+# Functions for adding and removing shell-type quoting
+
+proc shellquote {str} {
+ if {![string match "*\['\"\\ \t]*" $str]} {
+ return $str
+ }
+ if {![string match "*\['\"\\]*" $str]} {
+ return "\"$str\""
+ }
+ if {![string match "*'*" $str]} {
+ return "'$str'"
+ }
+ return "\"[string map {\" \\\" \\ \\\\} $str]\""
+}
+
+proc shellarglist {l} {
+ set str {}
+ foreach a $l {
+ if {$str ne {}} {
+ append str " "
+ }
+ append str [shellquote $a]
+ }
+ return $str
+}
+
+proc shelldequote {str} {
+ set ret {}
+ set used -1
+ while {1} {
+ incr used
+ if {![regexp -start $used -indices "\['\"\\\\ \t]" $str first]} {
+ append ret [string range $str $used end]
+ set used [string length $str]
+ break
+ }
+ set first [lindex $first 0]
+ set ch [string index $str $first]
+ if {$first > $used} {
+ append ret [string range $str $used [expr {$first - 1}]]
+ set used $first
+ }
+ if {$ch eq " " || $ch eq "\t"} break
+ incr used
+ if {$ch eq "'"} {
+ set first [string first "'" $str $used]
+ if {$first < 0} {
+ error "unmatched single-quote"
+ }
+ append ret [string range $str $used [expr {$first - 1}]]
+ set used $first
+ continue
+ }
+ if {$ch eq "\\"} {
+ if {$used >= [string length $str]} {
+ error "trailing backslash"
+ }
+ append ret [string index $str $used]
+ continue
+ }
+ # here ch == "\""
+ while {1} {
+ if {![regexp -start $used -indices "\[\"\\\\]" $str first]} {
+ error "unmatched double-quote"
+ }
+ set first [lindex $first 0]
+ set ch [string index $str $first]
+ if {$first > $used} {
+ append ret [string range $str $used [expr {$first - 1}]]
+ set used $first
+ }
+ if {$ch eq "\""} break
+ incr used
+ append ret [string index $str $used]
+ incr used
+ }
+ }
+ return [list $used $ret]
+}
+
+proc shellsplit {str} {
+ set l {}
+ while {1} {
+ set str [string trimleft $str]
+ if {$str eq {}} break
+ set dq [shelldequote $str]
+ set n [lindex $dq 0]
+ set word [lindex $dq 1]
+ set str [string range $str $n end]
+ lappend l $word
+ }
+ return $l
+}
+