% language=us runpath=texruns:manuals/math

\environment math-layout

\startcomponent math-numbering

\startchapter[title=Numbering]

Numbering equations can be a bit of a mess. Formuals can be unnumbers, numbered,
numbered with an associated reference. Numbers can go on the while formula and on
the rows in an alignment. Combine that with positioning left or right and left or
righ taligned formulas and the picture gets complicated. When something turns out
wrong, just let me know and the respective branch in the code can be adapted. Here
are some examples:

\startbuffer
\startplaceformula[a]
    \startformula
        (1)
    \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \getbuffer

\startbuffer
\startplaceformula[b]
    \startformula
        \startalignment
            \NC 1 \NC =     \NR
            \NC 2 \NC = (2) \NR
            \NC 3 \NC =     \NR
        \stopalignment
    \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \getbuffer

\startbuffer
\startplaceformula[c]
    \startformula
        \startalignment
            \NC 1 \NC = (3) \NR[x]
            \NC 2 \NC =     \NR
            \NC 3 \NC = (4) \NR[y]
        \stopalignment
    \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \getbuffer

\startbuffer
\startplaceformula[d]
    \startformula
        (5)
    \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \getbuffer

\startbuffer
\startplaceformula[e]
    \startformula
        (6)
    \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \getbuffer

In the next examples we demonstrate how we can avoid numbering, pass a reference as key,
use assignments instead and add a title or suffix.

\startbuffer
\startplaceformula
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[-]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[p]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[reference=foo]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[title=whatever]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[suffix=q]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[r]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \getbuffer

If you want consistent spacing you can enforce this:

\startbuffer
\startplaceformula[s]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[-]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[-]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\setupformulas[numberstrut=always]
\startplaceformula[-]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\startplaceformula[-]
    \startformula e=mc^2 \stopformula
\stopplaceformula
\stopbuffer

\typebuffer \start \showstruts \getbuffer \stop

Possible values for \type {numberstrut} are \type {yes} (the default), \type
{always} and \type {no}.

\stopchapter

\stopcomponent