preludes / elm.lisp

elm

Elm-style applications. Messages, update, commands, and Hiccup views, checked against closed vocabularies and lowered to Foldkit.

Prototype5 forms · 8 types · 109 linesForma for Elm-style apps →Source

Shared HttpApi client generation remains proposed. See the Elm prototype reference for current limits.

From the source

Purpose: Elm-style message, command, update, view, and application declarations. Requires: compiler.lisp; bootstrap separately from the ontology and HTTP API stacks. Used by: The optional TypeScript Elm linker and its Foldkit prototype examples.

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Forms 5

Keywords this prelude adds. Each is a form descriptor: its slots, their types, and the IR it produces.

(msg variant ...)elm.lisp:23

Declares message variant syntax for the Elm linker, which builds the Msg tagged type.

Slot	Type
variant	(List Syntax)

Produces ElmMessagesIR

Example

(type Model {:count Int})
(msg Increment)
(update [model message]
  Increment
  (with (assoc model :count (+ model.count 1))))
(view [model] [:div (str model.count)])
(app Counter :model Model :init (with (Model {:count 0})))

(command name operation {:keys [ok error]})elm.lisp:38

Declares a named command linked to an operation and success and optional error message syntax.

Slot	Type
name	(Declares ElmCommand)
operation	Symbol
ok	Syntax
error	(Option Syntax)

Produces ElmCommandIR · has a TypeScript :emit hook

Example

(type Model {:count Int})
(: read-count (Effect Int))
(define read-count 1)
(msg Load (Loaded {:count Int}))
(command load read-count :ok [n (Loaded {:count n})])
(update [model message]
  Load
  (with model :load)
  (Loaded {:count n})
  (with (assoc model :count n)))
(view [model] [:div (str model.count)])
(app Counter :model Model :init (with (Model {:count 0})))

(update bindings case ...)elm.lisp:63

Captures model and message bindings and update cases for the Elm linker to typecheck and lower.

Slot	Type
bindings	Syntax
case	(List Syntax)

Produces ElmUpdateIR

Example

(type Model {:count Int})
(msg Increment)
(update [model message]
  Increment
  (with (assoc model :count (+ model.count 1))))
(view [model] [:div (str model.count)])
(app Counter :model Model :init (with (Model {:count 0})))

(view bindings tree)elm.lisp:78

Captures model bindings and a Hiccup tree. The Elm linker checks element tags, attributes, and message handlers.

Slot	Type
bindings	Syntax
tree	Syntax

Produces ElmViewIR

Example

(type Model {:count Int})
(msg Increment)
(update [model message]
  Increment
  (with (assoc model :count (+ model.count 1))))
(view [model] [:div (str model.count)])
(app Counter :model Model :init (with (Model {:count 0})))

(app name {:keys [model init]})elm.lisp:93

Declares an Elm application name, model type, and initial model expression; the linker combines its messages, update, view, and commands.

Slot	Type
name	(Declares ElmApp)
model	Symbol
init	Syntax

Produces ElmAppIR · has a TypeScript :emit hook

Example

(type Model {:count Int})
(msg Increment)
(update [model message]
  Increment
  (with (assoc model :count (+ model.count 1))))
(view [model] [:div (str model.count)])
(app Counter :model Model :init (with (Model {:count 0})))

Types 8

Payload contracts and IR shapes, shown as authored.

ElmElementTagelm.lisp:9

The view linker accepts only these Hiccup element tags.

(type ElmElementTag (Union :div :span :button))

ElmTextAttributeelm.lisp:11

Text-valued Hiccup attributes; keywords select HtmlBuilder methods.

(type ElmTextAttribute (Union :class))

ElmMessageAttributeelm.lisp:13

Message-valued Hiccup event attributes checked by the Elm linker.

(type ElmMessageAttribute (Union :on-click))

ElmMessagesIRelm.lisp:15

(type ElmMessagesIR {:kind "ElmMessages" :variants (List RuntimeExpr)})

ElmCommandIRelm.lisp:16

(type ElmCommandIR
  {:kind "ElmCommand" :name Symbol :operation Symbol
   :ok RuntimeExpr :error (Option RuntimeExpr)})

ElmUpdateIRelm.lisp:19

(type ElmUpdateIR {:kind "ElmUpdate" :bindings RuntimeExpr :cases (List RuntimeExpr)})

ElmViewIRelm.lisp:20

(type ElmViewIR {:kind "ElmView" :bindings RuntimeExpr :tree RuntimeExpr})

ElmAppIRelm.lisp:21

(type ElmAppIR {:kind "ElmApp" :name Symbol :model Symbol :init RuntimeExpr})