rc

[fork] interactive rc shell
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commit 9475ab261beabd848267f925940c15f9fd6eb96e
parent 7a643120366f1ea24eac5ccb759d4df616e7789b
Author: Toby Goodwin <toby@paccrat.org>
Date:   Mon, 19 Mar 2018 21:59:02 +0000

Merge branch 'master' into ifnot

Diffstat:
MChangeLog | 2++
Mmain.c | 2++
Mrc.1 | 48++++++++++++++++++++++++++++++++++++++++--------
3 files changed, 44 insertions(+), 8 deletions(-)

diff --git a/ChangeLog b/ChangeLog @@ -919,3 +919,5 @@ Changes since rc-1.5b2 2018-03-19 Feature: implement `if not`. + + Feature: default values for $nl and $tab (github #43). diff --git a/main.c b/main.c @@ -83,11 +83,13 @@ quitopts: inithash(); initparse(); assigndefault("ifs", " ", "\t", "\n", (void *)0); + assigndefault("nl", "\n", (void *)0); #ifdef DEFAULTPATH assigndefault("path", DEFAULTPATH, (void *)0); #endif assigndefault("pid", nprint("%d", rc_pid), (void *)0); assigndefault("prompt", "; ", "", (void *)0); + assigndefault("tab", "\t", (void *)0); assigndefault("version", VERSION, "$Release: @(#)" PACKAGE " " VERSION " " DESCRIPTION " $", diff --git a/rc.1 b/rc.1 @@ -1194,14 +1194,15 @@ is used to split the output into list elements. By default, .Cr $ifs has the value space-tab-newline. +.PP The braces may be omitted if the command is a single word. Thus .Cr \`ls may be used instead of .Cr "\`{ls}" . -This last feature is useful when defining functions that expand -to useful argument lists. -A frequent use is: +This last feature can be used to create shortcuts by defining functions that +expand to useful argument lists. +For example: .Ds .Cr "fn src { echo *.[chy] }" .De @@ -1211,8 +1212,8 @@ followed by .Cr "wc \`src" .De .PP -(This will print out a word-count of all C source files in the current -directory.) +This will print out a word-count of all C source files in the current +directory. .PP In order to override the value of .Cr $ifs @@ -1232,10 +1233,31 @@ For example: .PP splits up .Cr /etc/passwd -into fields, assuming that +into fields. +.PP +As a convenience, +.I rc +defines .Cr $nl -contains a newline -as its value. +to contain the newline character, and +.Cr $tab +to contain the tab character. Thus, if you want to process everything in the +current directory, but in a random order, you could use: +.Ds +.Cr "for (f in \`\` $nl {ls | shuf}) { ... process $f }" +.De +.PP +This will correctly handle filenames that contain spaces. +.PP +Note that +.I rc +scripts that use backquote substitution should avoid relying on the default +values of +.Cr $ifs , +.Cr $nl , +or +.Cr $tab . +Instead, they should explicitly set what they need. .SH "SPECIAL VARIABLES" Several variables are known to .I rc @@ -1387,6 +1409,11 @@ backquote commands for digestion as a list. On startup, assigns the list containing the characters space, tab, and newline to .Cr $ifs . .TP +.Cr nl " (default)" +Contains the newline character (see +.BR "Backquote substitution" +above). +.TP .Cr path " (alias)" This is a list of directories to search in for commands. The empty string stands for the current directory. @@ -1469,6 +1496,11 @@ usually sets to .Cr "(0 0)" . .TP +.Cr tab " (default)" +Contains the tab character (see +.BR "Backquote substitution" +above). +.TP .Cr version " (default)" On startup, the first element of this list variable is initialized to a string which identifies this version of