yaml / json support (#32)

* support union types

* wip

* wip json support

* implement json

* wip json and tests

* add failing tests

* full yaml implementation

* all yaml test cases pass

* json export is now valid but ill-formatted

* all tests pass for json and yaml

* correct json format with variable indentation

* fix readme

* fix last test

README.md

@@ -246,14 +246,14 @@ The test script should print "Tests successful." at the end. If it does not prin
 
 ```bash
 $ java -jar ./dhall.jar --help
-dhall.jar
+java -jar dhall.jar --flags... command
   -f --file <str>    Path to the input Dhall file (default: stdin)
+  -o --output <str>  Path to the output file (default: stdout)
   -q --quoted        Quote all strings (for Yaml output only; default is false)
   -d --documents     Create a Yaml file with document separators (for Yaml output only; default is
                      false)
   -i --indent <int>  Indentation depth for JSON and Yaml (default: 2)
-  -o --output <str>  Path to the output file (default: stdout)
-  command <str>...   Optional command: decode, encode, hash, text, type, yaml
+  command <str>...   Optional command: decode, encode, hash, text, type, yaml, json
 ```
 
 Examples: 
@@ -264,13 +264,19 @@ $ java -jar ./dhall.jar --file ./scall-cli/src/test/resources/jar-tests/3.dhall
 { True = [1.23, 4.56], a = 2, b = None Bool, c = Some "abc", y = True }
 ```
 
-Compute the type of a Dhall expression.
+Print the inferred type of a Dhall expression.
 ```bash
 $ java -jar ./dhall.jar --file ./scall-cli/src/test/resources/jar-tests/3.dhall type
 { True : List Double, a : Natural, b : Optional Bool, c : Optional Text, y : Bool }
 ```
 
-Export a Dhall expression to Yaml format.
+Compute the SHA256 hash of a Dhall expression.
+```bash
+$ java -jar ./dhall.jar --file ./scall-cli/src/test/resources/jar-tests/3.dhall hash
+sha256:e06ccdb4df3721dba87291eb49754c87955462d73df626e5e4c77de3af06e87f
+```
+
+Export a Dhall expression to Yaml format. Default indentation is 2 spaces.
 ```bash
 $ java -jar ./dhall.jar --file ./scall-cli/src/test/resources/jar-tests/3.dhall yaml
 'True':
@@ -281,8 +287,18 @@ c: abc
 'y': true
 ```
 
-Compute the SHA256 hash of a Dhall expression.
+
+Export a Dhall expression to JSON format, with 4 spaces of indentation.
 ```bash
-$ java -jar ./dhall.jar --file ./scall-cli/src/test/resources/jar-tests/3.dhall hash
-sha256:e06ccdb4df3721dba87291eb49754c87955462d73df626e5e4c77de3af06e87f
+$ java -jar ./dhall.jar --file ./scall-cli/src/test/resources/jar-tests/3.dhall --indent 4 json
+{
+    "True":   [
+        1.23,
+        4.56
+    ],
+    "a":   2,
+    "c":   "abc",
+    "y":   true
+}
 ```
+

scall-cli/src/main/scala/io/chymyst/dhall/Main.scala

@@ -15,6 +15,7 @@ object Main {
     case object Dhall   extends OutputMode
     case object Text    extends OutputMode
     case object Yaml    extends OutputMode
+    case object Json    extends OutputMode
     case object Decode  extends OutputMode
     case object Encode  extends OutputMode
     case object GetType extends OutputMode
@@ -34,22 +35,22 @@ object Main {
             val result: Array[Byte] = valueType match {
               case TypecheckResult.Valid((tpe: Expression, expr: Expression)) =>
