Powershell: Add lookbehind to fix function interpolation inside strin…

…gs. Fix #1361

components/prism-powershell.js

@@ -15,7 +15,8 @@ Prism.languages.powershell = {
 			greedy: true,
 			inside: {
 				'function': {
-					pattern: /[^`]\$\(.*?\)/,
+					pattern: /(^|[^`])\$\(.*?\)/,
+					lookbehind: true,
 					// Populated at end of file
 					inside: {}
 				}

tests/languages/powershell/string_feature.test

@@ -9,39 +9,54 @@ an empty '' string
 'can''t'
 "a simple #comment string"
 "has $interpolated <# variables #>"
+"$($expression)"
+"`$(escaped expression)"
 
 ----------------------------------------------------
 
 [
 	["string", ["\"a simple string\""]],
 	["string", [
-		"\"has ",["variable", "$interpolated"]," variables\""]
-	],
+		"\"has ", ["variable", "$interpolated"], " variables\""
+	]],
 	["string", [
-		"\"has",
+		"\"has ",
 		[
 			"function",
 			[
-				" $",
+				"$",
 				["punctuation", "("],
 				["variable", "$nesting"],
 				["operator", "-and"],
 				["string", "'interpolation'"],
 				["punctuation", ")"]
 			]
 		],
-		"\""]
-	],
+		"\""
+	]],
 	["string", ["\"string `\"with`\" escaping\""]],
 	["string", "'non-interpolated $string'"],
 	["string", "'also ''with'' escaping'"],
 	["string", "'''twas also escaped'"],
-	"\r\nan empty ",["string", "''"], " string\r\n",
+	"\r\nan empty ", ["string", "''"], " string\r\n",
 	["string", "'can''t'"],
 	["string", ["\"a simple #comment string\""]],
 	["string", [
-		"\"has ",["variable", "$interpolated"]," <# variables #>\""]
-	]
+		"\"has ", ["variable", "$interpolated"], " <# variables #>\""
+	]],
+	["string", [
+		"\"",
+		["function", [
+			"$",
+			["punctuation", "("],
+			["variable", "$expression"],
+			["punctuation", ")"]
+		]],
+		"\""
+	]],
+	["string", [
+		"\"`$(escaped expression)\""
+	]]
 ]
 
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