| 123456789101112131415161718 | import { Expression } from './expression';export class InfixApp extends Expression {  constructor(op, left, right) {    super();    this.op = op;    this.left = left;    this.right = right;  }  toString () {    const l = this.left.toString();    const op = this.op.value;    const r = this.right.toString();    return l + op + r;  }}
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