Add starlark output format

pkl-core/src/main/java/org/pkl/core/OutputFormat.java

@@ -22,6 +22,7 @@ public enum OutputFormat {
   PCF("pcf"),
   PROPERTIES("properties"),
   PLIST("plist"),
+  STARLARK("starlark"),
   TEXTPROTO("textproto"),
   XML("xml"),
   YAML("yaml");

pkl-core/src/test/files/LanguageSnippetTests/input/api/starlarkRenderer1.pkl

@@ -0,0 +1,34 @@
+import "pkl:test"
+import "pkl:starlark"
+
+class Person {
+  name: String
+  age: Int
+}
+
+typealias Email = String
+
+local renderer = new starlark.Renderer {}
+
+res1 = renderer.renderValue(123)
+res2 = renderer.renderValue(1.23)
+res3 = renderer.renderValue(false)
+res4 = renderer.renderValue("pigeon")
+res6 = renderer.renderValue(List("pigeon", "parrot"))
+res7 = renderer.renderValue(Set("pigeon", "parrot"))
+res8 = renderer.renderValue(Map("name", "pigeon", "age", 42))
+res9 = renderer.renderValue(new Listing { "pigeon"; "parrot" })
+res10 = renderer.renderValue(new Mapping { ["name"] = "pigeon"; ["age"] = 42 })
+res11 = renderer.renderValue(new Dynamic { name = "pigeon"; age = 42 })
+res12 = renderer.renderValue(new Person { name = "pigeon"; age = 42 })
+res13 = renderer.renderValue(null)
+res15 = renderer.renderValue(Pair(1, 2))
+res16 = renderer.renderValue(Pair("pigeon", List(1, 2, 3)))
+
+res14 = test.catch(() -> renderer.renderValue(1.min))
+res17 = test.catch(() -> renderer.renderValue(1.mb))
+res18 = test.catch(() -> renderer.renderValue(Person))
+res19 = test.catch(() -> renderer.renderValue(Email))
+res20 = test.catch(() -> renderer.renderValue((x) -> x))
+res21 = test.catch(() -> new starlark.Renderer { converters { [Int] = (_) -> throw("ouch") } }.renderValue(42))
+res22 = test.catch(() -> renderer.renderValue(IntSeq(1, 4)))

pkl-core/src/test/files/LanguageSnippetTests/output/api/starlarkRenderer1.pcf

@@ -0,0 +1,62 @@
+res1 = "123"
+res2 = "1.23"
+res3 = "False"
+res4 = "\"pigeon\""
+res6 = """
+  [
+      "pigeon",
+      "parrot",
+  ]
+  """
+res7 = """
+  set([
+      "pigeon",
+      "parrot",
+  ])
+  """
+res8 = """
+  {
+      "name": "pigeon",
+      "age": 42,
+  }
+  """
+res9 = """
+  [
+      "pigeon",
+      "parrot",
+  ]
+  """
+res10 = """
+  {
+      "name": "pigeon",
+      "age": 42,
+  }
+  """
+res11 = """
+  struct(
+      age = 42,
+      name = "pigeon",
+  )
+  """
+res12 = """
+  Person(
+      name = "pigeon",
+      age = 42,
+  )
+  """
+res13 = "None"
+res15 = "(1, 2)"
+res16 = """
+  ("pigeon", [
+      1,
+      2,
+      3,
+  ])
+  """
+res14 = "Cannot render value of type `Duration` as Starlark. Value: 1.min"
+res17 = "Cannot render value of type `DataSize` as Starlark. Value: 1.mb"
+res18 = "Cannot render value of type `Class` as Starlark. Value: starlarkRenderer1#Person"
+res19 = "Cannot render value of type `TypeAlias` as Starlark. Value: starlarkRenderer1#Email"
+res20 = "Cannot render value of type `Function1` as Starlark. Value: new Function1 {}"
+res21 = "ouch"
+res22 = "Cannot render value of type `IntSeq` as Starlark. Value: IntSeq(1, 4)"

pkl-core/src/test/files/LanguageSnippetTests/output/errors/cannotFindStdLibModule.err

