Subcommand of dict. Tests whether a particular key exists in a dictionary (or nested set of dictionaries).
There's a difference in behaviour between tclsh (ActiveTcl) and tclkitsh (tested with both 8.5.11):
set theDict dict create one 1 two 2 three {3 x} puts dict exists $theDict four puts dict exists $theDict three 3 puts dict exists $theDict three 4 puts dict exists $theDict two y; <=========== Difference between tclsh and tclkitsh # tclkitsh8511 dicttest.tcl 0 1 0 missing value to go with key while executing "dict exists $theDict two y" invoked from within "puts dict exists $theDict two y" (file "dicttest.tcl" line 5) # tclsh dicttest.tcl 0 1 0 0