On: Tcl the misunderstood (2006)

[bch]

Since Tcl 8.5 (Dec 2007) interps have timed resource limits available for them.

  bch$ tclsh8.5
  % interp limit {} time -seconds [expr {[clock seconds] + 15}]
  % while 1 {set a 9} ;# 15s elapse, then...
  time limit exceeded
  bch$

edit: Add release date for Tcl 8.5