stanford-oval / thingtalk / 870

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Build # 870

Build Type

Pull #198

travis-ci-com

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web-flow

Commit Message

Merge 2608fea9f into 3b9a8f518

Pull Request Pull Request #198: Fixes in preparation to homework 2

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87.21

/lib/typecheck.js

// -*- mode: js; indent-tabs-mode: nil; js-basic-offset: 4 -*-
//
// This file is part of ThingTalk
//
// Copyright 2015-2016 The Board of Trustees of the Leland Stanford Junior University
//
// Author: Giovanni Campagna <gcampagn@cs.stanford.edu>
//
// See COPYING for details
"use strict";

// Typechecking is idempotent (two parallel typechecks of the same program will yield
// functionally equivalent results) so any data race is a false positive
/* eslint-disable require-atomic-updates */

const assert = require('assert');
const Units = require('thingtalk-units');

const Ast = require('./ast');
const Type = require('./type');
const Utils = require('./utils');
const Builtin = require('./builtin/defs');

const ALLOWED_PRINCIPAL_TYPES = new Set([
    'tt:contact', 'tt:username'
]);

function log(message) {
    let debug = false;
    if (debug) console.log(message);
}

class Scope {
    constructor(parentScope) {
        this._parentScope = parentScope || null;
        this._globalScope = {};
        this.clean();
    }

    has(name) {
        const here = name in this._scope || name in this._lambda_args || name in this._globalScope;
        if (here)
            return true;
        if (this._parentScope)
            return this._parentScope.has(name);
        return false;
    }

    addLambdaArgs(args) {
        for (let name in args)
            this._lambda_args[name] = args[name];
    }

    add(name, type) {
        this._scope[name] = type;
    }
    addAll(args) {
        for (let name in args)
            this._scope[name] = args[name];
    }

    addGlobal(name, schema) {
        if (name in this._globalScope)
            throw new TypeError(name + ' is already declared');
        this._globalScope[name] = schema;
    }

    remove(name) {
        delete this._scope[name];
    }

    merge(scope) {
        Object.assign(this._scope, scope._scope);
    }

    clean() {
        this._scope = {};
        this.$has_event = false;
        this._lambda_args = {};
    }

    clone() {
        const newself = new Scope(this._parentScope);
        Object.assign(newself._scope, this._scope);
        newself.$has_event = this.$has_event;
        Object.assign(newself._lambda_args, this._lambda_args);
        return newself;
    }

    cleanOutput() {
        this._scope = {};
    }

    prefix(prefix) {
        let new_scope = {};
        for (let name in this._scope) {
            new_scope[name] = this._scope[name];
            new_scope[prefix + '.' + name] = this._scope[name];
        }
        this._scope = new_scope;
    }

    get(name) {
        let v = this._scope[name] || this._lambda_args[name] || this._globalScope[name];
        if (!v && this._parentScope)
            v = this._parentScope.get(name);
        return v;
    }

    dump() {
        console.log();
        console.log('Scope:');
        for (let name in this._scope)
            console.log(name  +': ' + this._scope[name]);
    }
}

function loadNotifyAction(name) {
    if (name === 'notify')
        return Builtin.Actions.notify;
    else if (name === 'return')
        return Builtin.Actions['return'];
    else if (name === 'save')
        return Builtin.Actions['save'];
    else
        throw new TypeError('Invalid notification action ' + name);
}

function loadSchema(schemas, classes, prim, primType, useMeta) {
    assert(prim.selector.isDevice);
    return Utils.getSchemaForSelector(schemas, prim.selector.kind, prim.channel, primType, useMeta, classes);
}

async function typeCheckValue(value, scope, schemas, classes, useMeta) {
    if (value.type instanceof Type)
        return value.type;

    if (value.isComputation) {
        let operands = await Promise.all(value.operands.map((o) => typeCheckValue(o, scope, schemas, classes, useMeta)));
        const [overload, resultType] = resolveScalarExpressionOps(value.op, operands);

        value.overload = overload;
        return value.type = resultType;
    }
    if (value.isArrayField) {
        const paramType = await typeCheckValue(value.value, scope, schemas, classes, useMeta);
        if (!paramType.isArray || !paramType.elem.isCompound)
            throw new TypeError(`Invalid field access on value that is not array of record`);
        if (!(value.field in paramType.elem.fields))
            throw new TypeError(`Invalid field ${value.field} in type ${paramType.elem}`);

        const arg = paramType.elem.fields[value.field];
        value.arg = arg;
        return value.type = Type.Array(arg.type);
    }
    if (value.isFilter) {
        const paramType = await typeCheckValue(value.value, scope, schemas, classes, useMeta);
        if (!paramType.isArray)
            throw new TypeError(`Invalid aggregation on non-array parameter`);
        const args = [];
        if (paramType.elem.isCompound) {
            for (let field in paramType.elem.fields)
                args.push(new Ast.ArgumentDef(null, 'out', field, paramType.elem.fields[field].type, {}));
        } else {
            args.push(new Ast.ArgumentDef(null, 'out', 'value', paramType.elem, {}));
        }
        const localschema = new Ast.ExpressionSignature(null, 'query', null, [], args, {
            minimal_projection: [],
        });
        await typeCheckFilter(value.filter, localschema, new Scope(), schemas, classes, useMeta);
        return value.type = paramType;
    }

    if (value.isVarRef) {
        if (value.name.startsWith('__const_'))
            return value.getType();

        let type = scope.get(value.name);

        if (!type)
            throw new TypeError('Variable ' + value.name + ' is not in scope');
        value.type = type;
        return type;
    }
    if (value.isEvent && value.name !== 'program_id' && !scope.$has_event)
        throw new TypeError('Cannot access $event variables in the trigger');

    if (value.isArray) {
        const typeScope = {};
        if (value.value.length === 0)
            return Type.Array(Type.Any);

        let elem = await typeCheckValue(value.value[0], scope, schemas, classes, useMeta);

        for (let v of value.value) {
            let vtype = await typeCheckValue(v, scope, schemas, classes, useMeta);

