Well I haven't received any feedback pro or con re my suggested new Tcl
function so I am going to assume that it is such a good idea that no
one sees any point in discussing it. :-) I have made two changes -
I have merged this into pgtclCmds.c and I have taken out any code for
updating tuples after the loop body runs. See comments for discussion
of this.
I have also fixed up the error checking stuff so that break, continue
and syntax errors have the expected result.