2017-06-19 15:35:00

2 files changed, 54 insertions, 5 deletions

diff --git a/doc/context/sources/general/manuals/luatex/luatex-math.tex b/doc/context/sources/general/manuals/luatex/luatex-math.tex
index f8383e974..33b57ff3e 100644
--- a/doc/context/sources/general/manuals/luatex/luatex-math.tex
+++ b/doc/context/sources/general/manuals/luatex/luatex-math.tex
@@ -1227,6 +1227,28 @@ formula.
 
 % if needed we can put the value in stylenodes but maybe more should go there
 
+\subsection{Penalties: \type {\mathpenaltiesmode}}
+
+Only in inline math penalties will be added in a math list. You can force
+penalties (also in display math) by setting:
+
+\starttyping
+\mathpenaltiesmode = 1
+\stoptyping
+
+This primnitive is not really needed in \LUATEX\ because you can use the callback
+\type {mlist_to_hlist} to force penalties by just calling the regular routine
+with forced penalties. However, as part of opening up and control this primitive
+makes sense. As a bonus we also provide two extra penalties:
+
+\starttyping
+\prebinoppenalty = -100 % example value
+\prerelpenalty   =  900 % example value
+\stoptyping
+
+They default to inifinite which signals that they don't need to be inserted. When
+set they are injected before a binop or rel noad. This is an experimental feature.
+
 \subsection {Tracing}
 
 Because there are quite some math related parameters and values, it is possible
diff --git a/doc/context/sources/general/manuals/math/math-spacing.tex b/doc/context/sources/general/manuals/math/math-spacing.tex
index 02f2c71a8..3a665a7d8 100644
--- a/doc/context/sources/general/manuals/math/math-spacing.tex
+++ b/doc/context/sources/general/manuals/math/math-spacing.tex
@@ -397,24 +397,51 @@ Of course better is to fix the font.
 Inline formulas can span lines but display math normally sits on one line unless
 one uses alignment mechanisms. Take this:
 
-\startbuffer
+\startbuffer[demo]
 \startformula
     x\dorecurse{30}{ + #1x^{#1x}} = 10
 \stopformula
 \stopbuffer
 
-\typebuffer
+\typebuffer[demo]
 
-\par \start \setupformula[split=no]  \getbuffer \stop \par
+\par \start \setupformula[split=no]  \getbuffer[demo] \stop \par
 
 You can set \type {split} to \type {yes} using \type {\setupformula} and get the
 following:
 
-\par \start \setupformula[split=yes] \getbuffer \stop \par
+\par \start \setupformula[split=yes] \getbuffer[demo] \stop \par
 
 Maybe nicer is to also set \type {align} to \type {flushleft}:
 
-\par \start \setupformula[split=yes,align=flushleft] \getbuffer \stop \par
+\par \start \setupformula[split=yes,align=flushleft] \getbuffer[demo] \stop \par
+
+If you want the binary operators to start the lines you can set this:
+
+\startbuffer[setup]
+\setupmathematics[setups=math:spacing:split]
+\setupformulas[split=yes,align=flushleft]
+\stopbuffer
+
+\typebuffer[setup]
+
+\par \start \getbuffer[setup,demo] \stop \par
+
+You can prevent a split with a large penalty. Here is a test that yuou can run
+to play with this feature:
+
+\starttyping
+\dostepwiserecurse {30} {100} {1} {
+    \hsize \dimexpr 40pt + #1pt \relax
+    \startformula
+        y = a \dorecurse {50} {
+            \penalty 10000 {\bf + ##1b}
+             + ##1c^2
+        }
+    \stopformula
+    \page
+}
+\stoptyping
 
 There is an experimental alignment mechanism available. Watch the following
 examples: