[NTG-context] Re: Luametatex: nesting alignments in display math formulas

["ntg-contextmailingli.expedited080--- via ntg-context" <ntg-context@ntg.nl>]

On Sunday, November 10th, 2024 at 08:20, Mikael Sundqvist <mickep@gmail.com> wrote:

The output for this is perfect, Mikael. Your edit has a few surprises for me. I'll study it today.

Clearly a slog for anyone to go through. I appreciate it very much. Thank you!

> ------------------------------
> Hi,
> 
> On Sun, Nov 10, 2024 at 2:45 AM ntg-contextmailingli.expedited080---
> via ntg-context ntg-context@ntg.nl wrote:
> 
> > I'm test driving luametatex. My needs usually extend to expressing formulas in TLA+ using nested display math formulas. Although I have suitable templates for doing this in Mark IV, I can't reproduce these satisfactorily in luametatex. For example, here's a formula from Leslie Lamport's 2006 "Lower Bounds for Asynchronous Consensus":
> > 
> > ~~~~~~~~~~~ transitive_reduction.tex ~~~~~~~~~~~~~
> > 
> > \define\lbr {\lbrace \mkern 0.9mu}
> > \define\rbr {{}\mkern 0.9mu \rbrace}
> > \define\∀ {∀\mkern1mu}
> > \define\∃ {∃\mkern2mu}
> > 
> > \startdocument
> > 
> > \startplaceformula
> > \startformula [split=yes, align=flushleft, margin=standard, interlinespace=1ex]
> > \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=1, align={left,left}]
> > 
> > \NC \text{\it TransitiveClosure}(R) ≜
> > \NR
> > 
> > \NC \quad
> > \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=2, align={left,left,left}, location=top]
> > 
> > \NC \text{\sc let} \quad
> > \NC \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=1, align={left,left}, location=top]
> > 
> > \NC \text{\it Dom} ≜ \lbr r[1]: r ∈ R \rbr
> > \NR
> > 
> > \NC \text{\it Rng} ≜ \lbr r[2]: r ∈ R \rbr
> > \NR
> > 
> > \NC \text{\it TC}[i ∈ ℕ] ≜
> > \NR
> > 
> > \NC \quad
> > \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=1, align={left,left}, location=top]
> > 
> > \NC \text{\sc if}\ i = 0\
> > \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=2, align={left,left,left}, location=top]
> > 
> > \NC \text{\sc then}\
> > \NC R
> > \NR
> > 
> > \NC \text{\sc else}\
> > \NC
> > \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=1, align={left,left}, location=top]
> > 
> > \NC \lbr
> > 〈d, e 〉∈ \text{\it Dom} × \text{\it Rng}:
> > \NR
> > 
> > \NC \quad \∃ c ∈ \text{\it Dom} ∩ \text{\it Rng}:
> > \bgroup \setupinterlinespace [line=1ex]
> > \startalign [n=1, align={left,left}, location=top]
> > 
> > \NC ∧ 〈d, c〉∈ \text{\it TC}[i-1]
> > \NR
> > 
> > \NC ∧ 〈c, e〉∈ R \,\rbr
> > \NR
> > \stopalign \egroup
> > \NR
> > \stopalign \egroup
> > \NR
> > \stopalign \egroup
> > \NR
> > \stopalign \egroup
> > \NR
> > \stopalign \egroup
> > \NR
> > 
> > \NC \text{\sc in}\
> > \NC \text{\sc union}\ \lbr \text{\it TC}[i] : i ∈ ℕ \rbr
> > \NR
> > \stopalign \egroup
> > \NR
> > \stopalign \egroup \stopformula \stopplaceformula
> > 
> > \stopdocument
> > 
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > 
> > The command
> > 
> > $ context --luatex transitive_reduction.tex
> > 
> > produces the desired result, but
> > 
> > $ context transitive_reduction.tex
> > 
> > rejects the alignments and centers the lines instead. Can anyone suggest how I might adapt such nesting of alignments to luametatex?
> 
> 
> I must admit that I don't know what is the expected output and if I
> did break any of the rules or missed what you want, but the following
> could hopefully work as a start for you:
> 
> \define\lbr {\lbrace \mkern 0.9mu}
> \define\rbr {{}\mkern 0.9mu \rbrace}
> \define\∀ {∀\mkern1mu}
> \define\∃ {∃\mkern2mu}
> 
> \definemathsimplealign
> [myalign]
> [align=left,
> location=top]
> 
> \definemathsimplealign
> [myouteralign]
> [align=left,
> location=center]
> 
> \definemathsimplealign
> [mydistancedalign]
> [align=left,
> distance=1em,
> leftmargin=1em]
> 
> \definemathsimplealign
> [mymarginedalign]
> [align=left,
> leftmargin=1em]
> 
> \startdocument
> 
> \startplaceformula
> \startformula [align=flushleft]
> \startmyouteralign
> \NC \mathtextit{TransitiveClosure}(R) ≜
> \NR
> 
> \NC
> \startmydistancedalign
> \NC \mtext{\sc let}
> \NC
> \startmyalign
> \NC \mathtextit {Dom} ≜ \lbr r[1]: r ∈ R \rbr
> \NR
> \NC \mathtextit {Rng} ≜ \lbr r[2]: r ∈ R \rbr
> \NR
> \NC \mathtextit {TC\/}[i ∈ ℕ] ≜
> \NR
> \NC
> \startmymarginedalign
> \NC \text{\sc if } i = 0\
> \startmyalign
> \NC \text{\sc then}\
> \NC R
> \NR
> 
> \NC \text{\sc else}\
> \NC
> \startmyalign
> \NC \lbr
> 〈d, e 〉 ∈ \text{\it Dom} × \text{\it Rng}:
> \NR
> 
> \NC \quad \∃ c ∈ \text{\it Dom} ∩ \text{\it Rng}:
> \startmyalign
> 
> \NC ∧ 〈d, c〉 ∈ \mathtextit {TC\/}[i-1]
> \NR
> 
> \NC ∧ 〈c, e〉 ∈ R \rbr
> \NR
> \stopmyalign
> \NR
> \stopmyalign
> \NR
> \stopmyalign
> \NR
> \stopmymarginedalign
> \NR
> \stopmyalign
> \NR
> \NC \mtext{\sc in}
> \NC \mtext{\sc union } \lbr \mathtextit {TC\/}[i] : i ∈ ℕ \rbr
> \NR
> \stopmydistancedalign
> \NR
> \stopmyouteralign
> \stopformula \stopplaceformula
> 
> \stopdocument
> 
> /Mikael
> ___________________________________________________________________________________
> If your question is of interest to others as well, please add an entry to the Wiki!
> 
> maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
> webpage : https://www.pragma-ade.nl / https://context.aanhet.net (mirror)
> archive : https://github.com/contextgarden/context
> wiki : https://wiki.contextgarden.net
> ___________________________________________________________________________________

___________________________________________________________________________________
If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl
webpage  : https://www.pragma-ade.nl / https://context.aanhet.net (mirror)
archive  : https://github.com/contextgarden/context
wiki     : https://wiki.contextgarden.net
___________________________________________________________________________________