[erlang-questions] RFC: parse_trans for code generation

Vlad Dumitrescu <>
Tue Aug 10 22:24:25 CEST 2010

On Fri, Jul 2, 2010 at 12:44, Ulf Wiger <> wrote:
> I realize that quite the minority of list readers take an
> interest in parse transforms. Nevertheless, I thought I'd
> highlight a small addition to the parse_trans project to
> assist code generation.
> http://github.com/esl/parse_trans

Hi Ulf,

I think it's a very nice piece of work. I had once started something
similar, but didn't get even this far. I'm glad that you did :-)

The problem as I see it is that even if this was unanimously voted as
the greatest thing since sliced bread, it has some usability issues.
Without a simpler syntax, it's simply not going to be used,
unfortunately. Additionally, parse transforms (for all their coolness)
have the disadvantage that they make the code very difficult to debug
(except for the toy examples). So what is needed is extensible syntax
and tooling support ("un-parse transforms").

On the other hand, there is a place where this stuff is already
usable, working (maybe not 100%, but close) and much more amenable to
. I'm referring to LFE, of course. (Even the other beam-based
languages can be considered here, but I haven't used tham) I'm
guessing that the tooling support (with the debugger as the most
important part) is lagging behind, but my guess is that it would be
easier to develop than for Erlang-proper. The big question is when
someone will get an itch severe enough to actually start scratching at

best regards,

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