Function expandWordUnderCursor

static/js/codemirror/keymap/vim.js:1534–1582

(cm, inclusive, forward, bigWord, noSymbol)

    }

    function expandWordUnderCursor(cm, inclusive, forward, bigWord, noSymbol) {
      var cur = cm.getCursor();
      var line = cm.getLine(cur.line);
      var idx = cur.ch;

      // Seek to first word or non-whitespace character, depending on if
      // noSymbol is true.
      var textAfterIdx = line.substring(idx);
      var firstMatchedChar;
      if (noSymbol) {
        firstMatchedChar = textAfterIdx.search(/\w/);
      } else {
        firstMatchedChar = textAfterIdx.search(/\S/);
      }
      if (firstMatchedChar == -1) {
        return null;
      }
      idx += firstMatchedChar;
      textAfterIdx = line.substring(idx);
      var textBeforeIdx = line.substring(0, idx);

      var matchRegex;
      // Greedy matchers for the "word" we are trying to expand.
      if (bigWord) {
        matchRegex = /^\S+/;
      } else {
        if ((/\w/).test(line.charAt(idx))) {
          matchRegex = /^\w+/;
        } else {
          matchRegex = /^[^\w\s]+/;
        }
      }

      var wordAfterRegex = matchRegex.exec(textAfterIdx);
      var wordStart = idx;
      var wordEnd = idx + wordAfterRegex[0].length - 1;
      // TODO: Find a better way to do this. It will be slow on very long lines.
      var wordBeforeRegex = matchRegex.exec(reverse(textBeforeIdx));
      if (wordBeforeRegex) {
        wordStart -= wordBeforeRegex[0].length;
      }

      if (inclusive) {
        wordEnd++;
      }

      return { start: { line: cur.line, ch: wordStart },
        end: { line: cur.line, ch: wordEnd }};
    }

    /*
     * Returns the boundaries of the next word. If the cursor in the middle of