Longest string challenge: Difference between revisions

=={{header|Pike}}==

things of note:

the comparison of strings is done by converting the string into an array of indices: (<code>"abc"</code> becomes <code>({ 1,2,3 })</code>)

the - operation is the set operation <math>A/B</math> and not a numerical subtraction. it removes all the elements in the second array from the first.

if there are any left, we know that the string is longer.

now, once a longer string is found we call <code>write()</code> to print it.

however we don't write it out directly, but instead we store the call in queue of pikes backend. the backend is used to handle callbacks for non-blocking I/O, and it provides a facility to call functions after a delay of time. (<code>call_out(write, 5, "foo");</code> calls write after 5 seconds with the argument foo)

before we add the new call to write, we remove all older calls to write since we don't want them anymore.

<code>return -1;</code> starts the backend, which allows pike to execute the remaining call_outs and exit.

<lang Pike>int main(int argc, array argv)

{

string longest = "";

foreach(Stdio.stdin.line_iterator();; string line)

{

if( sizeof(indices(line) - indices(longest)))

{

while(!zero_type(remove_call_out(write)));

longest = line;

call_out(write, 0, line+"\n");

}

else if( !sizeof(indices(longest) - indices(line)))

{

call_out(write, 0, line+"\n");

}

}

call_out(exit, 0.01, 0);

return -1;

}</lang>