PHP: Add support for string interpolation inside double-quoted strings.

Fix #1146

components/prism-php.js

@@ -12,10 +12,6 @@
  */
 
 Prism.languages.php = Prism.languages.extend('clike', {
-	'string': {
-		pattern: /(["'])(?:\\[\s\S]|(?!\1)[^\\])*\1/,
-		greedy: true
-	},
 	'keyword': /\b(?:and|or|xor|array|as|break|case|cfunction|class|const|continue|declare|default|die|do|else|elseif|enddeclare|endfor|endforeach|endif|endswitch|endwhile|extends|for|foreach|function|include|include_once|global|if|new|return|static|switch|use|require|require_once|var|while|abstract|interface|public|implements|private|protected|parent|throw|null|echo|print|trait|namespace|final|yield|goto|instanceof|finally|try|catch)\b/i,
 	'constant': /\b[A-Z0-9_]{2,}\b/,
 	'comment': {
@@ -39,7 +35,7 @@ Prism.languages.insertBefore('php', 'keyword', {
 		pattern: /\?>|<\?(?:php|=)?/i,
 		alias: 'important'
 	},
-	'variable': /\$\w+\b/i,
+	'variable': /\$+(?:\w+\b|(?={))/i,
 	'package': {
 		pattern: /(\\|namespace\s+|use\s+)[\w\\]+/,
 		lookbehind: true,
@@ -57,6 +53,29 @@ Prism.languages.insertBefore('php', 'operator', {
 	}
 });
 
+Prism.languages.insertBefore('php', 'string', {
+	'single-quoted-string': {
+		pattern: /'(?:\\[\s\S]|[^\\'])*'/,
+		greedy: true,
+		alias: 'string'
+	},
+	'double-quoted-string': {
+		pattern: /"(?:\\[\s\S]|[^\\"])*"/,
+		greedy: true,
+		alias: 'string',
+		inside: {
+			interpolation: {
+				pattern: /{\$(?:{(?:{[^{}]+}|[^{}]+)}|[^{}])+}|(^|[^\\{])\$+(?:\w+(?:\[.+?]|->\w+)*)/,
+				lookbehind: true,
+				inside: {
+					rest: Prism.languages.php
+				}
+			}
+		}
+	}
+});
+delete Prism.languages.php['string'];
+
 // Add HTML support if the markup language exists
 if (Prism.languages.markup) {
 

