Powershell: Allow for one level of nesting in expressions inside stri…

…ngs. Fix #1407

components/prism-powershell.js

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

tests/languages/powershell/issue1407.test

@@ -0,0 +1,43 @@
+While($true){
+    Write-Output "$($($InFiles | Where-Object {$_.ToCopy -eq 0}).count)"
+}
+
+----------------------------------------------------
+
+[
+	["keyword", "While"],
+	["punctuation", "("],
+	["boolean", "$true"],
+	["punctuation", ")"],
+	["punctuation", "{"],
+	["function", "Write-Output"],
+	["string", [
+		"\"",
+		["function", [
+			"$",
+			["punctuation", "("],
+			"$",
+			["punctuation", "("],
+			["variable", "$InFiles"],
+			["punctuation", "|"],
+			["function", "Where-Object"],
+			["punctuation", "{"],
+			["variable", "$_"],
+			["punctuation", "."],
+			"ToCopy ",
+			["operator", "-eq"],
+			" 0",
+			["punctuation", "}"],
+			["punctuation", ")"],
+			["punctuation", "."],
+			"count",
+			["punctuation", ")"]
+		]],
+		"\""
+	]],
+	["punctuation", "}"]
+]
+
+----------------------------------------------------
+
+Checks for nested expressions in strings.

tests/languages/powershell/string_feature.test

@@ -11,6 +11,7 @@ an empty '' string
 "has $interpolated <# variables #>"
 "$($expression)"
 "`$(escaped expression)"
+"$($($exp))"
 
 ----------------------------------------------------
 
@@ -56,6 +57,19 @@ an empty '' string
 	]],
 	["string", [
 		"\"`$(escaped expression)\""
+	]],
+	["string", [
+		"\"",
+		["function", [
+			"$",
+			["punctuation", "("],
+			"$",
+			["punctuation", "("],
+			["variable", "$exp"],
+			["punctuation", ")"],
+			["punctuation", ")"]
+		]],
+		"\""
 	]]
 ]