From 8d12db7dbeb6518d5a3ea3a268e703fbf92dfb44 Mon Sep 17 00:00:00 2001
From: Kayne Ruse <kayneruse@gmail.com>
Date: Mon, 15 Aug 2022 03:12:10 +0100
Subject: [PATCH] Some declaration guards

---
 source/interpreter.c | 17 ++++++++++++++++-
 source/parser.c      |  6 ++++--
 source/scope.c       |  6 +++++-
 source/scope.h       |  1 +
 4 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/source/interpreter.c b/source/interpreter.c
index 2322820..b191fd8 100644
--- a/source/interpreter.c
+++ b/source/interpreter.c
@@ -311,6 +311,9 @@ static bool execVarDecl(Interpreter* interpreter, bool lng) {
 	}
 
 	if (!setScopeVariable(interpreter->scope, identifier, parseIdentifierToValue(interpreter, popLiteralArray(&interpreter->stack)) )) {
+		printf("Incorrect type assigned to variable \"");
+		printLiteral(identifier);
+		printf("\"\n");
 		return false;
 	}
 
@@ -328,7 +331,19 @@ static bool execVarAssign(Interpreter* interpreter) {
 		return false;
 	}
 
-	setScopeVariable(interpreter->scope, lhs, rhs);
+	if (!isDelcaredScopeVariable(interpreter->scope, lhs)) {
+		printf("Undeclared variable \"");;
+		printLiteral(lhs);
+		printf("\"\n");
+		return false;
+	}
+
+	if (!setScopeVariable(interpreter->scope, lhs, rhs)) {
+		printf("Incorrect type assigned to variable \"");
+		printLiteral(lhs);
+		printf("\"\n");
+		return false;
+	}
 
 	return true;
 }
diff --git a/source/parser.c b/source/parser.c
index 7e8ef66..88edf13 100644
--- a/source/parser.c
+++ b/source/parser.c
@@ -763,8 +763,10 @@ static void expressionStmt(Parser* parser, Node** nodeHandle) {
 	Node* ptr = NULL;
 	expression(parser, &ptr);
 
-	**nodeHandle = *ptr;
-	FREE(Node, ptr); //BUGFIX: this thread of execution is nuts
+	if (ptr != NULL) {
+		**nodeHandle = *ptr;
+		FREE(Node, ptr); //BUGFIX: this thread of execution is nuts
+	}
 
 	consume(parser, TOKEN_SEMICOLON, "Expected ';' at the end of expression statement");
 }
diff --git a/source/scope.c b/source/scope.c
index 9f5a455..90ccb46 100644
--- a/source/scope.c
+++ b/source/scope.c
@@ -59,7 +59,11 @@ bool declareScopeVariable(Scope* scope, Literal key, Literal type) {
 	return true;
 }
 
-//return false if undefined
+bool isDelcaredScopeVariable(Scope* scope, Literal key) {
+	return existsLiteralDictionary(&scope->variables, key);
+}
+
+//return false if undefined, or can't be assigned
 bool setScopeVariable(Scope* scope, Literal key, Literal value) {
 	//dead end
 	if (scope == NULL) {
diff --git a/source/scope.h b/source/scope.h
index 8e7afec..3d9bd65 100644
--- a/source/scope.h
+++ b/source/scope.h
@@ -14,6 +14,7 @@ Scope* popScope(Scope* scope);
 
 //returns false if error
 bool declareScopeVariable(Scope* scope, Literal key, Literal type);
+bool isDelcaredScopeVariable(Scope* scope, Literal key);
 
 //return false if undefined
 bool setScopeVariable(Scope* scope, Literal key, Literal value);