Differential D20454 Diff 48859 src/applications/fact/chart/PhabricatorComposeChartFunction.php

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src/applications/fact/chart/PhabricatorComposeChartFunction.php

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				<?php

				final class PhabricatorComposeChartFunction
				extends PhabricatorHigherOrderChartFunction {

				const FUNCTIONKEY = 'compose';

				protected function newArguments() {
				return array(
				$this->newArgument()
				->setName('f')
				->setType('function')
				->setRepeatable(true),
				);
				}

				public function evaluateFunction(array $xv) {
				$original_positions = array_keys($xv);
				$remaining_positions = $original_positions;
				foreach ($this->getFunctionArguments() as $function) {
				$xv = $function->evaluateFunction($xv);

				// If a function evaluates to "null" at some positions, we want to return
				// "null" at those positions and stop evaluating the function.

				// We also want to pass "evaluateFunction()" a natural list containing
				// only values it should evaluate: keys should not be important and we
				// should not pass "null". This simplifies implementation of functions.

				// To do this, first create a map from original input positions to
				// function return values.
				$xv = array_combine($remaining_positions, $xv);

				// If a function evaluated to "null" at any position where we evaluated
				// it, the result will be "null". We remove the position from the
				// vector so we stop evaluating it.
				foreach ($xv as $x => $y) {
				if ($y !== null) {
				continue;
				}

				unset($xv[$x]);
				}

				// Store the remaining original input positions for the next round, then
				// throw away the array keys so we're passing the next function a natural
				// list with only non-"null" values.
				$remaining_positions = array_keys($xv);
				$xv = array_values($xv);

				// If we have no more inputs to evaluate, we can bail out early rather
				// than passing empty vectors to functions for evaluation.
				if (!$xv) {
				break;
				}
				}


				$yv = array();
				$xv = array_combine($remaining_positions, $xv);
				foreach ($original_positions as $position) {
				if (isset($xv[$position])) {
				$y = $xv[$position];
				} else {
				$y = null;
				}
				$yv[$position] = $y;
				}

				return $yv;
				}

				}