tests/languages/php/string-interpolation_feature.test

@@ -0,0 +1,103 @@
+"This $variable is interpolated"
+"$foo[2], $bar[-4], $foo[$bar]"
+"$foo->bar"
+"More {$interpolation}"
+"{$arr['key']}, {$arr['foo'][3]}"
+"{${$name}}, but not {\${\$name}}"
+"the return value of getName(): {${getName()}}"
+"the return value of \$object->getName(): {${$object->getName()}}"
+"{$foo->$bar}, {$foo->{$baz[1]}}"
+
+----------------------------------------------------
+
+[
+	["double-quoted-string", [
+		"\"This ",
+		["interpolation", [["variable", "$variable"]]],
+		" is interpolated\""
+	]],
+	["double-quoted-string", [
+		"\"",
+		["interpolation", [["variable", "$foo"], ["punctuation", "["], ["number", "2"], ["punctuation", "]"]]],
+		", ",
+		["interpolation", [["variable", "$bar"], ["punctuation", "["], ["operator", "-"], ["number", "4"], ["punctuation", "]"]]],
+		", ",
+		["interpolation", [["variable", "$foo"], ["punctuation", "["], ["variable", "$bar"], ["punctuation", "]"]]],
+		"\""
+	]],
+	["double-quoted-string", [
+		"\"",
+		["interpolation", [["variable", "$foo"], ["operator", "-"], ["operator", ">"], ["property", "bar"]]],
+		"\""
+	]],
+	["double-quoted-string", [
+		"\"More ",
+		["interpolation", [["punctuation", "{"], ["variable", "$interpolation"], ["punctuation", "}"]]],
+		"\""
+	]],
+	["double-quoted-string", [
+		"\"",
+		["interpolation", [
+			["punctuation", "{"],
+			["variable", "$arr"], ["punctuation", "["], ["single-quoted-string", "'key'"], ["punctuation", "]"],
+			["punctuation", "}"]
+		]],
+		", ",
+		["interpolation", [
+			["punctuation", "{"],
+			["variable", "$arr"],
+			["punctuation", "["], ["single-quoted-string", "'foo'"], ["punctuation", "]"],
+			["punctuation", "["], ["number", "3"], ["punctuation", "]"],
+			["punctuation", "}"]
+		]],
+		"\""
+	]],
+	["double-quoted-string", [
+		"\"",
+		["interpolation", [
+			["punctuation", "{"], ["variable", "$"], ["punctuation", "{"],
+			["variable", "$name"],
+			["punctuation", "}"], ["punctuation", "}"]
+		]],
+		", but not {\\${\\$name}}\""
+	]],
+	["double-quoted-string", [
+		"\"the return value of getName(): ",
+		["interpolation", [
+			["punctuation", "{"], ["variable", "$"], ["punctuation", "{"],
+			["function", "getName"], ["punctuation", "("], ["punctuation", ")"],
+			["punctuation", "}"], ["punctuation", "}"]
+		]],
+		"\""
+	]],
+	["double-quoted-string", [
+		"\"the return value of \\$object->getName(): ",
+		["interpolation", [
+			["punctuation", "{"], ["variable", "$"], ["punctuation", "{"],
+			["variable", "$object"], ["operator", "-"], ["operator", ">"], ["function", "getName"], ["punctuation", "("], ["punctuation", ")"],
+			["punctuation", "}"], ["punctuation", "}"]
+		]],
+		"\""
+	]],
+	["double-quoted-string", [
+		"\"",
+		["interpolation", [
+			["punctuation", "{"],
+			["variable", "$foo"], ["operator", "-"], ["operator", ">"], ["variable", "$bar"],
+			["punctuation", "}"]
+		]],
+		", ",
+		["interpolation", [
+			["punctuation", "{"],
+			["variable", "$foo"], ["operator", "-"], ["operator", ">"], ["punctuation", "{"],
+			["variable", "$baz"], ["punctuation", "["], ["number", "1"], ["punctuation", "]"],
+			["punctuation", "}"],
+			["punctuation", "}"]
+		]],
+		"\""
+	]]
+]
+
+----------------------------------------------------
+
+Checks for interpolation inside strings.

tests/languages/php/string_feature.test

@@ -8,12 +8,12 @@ string'
 ----------------------------------------------------
 
 [
-	["string", "\"https://example.com\""],
-	["string", "\" /* not a comment */ \""],
-	["string", "\"multi-line\r\nstring\""],
-	["string", "'multi-line\r\nstring'"]
+	["double-quoted-string", ["\"https://example.com\""]],
+	["double-quoted-string", ["\" /* not a comment */ \""]],
+	["double-quoted-string", ["\"multi-line\r\nstring\""]],
+	["single-quoted-string", "'multi-line\r\nstring'"]
 ]
 
 ----------------------------------------------------
 
-Checks for strings with comments.
+Checks for strings.

tests/languages/php/variable_feature.test

@@ -1,13 +1,17 @@
 $f
 $foo
 $foobar_42
+$$bar
+${$foo}
 
 ----------------------------------------------------
 
 [
 	["variable", "$f"],
 	["variable", "$foo"],
-	["variable", "$foobar_42"]
+	["variable", "$foobar_42"],
+	["variable", "$$bar"],
+	["variable", "$"], ["punctuation", "{"], ["variable", "$foo"], ["punctuation", "}"]
 ]
 
 ----------------------------------------------------