            // merge enum types if necessary
            if (vtype.isEnum && vtype.entries[vtype.entries.length-1] === '*' &&
                elem.isEnum && elem.entries[elem.entries.length-1] === '*') {
                for (let entry of vtype.entries) {
                    if (elem.entries.includes(entry))
                        continue;
                    elem.entries.splice(elem.entries.length-1, 0, entry);
                }
            } else if (!Type.isAssignable(vtype, elem, typeScope)) {
                throw new TypeError(`Inconsistent type for array value`);
            }
        }

        return value.type = Type.Array(elem);
    }

    const type = value.getType();
    return type;
}

function resolveTypeVars(type, typeScope) {
    if (type === 'string')
        return resolveTypeVars(typeScope[type], typeScope);
    if (type.isArray)
        return Type.Array(resolveTypeVars(type.elem, typeScope));
    if (type.isTuple)
        return Type.Tuple(type.schema.map((t) => resolveTypeVars(t, typeScope)));
    if (type.isMeasure && typeScope._unit)
        return Type.Measure(typeScope._unit);
    return type;
}

async function typecheckPrincipal(principal, schemas, classes, useMeta) {
    if (principal.isUndefined)
        return;
    if (!principal.isConstant())
        throw new TypeError(`Program principal must be a constant`);

    const type = await typeCheckValue(principal, new Scope, schemas, classes, useMeta);
    if (!type.isEntity || !ALLOWED_PRINCIPAL_TYPES.has(type.type))
        throw new TypeError(`Invalid principal ${principal}, must be a contact or a group`);
}

function resolveOverload(overloads, operator, argTypes, allowCast) {
    for (let overload of overloads.types) {
        if (argTypes.length !== overload.length-1)
            continue;
        let typeScope = {};
        let good = true;
        for (let i = 0; i < argTypes.length; i++) {
            if (!Type.isAssignable(argTypes[i], overload[i], typeScope, allowCast)) {
                good = false;
                break;
            }
        }
        if (!good)
            continue;
        if (overload[overload.length-1].isMeasure && typeScope['_unit'])
            return [overload, Type.Measure(typeScope['_unit'])];
        return [overload, overload[overload.length-1]];
    }
    throw new TypeError(`Invalid parameter types ${argTypes.join(', ')} for ${operator}`);
}

function resolveScalarExpressionOps(operator, argTypes) {
    let op = Builtin.ScalarExpressionOps[operator];
    if (!op)
        throw new TypeError('Invalid operator ' + operator);
    return resolveOverload(op, operator, argTypes, true);
}

function resolveFilterOverload(type_lhs, operator, type_rhs) {
    log('resolve filter overload');
    let op = Builtin.BinaryOps[operator];
    if (!op)
        throw new TypeError('Invalid operator ' + operator);
    const [overload,] = resolveOverload(op, operator, [type_lhs, type_rhs], false);
    return overload;
}

async function typeCheckFilter(ast, schema, scope, schemas, classes, useMeta) {
    log('Type check filter ...');
    if (schema && schema.no_filter)
        throw new TypeError('Filter is not allowed on a query that has been filtered on a parameter marked as unique');
    return (async function recursiveHelper(ast) {
        if (!ast)
            return Promise.resolve();
        if (ast.isTrue || ast.isFalse)
            return Promise.resolve();
        if (ast.isAnd || ast.isOr)
            return Promise.all(ast.operands.map((op) => recursiveHelper(op)));
        if (ast.isNot)
            return recursiveHelper(ast.expr);

        if (ast.isDontCare) {
            let name = ast.name;
            let type_lhs = undefined;
            if (schema)
                type_lhs = schema.inReq[name] || schema.inOpt[name] || schema.out[name];
            if (!type_lhs)
                type_lhs = scope.get(name);
            if (!type_lhs)
                throw new TypeError('Invalid filter parameter ' + name);
            return Promise.resolve();
        }

        if (ast.isAtom) {
            let name = ast.name;
            let type_lhs = undefined;
            if (schema)
                type_lhs = schema.inReq[name] || schema.inOpt[name] || schema.out[name];
            if (!type_lhs)
                type_lhs = scope.get(name);
            if (!type_lhs)
                throw new TypeError('Invalid filter parameter ' + name);
            let type_rhs = await typeCheckValue(ast.value, scope, schemas, classes, useMeta);
            ast.overload = resolveFilterOverload(type_lhs, ast.operator, type_rhs);
            return Promise.resolve();
        }

        if (ast.isCompute) {
            let type_lhs = await typeCheckValue(ast.lhs, scope, schemas, classes, useMeta);
            let type_rhs = await typeCheckValue(ast.rhs, scope, schemas, classes, useMeta);
            ast.overload = resolveFilterOverload(type_lhs, ast.operator, type_rhs);
            return Promise.resolve();
        }

        assert(ast.isExternal);
        if (ast.schema === null)
            ast.schema = await loadSchema(schemas, classes, ast, 'query', useMeta);
        await typeCheckInputArgs(ast, ast.schema, scope, schemas, classes, useMeta);
        addRequiredInputParamsInvocation(ast, null);
        return typeCheckFilter(ast.filter, ast.schema, scope, schemas, classes, useMeta);
    })(ast);
}

function resolveAggregationOverload(ast, operator, field, schema) {
    let fieldType = schema.out[field];
    if (!fieldType)
        throw new TypeError('Invalid aggregation field ' + field);
    let ag = Builtin.Aggregations[operator];
    if (!ag)
        throw new TypeError('Invalid aggregation ' + operator);

    for (let overload of ag.types) {
        let typeScope = {};
        if (!Type.isAssignable(fieldType, overload[0], typeScope, true))
            continue;

        ast.overload = overload.map((t) => resolveTypeVars(t, typeScope));
        return ast.overload[1];
    }

    throw new TypeError('Invalid field type ' + fieldType + ' for ' + operator);
}

function cleanOutput(schema, scope) {
    scope.cleanOutput();
    const clone = schema.filterArguments((a) => a.is_input);
    clone.removeDefaultProjection();
    clone.removeMinimalProjection();
    assert(Array.isArray(clone.minimal_projection));
    return clone;
}

function addOutput(schema, name, type, scope, nl_annotations = {}) {
    scope.add(name, type);
    const clone = schema.addArguments([new Ast.ArgumentDef(schema.location,
        Ast.ArgDirection.OUT, name, type, { nl: nl_annotations })]);
    assert(Array.isArray(clone.minimal_projection));
    return clone;
}

