[RFC] Switch expression

Zend/tests/switch/001.phpt

@@ -0,0 +1,36 @@
+--TEST--
+Basic switch expression functionality test
+--FILE--
+<?php
+
+function wordify($x) {
+    return switch ($x) {
+        0 => 'Zero',
+        1 => 'One',
+        2 => 'Two',
+        3 => 'Three',
+        4 => 'Four',
+        5 => 'Five',
+        6 => 'Six',
+        7 => 'Seven',
+        8 => 'Eight',
+        9 => 'Nine',
+    };
+}
+
+for ($i = 0; $i <= 9; $i++) {
+    print wordify($i) . "\n";
+}
+
+?>
+--EXPECT--
+Zero
+One
+Two
+Three
+Four
+Five
+Six
+Seven
+Eight
+Nine

Zend/tests/switch/002.phpt

@@ -0,0 +1,19 @@
+--TEST--
+Switch expression omit trailing comma
+--FILE--
+<?php
+
+function print_bool($bool) {
+    echo switch ($bool) {
+        true => "true\n",
+        false => "false\n"
+    };
+}
+
+print_bool(true);
+print_bool(false);
+
+?>
+--EXPECT--
+true
+false

Zend/tests/switch/003.phpt

@@ -0,0 +1,24 @@
+--TEST--
+Switch expression default case
+--FILE--
+<?php
+
+function get_value($i) {
+    return switch ($i) {
+        1 => 1,
+        2 => 2,
+        default => 'default',
+    };
+}
+
+echo get_value(0) . "\n";
+echo get_value(1) . "\n";
+echo get_value(2) . "\n";
+echo get_value(3) . "\n";
+
+?>
+--EXPECT--
+default
+1
+2
+default

Zend/tests/switch/004.phpt

@@ -0,0 +1,31 @@
+--TEST--
+Switch expression with true as expression
+--FILE--
+<?php
+
+function get_range($i) {
+    return switch (true) {
+        $i >= 50 => '50+',
+        $i >= 40 => '40-50',
+        $i >= 30 => '30-40',
+        $i >= 20 => '20-30',
+        $i >= 10 => '10-20',
+        default => '0-10',
+    };
+}
+
+echo get_range(22) . "\n";
+echo get_range(0) . "\n";
+echo get_range(59) . "\n";
+echo get_range(13) . "\n";
+echo get_range(39) . "\n";
+echo get_range(40) . "\n";
+
+?>
+--EXPECT--
+20-30
+0-10
+50+
+10-20
+30-40
+40-50

Zend/tests/switch/005.phpt

@@ -0,0 +1,12 @@
+--TEST--
+Switch expression discarding result
+--FILE--
+<?php
+
+switch (1) {
+    1 => print "Executed\n",
+};
+
+?>
+--EXPECT--
+Executed

Zend/tests/switch/006.phpt

@@ -0,0 +1,10 @@
+--TEST--
+Switch expression with no cases
+--FILE--
+<?php
+
+$x = switch (true) {};
+
+?>
+--EXPECTF--
+Parse error: syntax error, unexpected '}' in %s on line %d

Zend/tests/switch/007.phpt

@@ -0,0 +1,26 @@
+--TEST--
+Switch expression exception on unhandled case
+--FILE--
+<?php
+
+function get_value($i) {
+    return switch ($i) {
+        1 => 1,
+        2 => 2,
+    };
+}
+
+echo get_value(1) . "\n";
+echo get_value(2) . "\n";
+echo get_value(3) . "\n";
+
+?>
+--EXPECTF--
+1
+2
+
+Fatal error: Uncaught UnhandledSwitchCaseError in %s
+Stack trace:
+#0 %s: get_value(3)
+#1 {main}
+  thrown in %s on line %d

Zend/tests/switch/008.phpt

@@ -0,0 +1,23 @@
+--TEST--
+Switch expression precedence
+--FILE--
+<?php
+
+print switch (!true) {
+    false => "! has higher precedence\n"
+};
+
+$throwableInterface = Throwable::class;
+print switch (new RuntimeException() instanceof $throwableInterface) {
+    true => "instanceof has higher precedence\n"
+};
+
+print switch (10 ** 2) {
+    100 => "** has higher precedence\n"
+};
+
+?>
+--EXPECT--
+! has higher precedence
+instanceof has higher precedence
+** has higher precedence

Zend/tests/switch/009.phpt

@@ -0,0 +1,25 @@
+--TEST--
+Switch expression multiple conditions per case
+--FILE--
+<?php
+
+function is_working_day($day) {
+    return switch ($day) {
+        1, 7 => false,
+        2, 3, 4, 5, 6 => true,
+    };
+}
+
+for ($i = 1; $i <= 7; $i++) {
+    var_dump(is_working_day($i));
+}
+
+?>
+--EXPECT--
+bool(false)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(false)

