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Re: Scheme help request: How can else of an if-statement be made to do n
From: |
Thomas Morley |
Subject: |
Re: Scheme help request: How can else of an if-statement be made to do nothing? |
Date: |
Sat, 17 Oct 2020 21:23:39 +0200 |
Am Sa., 17. Okt. 2020 um 20:33 Uhr schrieb David Kastrup <dak@gnu.org>:
>
> Thomas Morley <thomasmorley65@gmail.com> writes:
>
> > Am Sa., 17. Okt. 2020 um 19:39 Uhr schrieb Jean Abou Samra
> > <jean@abou-samra.fr>:
> >>
> >> The point of interpret-markup is to turn a markup into a stencil, so I'd
> >> use empty-stencil:
> >>
> >> \version "2.20.0"
> >>
> >> #(define-markup-command (print-if-defined layout props sym text)
> >> (symbol? markup?)
> >> (if (defined? sym)
> >> (interpret-markup layout props
> >> #{ \markup \with-color #'(0.8 0.2 0.2) #text #})
> >> empty-stencil))
> >>
> >> symA = "Something"
> >>
> >> \markup {
> >> \print-if-defined #'symA "Text"
> >> \print-if-defined #'symB "More text"
> >> }
> >>
> >
> > An empty stencil will still be spaced (unless removed by other
> > markup-commands).
>
> empty-stencil will typically not trigger additional spacing. That's
> typically what distinguishes it from point-stencil .
>
> --
> David Kastrup
Well, I'd say it depends how that empty-stencil is consumed. See:
\markup
\box
{ \stencil #point-stencil \stencil #empty-stencil \stencil #point-stencil }
Here I did something silly (of course there are warnings emitted) and
the output _is_ affected.
Thus, the detailed use-case is important...
Cheers,
Harm
- Scheme help request: How can else of an if-statement be made to do nothing?, Matthew Fong, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Matthew Fong, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Richard Shann, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Matthew Fong, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Jean Abou Samra, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Thomas Morley, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Matthew Fong, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, David Kastrup, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?,
Thomas Morley <=
- RE: Scheme help request: How can else of an if-statement be made to do nothing?, John Schlomann, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Thomas Morley, 2020/10/17
- Re: Scheme help request: How can else of an if-statement be made to do nothing?, Matthew Fong, 2020/10/17
- RE: Scheme help request: How can else of an if-statement be made to do nothing?, John Schlomann, 2020/10/17