function typeCheckAggregation(ast, scope) {
    let name, type, nl_annotations;
    if (ast.field === '*') {
        if (ast.operator !== 'count')
            throw new TypeError('* is not a valid argument to ' + ast.operator);
        type = Type.Number;
        ast.overload = [Type.Any, type];
        name = ast.alias ? ast.alias : 'count';
        nl_annotations = { canonical: 'count' };
    } else {
        type = resolveAggregationOverload(ast, ast.operator, ast.field, ast.table.schema);
        name = ast.alias ? ast.alias : ast.field;
        nl_annotations = ast.table.schema.getArgument(ast.field).nl_annotations;
    }

    ast.schema = addOutput(cleanOutput(ast.table.schema, scope), name, type, scope, nl_annotations);
}

async function typeCheckComputation(ast, innerSchema, scope, schemas, classes, useMeta) {
    let name = ast.alias ? ast.alias : Utils.getScalarExpressionName(ast.expression);
    let type = await typeCheckValue(ast.expression, scope, schemas, classes, useMeta);

    ast.type = type;
    ast.schema = addOutput(innerSchema, name, type, scope);
}

function typeCheckSort(ast, scope) {
    let fieldType = ast.table.schema.out[ast.field];
    if (!fieldType)
        throw new TypeError('Invalid sort field ' + ast.field);
    if (!fieldType.isComparable())
        throw new TypeError(`Invalid sort of non-comparable field ${ast.field}`);

    ast.schema = ast.table.schema;
}

async function typeCheckIndex(ast, scope, schemas, classes, useMeta) {
    if (ast.indices.length === 1) {
        const valueType = await typeCheckValue(ast.indices[0], scope, schemas, classes, useMeta);
        if (valueType.isArray) {
            if (!Type.isAssignable(valueType, Type.Array(Type.Number)))
                throw new TypeError(`Invalid index parameter, must be of type Array(Number)`);
        } else {
            if (!Type.isAssignable(valueType, Type.Number))
                throw new TypeError(`Invalid index parameter, must be a Number`);
        }
    } else {
        for (let index of ast.indices) {
            const valueType = await typeCheckValue(index, scope, schemas, classes, useMeta);
            if (!Type.isAssignable(valueType, Type.Number))
                throw new TypeError(`Invalid index parameter, must be a Number`);
        }
    }

    ast.schema = ast.table.schema;
}

async function typeCheckSlice(ast, scope, schemas, classes, useMeta) {
    const baseType = await typeCheckValue(ast.base, scope, schemas, classes, useMeta);
    const limitType = await typeCheckValue(ast.limit, scope, schemas, classes, useMeta);
    if (!Type.isAssignable(baseType, Type.Number))
        throw new TypeError(`Invalid slice offset parameter, must be a Number`);
    if (!Type.isAssignable(limitType, Type.Number))
        throw new TypeError(`Invalid slice limit parameter, must be a Number`);

    ast.schema = ast.table.schema;
}

function typeCheckMonitor(ast) {
    if (ast.args) {
        ast.args.forEach((arg) => {
            if (!ast.schema.hasArgument(arg) ||
                ast.schema.isArgInput(arg))
                throw new TypeError('Invalid field name ' + arg);
        });
    }
    if (!ast.schema.is_monitorable)
        throw new TypeError('monitor() applied to a non-monitorable query');

    return Promise.resolve();
}

function resolveFilter(filter, schema) {
    schema = schema.clone();

    // require_filter field is cleared after a filter
    schema.require_filter = false;
    if (schema.annotations)
        schema.annotations.require_filter = new Ast.Value.Boolean(false);

    schema.no_filter = false;
    /*
    schema.no_filter = (function recursiveHelper(ast) {
        if (!ast)
            return false;
        if (ast.isTrue || ast.isFalse)
            return false;
        if (ast.isCompute)
            return false;
        if (ast.isVarRef)
            return false;
        if (ast.isNot)
            return recursiveHelper(ast.expr);
        if (ast.isOr)
            return false;
        if (ast.isAnd) {
            const result = ast.operands.map((op) => recursiveHelper(op));
            if (result.includes(true))
                throw new TypeError('Filtering on parameter marked as unique cannot be combined with other filters');
            else
                return false;
        }
        if (ast.isAtom) {
            return !!schema.getArgument(ast.name).unique && ast.operator === '==';
        } else {
            assert(ast.isExternal);
            return false;
        }
    })(filter);
     */

    return schema;
}

function resolveProjection(args, schema, scope) {
    if (Object.keys(schema.out).length === 1)
        throw new TypeError('No projection is allowed if there is only one output parameter');
    if (args.length < 1) // this could be caused by normalization with nested projections
        throw new TypeError(`Invalid empty projection`);
    args = new Set(args);
    for (let arg of schema.minimal_projection)
        args.add(arg);
    for (let arg of args) {
        if (!schema.hasArgument(arg))
            throw new TypeError('Invalid field name ' + arg);
    }
    Object.keys(schema.out).forEach((arg) => {
        if (!args.has(arg))
            scope.remove(arg);
    });

    const clone = schema.clone();
    assert(clone !== schema);
    // if default_projection is non-empty, it's overwritten after a projection
    clone.default_projection = [];
    if (clone.annotations)
        clone.annotations.default_projection = new Ast.Value.Array([]);
    const result = clone.filterArguments((a) => a.is_input || args.has(a.name));
    assert(result !== schema && result !== clone);
    return result;
}

function resolveJoin(ast, lhs, rhs) {
    const joinargs = [];
    const joinargnames = new Set;
    const joinparams = new Set;
    for (let inParam of ast.in_params)
        joinparams.add(inParam.name);

    for (let rhsarg of rhs.iterateArguments()) {
        if (joinargnames.has(rhsarg.name))
            continue;
        if (joinparams.has(rhsarg.name))
            continue;
        joinargs.push(rhsarg);
        joinargnames.add(rhsarg.name);
    }
    for (let lhsarg of lhs.iterateArguments()) {
        if (joinargnames.has(lhsarg.name))
            continue;
        joinargs.push(lhsarg);
        joinargnames.add(lhsarg.name);
    }

