Targets · JSON · Array format

Array format

Every canonical node in the array form, keyword by keyword — the exact JSON that the Structure types serialise to. Field types and shared nodes link back to their definition on the Structure page.

JSON is the canonical command form every module is stored in — the interchange the other targets render from, not a language you run. These pages describe that form.

Introduction — what the JSON form is, and how to read the rest of this section.
Capabilities — which high-level features are possible — deferred to whichever target this JSON renders to.
Example — a full program using every keyword, in the canonical JSON form.
Naming considerations — how Program's dotted names are stored, verbatim and un-munged.
Object format — every node in the self-describing object form, keyword by keyword.
Array format — every node in the compact tagged-array form, keyword by keyword.
Project setup — there is no build; how a module file is stored, read and rendered onward.
Reserved words — why the canonical form has none, and never escapes a name.

Conventions

How each shape maps into array form, node by node:

Case	Object based	Array based
A keyword node	an object under its keyword, `{ "MODULE": { … } }`	a tagged array, `["MODULE", …]`
A union value (one option chosen from several)	a single-key object `{ "<option>": value }`	a two-element array `["<option>", value]`
An optional value that is absent	the field is `null`	the position is `null`
An optional value at the end of an array	the key is omitted	the trailing position is dropped entirely
A union option carrying no data (e.g. a direction)	the bare option name, `"binding"`	the bare option name, `"binding"`
An identifier (a declared name)	the bare name string, `"Greet"`	the bare name string, `"Greet"`

ROOT

["ROOT",
  [ ["MODULE", "App", [], [], [], [], [], []] ],
  [ ["NATIVE", "js", "globalThis.__boot = true;"] ],
  [ ["CALL", "App.Main", [], []] ]
]

ROOT keyword JSON array definition

Position	Type	Description
0 · tag	`"ROOT"`	Constant tag.
1 · modules	array of MODULE	The top-level modules.
2 · natives	array of NATIVE	Top-level native setup blocks.
3 · run	array of BodyCommand	The run body.

MODULE

["MODULE", "App", [], [
  ["TYPE", "Profile", [], [
    ["FIELD", "name", "Text"]
  ], [], []]
], [
  ["FUNCTION", "Greet", [], [
    ["INPUT", "name", "Text", "forward"]
  ], [], ["__return", "Text", null], ["implementations", [
    ["NATIVE", "js", "return 'Hi ' + name;"]
  ]]]
], [
  ["LET", "MaxRetries", "Maths.Integer", ["constant", ["literal", ["integer", 3]]]]
], [], []]

MODULE keyword JSON array definition

Position	Type	Description
0 · tag	`"MODULE"`	Constant tag.
1 · name	Identifier	The module's name.
2 · modules	array of MODULE	Nested modules.
3 · types	array of TYPE	The module's types.
4 · functions	array of FUNCTION	Derived functions.
5 · constants	array of LET	Module-level constants.
6 · natives	array of FUNCTION	Native functions.
7 · nativeTypes	array of native type	Native type declarations.

FUNCTION

["FUNCTION", "Welcome", [],
  [["INPUT", "profile", "App.Profile", "binding"]],
  [["HOLE", "row", "Text", [["INPUT", "line", "Text", "forward"]]]],
  ["__return", "Text", null],
  ["body", [
    ["LET", "label", "Text", ["reference", "profile"]]
  ]]
]

FUNCTION keyword JSON array definition

Position	Type	Description
0 · tag	`"FUNCTION"`	Constant tag.
1 · name	Identifier	The function's name.
2 · genericTypes	array of Reference	Generic type parameter names.
3 · inputs	array of INPUT	The typed parameters.
4 · holes	array of HOLE	The callback parameters.
5 · return	Return or null	The return, or null.
6 · body	FunctionBody union	`["body", […]]` or `["implementations", […]]`.

INPUT

["INPUT", "profile", "App.Profile", "binding"]

INPUT keyword JSON array definition

Position	Type	Description
0 · tag	`"INPUT"`	Constant tag.
1 · name	Identifier	The parameter name.
2 · type	Text	The parameter's type.
3 · direction	Direction	Forward, binding or reverse.
4 · optionalDefault	ConstantExpression, trailing	The default; omitted from the end when there is none.

