Templates, semantic slots, and expression selection
The program owns templates and preference order, inserted values are replaced only once, and the App supplies the random source for variants.
defineTextTemplate(master).render(values) replaces only {{word}} in the original template, throws on a missing field, and does not re-evaluate braces inside inserted values. defineSemanticSlots only checks whether namespaced semantic slots fall within the allowed keys and maxOccurrences; it does not perform replacement.
selectVariant returns a value or undefined; with multiple candidates it avoids previous when possible, and randomIndex(limit) must return a valid integer. resolvePreference selects by priority descending and then order descending, and returns undefined for an empty array. These are local expression strategies and do not decide authorization, fact priority, or business routing.
Progressive examples for the same business case
First compose an explanation with a program template
Beginner · Node.js
import { Presentation } from '@jangts/agent-core/kits/presentation';
const template = Presentation.defineTextTemplate('你好，{{name}}。{{body}}');
console.log(template.render({ name: '开发者', body: '普通对象也能实现接口。' }));import { Presentation } from '@jangts/agent-core/kits/presentation';
const template = Presentation.defineTextTemplate('你好，{{name}}。{{body}}');
console.log(template.render({ name: '开发者', body: '普通对象也能实现接口。' }));Add semantic key validation and a non-repeating variant to the same template
Configuration · Node.js
import { Presentation } from '@jangts/agent-core/kits/presentation';
const slots = Presentation.defineSemanticSlots({ namespace: 'tone', keys: ['brief', 'detailed'], maxOccurrences: 1 });
console.log(slots.isValid('{{tone:brief}}'));
const greeting = Presentation.selectVariant(['你好', '欢迎'], { previous: '你好', randomIndex: () => 0 });
const tone = Presentation.resolvePreference([{ value: 'brief', priority: 1, order: 0 }, { value: 'detailed', priority: 2, order: 1 }]);
const template = Presentation.defineTextTemplate('{{greeting}}，{{body}}');
console.log(template.render({ greeting: greeting ?? '你好', body: tone === 'detailed' ? '下面逐步说明接口。' : '普通对象即可。' }));import { Presentation } from '@jangts/agent-core/kits/presentation';
const slots = Presentation.defineSemanticSlots({ namespace: 'tone', keys: ['brief', 'detailed'], maxOccurrences: 1 });
console.log(slots.isValid('{{tone:brief}}'));
const greeting = Presentation.selectVariant(['你好', '欢迎'], { previous: '你好', randomIndex: () => 0 });
const tone = Presentation.resolvePreference([{ value: 'brief', priority: 1, order: 0 }, { value: 'detailed', priority: 2, order: 1 }]);
const template = Presentation.defineTextTemplate('{{greeting}}，{{body}}');
console.log(template.render({ greeting: greeting ?? '你好', body: tone === 'detailed' ? '下面逐步说明接口。' : '普通对象即可。' }));