TypeEnvironment.ts

import { ParserRuleContext } from 'antlr4ng';
import { ChicoryType } from './ChicoryTypes';
import { CompilationError } from './env';

export class TypeEnvironment {
    private bindings: Map<string, ChicoryType>;

    constructor(public parent: TypeEnvironment | null) {
        this.bindings = new Map();
    }

    getType(identifier: string): ChicoryType | undefined {
        let type = this.bindings.get(identifier);
        if (type) {
            return type;
        }
        if (this.parent) {
            return this.parent.getType(identifier);
        }
        return undefined;
    }
    
    declare(identifier: string, type: ChicoryType, context: ParserRuleContext, pushError: (str) => void): void {
        if (this.bindings.has(identifier)) {
            pushError(`Identifier '${identifier}' is already declared in this scope.`)
            return // We don't want to continue because this is an error
        }
        this.bindings.set(identifier, type);
    }

    pushScope(): TypeEnvironment {
        return new TypeEnvironment(this);
    }

    popScope(): TypeEnvironment {
        if (this.parent === null) {
            throw new Error('Cannot pop the global scope.');
        }
        return this.parent;
    }
    
    getAllTypes(): Map<string, ChicoryType> {
        return new Map(this.bindings);
    }
}