diff -r ac5833ebe6d1 -r 78a2030240f1 src/Pure/General/js.scala
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/General/js.scala	Fri Nov 11 21:35:33 2022 +0100
@@ -0,0 +1,39 @@
+/*  Title:      Pure/General/json.scala
+    Author:     Makarius
+
+Support for JavaScript syntax.
+*/
+
+package isabelle
+
+
+object JS {
+  /* basic syntax */
+
+  type Source = String
+
+  def arguments(args: Source*): Source = args.mkString("(", ", ", ")")
+  def function(f: Source, args: Source*): Source = f + arguments(args: _*)
+  def selection(a: Source, arg: Source): Source = a + "[" + arg + "]"
+
+  def commands(args: Source*): Source = args.mkString("; ")
+  def command_list(args: List[Source]): Source = args.mkString("; ")
+
+
+  /* JSON values */
+
+  def value(t: JSON.T): Source = JSON.Format(t)
+  def string(s: String): Source = value(s)
+
+  def json_parse(arg: Source): Source = function("JSON.parse", arg)
+  def json_print(arg: Source): Source = function("JSON.stringify", arg)
+
+
+  /* file-system operations */
+
+  def standard_path(p: Path, dir: Boolean = false): Source =
+    string(File.standard_path(p) + (if (dir) "/" else ""))
+
+  def platform_path(p: Path, dir: Boolean = false): Source =
+    string(File.platform_path(p) + (if (dir) File.platform_path(Path.root) else ""))
+}