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TomasVotrubaTomasVotruba
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[PHP 8.0] Add match expressions (#672)
RFC: https://wiki.php.net/rfc/match_expression_v2 Upstream implementation: php/php-src#5371 Closes #671.
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‎CHANGELOG.md‎

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@@ -1,7 +1,10 @@
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Version 4.6.1-dev
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-----------------
33

4-
Nothing yet.
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### Added
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* [PHP 8.0] Added support for match expressions. These are represented using a new `Expr\Match_`
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containing `MatchArm`s.
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Version 4.6.0 (2020-07-02)
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--------------------------

‎grammar/php5.y‎

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@@ -28,6 +28,7 @@ reserved_non_modifiers:
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| T_FUNCTION | T_CONST | T_RETURN | T_PRINT | T_YIELD | T_LIST | T_SWITCH | T_ENDSWITCH | T_CASE | T_DEFAULT
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| T_BREAK | T_ARRAY | T_CALLABLE | T_EXTENDS | T_IMPLEMENTS | T_NAMESPACE | T_TRAIT | T_INTERFACE | T_CLASS
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| T_CLASS_C | T_TRAIT_C | T_FUNC_C | T_METHOD_C | T_LINE | T_FILE | T_DIR | T_NS_C | T_HALT_COMPILER | T_FN
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| T_MATCH
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;
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semi_reserved:

‎grammar/php7.y‎

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@@ -28,6 +28,7 @@ reserved_non_modifiers:
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| T_FUNCTION | T_CONST | T_RETURN | T_PRINT | T_YIELD | T_LIST | T_SWITCH | T_ENDSWITCH | T_CASE | T_DEFAULT
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| T_BREAK | T_ARRAY | T_CALLABLE | T_EXTENDS | T_IMPLEMENTS | T_NAMESPACE | T_TRAIT | T_INTERFACE | T_CLASS
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| T_CLASS_C | T_TRAIT_C | T_FUNC_C | T_METHOD_C | T_LINE | T_FILE | T_DIR | T_NS_C | T_HALT_COMPILER | T_FN
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| T_MATCH
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;
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semi_reserved:
@@ -399,6 +400,25 @@ case_separator:
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| ';'
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;
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match:
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T_MATCH '(' expr ')' '{' match_arm_list '}' { $$ = Expr\Match_[$3, $6]; }
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;
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match_arm_list:
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/* empty */ { $$ = []; }
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| non_empty_match_arm_list optional_comma { $$ = $1; }
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;
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non_empty_match_arm_list:
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match_arm { init($1); }
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| non_empty_match_arm_list ',' match_arm { push($1, $3); }
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;
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match_arm:
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expr_list_allow_comma T_DOUBLE_ARROW expr { $$ = Node\MatchArm[$1, $3]; }
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| T_DEFAULT optional_comma T_DOUBLE_ARROW expr { $$ = Node\MatchArm[null, $4]; }
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;
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while_statement:
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statement { $$ = toArray($1); }
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| ':' inner_statement_list T_ENDWHILE ';' { $$ = $2; }
@@ -666,6 +686,7 @@ expr:
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| variable '=' expr { $$ = Expr\Assign[$1, $3]; }
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| variable '=' '&' variable { $$ = Expr\AssignRef[$1, $4]; }
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| new_expr { $$ = $1; }
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| match { $$ = $1; }
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| T_CLONE expr { $$ = Expr\Clone_[$2]; }
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| variable T_PLUS_EQUAL expr { $$ = Expr\AssignOp\Plus [$1, $3]; }
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| variable T_MINUS_EQUAL expr { $$ = Expr\AssignOp\Minus [$1, $3]; }
@@ -967,14 +988,14 @@ new_variable:
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member_name:
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identifier_ex { $$ = $1; }
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| '{' expr '}' { $$ = $2; }
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| simple_variable { $$ = Expr\Variable[$1]; }
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| '{' expr '}' { $$ = $2; }
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| simple_variable { $$ = Expr\Variable[$1]; }
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;
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property_name:
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identifier { $$ = $1; }
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| '{' expr '}' { $$ = $2; }
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| simple_variable { $$ = Expr\Variable[$1]; }
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| '{' expr '}' { $$ = $2; }
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| simple_variable { $$ = Expr\Variable[$1]; }
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| error { $$ = Expr\Error[]; $this->errorState = 2; }
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;
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‎grammar/tokens.y‎

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@@ -57,6 +57,7 @@
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%token T_ENDDECLARE
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%token T_AS
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%token T_SWITCH
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%token T_MATCH
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%token T_ENDSWITCH
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%token T_CASE
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%token T_DEFAULT

