while(<>){print if (m/foo/i)}
works quite well. It does what I expected it to do. It reads lines from STDIN and prints them if they match.

print while(<>)
also does what I expect it to do, it prints every line from STDIN.

print if(m/foo/i)
also does what I thought it would. It prints $_ if it matches foo.

print if(m/foo/i) while(<DICT>);
doesn't compile. Instead, I get an error message.

C:\>perl -e "use diagnostics; print if (m/foo/i) while(<>)"
syntax error at -e line 1, near ") while"
Execution of -e aborted due to compilation errors (#1)
Uncaught exception from user code:
        syntax error at -e line 1, near ") while"
Execution of -e aborted due to compilation errors.

[download]
.

It makes sense to me, the way I've written it. Maybe I'm asking perl to do to much magic with the if infront of the while. I've tried to find the answer in perlman:perlsyn and the camel (2nd ed.) but haven't had any luck. Maybe I'm not looking in the right place. Can anyone please shed some light?

In reply to Perl and the magic of the perl compiler by coolmichael

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