    return new Ast.ExpressionSignature(
        ast.location,
        ast instanceof Ast.Stream ? 'stream' : 'query',
        null,
        [],
        joinargs,
        {
            is_list: lhs.is_list || rhs.is_list,
            is_monitorable: lhs.is_monitorable && rhs.is_monitorable,
            require_filter: lhs.require_filter || rhs.require_filter,
            default_projection: [...new Set(lhs.default_projection.concat(rhs.default_projection))],
            minimal_projection: [...new Set(lhs.minimal_projection.concat(rhs.minimal_projection))],
            no_filter: lhs.no_filter && rhs.no_filter
        }
    );
}

const VALID_DEVICE_ATTRIBUTES = ['name'];

async function typeCheckInputArgs(ast, schema, scope, schemas, classes, useMeta) {
    if (!ast.isVarRef && !ast.isJoin) {
        assert(ast.selector);

        if (ast.selector.isDevice) {
            let dupes = new Set;

            const attrscope = scope ? scope.clone() : null;
            if (attrscope)
                attrscope.cleanOutput();
            for (let attr of ast.selector.attributes) {
                if (dupes.has(attr.name))
                    throw new TypeError(`Duplicate device attribute ${attr.name}`);
                dupes.add(attr.name);

                if (VALID_DEVICE_ATTRIBUTES.indexOf(attr.name) < 0)
                    throw new TypeError(`Invalid device attribute ${attr.name}`);

                if (!attr.value.isVarRef && !attr.value.isConstant())
                    throw new TypeError(`Device attribute ${attr.value} must be a constant or variable`);
                const valueType = await typeCheckValue(attr.value, attrscope, schemas, classes, useMeta);
                if (!Type.isAssignable(valueType, Type.String, {}, false) || attr.value.isUndefined)
                    throw new TypeError(`Invalid type for device attribute ${attr.name}, have ${valueType}, need String`);
            }

            if (ast.selector.id && ast.selector.all)
                throw new TypeError(`all=true device attribute is incompatible with setting a device ID`);

            if (ast.selector.kind in classes) {
                const classdef = classes[ast.selector.kind];

                if (classdef.extends && classdef.extends.length === 1 && classdef.extends[0] === 'org.thingpedia.builtin.thingengine.remote')
                    ast.__effectiveSelector = new Ast.Selector.Device(ast.selector.location, 'org.thingpedia.builtin.thingengine.remote', ast.selector.id, ast.selector.principal, ast.selector.attributes.slice());
                else
                    ast.__effectiveSelector = ast.selector;
            } else {
                ast.__effectiveSelector = ast.selector;
            }
        }
    }

    var presentParams = new Set;
    for (let inParam of ast.in_params) {
        let inParamType = schema.getArgType(inParam.name);
        if (!inParamType || !schema.isArgInput(inParam.name))
            throw new TypeError('Invalid input parameter ' + inParam.name);

        const valueType = await typeCheckValue(inParam.value, scope, schemas, classes, useMeta);
        if (!Type.isAssignable(valueType, inParamType, {}, true))
            throw new TypeError(`Invalid type for parameter ${inParam.name}, have ${valueType}, need ${inParamType}`);
        if (presentParams.has(inParam.name))
            throw new TypeError('Duplicate input param ' + inParam.name);
        presentParams.add(inParam.name);
    }

    return schema.filterArguments((arg) => !presentParams.has(arg.name));
}

async function typeCheckTable(ast, schemas, scope, classes, useMeta = false) {
    if (ast.isVarRef) {
        ast.schema = await typeCheckInputArgs(ast, ast.schema, scope, schemas, classes, useMeta);
        scope.addAll(ast.schema.out);
    } else if (ast.isInvocation) {
        ast.schema = await typeCheckInputArgs(ast.invocation, ast.invocation.schema, scope, schemas, classes, useMeta);
        scope.addAll(ast.schema.out);
    } else if (ast.isFilter) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        await typeCheckFilter(ast.filter, ast.table.schema, scope, schemas, classes, useMeta);
        ast.schema = resolveFilter(ast.filter, ast.table.schema);
    } else if (ast.isProjection) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        ast.schema = resolveProjection(ast.args, ast.table.schema, scope);
    } else if (ast.isAlias) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        ast.schema = ast.table.schema;
        scope.addGlobal(ast.name, ast.schema);
        scope.prefix(ast.name);
    } else if (ast.isAggregation) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        typeCheckAggregation(ast, scope);
    } else if (ast.isSort) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        typeCheckSort(ast, scope);
    } else if (ast.isIndex) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        await typeCheckIndex(ast, scope, schemas, classes, useMeta);
    } else if (ast.isSlice) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        await typeCheckSlice(ast, scope, schemas, classes, useMeta);
    } else if (ast.isJoin) {
        let leftscope = new Scope(scope);
        let rightscope = new Scope(scope);

        await typeCheckTable(ast.lhs, schemas, leftscope, classes, useMeta);
        await typeCheckTable(ast.rhs, schemas, rightscope, classes, useMeta);
        leftscope.$has_event = true;
        await typeCheckInputArgs(ast, ast.rhs.schema, leftscope, schemas, classes, useMeta);
        ast.schema = resolveJoin(ast, ast.lhs.schema, ast.rhs.schema);
        scope.merge(leftscope);
        scope.merge(rightscope);
    } else if (ast.isCompute) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        await typeCheckComputation(ast, ast.table.schema, scope, schemas, classes, useMeta);
    } else {
        throw new Error('Not Implemented');
    }
}

