Implement support for job inherits keyword

Adds the `inherits` keyword to job definitions, as described
on https://docs.gitlab.com/ee/ci/yaml/index.html#inherit.

Also examples/inherit-examples.dhall as a test & example.

Author: m4dc4p

.github/workflows/main.yml

@@ -17,3 +17,4 @@ jobs:
       - uses: dhall-lang/setup-dhall@v4
       - run: dhall text --file examples/single-job.dhall
       - run: dhall text --file examples/multiple-jobs.dhall
+      - run: dhall text --file examples/inehrit-examples.dhall

GitLab/Inherit/Type.dhall

@@ -0,0 +1,13 @@
+-- Several fields either allow you to set a global default (true/false)
+-- or a list of keywords (such as variable names). So we define `Choice`
+-- to represent those fields.
+let Choice = <Defaults : Bool | Keywords : List Text>
+
+-- Implements the `inherit` keyword provided for jobs (https://docs.gitlab.com/ee/ci/yaml/index.html#inherit)
+
+let Inherit = {
+    `default`: Optional Choice,
+    variables: Optional Choice
+}
+
+in { Inherit, Choice }

GitLab/Inherit/package.dhall

@@ -0,0 +1,7 @@
+let Types = ./Type.dhall
+
+in { Type = Types.Inherit
+, Choice = Types.Choice
+, default = None Types.Inherit
+, toJSON = ./toJSON.dhall
+}

GitLab/Inherit/toJSON.dhall

@@ -0,0 +1,32 @@
+let Prelude = ../Prelude.dhall
+
+let Optional/map = Prelude.Optional.map
+
+let Map = Prelude.Map
+
+let JSON = Prelude.JSON
+
+let dropNones = ../utils/dropNones.dhall
+
+let Types = ./Type.dhall
+
+let choiceToJSON = λ(choice : Types.Choice) → merge { 
+    Defaults = λ(b : Bool) → JSON.bool b,
+    Keywords = λ(ks : List Text) -> JSON.array
+      ( Prelude.List.map
+          Text
+          JSON.Type
+          JSON.string
+          ks
+      )
+  } choice
+
+let Inherit/toJSON : Types.Inherit → JSON.Type = λ(inherit : Types.Inherit) →
+  let everything = toMap {
+    `default` = Optional/map Types.Choice JSON.Type choiceToJSON inherit.`default`,
+    variables = Optional/map Types.Choice JSON.Type choiceToJSON inherit.variables
+  }
+
+  in  JSON.object (dropNones Text JSON.Type everything)
+
+in  Inherit/toJSON

GitLab/Job/Type.dhall

@@ -16,6 +16,8 @@ let Rule = ../Rule/Type.dhall
 
 let Trigger = ../Trigger/Type.dhall
 
+let Inherit = ../Inherit/package.dhall
+
 in  { stage : Optional Text
     , image : Optional Image
     , variables : Prelude.Map.Type Text Text
@@ -35,4 +37,5 @@ in  { stage : Optional Text
     , trigger : Optional Trigger
     , timeout : Optional Text
     , extends : List Text
+    , inherit : Optional Inherit.Type
     }

GitLab/Job/append.dhall

@@ -19,6 +19,8 @@ let Rule = ../Rule/package.dhall
 
 let Trigger = ../Trigger/package.dhall
 
+let Inherit = ../Inherit/package.dhall
+
 let mergeOptional = ../utils/mergeOptional.dhall
 
 let mergeOptionalRight = ../utils/mergeOptionalRight.dhall
@@ -60,6 +62,7 @@ let append
             mergeOptional Trigger.Type Trigger.append a.trigger b.trigger
         , timeout = mergeOptionalRight Text a.timeout b.timeout
         , extends = a.extends # b.extends
+        , inherit = mergeOptionalRight Inherit.Type a.inherit b.inherit
         }
 
 in  append

GitLab/Job/default.dhall

@@ -16,6 +16,8 @@ let Environment = ../Environment/Type.dhall
 
 let Trigger = ../Trigger/Type.dhall
 
+let Inherit = ../Inherit/package.dhall
+
 in    { stage = None Text
       , image = None Image
       , variables = Prelude.Map.empty Text Text
@@ -35,5 +37,6 @@ in    { stage = None Text
       , trigger = None Trigger
       , timeout = None Text
       , extends = [] : List Text
+      , inherit = None Inherit.Type
       }
     : ./Type.dhall

GitLab/Job/toJSON.dhall

@@ -32,6 +32,10 @@ let Optional/map = Prelude.Optional.map
 
 let Optional/toList = Prelude.Optional.toList
 
+let Inherit = ../Inherit/package.dhall
+
+let Inherit/toJSON = Inherit.toJSON
+
 in  let Job/toJSON
         : Job → JSON.Type
         = λ(job : Job) →
@@ -155,6 +159,8 @@ in  let Job/toJSON
                                         job.extends
                                     )
                                 )
+                    , inherit =
+                        Optional/map Inherit.Type JSON.Type Inherit/toJSON job.inherit
                     }
 
             in  JSON.object (dropNones Text JSON.Type everything)

GitLab/package.dhall

@@ -17,4 +17,5 @@
 , Defaults = ./Defaults/package.dhall
 , Service = ./Service/package.dhall
 , CachePolicy = ./CachePolicy/package.dhall
+, Inherit = ./Inherit/package.dhall
 }

Prelude.dhall

@@ -21,5 +21,5 @@
 -}
 
   env:DHALL_PRELUDE
-? https://raw.githubusercontent.com/dhall-lang/dhall-lang/v17.0.0/Prelude/package.dhall sha256:0c04cbe34f1f2d408e8c8b8cb0aa3ff4d5656336910f7e86190a6d14326f966d
+? https://raw.githubusercontent.com/dhall-lang/dhall-lang/v17.0.0/Prelude/package.dhall sha256:10db3c919c25e9046833df897a8ffe2701dc390fa0893d958c3430524be5a43e
 ? https://raw.githubusercontent.com/dhall-lang/dhall-lang/v17.0.0/Prelude/package.dhall