Version 0 of Dangerous constructs

Updated 2003-11-12 07:29:04

Arjen Markus (12 november 2003) In response to a recent discussion on the c.l.t. about a problem that arose in the context of regular expressions, I have started this page. Its sole purpose: document dangerous constructs in Tcl


Using the subst command on arbitrary data:

   set a "Hello,"
   set b "world!"
   set string "$a $b"
   puts [substr $string]

gives:

 Hello, world!

but:

   set string "\[exit\]"
   puts [subst $string]

stops you program!

The subst command allows you to suppress the execution of commands:

   puts [subst -nocommands $string]

gives:

  [exit]

Please: the next!


[ Arts and crafts of Tcl-Tk programming ]