X-Git-Url: http://git.vpit.fr/?a=blobdiff_plain;f=README;h=a90d17bb487d2dd27003ef652960605942ba4d82;hb=d98155fce615007c0caae395a82ebd178d4b3877;hp=bc02476f9e3f05f259c232398cd3f16c35f6deb9;hpb=e9cf334a2e89126f89a80ad04241b0a83ed913b2;p=perl%2Fmodules%2Fautovivification.git diff --git a/README b/README index bc02476..a90d17b 100644 --- a/README +++ b/README @@ -2,7 +2,7 @@ NAME autovivification - Lexically disable autovivification. VERSION - Version 0.01 + Version 0.05 SYNOPSIS no autovivification; @@ -40,8 +40,12 @@ METHODS * 'fetch' Turn off autovivification for rvalue dereferencing expressions, such - as "$value = $hashref->{key}[$idx]{$field}". "undef" is returned - when the expression would have autovivified. + as "$value = $hashref->{key}[$idx]{$field}", "keys + %{$hashref->{key}}" or "values %{$hashref->{key}}". Starting from + perl 5.11, it also covers "keys" and "values" on array references. + When the expression would have autovivified, "undef" is returned for + a plain fetch, while "keys" and "values" return 0 in scalar context + and the empty list in list context. * 'exists' @@ -59,8 +63,9 @@ METHODS * 'store' Turn off autovivification for lvalue dereferencing expressions, such - as "$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). @@ -88,6 +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. @@ -120,7 +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.