‎lib/PhpParser/Lexer/Emulative.php‎

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@@ -7,6 +7,7 @@
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use PhpParser\Lexer;
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use PhpParser\Lexer\TokenEmulator\CoaleseEqualTokenEmulator;
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use PhpParser\Lexer\TokenEmulator\FnTokenEmulator;
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use PhpParser\Lexer\TokenEmulator\MatchTokenEmulator;
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use PhpParser\Lexer\TokenEmulator\NumericLiteralSeparatorEmulator;
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use PhpParser\Lexer\TokenEmulator\TokenEmulatorInterface;
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use PhpParser\Parser\Tokens;
@@ -15,9 +16,11 @@ class Emulative extends Lexer
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{
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const PHP_7_3 = '7.3.0dev';
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const PHP_7_4 = '7.4.0dev';
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const PHP_8_0 = '8.0.0dev';
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const T_COALESCE_EQUAL = 1007;
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const T_FN = 1008;
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const T_MATCH = 1009;
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const FLEXIBLE_DOC_STRING_REGEX = <<<'REGEX'
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/<<<[ \t]*(['"]?)([a-zA-Z_\x80-\xff][a-zA-Z0-9_\x80-\xff]*)\1\r?\n
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parent::__construct($options);
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$this->tokenEmulators[] = new FnTokenEmulator();
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$this->tokenEmulators[] = new MatchTokenEmulator();
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$this->tokenEmulators[] = new CoaleseEqualTokenEmulator();
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$this->tokenEmulators[] = new NumericLiteralSeparatorEmulator();
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$this->tokenMap[self::T_COALESCE_EQUAL] = Tokens::T_COALESCE_EQUAL;
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$this->tokenMap[self::T_FN] = Tokens::T_FN;
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$this->tokenMap[self::T_MATCH] = Tokens::T_MATCH;
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}
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public function startLexing(string $code, ErrorHandler $errorHandler = null) {

‎lib/PhpParser/Lexer/TokenEmulator/FnTokenEmulator.php‎

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@@ -18,10 +18,8 @@ public function isEmulationNeeded(string $code) : bool
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public function emulate(string $code, array $tokens): array
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{
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// We need to manually iterate and manage a count because we'll change
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// the tokens array on the way
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foreach ($tokens as $i => $token) {
24-
if ($token[0] === T_STRING && $token[1] === 'fn') {
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if ($token[0] === T_STRING && strtolower($token[1]) === 'fn') {
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$previousNonSpaceToken = $this->getPreviousNonSpaceToken($tokens, $i);
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if ($previousNonSpaceToken !== null && $previousNonSpaceToken[0] === T_OBJECT_OPERATOR) {
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continue;

‎lib/PhpParser/Lexer/TokenEmulator/MatchTokenEmulator.php‎

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<?php declare(strict_types=1);
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namespace PhpParser\Lexer\TokenEmulator;
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use PhpParser\Lexer\Emulative;
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final class MatchTokenEmulator implements TokenEmulatorInterface
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{
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public function isEmulationNeeded(string $code) : bool
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{
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// skip version where this is supported
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if (version_compare(\PHP_VERSION, Emulative::PHP_8_0, '>=')) {
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return false;
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}
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return strpos($code, 'match') !== false;
17+
}
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public function emulate(string $code, array $tokens): array
20+
{
21+
foreach ($tokens as $i => $token) {
22+
if ($token[0] === T_STRING && strtolower($token[1]) === 'match') {
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$previousNonSpaceToken = $this->getPreviousNonSpaceToken($tokens, $i);
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if ($previousNonSpaceToken !== null && $previousNonSpaceToken[0] === T_OBJECT_OPERATOR) {
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continue;
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}
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$tokens[$i][0] = Emulative::T_MATCH;
29+
}
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}
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return $tokens;
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}
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/**
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* @param mixed[] $tokens
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* @return mixed[]|null
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*/
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private function getPreviousNonSpaceToken(array $tokens, int $start)
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{
41+
for ($i = $start - 1; $i >= 0; --$i) {
42+
if ($tokens[$i][0] === T_WHITESPACE) {
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continue;
44+
}
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return $tokens[$i];
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}
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return null;
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}
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}

‎lib/PhpParser/Node/Expr/Match_.php‎

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<?php declare(strict_types=1);
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namespace PhpParser\Node\Expr;
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use PhpParser\Node;
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use PhpParser\Node\MatchArm;
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class Match_ extends Node\Expr
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{
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/** @var Node\Expr */
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public $cond;
12+
/** @var MatchArm[] */
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public $arms;
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/**
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* @param MatchArm[] $arms
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*/
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public function __construct(Node\Expr $cond, array $arms = [], array $attributes = []) {
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$this->attributes = $attributes;
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$this->cond = $cond;
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$this->arms = $arms;
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}
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public function getSubNodeNames() : array {
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return ['cond', 'arms'];
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}
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public function getType() : string {
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return 'Expr_Match';
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}
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}

‎lib/PhpParser/Node/MatchArm.php‎

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<?php declare(strict_types=1);
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namespace PhpParser\Node;
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use PhpParser\Node;
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use PhpParser\NodeAbstract;
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class MatchArm extends NodeAbstract
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{
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/** @var null|Node\Expr[] */
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public $conds;
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/** @var Node\Expr */
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public $body;
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/**
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* @param null|Node\Expr[] $conds
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*/
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public function __construct($conds, Node\Expr $body, array $attributes = []) {
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$this->conds = $conds;
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$this->body = $body;
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$this->attributes = $attributes;
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}
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public function getSubNodeNames() : array {
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return ['conds', 'body'];
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}
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public function getType() : string {
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return 'MatchArm';
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}
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}

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