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Re: Appropriate last words

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From:
Larry Wall
Date:
September 3, 2018 18:15
Subject:
Re: Appropriate last words
Message ID:
20180903180935.GA29263@wall.org
On Mon, Sep 03, 2018 at 11:45:58AM -0500, Stephen Wilcoxon wrote:
: Why the change in die handling between Perl 5 and 6?  Suppressing line
: numbers with newline was very handy.  Alternatively, adding some sort of
: directive would be more straight-forward (at least for Perl 5 users moving
: to Perl 6).

Well, we did take Perl 5 users into account quite a lot, since many of
us came from that direction, and we hope more will come in the future.

On the other hand, language design is all tradeoffs, and every time you
add a low-powered feature (or keep one, in this case), you raise the
barrier to entry for folks coming from other cultures, and you waste
mindspace remembering things that don't buy you much.  For similar
reasons, <> changed to lines() and all the magic rules about which
variables are local to a loop went away. Likewise, a lot of the arcane
knowledge of how a given function behaves in scalar or list context went
away, mostly by splitting them into distinct operators that are easier
to read and document.  Of course, the tradeoff is that that are then
more operators.

So, sure, you could argue that we've just substituted one kind of arcane
knowledge for another, but at least you can justify something like

    exit note “Phooey”;

by mere function composition without appealing to the authority of
a particular paragraph in the manual.  And of course you could also
compose your own function if the situation ever rises more than once in
your program.

    my &eep = &exit ∘ &note;  eep “Phooey”;

In the specific case of this feature, one could also argue that putting
that much semantic weight on the final character of the string is
violating some kind of end-weight or one-pass principle, forcing a kind
of mental time-travel for the reader, if not for the compiler.

Anyway, don't be a language designer if you want to make everyone happy
all the time.  :-)

Well, actually, you can want it, just don't expect it... :-)

Larry

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