Online PHP editor | refs for i4JGc

<?php function find_words($in) { // stateful stream functions $len = strlen($in); if ($len === 0) { return array(); // nothing to lex } $pos = 0; $char = $in[0]; $peek = function() use ($in, &$pos, $len) { if ($pos+1 >= $len) { return null; } return $in[$pos+1]; }; $next = function() use ($peek, &$pos, &$char) { $char = $peek(); $pos++; return $char !== null; }; // stateless helper functions $upper = function ($c) { return 'A' <= $c && $c <= 'Z'; }; $lower = function ($c) { return 'a' <= $c && $c <= 'z'; }; $alpha = function ($c) use ($upper, $lower) { return $upper($c) || $lower($c); }; $num = function ($c) { return '0' <= $c && $c <= '9'; }; $alpha_num = function ($c) use ($alpha, $num) { return $alpha($c) || $num($c); }; // lexer states do action and return next lexer state $out = array(); $find_word = null; // cyclic dependency, declare first and pass by reference to dependents $upr_word = function() use (&$out, &$char, $next, $peek, $upper, $lower, &$find_word) { $word = $char; while ($next() && $upper($char)) { if ($lower($peek())) { // start of capitalized word (e.g. FOOBar at B) break; } $word .= $char; } $out[] = $word; return $find_word; }; $std_word = function() use (&$out, &$char, $next, $lower, &$find_word) { $word = $char; while ($next() && $lower($char)) { $word .= $char; } $out[] = $word; return $find_word; }; $num_word = function() use (&$out, &$char, $next, $num, &$find_word) { $word = $char; while ($next() && $num($char)) { $word .= $char; } $out[] = $word; return $find_word; }; $find_word = function () use (&$char, $alpha_num, $upper, $lower, $next, $peek, $std_word, $upr_word, $num_word) { // consume all non-alphanumeric characters while (!$alpha_num($char)) { if (!$next()) { return null; // nothing left } } if ($upper($char)) { if ($upper($peek())) { // uppercase word return $upr_word; } return $std_word; // capitalized word } if ($lower($char)) { return $std_word; // lowercase word } return $num_word; // number }; // churn through states $state = $find_word; while ($state !== null) { $state = $state(); } return $out; } print_r(array_map(function ($in) { return array( 'in' => $in, 'out' => find_words($in), ); }, array( 'FooBar123', 'FooBAR123', 'FOOBar123', 'foo_bar_123_Baz', 'FOO_bar_123BAZ', 'FOO_Bar_123baz', 'foo_BAR_123_baz', 'foo_Bar_123_Baz', 'Foo_bar_123_BAZ', )));