Multi-value schema

src/compiler/common/mod.ts

@@ -0,0 +1,2 @@
+export * from './ucc-list-options.js';
+export * from './unsupported-uc-schema.error.js';

src/compiler/common/ucc-list-options.ts

@@ -0,0 +1,3 @@
+export interface UccListOptions {
+  readonly single: 'accept' | 'as-is' | 'prefer' | 'reject';
+}

src/compiler/unsupported-uc-schema.error.ts → src/compiler/common/unsupported-uc-schema.error.ts

@@ -1,5 +1,5 @@
-import { ucModelName } from '../schema/uc-model-name.js';
-import { UcSchema } from '../schema/uc-schema.js';
+import { ucModelName } from '../../schema/uc-model-name.js';
+import { UcSchema } from '../../schema/uc-schema.js';
 
 export class UnsupportedUcSchemaError extends TypeError {
 

src/compiler/deserialization/list.ucrx.class.ts

@@ -14,6 +14,8 @@ import {
 import { UcList } from '../../schema/list/uc-list.js';
 import { ucModelName } from '../../schema/uc-model-name.js';
 import { UcModel } from '../../schema/uc-schema.js';
+import { UccListOptions } from '../common/ucc-list-options.js';
+import { UnsupportedUcSchemaError } from '../common/unsupported-uc-schema.error.js';
 import { UC_MODULE_CHURI } from '../impl/uc-modules.js';
 import { ucSchemaTypeSymbol } from '../impl/uc-schema-symbol.js';
 import { ucSchemaVariant } from '../impl/uc-schema-variant.js';
@@ -22,25 +24,30 @@ import { UcrxCore } from '../rx/ucrx-core.js';
 import { UcrxLib } from '../rx/ucrx-lib.js';
 import { UcrxBeforeMod, UcrxMethod } from '../rx/ucrx-method.js';
 import { UcrxClass, UcrxSignature } from '../rx/ucrx.class.js';
-import { UnsupportedUcSchemaError } from '../unsupported-uc-schema.error.js';
 import { UcdCompiler } from './ucd-compiler.js';
 
 export class ListUcrxClass<
   TItem = unknown,
   TItemModel extends UcModel<TItem> = UcModel<TItem>,
 > extends UcrxClass<UcrxSignature.Args, TItem[], UcList.Schema<TItem, TItemModel>> {
 
-  static uccProcessSchema(compiler: UcdCompiler.Any, { item }: UcList.Schema): UccConfig {
+  static uccProcessSchema(
+    compiler: UcdCompiler.Any,
+    schema: UcList.Schema,
+  ): UccConfig<UccListOptions> {
     return {
-      configure: () => {
-        compiler.useUcrxClass('list', (lib, schema: UcList.Schema) => new this(lib, schema));
-        compiler.processModel(item);
+      configure: options => {
+        compiler
+          .processModel(schema.item)
+          .useUcrxClass('list', (lib, schema: UcList.Schema) => new this(lib, schema))
+          .useUcrxClass(schema, (lib, schema: UcList.Schema) => new this(lib, schema, options));
       },
     };
   }
 
   readonly #itemClass: UcrxClass;
   readonly #isMatrix: boolean;
+  readonly #single: UccListOptions['single'];
 
   readonly #items: EsFieldHandle;
   readonly #addItem: EsMethodHandle<{ item: EsArg }>;
@@ -50,7 +57,11 @@ export class ListUcrxClass<
   readonly #setListField: EsFieldHandle | undefined;
   readonly #itemRx: EsPropertyHandle | undefined;
 
-  constructor(lib: UcrxLib, schema: UcList.Schema<TItem, TItemModel>) {
+  constructor(
+    lib: UcrxLib,
+    schema: UcList.Schema<TItem, TItemModel>,
+    { single }: UccListOptions = { single: 'reject' },
+  ) {
     let itemClass: UcrxClass;
 
     const { item } = schema;
@@ -80,6 +91,7 @@ export class ListUcrxClass<
 
     this.#itemClass = itemClass;
     this.#isMatrix = isMatrix;
+    this.#single = single;
 
     this.#items = new EsField('items', { visibility: EsMemberVisibility.Private }).declareIn(this, {
       initializer: () => '[]',
@@ -193,6 +205,18 @@ export class ListUcrxClass<
     return this.#items.get('this');
   }
 