async function typeCheckStream(ast, schemas, scope, classes, useMeta = false) {
    if (ast.isVarRef) {
        ast.schema = await typeCheckInputArgs(ast, ast.schema, scope, schemas, classes, useMeta);
        scope.addAll(ast.schema.out);
    } else if (ast.isTimer) {
        ast.schema = new Ast.ExpressionSignature(ast.location, 'stream', null, [], [], {
            is_list: false, is_monitorable: true,
            minimal_projection: []
        });
        if (!Type.isAssignable(await typeCheckValue(ast.base, scope, schemas, classes, useMeta), Type.Date, {}, true))
            throw new TypeError(`Invalid type for timer base`);
        if (!Type.isAssignable(await typeCheckValue(ast.interval, scope, schemas, classes, useMeta), Type.Measure('ms'), {}, true))
            throw new TypeError(`Invalid type for timer interval`);
        scope.addAll(ast.schema.out);
    } else if (ast.isAtTimer) {
        ast.schema = new Ast.ExpressionSignature(ast.location, 'stream', null, [], [], {
            is_list: false, is_monitorable: true,
            minimal_projection: []
        });
        for (let i = 0; i < ast.time.length; i++) {
            const value = ast.time[i];
            if (!Type.isAssignable(await typeCheckValue(value, scope, schemas, classes, useMeta), Type.Time, {}, true))
            throw new TypeError(`Invalid type for attimer time`);
        }
        if (ast.expiration_date !== null) {
            if (!Type.isAssignable(await typeCheckValue(ast.expiration_date, scope, schemas, classes, useMeta), Type.Date, {}, true))
                throw new TypeError(`Invalid type for attimer expiration_date`);
        }
        scope.addAll(ast.schema.out);
    } else if (ast.isMonitor) {
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        ast.schema = ast.table.schema;
        await typeCheckMonitor(ast);
    } else if (ast.isEdgeNew) {
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        ast.schema = ast.stream.schema;
    } else if (ast.isEdgeFilter) {
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        ast.schema = ast.stream.schema;
        await typeCheckFilter(ast.filter, ast.schema, scope, schemas, classes, useMeta);
    } else if (ast.isFilter) {
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        ast.schema = resolveFilter(ast.filter, ast.stream.schema);
        await typeCheckFilter(ast.filter, ast.schema, scope, schemas, classes, useMeta);
    } else if (ast.isAlias) {
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        ast.schema = ast.stream.schema;
        scope.addGlobal(ast.name, ast.schema);
        scope.prefix(ast.name);
    } else if (ast.isProjection) {
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        ast.schema = resolveProjection(ast.args, ast.stream.schema, scope);
    } else if (ast.isJoin) {
        let leftscope = new Scope(scope);
        let rightscope = new Scope(scope);

        await typeCheckStream(ast.stream, schemas, leftscope, classes, useMeta);
        await typeCheckTable(ast.table, schemas, rightscope, classes, useMeta);
        leftscope.$has_event = true;
        await typeCheckInputArgs(ast, ast.table.schema, leftscope, schemas, classes, useMeta);
        ast.schema = resolveJoin(ast, ast.stream.schema, ast.table.schema);
        scope.merge(leftscope);
        scope.merge(rightscope);
    } else if (ast.isCompute) {
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        await typeCheckComputation(ast, ast.stream.schema, scope, schemas, classes, useMeta);
    } else {
        throw new Error('Not Implemented');
    }
}

async function typeCheckAction(ast, schemas, scope, classes, useMeta) {
    if (ast.isNotify)
        ast.schema = await loadNotifyAction(ast.name);
    else if (ast.isInvocation)
        ast.schema = await typeCheckInputArgs(ast.invocation, ast.invocation.schema, scope, schemas, classes, useMeta);
    else
        ast.schema = await typeCheckInputArgs(ast, ast.schema, scope, schemas, classes, useMeta);
}

function addRequiredInputParamsInvocation(prim, extrainparams) {
    let present = new Set;
    for (let in_param of prim.in_params)
        present.add(in_param.name);

    for (let name in prim.schema.inReq) {
        if (!present.has(name) && (!extrainparams || !extrainparams.has(name)))
            prim.in_params.push(new Ast.InputParam(prim.location, name, new Ast.Value.Undefined(true)));
    }
}

function addRequiredInputParamsStream(stream) {
    if (stream.isTimer || stream.isAtTimer)
        return;
    if (stream.isJoin) {
        let extrainparams = new Set(stream.in_params.map((ip) => ip.name));
        addRequiredInputParamsStream(stream.stream);
        addRequiredInputParamsTable(stream.table, extrainparams);
        return;
    }

    if (stream.isVarRef)
        addRequiredInputParamsInvocation(stream, null);
    else if (Utils.isUnaryStreamToStreamOp(stream))
        addRequiredInputParamsStream(stream.stream);
    else if (Utils.isUnaryTableToStreamOp(stream))
        addRequiredInputParamsTable(stream.table, null);
    else
        throw new TypeError();
}
function addRequiredInputParamsTable(table, extrainparams) {
    if (table.isJoin) {
        let newextrainparams = new Set(table.in_params.map((ip) => ip.name));
        if (extrainparams) {
            for (let name in extrainparams)
                newextrainparams.add(name);
        }
        addRequiredInputParamsTable(table.lhs, extrainparams);
        addRequiredInputParamsTable(table.rhs, newextrainparams);
        return;
    }

    if (table.isVarRef)
        addRequiredInputParamsInvocation(table, extrainparams);
    else if (table.isInvocation)
        addRequiredInputParamsInvocation(table.invocation, extrainparams);
    else if (Utils.isUnaryStreamToTableOp(table))
        addRequiredInputParamsStream(table.stream);
    else if (Utils.isUnaryTableToTableOp(table))
        addRequiredInputParamsTable(table.table, extrainparams);
    else
        throw new TypeError();
}

function addRequiredInputParamsAction(action) {
    if (action.isNotify)
        return;

    if (action.isVarRef)
        addRequiredInputParamsInvocation(action, null);
    else if (action.isInvocation)
        addRequiredInputParamsInvocation(action.invocation, null);
    else
        throw new TypeError();
}

async function loadOneSchema(schemas, scope, classes, useMeta, primType, prim) {
    if (primType === 'table' || primType === 'filter')
        primType = 'query';

    let schema;
    if (prim.isVarRef) {
        if (scope.has(prim.name))
            schema = scope.get(prim.name);
        else
            schema = await schemas.getMemorySchema(prim.name, useMeta);
        if (schema === null)
            throw new TypeError(`Cannot find declaration ${prim.name} in memory`);
        if (!(schema instanceof Ast.ExpressionSignature) || schema.functionType !== primType)
            throw new TypeError(`Variable ${prim.name} does not name a ${primType}`);
    } else {
        schema = await loadSchema(schemas, classes, prim, primType, useMeta);
    }
    if (prim.schema === null)
        prim.schema = schema;
}

async function loadAllSchemas(ast, schemas, scope, classes, useMeta) {
    return await Promise.all(Array.from(ast.iteratePrimitives(true)).map(async ([primType, prim]) => {
        return loadOneSchema(schemas, scope, classes, useMeta, primType, prim);
    }));
}

async function typeCheckClass(klass, schemas, classes, useMeta, isLibrary) {
    if (!isLibrary) {
        if (klass.extends && klass.extends[0] === 'remote')
            klass.extends = ['org.thingpedia.builtin.thingengine.remote'];
        if (klass.extends && klass.extends.length !== 1 && klass.extends[0] !== 'org.thingpedia.builtin.thingengine.remote')
            throw new TypeError('Inline class definitions that extend other than @org.thingpedia.builtin.thingengine.remote are not supported');
    }

