diff options
Diffstat (limited to 'pod/perldelta.pod')
| -rw-r--r-- | pod/perldelta.pod | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/pod/perldelta.pod b/pod/perldelta.pod index 7400940dca..5c99211e62 100644 --- a/pod/perldelta.pod +++ b/pod/perldelta.pod @@ -169,6 +169,23 @@ also return the undefined value if a subroutine's return value will not be used at all, which allows subroutines to avoid a time-consuming calculation of a return value if it isn't going to be used. +=head2 C<eval EXPR> determines value of EXPR in scalar context + +Perl (version 5) used to determine the value of EXPR inconsistently, +sometimes incorrectly using the surrounding context for the determination. +Now, the value of EXPR (before being parsed by eval) is always determined in +a scalar context. Once parsed, it is executed as before, by providing +the context that the scope surrounding the eval provided. This change +makes the behavior Perl4 compatible, besides fixing bugs resulting from +the inconsistent behavior. This program: + + @a = qw(time now is time); + print eval @a; + print '|', scalar eval @a; + +used to print something like "timenowis881399109|4", but now (and in perl4) +prints "4|4". + =head2 Changes to tainting checks A bug in previous versions may have failed to detect some insecure |