+  protected countItems(_cx: EsSnippet): EsSnippet {
+    return esline`${this.#items.get('this')}.length`;
+  }
+
+  protected createSingle(_cx: EsSnippet): EsSnippet {
+    return esline`${this.#items.get('this')}[0]`;
+  }
+
+  protected createEmptyList(_cx: EsSnippet): EsSnippet {
+    return '[]';
+  }
+
   protected createNullList(cx: EsSnippet): EsSnippet;
   protected createNullList(_cx: EsSnippet): EsSnippet {
     return 'null';
@@ -261,24 +285,79 @@ export class ListUcrxClass<
             args: { cx },
           },
         }) => code => {
-          if (isNull) {
-            code
-              .write(esline`if (${isNull.get('this')}) {`)
-              .indent(esline`${this.#setList}(${this.createNullList(cx)});`)
-              .write(esline`} else if (${listCreated.get('this')}) {`);
-          } else {
-            code.write(esline`if (${listCreated.get('this')}) {`);
+          switch (this.#single) {
+            case 'reject':
+              if (isNull) {
+                code
+                  .write(esline`if (${isNull.get('this')}) {`)
+                  .indent(this.#storeNullList(cx))
+                  .write(esline`} else if (${listCreated.get('this')}) {`);
+              } else {
+                code.write(esline`if (${listCreated.get('this')}) {`);
+              }
+
+              code
+                .indent(this.#storeList(cx))
+                .write('} else {')
+                .indent(esline`${cx}.reject(${ucrxRejectSingleItem}(this));`)
+                .write('}');
+
+              break;
+            case 'accept':
+              if (isNull) {
+                code
+                  .write(esline`if (${isNull.get('this')}) {`)
+                  .indent(this.#storeNullList(cx))
+                  .write(esline`} else {`)
+                  .indent(this.#storeList(cx))
+                  .write('}');
+              } else {
+                code.write(this.#storeList(cx));
+              }
+
+              break;
+            case 'as-is':
+            case 'prefer':
+              if (isNull) {
+                code
+                  .write(esline`if (${isNull.get('this')}) {`)
+                  .indent(this.#storeNullList(cx))
+                  .write(esline`} else if (${listCreated.get('this')}) {`);
+              } else {
+                code.write(esline`if (${listCreated.get('this')}) {`);
+              }
+              code
+                .indent(
+                  this.#single === 'prefer' ? this.#storeSingleOrList(cx) : this.#storeList(cx),
+                )
+                .write('} else {')
+                .indent(this.#storeSingleOrEmpty(cx))
+                .write('}');
           }
-
-          code
-            .indent(esline`${this.#setList}(${this.createList(cx)});`)
-            .write(`} else {`)
-            .indent(esline`${cx}.reject(${ucrxRejectSingleItem}(this));`)
-            .write(`}`);
         },
     });
   }
 
+  #storeNullList(cx: EsSnippet): EsSnippet {
+    return esline`${this.#setList}(${this.createNullList(cx)});`;
+  }
+
+  #storeList(cx: EsSnippet): EsSnippet {
+    return esline`${this.#setList}(${this.createList(cx)});`;
+  }
+
+  #storeSingleOrList(cx: EsSnippet): EsSnippet {
+    return esline`${this.#setList}(${this.countItems(cx)} === 1 ? ${this.createSingle(
+      cx,
+    )} : ${this.createList(cx)});`;
+  }
+
+  #storeSingleOrEmpty(cx: EsSnippet): EsSnippet {
+    return esline`${this.#setList}(${this.countItems(cx)} ? ${this.createSingle(
+      cx,
+    )} : ${this.createEmptyList(cx)});`;
+  }
+
   #declareMatrixMethods(): void {
     const { itemClass } = this;
     const listCreated = this.#listCreated;

src/compiler/deserialization/map.ucrx-entry.ts

@@ -11,10 +11,10 @@ import {
 import { UcMap } from '../../schema/map/uc-map.js';
 import { ucModelName } from '../../schema/uc-model-name.js';
 import { UcModel, UcSchema } from '../../schema/uc-schema.js';
+import { UnsupportedUcSchemaError } from '../common/unsupported-uc-schema.error.js';
 import { ucSchemaTypeSymbol } from '../impl/uc-schema-symbol.js';
 import { UcrxLib } from '../rx/ucrx-lib.js';
 import { UcrxClass } from '../rx/ucrx.class.js';
-import { UnsupportedUcSchemaError } from '../unsupported-uc-schema.error.js';
 import { MapUcrxClass, MapUcrxStore } from './map.ucrx.class.js';
 
