Update how function works.

Now it's basically like `seeds/example-utility#expect` in that it's an array of expected parameters.

Part of #20.

README.md

@@ -660,7 +660,7 @@ Defines a procedure that other seeds can call with `call`.
 Note that semantically it's basically equivalent to a `let-multi` with named arguments, but using `function` communicates more clearly the intent that this is a callable-sub-procedure, which allows tooling to understand it better.
 
 Required parameters:
-- `arguments` - The object of name -> value pairs to set. These variable names should not include a namespace. Internally they will be prefixed with the `arg:` namespace.
+- `arguments` - The list of names of arguments that are expected to be passed. These variable names should not include a namespace. Internally they will be prefixed with the `arg:` namespace.
 - `block` - The sub-seed that will be evaluated where the environment will have `name=value`.
 
 #### call

seed-schema.json

@@ -2907,21 +2907,9 @@
 									"$ref": "#/definitions/seedData/anyOf/0/properties/prompt/anyOf/1"
 								},
 								{
-									"type": "object",
-									"additionalProperties": {
-										"anyOf": [
-											{
-												"$ref": "#/definitions/seedData/anyOf/27/properties/properties/additionalProperties/anyOf/0"
-											},
-											{
-												"$ref": "#/definitions/seedData/anyOf/0/properties/prompt/anyOf/1"
-											},
-											{
-												"$ref": "#/definitions/seedData/anyOf/5/properties/value/anyOf/2/anyOf/1/additionalProperties/anyOf/2"
-											}
-										]
-									},
-									"propertyNames": {
+									"type": "array",
+									"items": {
+										"type": "string",
 										"pattern": "^[a-zA-Z0-9-_.]*$"
 									},
 									"description": "The map of name -> variables to set"

src/grow.ts

@@ -694,17 +694,15 @@ const growFunction = async (seed : Seed<SeedDataFunction>, env : Environment) :
 	const data = seed.data;
 
 	const values = await getProperty(seed, env, data.arguments);
-	if (typeof values != 'object') throw new Error('Values must be an object');
-	if (Array.isArray(values)) throw new Error('Values must be an object');
-	if (!values) throw new Error('Values must be an object');
-	const vars : EnvironmentData = {};
-	for (const [key, val] of Object.entries(values)) {
-		if (isNamespaced(key)) throw new Error('arguments should not be namespaced');
-		const processedKey = getNamespacedID(key, FUNCTION_ARG_NAMESPACE);
-		vars[processedKey] = val;
+	if (!Array.isArray(values)) throw new Error('Values must be an array');
+	for (const name of values) {
+		if (typeof name != 'string') throw new Error('argument name must be string');
+		if (isNamespaced(name)) throw new Error('arguments should not be namespaced');
+		const processedKey = getNamespacedID(name, FUNCTION_ARG_NAMESPACE);
+		const val = env.get(processedKey);
+		if (val === null) throw new Error(`${val} was not set as expected`);
 	}
-	const newEnv = env.clone(vars);
-	return await getProperty(seed, newEnv, data.block);
+	return await getProperty(seed, env, data.block);
 };
 
 const growCall = async (seed : Seed<SeedDataCall>, env : Environment) : Promise<Value> => {

src/types.ts

@@ -945,11 +945,7 @@ const seedDataConfigFunction = {
 	type: z.literal('function'),
 	properties: {
 		//We don't use varName because we want a non-namespaced ID
-		arguments: z.record(genericExtraID, z.union([
-			lazySeedData,
-			seedReference,
-			inputValue
-		])).describe('The map of name -> variables to set'),
+		arguments: z.array(genericExtraID).describe('The map of name -> variables to set'),
 		block: inputNonObjectValue.describe('The sub-expression where name=value will be set in environment')
 	}
 };