Zend/tests/switch/010.phpt

@@ -0,0 +1,31 @@
+--TEST--
+Switch statement multiple conditions per case
+--FILE--
+<?php
+
+function is_working_day($day) {
+    switch ($day) {
+        case 1, 7:
+            return false;
+        case 2, 3, 4, 5, 6:
+            return true;
+    };
+
+    return null;
+}
+
+for ($i = 0; $i <= 8; $i++) {
+    var_dump(is_working_day($i));
+}
+
+?>
+--EXPECT--
+NULL
+bool(false)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(true)
+bool(false)
+NULL

Zend/tests/switch/011.phpt

@@ -0,0 +1,40 @@
+--TEST--
+Pretty printing for switch expression
+--FILE--
+<?php
+
+assert(switch ('foo') { default => false });
+
+assert(switch ('foo') {
+    'foo', 'bar' => false,
+    'baz' => false,
+});
+
+assert((function () {
+    switch ('foo') {
+        case 'foo', 'bar':
+            return false;
+        case 'baz':
+            return false;
+    }
+})());
+
+?>
+--EXPECTF--
+Warning: assert(): assert('foo' switch {
+    default => false,
+}) failed in %s on line %d
+
+Warning: assert(): assert('foo' switch {
+    'foo', 'bar' => false,
+    'baz' => false,
+}) failed in %s on line %d
+
+Warning: assert(): assert(function () {
+    switch ('foo') {
+        case 'foo', 'bar':
+            return false;
+        case 'baz':
+            return false;
+    }
+}()) failed in %s on line %d

Zend/zend_ast.c

@@ -1851,23 +1851,39 @@ static ZEND_COLD void zend_ast_export_ex(smart_str *str, zend_ast *ast, int prio
 			smart_str_appendc(str, '}');
 			break;
 		case ZEND_AST_SWITCH:
-			smart_str_appends(str, "switch (");
-			zend_ast_export_ex(str, ast->child[0], 0, indent);
-			smart_str_appends(str, ") {\n");
+			if (ast->attr & ZEND_SWITCH_EXPRESSION) {
+				zend_ast_export_ex(str, ast->child[0], 0, indent);
+				smart_str_appends(str, " switch {\n");
+			} else {
+				smart_str_appends(str, "switch (");
+				zend_ast_export_ex(str, ast->child[0], 0, indent);
+				smart_str_appends(str, ") {\n");
+			}
 			zend_ast_export_ex(str, ast->child[1], 0, indent + 1);
 			zend_ast_export_indent(str, indent);
 			smart_str_appendc(str, '}');
 			break;
 		case ZEND_AST_SWITCH_CASE:
 			zend_ast_export_indent(str, indent);
-			if (ast->child[0]) {
-				smart_str_appends(str, "case ");
-				zend_ast_export_ex(str, ast->child[0], 0, indent);
-				smart_str_appends(str, ":\n");
+			if (ast->attr & ZEND_SWITCH_EXPRESSION) {
+				if (ast->child[0]) {
+					zend_ast_export_list(str, (zend_ast_list*)ast->child[0], 1, 0, indent);
+					smart_str_appends(str, " => ");
+				} else {
+					smart_str_appends(str, "default => ");
+				}
+				zend_ast_export_ex(str, ast->child[1], 0, 0);
+				smart_str_appends(str, ",\n");
 			} else {
-				smart_str_appends(str, "default:\n");
+				if (ast->child[0]) {
+					smart_str_appends(str, "case ");
+					zend_ast_export_list(str, (zend_ast_list*)ast->child[0], 1, 0, indent);
+					smart_str_appends(str, ":\n");
+				} else {
+					smart_str_appends(str, "default:\n");
+				}
+				zend_ast_export_stmt(str, ast->child[1], indent + 1);
 			}
-			zend_ast_export_stmt(str, ast->child[1], indent + 1);
 			break;
 		case ZEND_AST_DECLARE:
 			smart_str_appends(str, "declare(");

Zend/zend_ast.h

@@ -52,6 +52,7 @@ enum _zend_ast_kind {
 	ZEND_AST_STMT_LIST,
 	ZEND_AST_IF,
 	ZEND_AST_SWITCH_LIST,
+	ZEND_AST_SWITCH_CASE_COND_LIST,
 	ZEND_AST_CATCH_LIST,
 	ZEND_AST_PARAM_LIST,
 	ZEND_AST_CLOSURE_USES,