Write a procedural macro to replace the `js!` macro on nightly (full JavaScript parser)

[koute]

Same as #6, except the fully parse the JavaScript code instead of only tokenizing and stringifying it.

This is significantly harder.

[ForsakenHarmony]

what would be the benefit of parsing the javascript?

[koute]

@ForsakenHarmony To make sure that it's actually syntactically valid JS without executing it. Also, there may be some optimizations we could do - e.g. if there is no return there there is no point in deserializing the return value.