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Inline nullable checks when casting #131

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Merged
merged 1 commit into from
Jan 29, 2022
Merged

Inline nullable checks when casting #131

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27 changes: 18 additions & 9 deletions src/main/php/lang/ast/emit/PHP.class.php
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Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
UnpackExpression,
Variable
};
use lang\ast\types\{IsUnion, IsFunction, IsArray, IsMap};
use lang\ast\types\{IsUnion, IsFunction, IsArray, IsMap, IsNullable};
use lang\ast\{Emitter, Node, Type};

abstract class PHP extends Emitter {
Expand Down Expand Up @@ -234,17 +234,26 @@ protected function emitVariable($result, $variable) {
protected function emitCast($result, $cast) {
static $native= ['string' => true, 'int' => true, 'float' => true, 'bool' => true, 'array' => true, 'object' => true];

$name= $cast->type->name();
if ('?' === $name[0]) {
$result->out->write('cast(');
$this->emitOne($result, $cast->expression);
$result->out->write(',\''.$name.'\', false)');
} else if (isset($native[$name])) {
$result->out->write('('.$cast->type->literal().')');
// Inline nullable checks using ternaries
if ($cast->type instanceof IsNullable) {
$t= $result->temp();
$result->out->write('null===('.$t.'=');
$this->emitOne($result, $cast->expression);
$result->out->write(')?null:');

$name= $cast->type->element->name();
$expression= new Variable(substr($t, 1));
} else {
$name= $cast->type->name();
$expression= $cast->expression;
}

if (isset($native[$name])) {
$result->out->write('('.$name.')');
$this->emitOne($result, $expression);
} else {
$result->out->write('cast(');
$this->emitOne($result, $cast->expression);
$this->emitOne($result, $expression);
$result->out->write(',\''.$name.'\')');
}
}
Expand Down
13 changes: 13 additions & 0 deletions src/test/php/lang/ast/unittest/emit/CastingTest.class.php
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Expand Up @@ -89,6 +89,19 @@ public function run($value) {
));
}

#[Test, Values([null, 'test'])]
public function nullable_string_cast_of_expression_returning($value) {
Assert::equals($value, $this->run(
'class <T> {
public function run($value) {
$values= [$value];
return (?string)array_pop($values);
}
}',
$value
));
}

#[Test]
public function cast_braced() {
Assert::equals(['test'], $this->run(
Expand Down