Re: [MTT users] &if funclet and quoting

[Ethan Mallove]

On Tue, Jun/12/2007 08:07:20AM, Jeff Squyres wrote:
> On Jun 11, 2007, at 6:02 PM, Ethan Mallove wrote:
> 
> > btls = &if("&regexp("&shell("hostname")", "v440-2|v20z-2")", \
> >            "&enumerate("self,sm,tcp")", \
> >            "&if("&regexp("&shell("hostname")", "v440-6")", \
> >                "&enumerate("udapl")", \
> >                "&enumerate("sm", "tcp", "sm,tcp", "udapl",  
> > "sm,udapl")"" \
> >            ) \
> >        )
> 
> Yowza!  We really need to make this quoting situation better  
> somehow.  :-(
> 
> Don't you have an extra ) in there at the end?
> 
> > How come EvaluateString() doesn't translate this:
> >
> > btls = &if("&regexp("&shell("hostname")", "v440-2|v20z-2")", \
> >            "&enumerate("self,sm,tcp")", \
> >            "&if("&regexp("&shell("hostname")", "v440-6")", \
> >                "&enumerate("udapl")", \
> >                "&enumerate("sm", "tcp", "sm,tcp", "udapl",  
> > "sm,udapl")"" \
> >            ) \
> >        )
> >
> > Into one big eval block like this:
> >
> > eval $btls = MTT::Functions::if(MTT::Functions::regexp 
> > (MTT::Functions::shell("hostname"), "v440-2|v20z-2"),
> >                  MTT::Functions::enumerate("self,sm,tcp"),
> >                  MTT::Functions::if("MTT::Functions::regexp 
> > ("MTT::Functions::shell("hostname"), "v440-6"),
> >                      MTT::Functions::enumerate("udapl"),
> >                      MTT::Functions::enumerate("sm", "tcp",  
> > "sm,tcp", "udapl", "sm,udapl")
> >                  )
> >      )
> >
> > So we could put the burden of the nasty recursive
> > parenthesis/quote parsing on perl, rather than MTT. That
> > would seem to naturally make the INI funclet syntax more
> > Perl-like.
> 
> Ah -- I had to think about this a bit before I figured it out/ 
> remembered.  I think we won't get the expansion effect if you do it  
> this way.  

No expansion effect? As long as the perl code evaluates to
an array, couldn't it to work? E.g.,

  exec = mpirun --mca btl @btls@ ...

  # Returns an array
  btls = ("sm", "tcp")

So EvaluateString() would do only this:

  * Substitute all &funcs() with MTT::Functions::funcs()
  * Substitute all $vars with same-INI-section params
  * Backslash escape @ symbols so they show up as strings in
    the eval'd result
  * Perform an "eval" on the final string
  * Iterate over the result of the above step's string,
    replacing "@multiplier" strings with the corresponding
    element of the @multiplier array 

> Although it might solve some other issues (e.g., https:// 
> svn.open-mpi.org/trac/mtt/ticket/184)...?
>

The mess atop this email would simplify to:

btls =  if ($hostname =~ /foo/) {                                \
            return ("self,sm,tcp");                              \
        } elsif ($hostname =~ /bar/) {                           \
            return ("udapl");                                    \
        } else {                                                 \
            return ("sm", "tcp", "sm,tcp", "udapl", "sm,udapl"); \
        }

-Ethan


> -- 
> Jeff Squyres
> Cisco Systems
> 
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