calcium-lang/dist/expression/attribute.js

Calcium language interpreter

import { AttributeNotFound, NameNotFound } from "../error";
import { default as Sym } from "../symbol";
import { evaluate } from "../util";
/**
 * access to the attribute of an objecct
 */
export default class Attribute {
    /**
     *
     * @param varName the identifier of the first referred object
     * @param attrsName each attribute's name
     */
    constructor(varName, attrsName) {
        this.varName = varName;
        this.attrsName = attrsName;
    }
    assign(rhs, env) {
        let target = env.context.lookUp(this.varName);
        if (target === undefined) {
            throw new NameNotFound(this.varName);
        }
        else {
            // repeat to the element before the last one that is the name of
            // the attribute to be created or updated
            for (let i = 0; i < this.attrsName.length - 1; ++i) {
                target = Reflect.get(target, this.attrsName[i]);
                if (target === undefined) {
                    throw new AttributeNotFound(this.attrsName[i]);
                }
            }
            const value = evaluate(rhs, env);
            Reflect.set(target, this.attrsName[this.attrsName.length - 1], value);
        }
    }
    [Sym.evaluate](env) {
        let target = env.context.lookUp(this.varName);
        if (target === undefined) {
            throw new NameNotFound(this.varName);
        }
        else {
            for (let attrName of this.attrsName) {
                target = Reflect.get(target, attrName);
                if (target === undefined) {
                    throw new AttributeNotFound(attrName);
                }
            }
            return target;
        }
    }
    get [Sym.description]() {
        return `${this.varName}.${this.attrsName.join(".")}`;
    }
}
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