From 6b3e004224ccba39199606f2683265c9e4606e43 Mon Sep 17 00:00:00 2001
From: Tucker Evans <tuckerevans24@gmail.com>
Date: Mon, 30 Sep 2019 19:05:12 -0400
Subject: Add check that function returns value

---
 pc.y        |  9 +++++++++
 sem_check.c | 27 +++++++++++++++++++++++++++
 sem_check.h |  1 +
 3 files changed, 37 insertions(+)

diff --git a/pc.y b/pc.y
index da58fb5..32be027 100644
--- a/pc.y
+++ b/pc.y
@@ -92,6 +92,8 @@ extern scope *cur_scope;
 
 %type <ival> TD
 
+%type <sval> sub_prog_head
+
 %%
 
 program
@@ -181,6 +183,9 @@ sub_prog_declaration
 	 sub_prog_declarations
 	 compound_statement
 	{
+		if ($1)
+			check_func_return($4, $1);
+
 		set_ret_type($4);
 #ifdef DEBUG
 		print_tree($4);
@@ -219,6 +224,8 @@ sub_prog_head
 		 * scope*/
 		cur_scope->ret_var = scope_insert(cur_scope, strdup($2));
 		cur_scope->ret_var->var_type = $5;
+
+		$$ = $2;
 	}
 	|PROC ID arguments ';'
 	{
@@ -237,6 +244,8 @@ sub_prog_head
 
 		assert(!set_func_types($3, tmp->func_info->argv, i));
 		free_tree($3);
+
+		$$ = NULL;
 	}
 ;
 
diff --git a/sem_check.c b/sem_check.c
index fd85c98..e30d8c5 100644
--- a/sem_check.c
+++ b/sem_check.c
@@ -206,3 +206,30 @@ ptree *t;
 		yyerror("Incorrect types in fuction arguments");
 
 }
+
+int func_ret(t, name)
+ptree *t;
+char *name;
+{
+	if (!t)
+		return 0;
+
+	if (t->type == ASSIGNOP && t->l)
+		if (t->l->type == ID && !strcmp(t->l->attr.nval->name, name))
+			return 1;
+
+	return func_ret(t->l, name) || func_ret(t->r, name);
+}
+
+void check_func_return(t,name)
+ptree *t;
+char *name;
+{
+	char buf[100];
+
+	if (!func_ret(t,name)) {
+		snprintf(buf, 100, "Function %s does not return a value\n",
+				name);
+		yyerror(buf);
+	}
+}
diff --git a/sem_check.h b/sem_check.h
index 0da2cc9..8f5394a 100644
--- a/sem_check.h
+++ b/sem_check.h
@@ -12,4 +12,5 @@ int check_ret_type(ptree*);
 
 void check_call(ptree*);
 
+void check_func_return(ptree*, char*);
 #endif
-- 
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