redo - start this loop iteration over again |
redo - start this loop iteration over again
redo LABEL
redo
The redo
command restarts the loop block without evaluating the
conditional again. The continue
block, if any, is not executed. If
the LABEL is omitted, the command refers to the innermost enclosing
loop. Programs that want to lie to themselves about what was just input
normally use this command:
# a simpleminded Pascal comment stripper # (warning: assumes no { or } in strings) LINE: while (<STDIN>) { while (s|({.*}.*){.*}|$1 |) {} s|{.*}| |; if (s|{.*| |) { $front = $_; while (<STDIN>) { if (/}/) { # end of comment? s|^|$front\{|; redo LINE; } } } print; }
redo
cannot be used to retry a block which returns a value such as
eval {}
, sub {}
or do {}
, and should not be used to exit
a grep()
or map()
operation.
Note that a block by itself is semantically identical to a loop
that executes once. Thus redo
inside such a block will effectively
turn it into a looping construct.
See also continue in the perlfunc manpage for an illustration of how last
, next
, and
redo
work.
redo - start this loop iteration over again |