ES6 Parser in Dlang

[Sebastiaan Koppe]

On Thursday, 27 February 2020 at 14:06:19 UTC, James Lu wrote:
> I want to implement an ES6 (JavaScript) parser in Dlang so I 
> can implement a transpiler. Because it's a transpiler, I need 
> to be able to visit and rewrite AST nodes, then generate code 
> from the AST. Ideally, the parser generator supports streaming 
> the input into the AST visitor out to the output.
>
> What parser generator library should I use for this purpose?

I dunno. I wrote the es6-grammar library that uses pegged. Then I 
decided to hand write mine own.

https://github.com/skoppe/jazr

It is a pretty complete and fast JS minifier. It has lots of 
passes and minifies code pretty well:

https://github.com/skoppe/jazr/blob/master/source/es6/minifier.d#L286

In general it is about 30 times faster than uglify-js (and uses 
3-4 times less memory). It parses JS code at about 60 Mb/s. The 
minifier was a bit slower at 20 Mb/s if I remember correctly.

I fuzzed the lexer and parser, so there are little to no spurious 
crashes on weird input.

Use it as you please, or just as an indication of the effort 
involved.