1  import * as Plan from './plan.js'
 2  import * as JSON from '../json.js'
 3  import { toDebugString } from '../debug.js'
 4  
 5  export class Negation {
 6    /**
 7     * @param {Plan.Constraint} operand
 8     */
 9    constructor(operand) {
10      this.operand = operand
11    }
12  
13    /**
14     * @param {Plan.EvaluationContext} context
15     */
16    *evaluate({ selection, ...context }) {
17      const matches = []
18      for (const frame of selection) {
19        const excluded = yield* this.operand.evaluate({
20          ...context,
21          selection: [frame],
22        })
23  
24        if (excluded.length === 0) {
25          matches.push(frame)
26        }
27      }
28  
29      return matches
30    }
31  
32    toJSON() {
33      return { not: JSON.from(this.operand) }
34    }
35  
36    toDebugString() {
37      return `{ not: ${toDebugString(this.operand)} }`
38    }
39  }