I was in an interview today and the interviewer drew a bunch of binary op-trees on the board and said: "show me how you would process these." Since I had my trusty laptop with me, I said "can I write a program?" He said "sure."... so here is what I wrote. I would like to see this code optimized in terms of number of lines used. I am particularly keen on unifying my checks for simple versus complex right and left operands, in other words, the lines like 
if (ref($op_tree->[0]) eq 'ARRAY') {

[download]

It just occurred to me that some people might be thinking this would help me with my interview. But it won't the interview is over and I am just trying to improve my skills. 

use strict;


sub proc;
sub proc {
    my $op_tree = shift;
    if (ref($op_tree->[0]) eq 'ARRAY') {
        $op_tree->[0] = proc $op_tree->[0] ;
    }
    if (ref($op_tree->[2]) eq 'ARRAY') {
        $op_tree->[2] = proc $op_tree->[2] ;
    }

    my $expr = sprintf '%d %s %d', @$op_tree;
    warn "EXPR $expr";
    eval $expr;
}

my $sched1 = [ 1,       '||',   0 ];
my $sched2 = [ 1,       '&&',   0 ];
my $sched3 = [ $sched1, '&&',   1 ];
my $sched4 = [ $sched1, '&&',   $sched2 ];

warn proc $sched1;
warn proc $sched2;
warn proc $sched3;
warn proc $sched4;

[download]

Edit Masem 2001-11-13 - Small code fix

In reply to optimizing a binary expression processor by princepawn

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