in reply to while() {}

There is some inconsistency here?.
While while() as prefix is an infinite loop: 
$ perl -MO=Deparse -e 'while() { print "1\n" }'
while (1) {
    print "1\n";
}
-e syntax OK

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as suffix never executes: 
$ perl -MO=Deparse -e 'print "1\n" while ()'
print "1\n" while ();
-e syntax OK

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Casiano

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Re^2: while() {}
by ikegami (Patriarch) on May 03, 2008 at 10:56 UTC
    The syntax for the suffix notation is 
    EXPR while EXPR;

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    and not 
    EXPR while ( EXPR );

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    Therefore, you are comparing apples and oranges.
    In while() { print "1\n" }, the expression is "".
    In print "1\n" while ();, the expression is "()", the empty list, which is false in boolean context.

    You're right about there being an inconsistency, though, just not the one you mentioned. 

    >perl -MO=Deparse -e"while() { print 1 }"
while (1) {
    print 1;
}
-e syntax OK

>perl -MO=Deparse -e"print 1 while;"
syntax error at -e line 1, at EOF
-e had compilation errors.

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