package require Tk
 
 proc doIndent {indent} {
    set d [string trimright [.text get 1.0 end] " \r\n"]
    set nd ""
    foreach line [split $d \n] {
         if {$indent && ([string index $line 0] != " ")} {
             set line " $line"
         }  elseif {(!$indent) && ([string index $line 0] == " ") && ([string index $line 1] != " ")} {
             set line [string range $line 1 end]
         }
         append nd $line \n
    }
    set nd [string trimright $nd " \r\n"]
    .text delete 1.0 end
    .text insert end $nd
 }
 
 text .text -yscrollcommand [list .scroll set] -font {{Lucida Console} 8}
 scrollbar .scroll -command [list .text yview]
 
 grid .text .scroll -sticky news
 grid columnconfigure . 0 -weight 1
 grid rowconfigure . 0 -weight 1
 
 bind all <F2> {doIndent 0}
 bind all <F3> {doIndent 1}

 package require Tk
 
 pack [text .t] -expand yes -fill both
 bind .t <F2> {
     set src [.t get 1.0 end-1chars]
     .t delete 1.0 end-1chars
     .t insert 1.0 [pp $src]
 }
 
 proc indentAtLine {str nr}  {
     set allLines [split $str \n]
     set lines [lrange $allLines 0 [expr {$nr - 1}]]
     set testStr [join $lines]
     set indent 0
     while {![info complete $testStr]} {
         incr indent
         append testStr \}
     }
     if {[string index [string trim [lindex $allLines $nr]] 0] eq "\}"} then {
         incr indent -1
     }
     set indentStr [string repeat " " 4]
     string repeat $indentStr $indent
 }
 
 proc pp {str} {
     set result ""
     set i 0
     foreach line [split $str \n] {
         append result " "\
                 [indentAtLine $str $i]\
                 [string trim $line]\
                 \n
         incr i
     }
     string trimright $result
 }