Comment #6 on issue 5590 by
[hidden email]: Rounding a float: 10.123
round: 2 => 10.12
http://code.google.com/p/pharo/issues/detail?id=5590asInteger will truncate not round, try
0.126 round: 2.
So #asInteger must be replaced with #rounded.
As for selector name, the intention is roundToDecimalPlaces: but you may
prefer round:...
The operations are inexact but maybe it's enough for your needs, I don't
know...
It's yet better than rounTo: 0.01, because (10 raisedTo: n) is exact up to
n = 22 (5^3 < 2^7, 5^21 < 2^49, 5^22 < 2^52)
(20 to: 30) detect: [:n | (10 raisedTo: n) asFloat asInteger ~= (10
raisedTo: n)].
-> 23
Despite this good property, here is an illustration of inexactness of the
multiplication (self * (10 raisedTo: n)) :
0.995 < (995/1000) -> true, so (0.995 printShowingDecimalPlaces: 2)
-> '0.99'.
Though, (0.995 * 100) rounded -> 100, so (0.995 round: 2) -> 1.0 (once you
use rounded rather than asInteger).
If such mismatch does not matter, then proceed with the modified version
(rounded instead of asInteger).
Otherwise, the same algorithm than printString must be used.
The one in
http://ss3.gemstone.com/ss/NumberPrinter.html is better than
current usage of asTrueFraction in printShowingDecimalPlaces, because it
avoid printing of insignificand digits.
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