Re: Adding a custom symbol

[Valeriy E. Ushakov]

On Mon, Jan 16, 2012 at 09:33:02 +0000, Mark Summerfield wrote:

> On Fri, 13 Jan 2012 21:55:12 +0400
> "Valeriy E. Ushakov" <address@hidden> wrote:
> [snip]
> > Ok, got around to actually test it:
> > 
> > @SysInclude { doc }
> > 
> > export @Monochrome
> > def @MyOptions
> >   named @Monochrome { No }
> > {}
> > 
> > @Use { @MyOptions }
> > 
> > @Doc @Text @Begin
> > @LP Monochrome is @Monochrome
> > @End @Text
> > 
> > 
> > $ lout -p -s override.lt | uniq
> > 
> >           Monochrome is No
> > 
> > $ lout -p -s --'@Monochrome{Yes}' override.lt | uniq
> > 
> >           Monochrome is Yes
> 
> I did this and put lines like this in my document:
> 
>     @CD @Monochrome @Case {
>     Yes @Yield @IncludeGraphic{"images/quadratic2-linux-bw.eps.gz"}
>     else @Yield @IncludeGraphic{"images/quadratic2-linux.eps.gz"}
>     }
> 
> This gave no error messages but didn't work reliably.
> 
> So I changed them to this:
> 
>     @CD @Monochrome @Case {
>     Yes @Yield @IncludeGraphic{"images/quadratic2-linux-bw.eps.gz"}
>     No @Yield @IncludeGraphic{"images/quadratic2-linux.eps.gz"}
>     }
> 
> This seems to work reliably but outputs some strange error messages (but
> only in the --'@Monochrome{Yes}' case:
> 
>     replacing unknown @Case option ?? by Yes
> 
> Anyway, it works, so that you very much:-)

Only by chance.  Try it with --'@Monochrome{No}' :)


Now, this is weird.  Consider this:

---8<------8<------8<------8<---
@SysInclude { doc }

export @Monochrome
def @MyOptions
  named @Monochrome { No }
{}

@Use { @MyOptions }

#def @WHATEVER { @Monochrome }

@Doc @Text @Begin
@LP Monochrome is @Monochrome

@LP @Monochrome @Case {
Yes @Yield { Black and White }
No  @Yield { Colorful }
}

@End @Text
---8<------8<------8<------8<---


It generates "replacing unknown @Case option ?? by Yes".  But if you
uncomment definition of @WHATEVER (unused!), it puts the lout on the
right track.

I thoroughly forgot most of the internals, so I guess Jeff will have
to comment on this.

-uwe