    Object.entries(klass.metadata).forEach(([name, value]) => {
        if (typeof value !== 'string')
            throw new TypeError('Invalid value type for natural language annotations');
    });
    let imported = new Set();
    for (let import_stmt of klass.imports) {
        if (import_stmt.isMixin) {
            for (let facet of import_stmt.facets) {
                if (['config', 'loader'].includes(facet) && klass.is_abstract)
                    throw new TypeError('Abstract class should not contain config or loader modules');
                if (imported.has(facet))
                    throw new TypeError(`${facet} mixin imported multiple times`);
                imported.add(facet);
            }
            let mixin = await schemas.getMixins(import_stmt.module);
            await typeCheckMixin(import_stmt, mixin, schemas, classes, useMeta);
        }
    }
    Object.entries(klass.queries).forEach(([name, query]) => {
        typeCheckFunctionDef('query', query);
    });
    Object.entries(klass.actions).forEach(([name, action]) => {
        typeCheckFunctionDef('action', action);
    });
}

async function typeCheckMixin(import_stmt, mixin, schemas, classes, useMeta) {
    let presentParams = new Set();
    for (let in_param of import_stmt.in_params) {
        if (!in_param.value.isConstant())
            throw new TypeError(`Mixin parameter ${in_param.name} must be a constant`);
        let i = mixin.args.indexOf(in_param.name);
        if (i === -1 || !mixin.is_input[i])
            throw new TypeError(`Invalid parameter ${in_param.name} for mixin ${mixin.kind}`);
        let inParamType = mixin.types[i];
        const valueType = await typeCheckValue(in_param.value, new Scope, schemas, classes, useMeta);
        if (!Type.isAssignable(valueType, inParamType, {}, true))
            throw new TypeError(`Invalid type for parameter ${in_param.name}, have ${valueType}, need ${inParamType}`);
        if (presentParams.has(in_param.name))
            throw new TypeError(`Duplicate input parameter ${in_param.name}`);
        presentParams.add(in_param.name);
    }
    for (let i = 0; i < mixin.args.length; i ++ ) {
        if (mixin.required[i] && !presentParams.has(mixin.args[i]))
            throw new TypeError(`Missing required parameter ${mixin.args[i]}`);
    }
}

function typeCheckMetadata(func) {
    /*Object.entries(func.metadata).forEach(([name, value]) => {
        if (name === 'canonical' && typeof value === 'object') {
            if (!('default' in value))
                throw new TypeError(`"default" is required in canonical to specify which phrase to use by default`);
            if (!(value.default in value))
                throw new TypeError(`Missing the specified default phrase in canonical.`);
            Object.entries(value).forEach(([name, value]) => {
                if (name === 'default') {
                    if (typeof value !== 'string')
                        throw new TypeError(`Invalid value type for ${name} in canonical, expected a string`);
                } else if (name === 'apv' || name === 'npv') {
                    if (typeof value !== 'boolean')
                        throw new TypeError(`Invalid value type for ${name} in canonical, expected a boolean`);
                } else {
                    if (!Array.isArray(value))
                        throw new TypeError(`Invalid value type for ${name} in canonical, expected an array`);
                    value.forEach((v) => {
                        if (typeof v !== 'string')
                            throw new TypeError(`Invalid value type for ${name} in canonical, expected an array of strings`);
                    });
                }
            });
        } else if (name === 'formatted') {
            // FIXME check harder
            if (!Array.isArray(value))
                throw new TypeError('Expected an array for "formatted" annotation');
        } else if (typeof value !== 'string') {
            throw new TypeError(`Invalid value type for natural language annotation ${name}`);
        }
    });
    */
}

function typeCheckFunctionAnnotations(func) {
    Object.entries(func.annotations).forEach(([name, value]) => {
        if (!value.isConstant())
            throw new Error(`Annotation #[${name}] must be a constant`);

        switch (name) {
            case 'doc':
            case 'url':
                if (!value.isString)
                    throw new TypeError(`Invalid type ${value.getType()} for #[${name}] annotation, expected a string`);
                break;
            case 'handle_thingtalk':
            case 'require_filter':
                if (!value.isBoolean)
                    throw new TypeError(`Invalid type ${value.getType()} for #[${name}] annotation, expected a boolean`);
                break;
            case 'default_projection':
                if (!value.isArray)
                    throw new TypeError(`Invalid type ${value.getType()} for #[${name}] annotation, expected an array`);
                value.value.forEach((param) => {
                    if (!param.isString)
                        throw new TypeError(`Invalid type ${param.getType()} for ${param.value} in #[${name}] annotation, expected a string`);
                    if (!func.args.includes(param.value))
                        throw new TypeError(`Invalid parameter ${param.value} in #[${name}] annotation, the parameter does not exist.`);
                });
                break;
            default:
        }
    });
}

function typeEqual(t1, t2) {
    // TODO: replace this once we switch away from adt
    if (t1.isCompound && t2.isCompound) {
        if (t1.name !== t2.name)
            return false;
        if (Object.keys(t1.fields).length !== Object.keys(t2.fields).length)
            return false;
        for (let f in t1.fields) {
            if (!(f in t2.fields))
                return false;
            if (!typeEqual(t1.fields[f].type, (t2.fields[f].type)))
                return false;
        }
        return true;
    } else if (t1.isEnum && t2.isEnum) {
        if (t1.entries.length !== t2.entries.length)
            return false;
        for (let entry of t1.entries) {
            if (!t2.entries.includes(entry))
                return false;
        }
        return true;
    } else {
        return t1.equals(t2);
    }
}

