add declaring and assignment with parser LHS support

src/parser/assignable/identifier/identifier.c

@@ -0,0 +1,12 @@
+#include "identifier.h"
+#include "../../../lexer/token.h"
+#include "../../parser.h"
+#include <string.h>
+#include "../../../memory.h"
+
+ParsedValue *parse_identifier(Token *token) {
+  ParsedValue *parsedValue = checked_malloc(sizeof(ParsedValue));
+  parsedValue->type = AST_IDENTIFIER;
+  parsedValue->data = strcpy(checked_malloc(sizeof(token->value)), token->value);
+  return parsedValue;
+}