HOLE

["HOLE", "row", "Text", [
  ["INPUT", "line", "Text", "forward"]
]]

HOLE keyword JSON array definition

Position	Type	Description
0 · tag	`"HOLE"`	Constant tag.
1 · name	Identifier	The hole's name.
2 · type	Text or null	The block's return type, or null.
3 · inputs	array of INPUT	The values passed into the block.

NATIVE

["NATIVE", "js", "return 'Hi ' + name;"]

NATIVE keyword JSON array definition

Position	Type	Description
0 · tag	`"NATIVE"`	Constant tag.
1 · platform	Text	The target name.
2 · code	Text	The host source for that target.

TYPE

["TYPE", "Status", [], [], [
  ["OPTION", "active", "App.Profile"],
  ["OPTION", "pending", "Text"]
], []]

TYPE keyword JSON array definition

Position	Type	Description
0 · tag	`"TYPE"`	Constant tag.
1 · name	Identifier	The type's name.
2 · genericTypes	array of Reference	Generic type parameter names.
3 · fields	array of FIELD	The record's fields.
4 · options	array of OPTION	The union's options.
5 · natives	array of NATIVE	Per-target native implementations.

FIELD

["FIELD", "age", "Maths.Integer"]

FIELD keyword JSON array definition

Position	Type	Description
0 · tag	`"FIELD"`	Constant tag.
1 · name	Identifier	The field name.
2 · type	Text	The field's type.
3 · optionalDefault	ConstantExpression, trailing	The default; omitted from the end when there is none.

OPTION

["OPTION", "active", "App.Profile"]

OPTION keyword JSON array definition

Position	Type	Description
0 · tag	`"OPTION"`	Constant tag.
1 · name	Identifier	The option name.
2 · type	Text	The option's payload type.

LET

["LET", "label", "Text",
  ["call", ["Maths.Integer.ToString", [], [["reference", "count"]]]]
]

LET keyword JSON array definition

Position	Type	Description
0 · tag	`"LET"`	Constant tag.
1 · name	Identifier	The bound name.
2 · type	Text	The value's type.
3 · value	AssignmentValue union	`["reference", name]` or `["call", FunctionCall]`.

STATE

["STATE", "count", "Maths.Integer", ["constant", ["literal", ["integer", 0]]], false]

STATE keyword JSON array definition

Position	Type	Description
0 · tag	`"STATE"`	Constant tag.
1 · name	Identifier	The cell's name.
2 · type	Text	The cell's type.
3 · initial	AssignmentValue or null	The starting value, or null.
4 · lockable	Logic.Maybe	Whether the cell is lockable.

REVERSE

["REVERSE", "submit", "App.Profile",
  [["SET", "saved", "response"]],
  [
    ["LET", "response", "Network.Web.Response",
      ["call", ["Network.Web.Client.Post", [], [["reference", "profile"]]]]]
  ]
]

REVERSE keyword JSON array definition

Position	Type	Description
0 · tag	`"REVERSE"`	Constant tag.
1 · name	Identifier	The reverse's name.
2 · type	Text	The type being written back.
3 · setters	array of SET	The write-backs into outer state.
4 · body	array of BodyCommand	The work done before the write.

SET

["SET", "saved", "response"]

SET keyword JSON array definition

Position	Type	Description
0 · tag	`"SET"`	Constant tag.
1 · outerSettable	Text	The outer state cell to write into.
2 · innerValue	Text	The inner value to write.

WITH

["WITH", "Network.Web.Client", "Network.Web.Mock", [
  ["LET", "response", "Network.Web.Response",
    ["call", ["Network.Web.Client.Post", [], [["reference", "profile"]]]]]
]]

WITH keyword JSON array definition

Position	Type	Description
0 · tag	`"WITH"`	Constant tag.
1 · module	Text	The module whose implementation is swapped.
2 · replacement	Text	The module swapped in.
3 · body	array of BodyCommand	The commands the swap applies over.