From 60507214c098beaf3ae01a202e564bfe2f7c8364 Mon Sep 17 00:00:00 2001
From: Tucker Evans <tuckerevans24@gmail.com>
Date: Sat, 27 Jul 2019 21:08:22 -0400
Subject: Add basic scoping

---
 main.c   |  5 +++++
 makefile | 17 +++++++++++------
 pc.l     |  8 +++++---
 pc.y     |  3 ++-
 scope.c  | 35 +++++++++++++++++++----------------
 scope.h  |  8 ++++----
 6 files changed, 46 insertions(+), 30 deletions(-)

diff --git a/main.c b/main.c
index fbd96d0..dba3b7f 100644
--- a/main.c
+++ b/main.c
@@ -10,6 +10,8 @@
 extern char *yytext;
 extern int line_num;
 
+scope *cur_scope;
+
 char* pretty_type(t)
 int t;
 {
@@ -136,6 +138,9 @@ char* msg;
 
 int main()
 {
+	cur_scope = mkscope();
+	assert(cur_scope);
+
 	yyparse();
 
 	return 0;
diff --git a/makefile b/makefile
index 8dd5899..c429f3c 100644
--- a/makefile
+++ b/makefile
@@ -3,19 +3,22 @@ FLAGS = -g
 YACC = yacc
 LEX = lex
 
-mypc: y.tab.o lex.yy.o tree.o scope.o node.o pc.o
-	$(CC) $(FLAGS) -o mypc main.o tree.o scope.o node.o y.tab.o lex.yy.o -lfl -ly
+mypc: y.tab.o lex.yy.o tree.o scope.o node.o pc.o sem_check.o
+	$(CC) $(FLAGS) -o mypc main.o tree.o scope.o sem_check.o node.o y.tab.o lex.yy.o -lfl -ly
 
-pc.o: main.c pc.h
+pc.o: main.c headers
 	$(CC) $(FLAGS) -c main.c
 
-tree.o: tree.c tree.h
+tree.o: tree.c headers
 	$(CC) $(FLAGS) -c tree.c
 
-scope.o: scope.c scope.h
+sem_check.o: sem_check.c headers
+	$(CC) $(FLAGS) -c sem_check.c
+
+scope.o: scope.c headers
 	$(CC) $(FLAGS) -c scope.c
 
-node.o: node.c node.h
+node.o: node.c headers
 	$(CC) $(FLAGS) -c node.c
 
 y.tab.o: y.tab.c
@@ -30,5 +33,7 @@ y.tab.c: pc.y
 lex.yy.c: pc.l
 	$(LEX) -l pc.l
 
+headers: pc.h tree.h sem_check.h y.tab.h scope.h node.h y.tab.c
+
 clean:
 	rm -f mypc *.o y.tab.* lex.yy.*
diff --git a/pc.l b/pc.l
index 1a686d3..657f080 100644
--- a/pc.l
+++ b/pc.l
@@ -1,9 +1,11 @@
 %{
-
+#include "node.h"
+#include "scope.h"
 #include "y.tab.h"
 #include "pc.h"
 
 int line_num=1;
+extern scope *cur_scope;
 
 %}
 
@@ -39,13 +41,13 @@ id	[A-Za-z][A-Za-z0-9_]*
 
 "procedure" {
 	debug_print(PROC, NULL);
-	/*s = push_scope(s);*/
+	push_scope(&cur_scope);
 	return PROC;
 }
 
 "function" {
 	debug_print(FUNC, NULL);
-	/*s = push_scope(s);*/
+	push_scope(&cur_scope);
 	return FUNC;
 }
 
diff --git a/pc.y b/pc.y
index e8f2baa..e7cb06e 100644
--- a/pc.y
+++ b/pc.y
@@ -7,7 +7,7 @@
 #include "tree.h"
 #include "y.tab.h"
 #include "pc.h"
-/*#include "sem_check.h"*/
+#include "sem_check.h"
 
 /*
 TODO:
@@ -15,6 +15,7 @@ TODO:
 */
 
 extern int yylex();
+extern scope *cur_scope;
 
 %}
 
diff --git a/scope.c b/scope.c
index d09f1b4..379be97 100644
--- a/scope.c
+++ b/scope.c
@@ -56,26 +56,29 @@ char* s;
 	return h % HASH_SIZE;
 }
 
-scope* push_scope(root)
-scope *root;
+void push_scope(root)
+scope **root;
 {
-	scope *p = mkscope();
-	p->next = root;
-	return p;
+	scope *tmp = mkscope();
+	
+	assert(tmp);
+
+	tmp->prev = *root;
+	*root = tmp;
 }
 
-scope* pop_scope(root)
-scope *root;
+void pop_scope(root)
+scope **root;
 {
-	scope *p;
+	scope *tmp;
 
-	if (!root)
-		return NULL;
+	if (!*root)
+		return;
 
-	p = root->next;
+	tmp = *root;
+	*root = (*root)->prev;
 
-	free_scope(root);
-	return p;
+	free_scope(tmp);
 }
 
 node* scope_insert(root, name)
@@ -105,7 +108,7 @@ char *name;
 	scope *p;
 	node *tmp;
 
-	for (p = root; p; p = p->next)
+	for (p = root; p; p = p->prev)
 		if (tmp = scope_search(p, name))
 			return tmp;
 
@@ -119,10 +122,10 @@ char *name;
 	scope *p;
 	node *tmp;
 
-	for (p = root; p; p = p->next) {
+	for (p = root; p; p = p->prev) {
 		if (tmp = scope_search(p, name))
 			return tmp;
-		if (p->function_boundry)
+		if (p->ret_var)
 			return NULL;
 	}
 
diff --git a/scope.h b/scope.h
index 7160b5e..0a07a26 100644
--- a/scope.h
+++ b/scope.h
@@ -5,16 +5,16 @@
 
 typedef struct hash {
 	node* table[HASH_SIZE];
-	struct hash *prev, *next;
-	char function_boundry;
+	struct hash *prev;
+	node* ret_var;
 } scope;
 
 scope* mkscope();
 void free_scope(scope*);
 
 /*stack routines*/
-scope* pop_scope(scope*);
-scope* push_scope(scope*);
+void pop_scope(scope**);
+void push_scope(scope**);
 
 /*helpers*/
 node* scope_insert(scope*, char*);
-- 
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