 export class MapUcrxEntry {

src/compiler/deserialization/ucd-function.ts

@@ -2,10 +2,10 @@ import { EsCode, EsFunction, EsSnippet, EsSymbol, EsVarKind, EsVarSymbol, esline
 import { UcDeserializer } from '../../schema/uc-deserializer.js';
 import { ucModelName } from '../../schema/uc-model-name.js';
 import { UcSchema } from '../../schema/uc-schema.js';
+import { UnsupportedUcSchemaError } from '../common/unsupported-uc-schema.error.js';
 import { UC_MODULE_DESERIALIZER } from '../impl/uc-modules.js';
 import { ucSchemaTypeSymbol } from '../impl/uc-schema-symbol.js';
 import { UcrxClass } from '../rx/ucrx.class.js';
-import { UnsupportedUcSchemaError } from '../unsupported-uc-schema.error.js';
 import { UcdExportSignature } from './ucd-export.signature.js';
 import { UcdLib } from './ucd-lib.js';
 

src/compiler/mod.ts

@@ -1,13 +1,13 @@
 /**
- * Schema compiler API.
+ * Schema compiler SPI.
  *
- * __Schema compiler API considered unstable__ and may change for minor releases.
+ * __Schema compiler SPI considered unstable__ and may change for minor releases.
  *
  * @module churi/compiler.js
  */
+export * from './common/mod.js';
 export * from './deserialization/mod.js';
 export * from './processor/mod.js';
 export * from './rx/mod.js';
 export * from './serialization/mod.js';
-export * from './unsupported-uc-schema.error.js';
 export * from './validation/mod.js';

src/compiler/serialization/ucs-function.ts

@@ -1,9 +1,9 @@
 import { EsFunction, EsSnippet, EsVarSymbol, esline } from 'esgen';
 import { ucModelName } from '../../schema/uc-model-name.js';
 import { UcSchema } from '../../schema/uc-schema.js';
+import { UnsupportedUcSchemaError } from '../common/unsupported-uc-schema.error.js';
 import { ucSchemaSymbol } from '../impl/uc-schema-symbol.js';
 import { ucSchemaVariant } from '../impl/uc-schema-variant.js';
-import { UnsupportedUcSchemaError } from '../unsupported-uc-schema.error.js';
 import { UcsExportSignature } from './ucs-export.signature.js';
 import { UcsLib } from './ucs-lib.js';
 import { UcsWriterClass, UcsWriterSignature } from './ucs-writer.class.js';

src/compiler/serialization/ucs-support-list.ts

@@ -3,24 +3,68 @@ import { UcList } from '../../schema/list/uc-list.js';
 import { ucModelName } from '../../schema/uc-model-name.js';
 import { ucNullable } from '../../schema/uc-nullable.js';
 import { ucOptional } from '../../schema/uc-optional.js';
-import { UcModel } from '../../schema/uc-schema.js';
+import { UcModel, UcSchema } from '../../schema/uc-schema.js';
+import { UccListOptions } from '../common/ucc-list-options.js';
+import { UnsupportedUcSchemaError } from '../common/unsupported-uc-schema.error.js';
 import { UC_MODULE_SERIALIZER } from '../impl/uc-modules.js';
 import { UccConfig } from '../processor/ucc-config.js';
-import { UnsupportedUcSchemaError } from '../unsupported-uc-schema.error.js';
 import { UcsCompiler } from './ucs-compiler.js';
 import { UcsFunction } from './ucs-function.js';
 import { UcsSignature } from './ucs.signature.js';
 
