleanexpr simple_stmt
                     {$$ = stmt_create(STMT_IF, NULL, NULL, $2, NULL, $3, NULL, NULL);}
                 | TOKEN_ELSE simple_stmt
-                    {$$ = stmt_create(STMT_IF, NULL, NULL, NULL, NULL, $2, NULL, NULL);}
+                    {$$ = stmt_create(STMT_IF, NULL, NULL, expr_create(EXPR_EQUAL_EQUAL, expr_create_integer_literal(0), expr_create_integer_literal(0)), NULL, $2, NULL, NULL);}
                 | TOKEN_END_IF
                     {$$ = NULL;}
 perform_stmt    : TOKEN_PERFORM TOKEN_VARYING ident TOKEN_KEYWORD_FROM TOKEN_INTEGER TOKEN_KEYWORD_BY TOKEN_INTEGER TOKEN_UNTIL op_parms

lab-5/samples/branching.cbl

@@ -1,8 +1,14 @@
 IDENTIFICATION DIVISION.
 PROGRAM-ID. BRANCHING.
+DATA DIVISION.
+    WORKING-STORAGE SECTION.
+        05 A PIC S9(2) VALUE 1.
+        05 B PIC S9(2) VALUE 2.
 PROCEDURE DIVISION.
-    IF A > B THEN
+    IF A > B
         DISPLAY 'A is greater than B'
+    ELSE IF A = B
+        DISPLAY 'A is equal to B'
     ELSE
         DISPLAY 'B is greater than A'
     END-IF

lab-5/samples/outputs/branching_evaluate.txt

@@ -0,0 +1 @@
+B is greater than A

lab-5/samples/outputs/branching_print.txt

@@ -0,0 +1,21 @@
+section
+section
+section
+section
+A = 1;
+B = 2;
+section
+if (A>B) then
+print A is greater than B;
+endif
+else if (0==0) then
+if (A==B) then
+print A is equal to B;
+endif
+else if (0==0) then
+print B is greater than A;
+endif
+
+endif
+
+stop run

lab-5/samples/outputs/quadratic_print.txt

@@ -2,9 +2,9 @@ section
 section
 section
 section
-a = ();
-b = ();
-c = ();
+a = 1;
+b = 5;
+c = 6;
 discriminant = ();
 root1 = ();
 root2 = ();
@@ -20,13 +20,13 @@ print The equation has two distinct real roots: ;
 print Root 1: root1;
 print Root 2: root2;
 endif
-else if  then
+else if (0==0) then
 if (discriminant==0) then
 compute root1 = (-b/(2*a));
 print The equation has one real root: ;
 print Root: root1;
 endif
-else if  then
+else if (0==0) then
 print The equation has no real roots.;
 endif