Re^2: How to use sprintf %n formatting pattern

the arguments to printf need to be evaluated before printf goes about the business of generating its output

I'm not sure what you mean by this - as far as I know the arguments are scalars, and it doesn't look at them until it needs to.

I suspect you probably could achieve this with a tied scalar dynamically returning $max_width - $stored_width. I think it'd be a pretty insane thing to do unless there was some really strong reason not to split it into two prints, but I'm ok with a bit of insanity, I might have a go at it after some sleep.

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Re^3: How to use sprintf %n formatting pattern by GrandFather (Saint) on Jun 09, 2022 at 03:38 UTC
Consider: `my $str = '1234567890' x 6; my $prefixLen; printf "Prefix stuff %n%s\n", $prefixLen, substr $str, 0, 35 - $prefix +Len;` [download] What value does substr see for $prefixLen? How can printf get the substr generated parameter generated after printf has set about generating the output? Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond	[reply] [d/l]
Re^4: How to use sprintf %n formatting pattern by hv (Prior) on Jun 09, 2022 at 11:54 UTC
By using a sprintf parameter to determine the width: `my $str = '1234567890' x 6; my $prefixLen; my $magicLimit = tie_me_a_scalar(sub { $max_width - $prefixLen }); printf "Prefix stuff %n%.s", $prefixLen, $magicLimit, $str;` [download] Update: corrected `%s` to `%.s`*	[reply] [d/l] [select]
Re^5: How to use sprintf %n formatting pattern by GrandFather (Saint) on Jun 09, 2022 at 12:44 UTC
It's not clear to me how a tied scalar gets around the evaluation order issue with printf's arguments. Maybe you could provide a fully worked example? Optimising for fewest key strokes only makes sense transmitting to Pluto or beyond	[reply]