X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=README;h=a90d17bb487d2dd27003ef652960605942ba4d82;hb=125c37754d5bbb6bdd09036f7fdc48fcd11994e9;hp=88c204c741053cbce03bceb198849f31fe385161;hpb=029cd913066b88040c4efaa966c96bf2d4e584d9;p=perl%2Fmodules%2Fautovivification.git diff --git a/README b/README index 88c204c..a90d17b 100644 --- a/README +++ b/README @@ -2,7 +2,7 @@ NAME autovivification - Lexically disable autovivification. VERSION - Version 0.02 + Version 0.05 SYNOPSIS no autovivification; @@ -41,10 +41,11 @@ METHODS Turn off autovivification for rvalue dereferencing expressions, such as "$value = $hashref->{key}[$idx]{$field}", "keys - %{$hashref->{key}}" or "values %{$hashref->{key}}". When the - expression would have autovivified, "undef" is returned for a plain - fetch, while "keys" and "values" return 0 in scalar context and the - empty list in list context. + %{$hashref->{key}}" or "values %{$hashref->{key}}". Starting from + perl 5.11, it also covers "keys" and "values" on array references. + When the expression would have autovivified, "undef" is returned for + a plain fetch, while "keys" and "values" return 0 in scalar context + and the empty list in list context. * 'exists' @@ -62,8 +63,9 @@ METHODS * 'store' Turn off autovivification for lvalue dereferencing expressions, such - as "$hashref->{key}[$idx]{$field} = $value". An exception is thrown - if vivification is needed to store the value, which means that + as "$hashref->{key}[$idx]{$field} = $value" or "for + ($hashref->{key}[$idx]{$field}) { ... }". An exception is thrown if + vivification is needed to store the value, which means that effectively you can only assign to levels that are already defined (in the example, this would require "$hashref->{key}[$idx]" to already be a hash reference). @@ -91,6 +93,14 @@ METHODS When @opts is empty, it defaults to restoring the original Perl autovivification behaviour. +CAVEATS + The pragma doesn't apply when one dereferences the returned value of an + array or hash slice, as in "@array[$id]->{member}" or + @hash{$key}->{member}. This syntax is valid Perl, yet it's discouraged + as the slice is here useless since the dereferencing enforces scalar + context. If warnings are turned on, Perl will complain about one-element + slices. + DEPENDENCIES perl 5.8. @@ -123,7 +133,7 @@ ACKNOWLEDGEMENTS Matt S. Trout asked for it. COPYRIGHT & LICENSE - Copyright 2009 Vincent Pit, all rights reserved. + Copyright 2009,2010 Vincent Pit, all rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.