&|What|switch using -matchvar|&
&|Description|There is an error in manual|&
&|Where|http://www.tcl.tk/man/tcl/TclCmd/switch.htm|&
&|Requires|tdom, Tk|&
&|tags|switch matchvar |&
&|Updated|21.10.2011|&

----
I was looking for a solution for a problem like this:

======
 set value_01 {abc}
 set value_02 {bcd}
        
 foreach value {abc bcd cde cdde def deeef any} {
     $value_01 {...}
     $value_02 {...}
     default   {...}
 }
======

there is an example in the manual. 
I hoped this can help me, but it does not work.

http://www.tcl.tk/man/tcl/TclCmd/switch.htm
======
 set foo "abc"

 switch -regexp -matchvar foo -- $bar {
   a(b*)c {
      puts "Found [string length [lindex $foo 1]] 'b's"
   }
   d(e*)f(g*)h {
      puts "Found [string length [lindex $foo 1]] 'e's and\
            [string length [lindex $foo 2]] 'g's"
   }
 }
======
this example raise an error:
======
can't read "bar": no such variable
======

so whats on?

I did some trials:
First on the switch: "-matchvar" to correct above example

I had to change the use of the variables $bar and $foo:
   * $bar is not set
   * $foo is the matching varible inside the switch control

======
 set foo "abc"
 catch {unset bar}

 switch -regexp -matchvar bar -- $foo {
   a(b*)c {
      puts "Found [string length [lindex $bar 1]] 'b's"
   }
   d(e*)f(g*)h {
      puts "Found [string length [lindex $bar 1]] 'e's and\
            [string length [lindex $bar 2]] 'g's"
   }
 }
======

and the solution for my problem looks like this:

======
 set value_01 {abc}
 set value_02 {bcd}

 foreach value {abc bcd cde cdde def deeef any} {
    switch -regexp -matchvar foo -- $value \
        $value_01 {
                puts "\n    ... \$value_01: $value_01"
                puts   "    ...... \$value:   $value"
                puts   "    ...... \$foo:     $foo"
        } \
        $value_02 {
                puts "\n    ... \$value_02: $value_02"
                puts "      ...... \$value:   $value"
                puts "      ...... \$foo:     $foo"
        } \
        c(d*)e {
                puts "\n    ... c(d*)e"
                puts "      ...... \$value: $value"
                puts "      ...... \$foo:   $foo"
        } \
        d(e*)f {
                puts "\n    ... d(e*)f"
                puts "      ...... \$value: $value"
                puts "      ...... \$foo:   $foo"
        } \
        default {
                puts "\n    ... default"
                puts "      ...... \$value: $value"
                puts "      ...... \$foo:   $foo"
            }         
 }

======

I hope this shows the aim of the "-matchvar" switch


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