Re: Adding a custom symbol

[Valeriy E. Ushakov]

On Fri, Jan 13, 2012 at 17:33:17 +0000, Mark Summerfield wrote:

> On Fri, 13 Jan 2012 16:20:47 +0400
> "Valeriy E. Ushakov" <address@hidden> wrote:
> > On Fri, Jan 13, 2012 at 10:45:38 +0000, Mark Summerfield wrote:
> > 
> > > I need to generate 2 different versions of a document. I'd like to
> > > do this:
> > > 
> > >     $ lout --'@Monochrome{Yes}' main.lout > bw.ps
> > > 
> > > and
> > > 
> > >     $ lout main.lout > color.ps
> > > 
> > > How can I add @Monochrome{No} as a default value somewhere?
> > 
> > IIRC, define that symbol as a named parameter (with appropriate
> > default) to, say, @MySetup and @Use @MySetup.  Command line options
> > are consulted for overrides when a symbol is @Use'd (see calls to
> > HuntCommandOption in z06.c).
> > 
> > Consider the manual page example @PageType which is a named parameter
> > to @DocumentSetup.
> 
> Hi Uwe,
> 
> I think that's a bit advanced for me, but I'll see if I can find where
> @PageType is defined & see if I can imitate it.

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

-uwe