Extract pipeline emulation into trait

Once php/php-src#17118 is merged, we can create a PHP 8.5 emitter which
does not include it and emits pipes natively

Author: thekid

src/main/php/lang/ast/emit/EmulatePipelines.class.php

@@ -0,0 +1,48 @@
+<?php namespace lang\ast\emit;
+
+use lang\ast\nodes\{CallableExpression, CallableNewExpression, Variable};
+
+/**
+ * Emulates pipelines
+ *
+ * @see  https://wiki.php.net/rfc/pipe-operator-v3#precedence
+ * @test lang.ast.unittest.emit.PipelinesTest
+ */
+trait EmulatePipelines {
+
+  protected function emitPipeTarget($result, $target, $arg) {
+    if ($target instanceof CallableNewExpression) {
+      $target->type->arguments= [new Variable(substr($arg, 1))];
+      $this->emitOne($result, $target->type);
+      $target->type->arguments= null;
+    } else if ($target instanceof CallableExpression) {
+      $this->emitOne($result, $target->expression);
+      $result->out->write('('.$arg.')');
+    } else {
+      $result->out->write('(');
+      $this->emitOne($result, $target);
+      $result->out->write(')('.$arg.')');
+    }
+  }
+
+  protected function emitPipe($result, $pipe) {
+
+    // $expr |> strtoupper(...) => [$arg= $expr, strtoupper($arg)][1]
+    $t= $result->temp();
+    $result->out->write('['.$t.'=');
+    $this->emitOne($result, $pipe->expression);
+    $result->out->write(',');
+    $this->emitPipeTarget($result, $pipe->target, $t);
+    $result->out->write('][1]');
+  }
+
+  protected function emitNullsafePipe($result, $pipe) {
+
+    // $expr ?|> strtoupper(...) => null === ($arg= $expr) ? null : strtoupper($arg)
+    $t= $result->temp();
+    $result->out->write('null===('.$t.'=');
+    $this->emitOne($result, $pipe->expression);
+    $result->out->write(')?null:');
+    $this->emitPipeTarget($result, $pipe->target, $t);
+  }
+}

src/main/php/lang/ast/emit/PHP.class.php

@@ -1158,40 +1158,20 @@ protected function emitNullsafeInstance($result, $instance) {
     $this->emitOne($result, $instance->member);
   }
 
-  protected function emitPipeTarget($result, $target, $arg) {
-    if ($target instanceof CallableNewExpression) {
-      $target->type->arguments= [new Variable(substr($arg, 1))];
-      $this->emitOne($result, $target->type);
-      $target->type->arguments= null;
-    } else if ($target instanceof CallableExpression) {
-      $this->emitOne($result, $target->expression);
-      $result->out->write('('.$arg.')');
-    } else {
-      $result->out->write('(');
-      $this->emitOne($result, $target);
-      $result->out->write(')('.$arg.')');
-    }
-  }
-
   protected function emitPipe($result, $pipe) {
-
-    // $expr |> strtoupper(...) => [$arg= $expr, strtoupper($arg)][1]
-    $t= $result->temp();
-    $result->out->write('['.$t.'=');
     $this->emitOne($result, $pipe->expression);
-    $result->out->write(',');
-    $this->emitPipeTarget($result, $pipe->target, $t);
-    $result->out->write('][1]');
+    $result->out->write('|>');
+    $this->emitOne($result, $pipe->target);
   }
 
   protected function emitNullsafePipe($result, $pipe) {
 
-    // $expr ?|> strtoupper(...) => null === ($arg= $expr) ? null : strtoupper($arg)
+    // $expr ?|> strtoupper(...) => null === ($t= $expr) ? null : $t |> strtoupper(...)
     $t= $result->temp();
     $result->out->write('null===('.$t.'=');
     $this->emitOne($result, $pipe->expression);
-    $result->out->write(')?null:');
-    $this->emitPipeTarget($result, $pipe->target, $t);
+    $result->out->write(')?null:'.$t.'|>');
+    $this->emitOne($result, $pipe->target);
   }
 
   protected function emitUnpack($result, $unpack) {

src/main/php/lang/ast/emit/PHP74.class.php

@@ -14,6 +14,7 @@ class PHP74 extends PHP {
     AttributesAsComments,
     CallablesAsClosures,
     ChainScopeOperators,
+    EmulatePipelines,
     MatchAsTernaries,
     NonCapturingCatchVariables,
     NullsafeAsTernaries,

src/main/php/lang/ast/emit/PHP80.class.php

@@ -21,6 +21,7 @@ class PHP80 extends PHP {
   use
     ArrayUnpackUsingMerge,
     CallablesAsClosures,
+    EmulatePipelines,
     OmitConstantTypes,
     ReadonlyClasses,
     RewriteBlockLambdaExpressions,

src/main/php/lang/ast/emit/PHP81.class.php

@@ -20,6 +20,7 @@
  */
 class PHP81 extends PHP {
   use
+    EmulatePipelines,
     RewriteBlockLambdaExpressions,
     RewriteDynamicClassConstants,
     RewriteStaticVariableInitializations,

src/main/php/lang/ast/emit/PHP82.class.php

@@ -20,6 +20,7 @@
  */
 class PHP82 extends PHP {
   use
+    EmulatePipelines,
     RewriteBlockLambdaExpressions,
     RewriteDynamicClassConstants,
     RewriteStaticVariableInitializations,

src/main/php/lang/ast/emit/PHP83.class.php

@@ -18,7 +18,7 @@
  * @see  https://wiki.php.net/rfc#php_83
  */
 class PHP83 extends PHP {
-  use RewriteBlockLambdaExpressions, RewriteProperties;
+  use EmulatePipelines, RewriteBlockLambdaExpressions, RewriteProperties;
 
   public $targetVersion= 80300;
 

src/main/php/lang/ast/emit/PHP84.class.php

@@ -18,7 +18,7 @@
  * @see  https://wiki.php.net/rfc#php_84
  */
 class PHP84 extends PHP {
-  use RewriteBlockLambdaExpressions;
+  use EmulatePipelines, RewriteBlockLambdaExpressions;
 
   public $targetVersion= 80400;