function typeCheckFunctionInheritance(func) {
    if (func.extends.length === 0)
        return;
    const functions = [];
    const args = {};
    for (let fname of func.iterateBaseFunctions()) {
        if (functions.includes(fname))
            continue;
        functions.push(fname);
        const f = func.class.getFunction(func.functionType, fname);
        if (!f)
            throw new TypeError(`Cannot find ${func.functionType} with name ${fname}`);
        for (let a of f.args) {
            // parameters with the same name are allowed, but must have the same type
            if (a in args) {
                // skip entities when check correctness
                // FIXME: implement entity inheritance
                if (args[a].isEntity && f.getArgType(a).isEntity)
                    continue;
                if (!typeEqual(args[a], (f.getArgType(a))))
                    throw new TypeError(`Parameter ${a} is defined multiple times in ${func.functionType} ${func.name} with different types`);
            } else {
                args[a] = f.getArgType(a);
            }
        }

        if (func.is_monitorable && !f.is_monitorable)
            throw new TypeError(`Monitorable query ${func.name} cannot extends non-monitorable query ${f.name}`);
            // the reverse is allowed
            // e.g., if func add a new non-monitorable parameter to monitable function f, func becomes non-monitorable
    }
}

function typeCheckFunctionDef(type, func) {
    for (let argname of func.args) {
        const type = func.getArgType(argname);
        if (type.isUnknown)
            throw new TypeError(`Invalid type ${type.name}`);
        typeCheckMetadata(func.getArgument(argname));
    }

    typeCheckMetadata(func);
    typeCheckFunctionAnnotations(func);
    typeCheckFunctionInheritance(func);

    if (type === 'query') {
        if (func.is_monitorable) {
            let poll_interval = func.annotations['poll_interval'];
            if (poll_interval) {
                if (!(poll_interval.isMeasure) || Units.normalizeUnit(poll_interval.unit) !== 'ms')
                    throw new TypeError(`Invalid value type for poll_interval.`);
            }
        } else if ('poll_interval' in func.annotations) {
            throw new TypeError(`Invalid annotation poll_interval for non-monitorable query ${func.name}.`);
        }
    }

    if (type === 'action') {
        if ('poll_interval' in func.annotations)
            throw new TypeError(`Invalid annotation poll_interval for action ${func.name}.`);
        // this is syntactically impossible, but also not meaningful
        // the other check, is_list, is also syntactically impossible but might be allowed in the future
        // so we don't throw
        if (func.is_monitorable)
            throw new TypeError(`Actions cannot be monitorable.`);
    }
}

function typeCheckDeclarationArgs(args) {
    for (let name in args) {
        let type = args[name];
        if (type.isUnknown)
            throw new TypeError(`Invalid type ${type.name}`);
    }
}

async function typeCheckProcedure(ast) {
    let hasNotify = false;
    for (let stmt of ast.value.rules) {
        if (stmt.isRule)
            throw new TypeError(`Continuous statements are not allowed in nested procedures`);

        if (stmt.isAssignment)
            continue;
        assert(stmt.isCommand);
        if (stmt.actions.some((a) => a.isNotify)) {
            if (hasNotify)
                throw new TypeError(`Multiple statements with 'notify' are not allowed in nested procedures`);
            hasNotify = true;
        }
    }
}

async function typeCheckDeclarationCommon(ast, schemas, scope, classes, useMeta) {
    typeCheckDeclarationArgs(ast.args);
    scope.addLambdaArgs(ast.args);
    await loadAllSchemas(ast, schemas, scope, classes, useMeta);

    switch (ast.type) {
        case 'stream':
            addRequiredInputParamsStream(ast.value);
            await typeCheckStream(ast.value, schemas, scope, classes, useMeta);
            break;
        case 'query':
            addRequiredInputParamsTable(ast.value, null);
            await typeCheckTable(ast.value, schemas, scope, classes, useMeta);
            break;
        case 'action':
            addRequiredInputParamsAction(ast.value);
            await typeCheckAction(ast.value, schemas, scope, classes, useMeta);
            break;
        case 'program':
        case 'procedure':
            await typeCheckProgram(ast.value, schemas, useMeta, classes, scope);
            if (ast.type === 'procedure')
                await typeCheckProcedure(ast);

            break;
        default:
            throw new TypeError(`Invalid declaration type ${ast.type}`);
    }
}

function makeFunctionSchema(ast) {
    // remove all input parameters (which will be filled with undefined)
    // and add the lambda arguments
    const argdefs = ast.value.schema.args
        .map((argname) => ast.value.schema.getArgument(argname))
        .filter((arg) => !arg.is_input)
        .concat(Object.keys(ast.args).map((name) =>
        new Ast.ArgumentDef(ast.location, Ast.ArgDirection.IN_REQ, name, ast.args[name], {})));

    return new Ast.FunctionDef(
        ast.location,
        ast.type,
        ast.value.class,
        ast.name,
        [],
        {
            is_list: ast.value.schema.is_list,
            is_monitorable: ast.value.schema.is_monitorable
        },
        argdefs,
        {
            nl: ast.nl_annotations,
            impl: ast.impl_annotations
        }
    );
}

function makeProgramSchema(ast, isProcedure) {
    const args = Object.keys(ast.args).map((name) =>
        new Ast.ArgumentDef(ast.location, Ast.ArgDirection.IN_REQ, name, ast.args[name], {}));

    if (isProcedure) {
        // add output arguments from the statement that includes a `notify` clause
        // (there can be at most once)
        for (const stmt of ast.value.rules) {
            if (!stmt.isCommand)
                continue;

            if (!stmt.actions.some((a) => a.isNotify))
                continue;

            const outargs = Array.from(stmt.table.schema.iterateArguments()).filter((a) => !a.is_input);
            args.push(...outargs);
        }
    }

