It appears that Tcl_GetBooleanFromObj always
calls SetBooleanFromAny which always
generates and reparses a string rep.
At the very least, a Tcl_Obj that is already
of tclBooleanType ought to just report its
internal rep. Seems it would be easy
to make more efficient conversions
from integer and internal types as well,
and leave the string processing for only
when it's really necessary.