New feature in #Tcl9 – part 30:

clock scan ... -validate ...

With Tcl 8.6 you could just write `clock scan 2026-01-34` and Tcl would spit out "1770044400" which is equivalent to "Tue Feb 03 00:00:00 JST 2026". But maybe, you want to avoid such invalid dates in the first place. Who says I meant Feb3? It could have been a type from a user?

This is now possible with the `-validate` option. If true (and this is the default now), you will get an "invalid day" error. Very convenient!