diff --git a/lang/compile.py b/lang/compile.py
index 14901ed..b1c21ec 100755
--- a/lang/compile.py
+++ b/lang/compile.py
@@ -156,7 +156,7 @@
 		print("not a call? line: %s" % (' '.join(line)))
 		return None
 	subject = parse_value(cut[0])
-	if not subject:
+	if subject is None:
 		print("not a subject? line: %s" % (' '.join(line)))
 		return None
 	verb = None
@@ -165,7 +165,7 @@
 	args = []
 	for arg in cut[2:]:
 		val = parse_value(arg)
-		if not val:
+		if val is None:
 			print("not a arg value? line: %s" % (' '.join(line)))
 			return None
 		args.append(val)
@@ -176,7 +176,7 @@
 		print("not a set? line: %s" % (' '.join(line)))
 		return None
 	call = parse_call(line, 4)
-	if not call:
+	if call is None:
 		return None
 	return ASTSet(line[1], call)
 
@@ -185,7 +185,7 @@
 		print("not a return? line: %s" % (' '.join(line)))
 		return None
 	value = parse_value(line[1])
-	if not value:
+	if value is None:
 		print("not a return value? line: %s" % (' '.join(line)))
 		return None
 	return ASTReturn(value)
@@ -195,7 +195,7 @@
 		print("not a jump? line: %s" % (' '.join(line)))
 		return None
 	jump_call = parse_call(line, 2)
-	if not jump_call:
+	if jump_call is None:
 		print("not a jump call? line: %s" % (' '.join(line)))
 		return None
 	return ASTJump(jump_call)
@@ -209,7 +209,7 @@
 		command = parse_return(line)
 	elif instr == "Jump":
 		command = parse_jump(line)
-	if not command:
+	if command is None:
 		print("not a command? line: %s" % (' '.join(line)))
 		return None
 	return ASTCommand(command)
@@ -251,7 +251,7 @@
 		(command, new_lines) = parse_conditional(lines)
 	else:
 		command = parse_command(line)
-	if not command:
+	if command is None:
 		print("not a statement? line: %s" % (' '.join(line)))
 		return (None, [])
 	return (ASTStatement(command), new_lines)
@@ -477,15 +477,15 @@
 def generate_ir_call(ast, is_jump):
 	final_ir = []
 	subject_ir = generate_ir_value(ast.subject)
-	if not subject_ir:
+	if subject_ir is None:
 		print("Unknown subject ast node: %s" % (node))
 		return None
-	if not ast.verb:
+	if ast.verb is None:
 		return subject_ir
 	args_ir = []
 	for arg in ast.args:
 		arg_ir = generate_ir_value(arg)
-		if not arg_ir:
+		if arg_ir is None:
 			print("Unknown arg ast node: %s" % (arg))
 			return None
 		args_ir = args_ir + arg_ir
@@ -508,7 +508,7 @@
 def generate_ir_set(ast, create):
 	command = ast.command
 	sub_ir = generate_ir_call(command, False)
-	if not sub_ir:
+	if sub_ir is None:
 		print("Unknown set ast node: %s" % (node))
 		return None
 	store = IRStore(ast.name, -1, create)
@@ -516,7 +516,7 @@
 
 def generate_ir_return(ast):
 	value_ir = generate_ir_value(ast.value)
-	if not value_ir:
+	if value_ir is None:
 		print("Unknown return ast node: %s" % (node))
 		return None
 	store_ret = IRStore("Return", -1, False)
@@ -532,7 +532,7 @@
 		sub_ir = generate_ir_return(node)
 	elif isinstance(node, ASTJump):
 		sub_ir = generate_ir_jump(node)
-	if not sub_ir:
+	if sub_ir is None:
 		print("Unknown command ast node: %s" % (node))
 		return None
 	return sub_ir
@@ -568,7 +568,7 @@
 		sub_ir = generate_ir_command(node, True)
 	elif isinstance(node, ASTJump):
 		sub_ir = generate_ir_jump(node)
-	if not sub_ir:
+	if sub_ir is None:
 		print("Unknown statement ast node: %s" % (node))
 		return None
 	return sub_ir
@@ -581,7 +581,7 @@
 		sub_ir = None
 		if isinstance(node, ASTStatement):
 			sub_ir = generate_ir_statement(node, statement_id)
-		if not sub_ir:
+		if sub_ir is None:
 			print("Unknown function statement ast node: %s" % (node))
 			return None
 		ir = ir + sub_ir
@@ -599,7 +599,7 @@
 			sub_ir = generate_ir_metadata(node)
 		elif isinstance(node, ASTFunction):
 			sub_ir = generate_ir_function(node)
-		if not sub_ir:
+		if sub_ir is None:
 			print("Unknown ast node: %s" % (node))
 			return None
 		ir.append(sub_ir)
@@ -661,7 +661,7 @@
 
 def registers_allocate_func(ir):
 	registers = find_variables(ir)
-	if not registers:
+	if registers is None:
 		return None
 	new_ir = replace_variables(ir, registers)
 	name = ir.name
@@ -699,7 +699,7 @@
 	fixups = {}
 	for node in ir.statements:
 		pos = len(bytes)
-		if not comments.get(pos):
+		if comments.get(pos) is None:
 			comments[pos] = []
 		comments[pos].append(str(node))
 		if isinstance(node, IRNumber):
@@ -882,23 +882,23 @@
 
 def compile(code, id):
 	lines = tokenize(code)
-	if not lines:
+	if lines is None:
 		print("Failed to tokenize file")
 		return None
 	ast = parse_toplevel(lines, id)
-	if not ast:
+	if ast is None:
 		print("Failed to parse file")
 		return None
 	ir = generate_ir(ast)
-	if not ir:
+	if ir is None:
 		print("Failed to generate IR")
 		return None
 	ir_reg = registers_allocate(ir)
-	if not ir_reg:
+	if ir_reg is None:
 		print("Failed to allocate registers")
 		return None
 	c_code = generate_c_file(ir_reg, code)
-	if not c_code:
+	if c_code is None:
 		print("Failed to generate C file")
 		return None
 	return c_code