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47 lines
1.3 KiB
47 lines
1.3 KiB
3 years ago
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// @flow
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import type {Type} from '../types.js';
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import type {Expression} from '../expression.js';
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import type ParsingContext from '../parsing_context.js';
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import type EvaluationContext from '../evaluation_context.js';
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class Var implements Expression {
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type: Type;
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name: string;
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boundExpression: Expression;
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constructor(name: string, boundExpression: Expression) {
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this.type = boundExpression.type;
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this.name = name;
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this.boundExpression = boundExpression;
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}
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static parse(args: $ReadOnlyArray<mixed>, context: ParsingContext): void | Var {
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if (args.length !== 2 || typeof args[1] !== 'string')
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return context.error(`'var' expression requires exactly one string literal argument.`);
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const name = args[1];
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if (!context.scope.has(name)) {
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return context.error(`Unknown variable "${name}". Make sure "${name}" has been bound in an enclosing "let" expression before using it.`, 1);
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}
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return new Var(name, context.scope.get(name));
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}
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evaluate(ctx: EvaluationContext): any {
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return this.boundExpression.evaluate(ctx);
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}
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eachChild() {}
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outputDefined(): boolean {
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return false;
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}
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serialize(): Array<string> {
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return ["var", this.name];
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}
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}
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export default Var;
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