                 outputMode match {
-                  case OutputMode.Dhall   => (expr.print + "\n").getBytes("UTF-8")
-                  case OutputMode.Text    =>
+                  case OutputMode.Dhall                  => (expr.print + "\n").getBytes("UTF-8")
+                  case OutputMode.Text                   =>
                     (expr.scheme match {
                       case ExpressionScheme.TextLiteral(List(), trailing) => trailing + "\n"
                       case s                                              => s"Error: Dhall expression should have type Text but is instead: $s\n"
                     }).getBytes("UTF-8")
-                  case OutputMode.Yaml    =>
+                  case OutputMode.Yaml | OutputMode.Json =>
                     (Yaml.toYaml(dhallFile.copy(value = expr), options) match {
                       case Left(value)  => value + "\n"
                       case Right(value) => value
                     }).getBytes("UTF-8")
-                  case OutputMode.Encode  =>
+                  case OutputMode.Encode                 =>
                     expr.toCBORmodel.encodeCbor2
-                  case OutputMode.GetType =>
+                  case OutputMode.GetType                =>
                     (tpe.print + "\n").getBytes("UTF-8")
-                  case OutputMode.GetHash =>
+                  case OutputMode.GetHash                =>
                     ("sha256:" + Semantics.semanticHash(expr, Paths.get(".")) + "\n").getBytes("UTF-8")
                 }
 
@@ -67,6 +68,7 @@ object Main {
   def parseArgs(args: Array[String]): OutputMode = args.lastOption match {
     case Some("text")   => OutputMode.Text
     case Some("yaml")   => OutputMode.Yaml
+    case Some("json")   => OutputMode.Json
     case Some("decode") => OutputMode.Decode
     case Some("encode") => OutputMode.Encode
     case Some("type")   => OutputMode.GetType
@@ -77,8 +79,8 @@ object Main {
   val defaultIndent = 2
 
   // $COVERAGE-OFF$
-  @main // This method will be called by `ParserForMethods.runOrExist()` automatically.
-  def `dhall.jar`(
+  @main                                         // This method will be called by `ParserForMethods.runOrExist()` automatically.
+  def `java -jar dhall.jar --flags... command`( // The name `dhall.jar` will be printed at the top of the help text.
     @arg(short = 'f', doc = "Path to the input Dhall file (default: stdin)")
     file: Option[String],
     @arg(short = 'o', doc = "Path to the output file (default: stdout)")
@@ -89,7 +91,7 @@ object Main {
     documents: Flag,
     @arg(short = 'i', doc = "Indentation depth for JSON and Yaml (default: 2)")
     indent: Option[Int],
-    @arg(doc = "Optional command: decode, encode, hash, text, type, yaml")
+    @arg(doc = "Optional command: decode, encode, hash, text, type, yaml, json")
     command: Leftover[String],
   ): Unit = {
     val (inputPath, inputStream) = file match {
@@ -102,12 +104,18 @@ object Main {
       case Some(outputFile) => new FileOutputStream(outputFile)
       case None             => System.out
     }
+    val outputMode               = parseArgs(command.value.toArray)
     process(
       inputPath,
       inputStream,
       outputStream,