@@ -25,6 +25,7 @@ pkl:release
 pkl:semver
 pkl:settings
 pkl:shell
+pkl:starlark
 pkl:test
 pkl:xml
 pkl:yaml

pkl-core/src/test/kotlin/org/pkl/core/EvaluateOutputTextTest.kt

@@ -42,6 +42,11 @@ class EvaluateOutputTextTest {
     checkRenderedOutput(OutputFormat.PLIST)
   }
 
+  @Test
+  fun `render Starlark`() {
+    checkRenderedOutput(OutputFormat.STARLARK)
+  }
+
   private fun checkRenderedOutput(format: OutputFormat) {
     val evaluator = EvaluatorBuilder.preconfigured().setOutputFormat(format).build()
 

pkl-core/src/test/resources/org/pkl/core/rendererTest.starlark

@@ -0,0 +1,112 @@
+int = 123
+
+float = 1.23
+
+bool = True
+
+string = "Pigeon"
+
+unicodeString = "abc😀abc😎abc"
+
+multiLineString = "have a\ngreat\nday"
+
+list = [
+    123,
+    1.23,
+    True,
+    "Pigeon",
+    "abc😀abc😎abc",
+    "have a\ngreat\nday",
+    [
+        1,
+        2,
+        3,
+    ],
+    set([
+        1,
+        2,
+        3,
+    ]),
+    {
+        "one": 1,
+    },
+    struct(
+        name = "Pigeon",
+    ),
+]
+
+set = set([
+    123,
+    1.23,
+    True,
+    "Pigeon",
+    "abc😀abc😎abc",
+    "have a\ngreat\nday",
+    [
+        1,
+        2,
+        3,
+    ],
+    set([
+        1,
+        2,
+        3,
+    ]),
+    {
+        "one": 1,
+    },
+    struct(
+        name = "Pigeon",
+    ),
+])
+
+map = {
+    "one": 123,
+    "two": 1.23,
+    "three": True,
+    "four": "Pigeon",
+    "five": "abc😀abc😎abc",
+    "six": "have a\ngreat\nday",
+    "seven": [
+        1,
+        2,
+        3,
+    ],
+    "eight": set([
+        1,
+        2,
+        3,
+    ]),
+    "nine": {
+        "one": 1,
+    },
+    "ten": struct(
+        name = "Pigeon",
+    ),
+}
+
+Person(
+    name = "typedObject",
+    address = Address(
+        street = "Folsom St.",
+    ),
+    age = 30,
+    hobbies = [
+        "swimming",
+        "gardening",
+        "reading",
+    ],
+)
+
+container = struct(
+    address = struct(
+        hobbies = [
+            "swimming",
+            "gardening",
+            "reading",
+        ],
+        street = "Folsom St.",
+    ),
+    age = 30,
+    name = "Pigeon",
+)

stdlib/base.pkl

@@ -26,6 +26,7 @@ import "pkl:jsonnet"
 import "pkl:math"
 import "pkl:pklbinary"
 import "pkl:protobuf"
+import "pkl:starlark"
 import "pkl:xml"
 import "pkl:yaml"
 
@@ -119,13 +120,15 @@ abstract external class Module {
           new protobuf.Renderer {}
         else if (format == "xml")
           new xml.Renderer {}
+        else if (format == "starlark")
+          new starlark.Renderer {}
         else if (format == "yaml")
           new YamlRenderer {}
         else if (format == "pkl-binary")
           new pklbinary.Renderer {}
         else
           throw(
-            "Unknown output format: `\(format)`. Supported formats are `json`, `jsonnet`, `pcf`, `plist`, `properties`, `textproto`, `xml`, `yaml`, `pkl-binary`."
+            "Unknown output format: `\(format)`. Supported formats are `json`, `jsonnet`, `pcf`, `plist`, `properties`, `starlark`, `textproto`, `xml`, `yaml`, `pkl-binary`."
           )
     text =
       if (renderer is ValueRenderer)