json: Parser types

src/Parser/JSON.md

@@ -5,8 +5,92 @@ module Parser.JSON
 
 import public Parser
 import public Parser.Numbers
+
+import Structures.Dependent.DList
 ```
 
 <!-- idris
 import System
+import Derive.Prelude
+import Generics.Derive
+
+%hide Generics.Derive.Eq
+%hide Generics.Derive.Ord
+%hide Generics.Derive.Show
+
+%language ElabReflection
 -->
+
+## JSON components
+
+Types a JSON value is allowed to have
+
+```idris
+public export
+data JSONType : Type where
+  TObject : JSONType
+  TArray : JSONType
+  TString : JSONType
+  TNumber : JSONType
+  TBool : JSONType
+  TNull : JSONType
+%runElab derive "JSONType" [Generic, Meta, Eq, Ord, Show, DecEq]
+%name JSONType type, type2, type3
+```
+
+A JSON value indexed by its type
+
+```idris
+public export
+data JSONValue : JSONType -> Type where
+  VObject : {types : List JSONType} 
+    -> DList JSONType (\t => (String, JSONValue t)) types -> JSONValue TObject
+  VArray : {types : List JSONType}
+    -> DList JSONType JSONValue types -> JSONValue TArray
+  VString : (s : String) -> JSONValue TString
+  VNumber : (d : Double) -> JSONValue TNumber
+  VBool : (b : Bool) -> JSONValue TBool
+  VNull : JSONValue TNull
+%name JSONValue value, value2, value3
+```
+
+<!-- idris
+Show (JSONValue t) where
+  show (VObject xs) = 
+    let xs = dMap (\_,(key, value) => "\"\{key}\":\{show value}") xs
+    in assert_total $ "{\{joinBy "," xs}}"
+  show (VArray xs) = 
+    let xs = dMap (\_,e => show e) xs
+    in assert_total $ "[\{joinBy "," . map show $ xs}]"
+  show (VString s) = "\"\{s}\""
+  show (VNumber d) = show d
+  show (VBool False) = "false"
+  show (VBool True) = "true"
+  show VNull = "null"
+-->
+
+## Parsers
+
+We are going to get mutually recursive here. Instead of using a `mutual` block,
+we will use the more modern style of declaring all our types ahead of our
+definitions.
+
+```idris
+export
+object : Parser (JSONValue TObject)
+
+export
+array : Parser (JSONValue TArray)
+
+export
+string : Parser (JSONValue TString)
+
+export
+number : Parser (JSONValue TNumber)
+
+export
+bool : Parser (JSONValue TBool)
+
+export
+null : Parser (JSONValue TNull)
+```