From e8979feb063868c3b91b384072e2b790917e6054 Mon Sep 17 00:00:00 2001 From: Eric Abrahamsen Date: Thu, 18 Dec 2014 18:04:00 +0800 Subject: [PATCH] Mention calc-units in the spreadsheet documentation * doc/org.texi: Outline using units in tables, link to appropriate part of the Calc manual. --- doc/org.texi | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) diff --git a/doc/org.texi b/doc/org.texi index 33a6a0d..d8a5785 100644 --- a/doc/org.texi +++ b/doc/org.texi @@ -2758,6 +2758,27 @@ should be padded with 0 to the full size. You can add your own Calc functions defined in Emacs Lisp with @code{defmath} and use them in formula syntax for Calc. +Calc also comes with support for unit calculations, via the @code{calc-units} +package. For a complete list of recognized units, call +@code{calc-view-units-table}. Units can be specified with or without a space +between the number and the unit name, e.g., @samp{2 ft} is equivalent to +@samp{2ft}. Rates are handled automatically: multiplying @samp{3 m/s} by two +will give @samp{6 m / s}. By default, @code{calc-units} only defines one +units-related function for use in table formulas, @code{usimplify}, which can +take an expression such as @samp{42 km / 2.5 h} and return @samp{16.8 km / +hr}. Another useful function to define might be @code{math-convert-units}, +e.g.: + +@lisp +(defmath uconv (expr target-units &optional pure) + (math-convert-units expr target-units pure)) +@end lisp + +Which would allow you to use @samp{uconv($1, ft)} in table formulas to, for +example, convert a distance specified in cell @samp{$1} into feet. The +optional @code{pure} argument strips the units designator from the number in +the results. @xref{Units, Operating on Units,,calc}. + @node Formula syntax for Lisp @subsection Emacs Lisp forms as formulas @cindex Lisp forms, as table formulas -- 2.2.1