Dhall Cheatsheet for Spago PR

cheatsheet.dhall

-- Summary of https://hackage.haskell.org/package/dhall-1.40.1/docs/Dhall-Core.html#t:Expr
-- <dhall expression> -- haskell syntax

"text" -- TextLit (Chunks [] "text")
"an ${interpolatedValue} text" -- Text (Chunks [("an ", interpolatedValue)] " text")

["foo"] -- ListLit Nothing (Seq.singleton (TextLit [] "foo"))
[] : List Text -- ListLit (Just (App List Text)) Seq.empty
["foo"] # ["bar"] -- ListAppend fooExpr barExpr
["foo"] # ["bar"] # ["baz"] -- ListAppend (ListAppend fooExpr barExpr) bazExpr

{ key = "value" } -- RecordLit (Dhall.Map.singleton "key" (RecordField { recordFieldValue = "value", .. }))
recordExpr.keyName -- Field recordExpr (FieldSelection { fieldSelectionValue = "keyName", .. })
recordExpr.key1.key2 -- Field (Field recordExpr key1Selector) key2Selector
{ key = "old" } // { key = "new", addedKey = "bar" } -- Prefer oldExpr newWithAddedExpr
{ key = "old" } with key = "new" -- With oldExpr ("key" :| []) newExpr
{ key1 = { key2 = "old" } with key1.key2 = "new" -- With oldExpr ("key1" :| ["key2"]) newExpr

let x = "foo" in x -- Let (Binding { variable = "x", value = fooExpr }) (Var (V "x" 0))
let x = "A" let x = "B" in x -- Let (mkBinding "x" exprA) (Let (mkBinding "x" exprB) (Var (V "x" 0)))

./spago.dhall -- Embed importExpr

-- Not supported in Spago PR
λ(x : A) -> b -- Lam _ xBindingExpr bExpr
(λ(x : Text) -> [x]) "foo" -- App (Lam _ xExpr listExpr) fooExpr
if x then y else z -- BoolIf cond thenPath elsePath
recordExpr.{ key1, key2 } -- Project recordExpr (Left recordLitExpr)
-- not sure how to produce this... -- Project someExpr (Right [text])