diff options
Diffstat (limited to 'doc/context/sources/general/manuals/lowlevel/lowlevel-grouping.tex')
| -rw-r--r-- | doc/context/sources/general/manuals/lowlevel/lowlevel-grouping.tex | 38 |
1 files changed, 12 insertions, 26 deletions
diff --git a/doc/context/sources/general/manuals/lowlevel/lowlevel-grouping.tex b/doc/context/sources/general/manuals/lowlevel/lowlevel-grouping.tex index a3bfe79c9..12d12f7f4 100644 --- a/doc/context/sources/general/manuals/lowlevel/lowlevel-grouping.tex +++ b/doc/context/sources/general/manuals/lowlevel/lowlevel-grouping.tex @@ -6,15 +6,15 @@ [title=grouping, color=middlecyan] -\startsection[title=Introduction] +\startsectionlevel[title=Introduction] This is a rather short explanation. I decided to write it after presenting the other topics at the 2019 \CONTEXT\ meeting where there was a question about grouping. -\stopsection +\stopsectionlevel -\startsection[title=\PASCAL] +\startsectionlevel[title=\PASCAL] In a language like \PASCAL, the language that \TEX\ has been written in, or \MODULA, its successor, there is no concept of grouping like in \TEX. But we can @@ -30,9 +30,9 @@ instance an assignment in \METAPOST\ uses \type {:=} too. However, the \type can have local variables in a procedure or function but the block is just a way to pack a sequence of statements. -\stopsection +\stopsectionlevel -\startsection[title=\TEX] +\startsectionlevel[title=\TEX] In \TEX\ macros (or source code) the following can occur: @@ -79,9 +79,9 @@ The bottomline is: if you want a value to persist after the group, you need to explicitly change its value globally. This makes a lot of sense in the perspective of \TEX. -\stopsection +\stopsectionlevel -\startsection[title=\METAPOST] +\startsectionlevel[title=\METAPOST] The \METAPOST\ language also has a concept of grouping but in this case it's more like a programming language. @@ -110,9 +110,9 @@ implicit. So, in \METAPOST\ all assignments are global, unless a variable is explicitly saved inside a group. -\stopsection +\stopsectionlevel -\startsection[title=\LUA] +\startsectionlevel[title=\LUA] In \LUA\ all assignments are global unless a variable is defines local: @@ -132,9 +132,9 @@ some \METAPOST\ coding or using \type {end} instead of \type {endfor} in \METAPOST\ which can make the library wait for more without triggering an error. Proper syntax highlighting in an editor clearly helps. -\stopsection +\stopsectionlevel -\startsection[title=\CCODE] +\startsectionlevel[title=\CCODE] The \LUA\ language is a mix between \PASCAL\ (which is one reason why I like it) and \CCODE. @@ -151,20 +151,6 @@ for (i=1; i<=10;i++) { The semicolon is also used in \PASCAL\ but there it is a separator and not a statement end, while in \METAPOST\ it does end a statement (expression). -\stopsection - -\stopsection - -\startsubject[title=Colofon] - -\starttabulate -\NC Author \NC Hans Hagen \NC \NR -\NC \CONTEXT \NC \contextversion \NC \NR -\NC \LUAMETATEX \NC \texengineversion \NC \NR -\NC Support \NC www.pragma-ade.com \NC \NR -\NC \NC contextgarden.net \NC \NR -\stoptabulate - -\stopsubject +\stopsectionlevel \stopdocument |