commit: 5f009121094ef4e40780a09b3017ad8afe88969f
parent: 040e1d1b17c56437a976ca209c65a236d985e023
author: Chris Noxz <chris@noxz.tech>
date: Fri, 20 Sep 2019 15:36:19 +0200
Create guides section and some groff tricks
2 files changed, 83 insertions(+)
diff --git a/noxz.tech/guides/groff/index.md b/noxz.tech/guides/groff/index.md
@@ -0,0 +1,68 @@
+groff (GNU troff)
+=================
+As these guides are created for *groff*, I cannot guarantee that they are
+applicable to *troff*. If you use *troff* and can confirm them to work for it
+-- please let me know.
+
+Apart from *groff* these guides may include other programs used together with
+*groff*, such as *eqn*, *tbl*, and so on. I will try make this clear in the
+description of each guide.
+
+Crossing out expressions in *eqn*
+---------------------------------
+In the *man* page of *eqn* you can read about defining a macro for canceling an
+expression. This macro draws a line over the expression, as an indication it's
+canceled. When using paper and pen I usually use a cross instead, so this is
+how you do the same in *eqn*
+
+ \# define cancel_cross macro for expressions
+ .defcolor cancelcolor rgb 0.0f 0.0f 0.0f
+ .EQ }
+ define cancel_cross 'special Cax'
+ .EN
+ .de Cax
+ . ds 0s \
+ \Z'\\*(0s'\
+ \Z'\D't 0.75p''\
+ \m[cancelcolor]\
+ \v'\\n(0du'\
+ \D'l \\n(0wu -\\n(0hu-\\n(0du'\
+ \h'-\\n(0wu'\
+ \D'l \\n(0wu \\n(0hu+\\n(0du'\
+ \v'-\\n(0hu-\\n(0du'\
+ \Z'\D't 0.5p''\
+ \m[default]\
+ \v'\\n(0hu'
+ ..
+
+Then use it for example like this: `{ 4 times 1 } over { 4 times 5 }
+= { cancel_cross 4 times 1 } over { cancel_cross 4 times 5 }`.
+
+You can of course name your macro `cancel` instead of `cancel_cross`. The
+`cancelcolor` is also optional, and in the case above redundant.
+
+Simplify expressions in *eqn*
+-----------------------------
+When writing *eqn* expressions in *groff* it's easier to distinguish what is
+*groff* and what is *eqn* using distinct delimiters for *eqn*. This is simply
+accomplished this way:
+
+ .EQ
+ set default_rule_thickness 13
+ delim ##
+ .EN
+
+Then use it like this:
+
+ [...]
+ .LP
+ Calculate the sum of #-4# och #-7#
+ .sp 1
+ .RS
+ # (-4) + (-7) #
+
+ # = -4 - 7 #
+
+ # = -11
+ .RE
+ [...]
diff --git a/noxz.tech/guides/index.md b/noxz.tech/guides/index.md
@@ -0,0 +1,15 @@
+Guides
+======
+The following is a collection of guides, hacks, HOWTOs, tips and tricks -- I
+have acquired over the years -- for various programs and concepts. I will fill
+this list over a period of time, so it's far from complete -- and probably
+won't be.
+
+Programs
+--------
+{:: class="definition"}
+**[groff](/guides/groff)** (also called GNU troff) is a typesetting system
+that creates formatted output when given plain text mixed with formatting
+commands. Output may be PostScript or PDF, html, or ASCII/UTF8 for display at
+the terminal.
+{::}