-export function ucsSupportList(compiler: UcsCompiler, schema: UcList.Schema): UccConfig;
-export function ucsSupportList(compiler: UcsCompiler, { item }: UcList.Schema): UccConfig {
+export function ucsSupportList(
+  compiler: UcsCompiler,
+  schema: UcList.Schema,
+): UccConfig<UccListOptions> {
   return {
-    configure() {
-      compiler.useUcsGenerator('list', ucsWriteList).processModel(item);
+    configure(options) {
+      compiler
+        .processModel(schema.item)
+        .useUcsGenerator(schema, (fn, schema, args) => ucsWriteList(fn, schema, args, options));
     },
   };
 }
 
 function ucsWriteList<TItem, TItemModel extends UcModel<TItem>>(
+  fn: UcsFunction,
+  schema: UcList.Schema<TItem, TItemModel>,
+  args: UcsSignature.AllValues,
+  { single }: UccListOptions,
+): EsSnippet {
+  const { writer, value } = args;
+  const itemSchema = schema.item.optional
+    ? ucOptional(ucNullable(schema.item), false) // Write `undefined` items as `null`
+    : schema.item;
+
+  switch (single) {
+    case 'prefer':
+      return code => {
+        code
+          .write(esline`if (!Array.isArray(${value})) {`)
+          .indent(ucsWriteItem(fn, itemSchema, { writer, value }))
+          .write(esline`} else if (${value}.length === 1) {`)
+          .indent(ucsWriteItem(fn, itemSchema, { writer, value: esline`${value}[0]` }))
+          .write('} else {')
+          .indent(ucsWriteListItems(fn, schema, args))
+          .write('}');
+      };
+    case 'as-is':
+      return code => {
+        code
+          .write(esline`if (Array.isArray(${value})) {`)
+          .indent(ucsWriteListItems(fn, schema, args))
+          .write(esline`} else {`)
+          .indent(ucsWriteItem(fn, itemSchema, { writer, value }))
+          .write('}');
+      };
+    case 'accept':
+    case 'reject':
+      // Always an array.
+      return ucsWriteListItems(fn, schema, args);
+  }
+}
+
+function ucsWriteListItems<TItem, TItemModel extends UcModel<TItem>>(
   fn: UcsFunction,
   schema: UcList.Schema<TItem, TItemModel>,
   { writer, value, asItem }: UcsSignature.AllValues,
@@ -44,20 +88,7 @@ function ucsWriteList<TItem, TItemModel extends UcModel<TItem>>(
         esline`await ${writer}.ready;`,
         esline`${writer}.write(${itemWritten} || !${asItem} ? ${comma} : ${openingParenthesis});`,
         esline`${itemWritten} = true;`,
-        fn.serialize(
-          itemSchema,
-          {
-            writer,
-            value: itemValue,
-            asItem: '1',
-          },
-          (schema, fn) => {
-            throw new UnsupportedUcSchemaError(
-              schema,
-              `${fn}: Can not serialize list item of type "${ucModelName(schema)}"`,
-            );
-          },
-        ),
+        ucsWriteItem(fn, itemSchema, { writer, value: itemValue }),
       )
       .write(`}`)
       .write(esline`if (${asItem}) {`)
@@ -70,3 +101,16 @@ function ucsWriteList<TItem, TItemModel extends UcModel<TItem>>(
       .write(`}`);
   };
 }
+
+function ucsWriteItem(
+  fn: UcsFunction,
+  itemSchema: UcSchema,
+  args: Omit<UcsSignature.AllValues, 'asItem'>,
+): EsSnippet {
+  return fn.serialize(itemSchema, { ...args, asItem: '1' }, (schema, fn) => {
+    throw new UnsupportedUcSchemaError(
+      schema,
+      `${fn}: Can not serialize list item of type "${ucModelName(schema)}"`,
+    );
+  });
+}

src/compiler/serialization/ucs-support-map.ts

@@ -13,10 +13,10 @@ import { ucModelName } from '../../schema/uc-model-name.js';
 import { ucNullable } from '../../schema/uc-nullable.js';
 import { ucOptional } from '../../schema/uc-optional.js';
 import { UcSchema } from '../../schema/uc-schema.js';
+import { UnsupportedUcSchemaError } from '../common/unsupported-uc-schema.error.js';
 import { UC_MODULE_SERIALIZER } from '../impl/uc-modules.js';
 import { ucsCheckConstraints } from '../impl/ucs-check-constraints.js';
 import { UccConfig } from '../processor/ucc-config.js';
-import { UnsupportedUcSchemaError } from '../unsupported-uc-schema.error.js';
 import { UcsCompiler } from './ucs-compiler.js';
 import { UcsFunction } from './ucs-function.js';
 import { UcsLib } from './ucs-lib.js';

src/schema/list/mod.ts

@@ -1 +1,2 @@
 export * from './uc-list.js';
+export * from './uc-multi-value.js';