public function parenthesize(Node $node, ExpressionNode $cutoff, $prepend = '', $conservative = false)
{
$text = $node->accept($this);
if ($node instanceof ExpressionNode) {
// Second term is a unary minus
if ($node->getOperator() == '-' && $node->getRight() == null) {
return "({$text})";
}
if ($cutoff->getOperator() == '-' && $node->lowerPrecedenceThan($cutoff)) {
return "({$text})";
}
if ($conservative) {
// Add parentheses more liberally for / and ^ operators,
// so that e.g. x/(y*z) is printed correctly
if ($cutoff->getOperator() == '/' && $node->lowerPrecedenceThan($cutoff)) {
return "({$text})";
}
if ($cutoff->getOperator() == '^' && $node->getOperator() == '^') {
return "({$text})";
}
}
if ($node->strictlyLowerPrecedenceThan($cutoff)) {
return "({$text})";
}
}
if (($node instanceof NumberNode || $node instanceof IntegerNode || $node instanceof RationalNode) && $node->getValue() < 0) {
return "({$text})";
}
// Treat rational numbers as divisions on printing
if ($node instanceof RationalNode && $node->getDenominator() != 1) {
$fakeNode = new ExpressionNode($node->getNumerator(), '/', $node->getDenominator());
if ($fakeNode->lowerPrecedenceThan($cutoff)) {
return "({$text})";
}
}
return "{$prepend}{$text}";
}
/**
* Add curly braces around the LaTex representation of $node if needed.
*
* Nodes representing a single ConstantNode, VariableNode or NumberNodes (0--9)
* are returned as-is. Other Nodes get curly braces around their LaTeX code.
*
* @param Node $node AST to parse
* @retval string
*/
public function bracesNeeded(Node $node)
{
if ($node instanceof VariableNode || $node instanceof ConstantNode) {
return $node->accept($this);
} elseif ($node instanceof IntegerNode && $node->getValue() >= 0 && $node->getValue() <= 9) {
return $node->accept($this);
} else {
return '{' . $node->accept($this) . '}';
}
}