-      parseArgs(command.value.toArray),
-      YamlOptions(quoteAllStrings = quoted.value, createDocuments = documents.value, indent = indent.getOrElse(defaultIndent)),
+      outputMode,
+      YamlOptions(
+        quoteAllStrings = quoted.value,
+        createDocuments = documents.value,
+        indent = indent.getOrElse(defaultIndent),
+        jsonFormat = outputMode == OutputMode.Json,
+      ),
     )
   }
   def main(args: Array[String]): Unit = ParserForMethods(this).runOrExit(args)

scall-cli/src/test/resources/yaml-main-cases/01.dhall

@@ -0,0 +1 @@
+{a = < A | B>.A }

scall-cli/src/test/resources/yaml-main-cases/01.json

@@ -0,0 +1,3 @@
+{
+  "a": "A"
+}

scall-cli/src/test/resources/yaml-main-cases/01.yaml

@@ -0,0 +1 @@
+a: A

scall-cli/src/test/resources/yaml-main-cases/02.dhall

@@ -0,0 +1 @@
+{a = < A | B : Natural>.B 123 }

scall-cli/src/test/resources/yaml-main-cases/02.json

@@ -0,0 +1,3 @@
+{
+  "a": 123
+}

scall-cli/src/test/resources/yaml-main-cases/02.yaml

@@ -0,0 +1 @@
+a: 123

scall-cli/src/test/resources/yaml-main-cases/03.dhall

@@ -0,0 +1 @@
+{a.b = [] : List Bool }

scall-cli/src/test/resources/yaml-main-cases/03.json

@@ -0,0 +1,5 @@
+{
+  "a": {
+    "b": []
+  }
+}

scall-cli/src/test/resources/yaml-main-cases/03.yaml

@@ -0,0 +1,2 @@
+a:
+  b: []

scall-cli/src/test/resources/yaml-main-cases/04.dhall

@@ -0,0 +1 @@
+{a.b = {=} }

scall-cli/src/test/resources/yaml-main-cases/04.json

@@ -0,0 +1,5 @@
+{
+  "a": {
+    "b": {}
+  }
+}

scall-cli/src/test/resources/yaml-main-cases/04.yaml

@@ -0,0 +1,2 @@
+a:
+  b: {}

scall-cli/src/test/resources/yaml-main-cases/05.dhall

@@ -0,0 +1 @@
+{a.b ="e" }

scall-cli/src/test/resources/yaml-main-cases/05.json

@@ -0,0 +1,5 @@
+{
+  "a": {
+    "b": "e"
+  }
+}

scall-cli/src/test/resources/yaml-main-cases/05.yaml

@@ -0,0 +1,2 @@
+a:
+  b: 'e'

scall-cli/src/test/resources/yaml-main-cases/06.dhall

@@ -0,0 +1 @@
+{a.b ="e", a.c = "f" }

scall-cli/src/test/resources/yaml-main-cases/06.json

@@ -0,0 +1,6 @@
+{
+  "a": {
+    "b": "e",
+    "c": "f"
+  }
+}

scall-cli/src/test/resources/yaml-main-cases/06.yaml

@@ -0,0 +1,3 @@
+a:
+  b: 'e'
+  c: f

scall-cli/src/test/resources/yaml-main-cases/07.dhall

@@ -0,0 +1 @@
+{a = ["e"]}

scall-cli/src/test/resources/yaml-main-cases/07.json

@@ -0,0 +1,5 @@
+{
+  "a": [
+    "e"
+  ]
+}

scall-cli/src/test/resources/yaml-main-cases/07.yaml

@@ -0,0 +1,2 @@
+a:
+  - 'e'

scall-cli/src/test/resources/yaml-main-cases/08.dhall

@@ -0,0 +1 @@
+{a = [" - c","d","e"]}

scall-cli/src/test/resources/yaml-main-cases/08.json

@@ -0,0 +1,7 @@
+{
+  "a": [
+    " - c",
+    "d",
+    "e"
+  ]
+}

scall-cli/src/test/resources/yaml-main-cases/08.yaml

@@ -0,0 +1,4 @@
+a:
+  - " - c"
+  - d
+  - 'e'

scall-cli/src/test/resources/yaml-main-cases/09.dhall

@@ -0,0 +1 @@
+{a = "a-b: c"}

scall-cli/src/test/resources/yaml-main-cases/09.json

@@ -0,0 +1,3 @@
+{
+  "a": "a-b: c"
+}

scall-cli/src/test/resources/yaml-main-cases/09.yaml

@@ -0,0 +1 @@
+a: "a-b: c"

scall-cli/src/test/resources/yaml-main-cases/10.dhall

@@ -0,0 +1 @@
+{a = ["-\n\"-\"", "a", "b"]}

scall-cli/src/test/resources/yaml-main-cases/10.json

@@ -0,0 +1,7 @@
+{
+  "a": [
+    "-\n\"-\"",
+    "a",
+    "b"
+  ]
+}

