Improve int parsing and allow negatives

src/parse.c

@@ -9,6 +9,7 @@
 #include <assert.h>
 #include <stdlib.h>
 #include <string.h>
+#include <errno.h>
 
 #define START_LIST_CHAR '('
 #define END_LIST_CHAR ')'
@@ -71,14 +72,24 @@ struct ucl_object *ucl_token_next(const char **curr_src) {
                 str = strndup(start + 1, *curr_src - start - 2);
                 // TODO: free
                 return ucl_string_create(str);
+            case '-':
+            case '+':
             case '0'...'9': {
-                // TODO: Add support for negative integers
                 char *end = NULL;
+                errno = 0;
                 long value = strtol(*curr_src, &end, 0);
+                if (errno || *curr_src == end) {
+                    goto symbol_case;
+                }
+
                 *curr_src = end;
+                if (!ucl_is_delimiter(*end)) {
+                    return ucl_error_create("Integer value contained non-digits");
+                }
                 return ucl_int_create(value);
             }
             default:
+                symbol_case:
                 while (!ucl_is_delimiter(**curr_src)) {
                     (*curr_src)++;
                 }
@@ -100,6 +111,7 @@ struct ucl_object *ucl_tokenize(const char *source) {
     const char *curr_src = source;
 
     while ((curr_token = ucl_token_next(&curr_src)) != NULL) {
+        UCL_RET_IF_ERROR(curr_token);
         tokens_tail = ucl_list_append(tokens_tail, curr_token);
     }