eclass/my-god-its-full-of-quotation-marks: new eclass

Refactor duplicated my-god-its-full-of-quotation-marks "pretty"-printer
functions into shared, dedicated eclass.  Also change implementation not
to add quotes to foo=bar inputs, but only to foo=bar\ baz inputs, and to
add '\' -> '\\' and '"' -> '\"' pseudo-escapes to output so that these
characters will not introduce ambiguities in the output, if they are
present in the input.

Signed-off-by: Gregory M. Turner <gmt@be-evil.net>

1 files changed, 59 insertions, 0 deletions

diff --git a/eclass/my-god-its-full-of-quotation-marks.eclass b/eclass/my-god-its-full-of-quotation-marks.eclass
new file mode 100644
index 0000000..69f5083
--- /dev/null
+++ b/eclass/my-god-its-full-of-quotation-marks.eclass
@@ -0,0 +1,59 @@
+# Copyright 1999-2013 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+# $Header: $
+
+# @ECLASS: my-god-its-full-of-quotation-marks.eclass 
+# @MAINTAINER:
+# Gregory M. Turner <gmt@be-evil.net>
+# @AUTHOR:
+# Gregory M. Turner <gmt@be-evil.net
+# @BLURB: pretty printing for lists of arguments possibly containing spaces
+# @DESCRIPTION:
+# my-god-its-full-of-quotation-marks.eclass provides, unsurprisingly, perhaps, the
+# my-god-its-full-of-quotation-marks function.
+
+# @FUNCTION: my-god-its-full-of-quotation-marks
+# @USAGE: [list of moderately sane string arguments, each possibly containing spaces]
+# @RETURN: 0
+# @DESCRIPTION:
+# Pretty printer for configure-type arguments, which simply dumps its arguments
+# back to stdout after adding quotation marks to ensure unambiguous display
+# when some of the arguments may include spaces.  Note that this is designed for
+# consumption by human eyeballs, not parsers!!!  Use printf "%q" for the latter.
+# Here we concern ourselves only with dismbiguating the display of (otherwise
+# presumptively pre-sanitized) lists of arguments which may contain spaces.
+#
+# Also replaces any backslashes in the arguments with double-backslashes, and then
+# any quotation marks in the arguments with \". These pseudo-escapes
+# should preserve disambiguation in the face of quotation-mark- or backslash-containing
+# arguments.
+my-god-its-full-of-quotation-marks() {
+	local foo bar
+	for foo in "$@" ; do
+		# add a space if bar is nonempty
+		bar="${bar}${bar:+ }"
+		# add pseudo-escapes for '\' and '"'
+		foo="${foo//\\/\\\\}"
+		foo="${foo//\"/\\\"}"
+		case $foo in
+			"")
+				bar="${bar}\"\""
+				;;
+			*\ *=*)
+				# jesus, wtf
+				bar="${bar}\"${foo}\""
+				;;
+			*=*\ *)
+				bar="${bar}${foo%%=*}=\"${foo#*=}\""
+				;;
+			*\ *)
+				bar="${bar}\"${foo}\""
+				;;
+			*)
+				bar="${bar}${foo}"
+				;;
+		esac
+	done
+	echo "${bar}"
+}
+