scripts/bash_aliases: Make man_lsfunc() more robust; Add sed_rm_ccomments().

This patch makes man_lsfunc() search for the function prototypes,
instead of relying on the current manual page formatting,
which might change in the future, and break this function.

It also simplifies the code, by reusing man_section().

Create a new function sed_rm_ccomments(), which is needed by
man_lsfunc(), and may also be useful in other cases.

Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

scripts/bash_aliases

@@ -20,6 +20,21 @@
 EX_OK=0;
 EX_USAGE=64;
 
+########################################################################
+#	C
+
+#  sed_rm_ccomments()  removes C comments.
+# It can't handle multiple comments in a sinlge line correctly,
+# nor mixed or embedded //... and /*...*/ comments.
+# Use as a filter (see man_lsfunc() in this file).
+
+function sed_rm_ccomments()
+{
+	sed 's%/\*.*\*/%%' \
+	|sed -E '\%/\*%,\%\*/%{\%(\*/|/\*)%!d; s%/\*.*%%; s%.*\*/%%;}' \
+	|sed 's%//.*%%';
+}
+
 ########################################################################
 #	Linux kernel
 
@@ -106,25 +121,13 @@ function man_lsfunc()
 		return ${EX_USAGE};
 	fi
 
-	find "${@}" -type f \
-	|xargs grep -l "\.SH SYNOPSIS" \
-	|sort -V \
-	|while read -r manpage; do
-		<${manpage} \
-		sed -n \
-			-e '/^\.TH/,/^\.SH/{/^\.SH/!p}' \
-			-e "/^\.SH SYNOPSIS/p" \
-			-e "/^\.SH SYNOPSIS/,/^\.SH/{/^\.SH/!p}" \
-		|sed \
-			-e '/Feature/,$d' \
-			-e '/{/,/}/d' \
-		|man -P cat -l - 2>/dev/null;
+	for arg in "$@"; do
+		man_section "${arg}" 'SYNOPSIS';
 	done \
-	|sed -n "/^SYNOPSIS/,/^\w/p" \
-	|grep '^       \w' \
-	|grep -v ':' \
-	|sed 's/^[^(]* \**\(\w*\)(.*/\1/' \
-	|grep '^\w' \
+	|sed_rm_ccomments \
+	|pcregrep -Mn '(?s)^ [\w ]+ \**\w+\([\w\s(,)[\]*]+?(...)?\s*\); *$' \
+	|grep '^[0-9]' \
+	|sed -E 's/^[^(]+ \**(\w+)\(.*/\1/' \
 	|uniq;
 }