Dear Monks,
doing some exercises from the Alpaca book I noticed a strange behavior of the grep operator.
The exercise was to filter the files smaller than 1000 bytes.
This code (if called with C:\perl\bin>perl script.pl N:/TEMP/*): 
#!/usr/bin/perl -l
use strict;
use warnings;
@ARGV = map{glob} @ARGV;
my @selection =  grep { -s < 1000 } @ARGV;
print for @selection;

[download]
produces the following error message: 
Warning: Use of "-s" without parentheses is ambiguous at script.pl lin
+e 7.
Unterminated <> operator at script.pl line 7.

[download]
If I use the parenthesis it runs ok: 
#!/usr/bin/perl -l
use strict;
use warnings;
@ARGV = map{glob} @ARGV;
my @selection =  grep { (-s) < 1000 } @ARGV;
print for @selection;

[download]
If I search for files bigger than 1000 the parentheses are not necessary.
It seems that perl interprets the less than sign as a part of a diamond operator.
In the answers part of the book however there is a line exact as my original line without parentheses: 
my @smaller_than_1000 = grep { -s < 1000 } @ARGV;

[download]
Is it the windows peculiarity which I have here?
Thanks in advance!
VE

In reply to The "<" in the grep block by vagabonding electron

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