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#640 [try] desired missing funciton

open
Don Porter
18. Commands M-Z (28)
5
2012-11-30
2012-11-30
Don Porter
No

The recipe

catch $script m o
return -options $o $m

lets me reproduce what evaluation of $script
alone would do. Other than the variables m and o
and some trivial unimportant things, they are
indistinguishable. Most importantly to me
they leave the same -errorinfo value in the
interp to be captured by another enclosing [catch].

I want some set of options to [try] to be able to
do the same thing. Right now, that appears
impossible because [try] seems to be pretty
insistent on leaving decorations on the errorInfo
value.

Since I have the [catch; return] combo that does what
I want, you might ask why that's not enough. Well
there are some places where only a single command
will do.

A [tailcall try $script] that didn't leave [try] droppings
on the stack trace would be nice.

Discussion

  • Donal K. Fellows

    Donal K. Fellows - 2012-12-01

    I'm not sure what the right thing to do here is.

    The offending message is tclCmdMZ.c:4393 (i.e., the *second* place in the function TryPostBody that looks like it is relevant; the first is in the unwind/limit handling).

     

  • Alexandre Ferrieux

    Alexandre Ferrieux - 2012-12-01

    As a side note, it turns out that [info errorstack] is unaffected (being only concerned with scope levels, not with internal constructs like [while] or, for that matter, [try] or [catch]):

    % proc f {} g
    % proc g {} {try {error FOO} on error {m o} {return -options $o $m}}
    % f
    FOO
    % info errorstack
    INNER {returnStk FOO} CALL g CALL f

    % proc f2 {} g2
    % proc g2 {} {error FOO}
    % f2
    FOO
    % info errorstack
    INNER {returnStk FOO} CALL g2 CALL f2