scall-cli/src/test/resources/yaml-main-cases/10.yaml

@@ -0,0 +1,6 @@
+a:
+  - |
+    -
+    "-"
+  - a
+  - b

scall-cli/src/test/resources/yaml-main-cases/11.dhall

@@ -0,0 +1 @@
+[  "-\n\"-\"", "a", "b"]

scall-cli/src/test/resources/yaml-main-cases/11.json

@@ -0,0 +1,5 @@
+[
+  "-\n\"-\"",
+  "a",
+  "b"
+]

scall-cli/src/test/resources/yaml-main-cases/11.yaml

@@ -0,0 +1,5 @@
+- |
+  -
+  "-"
+- a
+- b

scall-cli/src/test/resources/yaml-main-cases/12.dhall

@@ -0,0 +1 @@
+{a = "-\n\"-\""}

scall-cli/src/test/resources/yaml-main-cases/12.json

@@ -0,0 +1,3 @@
+{
+  "a": "-\n\"-\""
+}

scall-cli/src/test/resources/yaml-main-cases/12.yaml

@@ -0,0 +1,3 @@
+a: |
+  -
+  "-"

scall-cli/src/test/resources/yaml-main-cases/13.dhall

@@ -0,0 +1 @@
+{a = "\"abc\""}

scall-cli/src/test/resources/yaml-main-cases/13.json

@@ -0,0 +1,3 @@
+{
+  "a": "\"abc\""
+}

scall-cli/src/test/resources/yaml-main-cases/13.yaml

@@ -0,0 +1 @@
+a: "\"abc\""

scall-cli/src/test/resources/yaml-main-cases/14.dhall

@@ -0,0 +1 @@
+{a = "a-b"}

scall-cli/src/test/resources/yaml-main-cases/14.json

@@ -0,0 +1,3 @@
+{
+  "a": "a-b"
+}

scall-cli/src/test/resources/yaml-main-cases/14.yaml

@@ -0,0 +1 @@
+a: a-b

scall-cli/src/test/resources/yaml-main-cases/15.dhall

@@ -0,0 +1 @@
+{a = "-"}

scall-cli/src/test/resources/yaml-main-cases/15.json

@@ -0,0 +1,3 @@
+{
+  "a": "-"
+}

scall-cli/src/test/resources/yaml-main-cases/15.yaml

@@ -0,0 +1 @@
+a: "-"

scall-cli/src/test/resources/yaml-main-cases/16.dhall

@@ -0,0 +1 @@
+{a = [1, 2, 3], b= [4, 5]}

scall-cli/src/test/resources/yaml-main-cases/16.json

@@ -0,0 +1,11 @@
+{
+  "a": [
+    1,
+    2,
+    3
+  ],
+  "b": [
+    4,
+    5
+  ]
+}

scall-cli/src/test/resources/yaml-main-cases/16.yaml

@@ -0,0 +1,7 @@
+a:
+  - 1
+  - 2
+  - 3
+b:
+  - 4
+  - 5

scall-cli/src/test/resources/yaml-main-cases/17.dhall

@@ -0,0 +1 @@
+[{mapKey="a",mapValue=123},{mapKey="b",mapValue=456}]

scall-cli/src/test/resources/yaml-main-cases/17.json

@@ -0,0 +1,4 @@
+{
+  "a": 123,
+  "b": 456
+}

scall-cli/src/test/resources/yaml-main-cases/17.yaml

@@ -0,0 +1,2 @@
+a: 123
+b: 456

scall-cli/src/test/resources/yaml-main-cases/18.dhall

@@ -0,0 +1 @@
+{x = Some {a = 1, b = Some 2, c = None Natural}, z = None Bool, y = {c = Some 3, d = 4}}

scall-cli/src/test/resources/yaml-main-cases/18.json

@@ -0,0 +1,10 @@
+{
+  "x": {
+    "a": 1,
+    "b": 2
+  },
+  "y": {
+    "c": 3,
+    "d": 4
+  }
+}

scall-cli/src/test/resources/yaml-main-cases/18.yaml

@@ -0,0 +1,6 @@
+x:
+  a: 1
+  b: 2
+'y':
+  c: 3
+  d: 4

scall-cli/src/test/resources/yaml-main-cases/19.dhall

@@ -0,0 +1 @@
+{x = {a = 1, b = 2}, y = {c = 3, d = 4}}

scall-cli/src/test/resources/yaml-main-cases/19.json

@@ -0,0 +1,10 @@
+{
+  "x": {
+    "a": 1,
+    "b": 2
+  },
+  "y": {
+    "c": 3,
+    "d": 4
+  }
+}

scall-cli/src/test/resources/yaml-main-cases/19.yaml

@@ -0,0 +1,6 @@
+x:
+  a: 1
+  b: 2
+'y':
+  c: 3
+  d: 4

scall-cli/src/test/resources/yaml-main-cases/20.dhall

@@ -0,0 +1 @@
+[Some {a = 1, b = 2}, None { a : Natural, b : Natural },  Some {a = 3, b = 4}]

scall-cli/src/test/resources/yaml-main-cases/20.json

@@ -0,0 +1,11 @@
+[
+  {
+    "a": 1,
+    "b": 2
+  },
+  null,
+  {
+    "a": 3,
+    "b": 4
+  }
+]