Split by character, but not inside scopes

Scope-Preserving-Split.hx

function scopePreservingSplit(str: String, by: String) {
      var scopePairs = ['()', '[]', '{}', '<>'];
      var scopeState = [0, 0, 0, 0];
      var parts = new Array<String>();
      var buffer = '';

      inline function handleScope(c) {
          for (i in 0...scopePairs.length) {
              var open = scopePairs[i].charAt(0);
              var close = scopePairs[i].charAt(1);
              if (c == open) {
                  scopeState[i]++;
                  break;
              }
              if (c == close) {
                  scopeState[i]--;
                  break;
              }
          }
      }

      for (i in 0...str.length) {
          var c = str.charAt(i);

          handleScope(c);

          var withinScope = Lambda.find(scopeState, s -> s > 0) != null;

          if (c == ',' && !withinScope) {
              parts.push(buffer);
              buffer = '';
          } else {
              buffer += c;
          }
      }

      parts.push(buffer);

      return parts;
  }