parse(context, start) {
      this.context = context;
      const {
        inFlow,
        src
      } = context;
      let offset = start;
      const ch = src[offset];

      if (ch && ch !== '#' && ch !== '\n') {
        offset = PlainValue.endOfLine(src, start, inFlow);
      }

      this.valueRange = new _Range.default(start, offset);
      offset = _Node.default.endOfWhiteSpace(src, offset);
      offset = this.parseComment(offset);

      if (!this.hasComment || this.valueRange.isEmpty()) {
        offset = this.parseBlockValue(offset);
      }

      return offset;
    }
Parses a plain value from the source

Accepted forms are:
```
#comment

first line

first line #comment

first line
block
lines

#comment
block
lines
```
where block lines are empty or have an indent level greater than `indent`.

@param {ParseContext} context
@param {number} start - Index of first character
@returns {number} - Index of the character after this scalar, may be `\n`