[Omake] scanning of .mly files

[Aleksey Nogin]

On 12.06.2006 11:39, Benjamin Pierce wrote:

> I'd prefer something more eager/aggressive: I wish we could interpret
> 
>        .PREBUILD: %.ml: %.mly
> 
> as "If foo.mly [n.b.] is in the project, then generate foo.ml before  
> scanning other things."
> 
> But I worry that both of these approaches may lead to difficulties,  
> since it is not very clear exactly what "before scanning" means.   E.g., 
> in the case of Harmony, the file parser.mly is itself generated  from 
> yet another file, parser.srcy, using a little OCaml program that  must, 
> in turn, get built before it can be used...

Right, and this setup is fairly common as well. I would argue that the 
general solution would be to have ocamldep take a list of "interface 
extensions" and another list of "implementation extensions". You would 
then just use something like

OCAMLDEPFLAGS[] +=
   -intf .srcy
   -impl .srcy

and all will be well.

The OCamlGeneratedFiles function is definitely a big hack and is 
equivalent to manually specifying the dependencies where a tool 
(ocamldep, not OMake, I would argue) fails to discover them automatically.

BTW, in your situation, Benjamin, you should be able fine-tune the 
OCamlGeneratedFiles approach, if necessary - just take a look at how 
OCamlGeneratedFiles is implemented in OCaml.om

P.S. The only truly truly general solution would be to have some sort of 
interface where ocamldep (or any other dependency scanner) would instead 
of asking the filesystem the question "does foo.ml exist?" (which is 
what it does now) would be capable of asking OMake "is foo.ml buildable?".

-- 
Aleksey Nogin

Home Page: http://nogin.org/
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