`parseNodeQ` makes code unclear

[ntrel]

    template parseNodeQ(string VarName, string NodeName)
    {
        enum parseNodeQ = `{ if ((` ~ VarName ~ ` = parse` ~ NodeName ~ `()) is null) return null; }`;
    }
// many lines...
    mixin(parseNodeQ!(`node.type`, `Type`));

This hides the important code of node.type = parseType. Clearer mixin usage would be something like:

    mixin(checkNull!`node.type = parseType()`);

And it's only 2 characters longer. Now the important code is at least visible and will show up when grepping for parseType. (Or for more clarity the mixin could be named returnIfNull).

I'm happy to make a PR if this is acceptable.