ocamlbuild rule with recursive action

ocamlbuild rule with recursive action

[Daniel Bünzli]

Hello,

Is it possible to define a rule with an action that is performed  
repeatedly until a condition is reached ?

Best,

Daniel

Re: [Caml-list] ocamlbuild rule with recursive action

[DooMeeR]

Daniel Bünzli a écrit :
> Hello,
> 
> Is it possible to define a rule with an action that is performed 
> repeatedly until a condition is reached ?
> 
> Best,
> 
> Daniel

Well, you can define a rule like this :

rule ~prod: "%.rec" (fun env build ->
   let x = env "%2.rec" in (* a new fresh name *)
   if some condition then build x else Nop)

When your rule is executed, for exemple to produce "toto.rec", it will 
(if some condition) first produce "toto2.rec", which will produce 
"toto22.rec", and so on until some condition is false.

I didn't try it though.

-- 
Romain Bardou

Re: [Caml-list] ocamlbuild rule with recursive action

[Daniel Bünzli]

Le 2 déc. 08 à 12:27, DooMeeR a écrit :

> Well, you can define a rule like this :

Thanks. I'll try something along these lines.

But that's kind of ugly. In the future could maybe ocamlbuild add  
another case in the command type, something like

Rec of action -> (command * bool)

Or maybe there is another way ?

Daniel

Re: [Caml-list] ocamlbuild rule with recursive action

[Romain Bardou]

Daniel Bünzli a écrit :
> 
> Le 2 déc. 08 à 12:27, DooMeeR a écrit :
> 
>> Well, you can define a rule like this :
> 
> Thanks. I'll try something along these lines.
> 
> But that's kind of ugly. In the future could maybe ocamlbuild add 
> another case in the command type, something like
> 
> Rec of action -> (command * bool)
> 
> Or maybe there is another way ?
> 
> Daniel

Well, you can also simply execute the commands yourself, in a loop, 
using Command.execute or Command.execute_many.

-- 
Romain Bardou

Re: [Caml-list] ocamlbuild rule with recursive action

[Daniel Bünzli]

Le 3 déc. 08 à 10:44, Romain Bardou a écrit :

> Well, you can also simply execute the commands yourself, in a loop,  
> using Command.execute or Command.execute_many.

But doesn't this break things ? Actions are supposed to build the  
command not execute it.

Daniel

P.S. something like

Rec of 'a * ('a -> action -> [ `Stop | `Step of command * 'a ])

would be better or

Rec of 'a * ('a -> action-> command * 'a) with the convention that  
returning Nop stops the recursion.