There may be many handlers, each of which is described by 4 words. There are currently two types of handler defined:
- on code variableList script
- Exact matching of the exception code (i.e. the value returned by a catch).
- trap errorPrefixList variableList script
- List-prefix matching of the errorcode.
Documentation
http://www.tcl.tk/man/tcl8.6/TclCmd/try.htm