    // a program/procedure can be called on the action side, so it's an action
    return new Ast.FunctionDef(ast.location, 'action', null, ast.name, [],
        { is_list: false, is_monitorable: false}, args,
        { nl: ast.nl_annotations, impl: ast.impl_annotations });
}

async function typeCheckDeclaration(ast, schemas, scope, classes, useMeta) {
    await typeCheckDeclarationCommon(ast, schemas, scope, classes, useMeta);
    typeCheckMetadata(ast);

    if (ast.type === 'program' || ast.type === 'procedure')
        ast.schema = makeProgramSchema(ast, ast.type === 'procedure');
    else
        ast.schema = makeFunctionSchema(ast);
    scope.addGlobal(ast.name, ast.schema);
}

async function typeCheckExample(ast, schemas, classes = {}, useMeta = false) {
    await typeCheckDeclarationCommon(ast, schemas, new Scope(), classes, useMeta);

    if (!Array.isArray(ast.utterances))
        throw new TypeError('Utterances annotation expects an array');
    for (let utterance of ast.utterances) {
        if (typeof utterance !== 'string')
            throw new TypeError('Utterance can only be a string');
    }
}

async function typeCheckAssignment(ast, schemas, scope, classes, useMeta = false) {
    // if the value is an invocation or varref, without any computation on the result,
    // we allow it to be an action or varref to an action
    if (ast.value.isInvocation || ast.value.isVarRef) {
        try {
            await loadOneSchema(schemas, scope, classes, useMeta, 'action', ast.value);
            ast.isAction = true;
        } catch(e) { /* ignore if it is not an action */ }
    }

    if (!ast.isAction) {
        await loadAllSchemas(ast, schemas, scope, classes, useMeta);

        // if isAction was `undefined` (before typechecking) overwrite it to `false`
        ast.isAction = false;
    }

    addRequiredInputParamsTable(ast.value, null);
    await typeCheckTable(ast.value, schemas, scope, classes, useMeta);

    // remove all input parameters (which we have filled with $undefined)
    const args = Array.from(ast.value.schema.iterateArguments()).filter((a) => !a.is_input);
    ast.schema = new Ast.FunctionDef(ast.location, 'query', null, ast.name, [],
        { is_list: ast.value.schema.is_list, is_monitorable: false }, args, {});
    scope.addGlobal(ast.name, ast.schema);
}

async function typeCheckRule(ast, schemas, scope, classes, useMeta = false) {
    await loadAllSchemas(ast, schemas, scope, classes, useMeta);

    if (ast.table !== undefined && ast.table !== null) {
        addRequiredInputParamsTable(ast.table, null);
        await typeCheckTable(ast.table, schemas, scope, classes, useMeta);
        if (ast.table.schema.require_filter)
            throw new TypeError('Filter required');
    } else if (ast.stream !== undefined && ast.stream !== null) {
        addRequiredInputParamsStream(ast.stream);
        await typeCheckStream(ast.stream, schemas, scope, classes, useMeta);
        if (ast.stream.schema.require_filter)
            throw new TypeError('Filter required');
    }
    scope.$has_event = !!(ast.table || ast.stream);

    if (ast.actions.some((a) => a.isNotify) && !ast.stream && !ast.table)
        throw new TypeError('Cannot return a result without a GET function');

    for (let prim of ast.actions)
        addRequiredInputParamsAction(prim);
    await Promise.all(
        ast.actions.map((action) => typeCheckAction(action, schemas, scope, classes, useMeta)));
}

async function typeCheckProgram(ast, schemas, useMeta = false, classes = {}, parentScope = null) {
    ast.classes.forEach((ast) => {
        classes[ast.name] = ast;
    });

    const scope = new Scope(parentScope);
    if (ast.principal !== null)
        await typecheckPrincipal(ast.principal, schemas, classes, useMeta);

    for (let klass of ast.classes)
        await typeCheckClass(klass, schemas, classes, useMeta, false);
    for (let decl of ast.declarations) {
        scope.clean();
        await typeCheckDeclaration(decl, schemas, scope, classes, useMeta);
    }
    /*if (ast.rules.length === 0 && ast.oninputs.length === 0)
        throw new TypeError(`A program must include at least one executable or oninput statement`);*/

    for (let decl of ast.rules) {
        scope.clean();
        if (decl.isAssignment)
            await typeCheckAssignment(decl, schemas, scope, classes, useMeta);
        else
            await typeCheckRule(decl, schemas, scope, classes, useMeta);
    }
    for (let choice of ast.oninputs) {
        scope.clean();
        await typeCheckRule(choice, schemas, scope, classes, useMeta);
    }
}

async function typeCheckDialogue(ast, schemas, useMeta = false) {
    for (let item of ast.history) {
        const scope = new Scope(null);
        await typeCheckRule(item.stmt, schemas, scope, {}, useMeta);

        if (item.results !== null) {
            if (!item.results.count.isConstant() ||
                !Type.isAssignable(await typeCheckValue(item.results.count, new Scope, schemas, {}, useMeta), Type.Number, {}))
                throw new TypeError(`History annotation #[count] must be a constant of Number type`);
            if (item.results.error) {
                if (!item.results.error.isConstant())
                    throw new TypeError(`History annotation #[error] must be a constant of String or Enum type`);

                const type = await typeCheckValue(item.results.error, new Scope, schemas, {}, useMeta);
                if (!type.isString && !type.isEnum)
                    throw new TypeError(`History annotation #[error] must be a constant of String or Enum type`);
            }

            for (let result of item.results.results) {
                for (let key in result.value) {
                    if (!result.value[key].isConstant())
                        throw new TypeError(`Program results must be constants, found ${result.value[key]}`);
                }
            }
        }
    }
}

async function getAllowedSchema(allowed, schemaType, schemas, getMeta) {
    if (!allowed.isSpecified || allowed.schema)
        return;

    allowed.schema = await Utils.getSchemaForSelector(schemas, allowed.kind, allowed.channel, schemaType, getMeta, {});
}

async function typecheckPermissionFunction(fn, scope, schemas, getMeta) {
    if (!fn.isSpecified)
        return;

    await typeCheckFilter(fn.filter, fn.schema, scope, schemas, {}, getMeta);
}

async function typeCheckPermissionRule(permissionRule, schemas, getMeta = false) {
    await Promise.all([
        getAllowedSchema(permissionRule.query, 'query', schemas, getMeta),
        getAllowedSchema(permissionRule.action, 'action', schemas, getMeta),
    ]);

    {
        const scope = new Scope();
        scope.add('source', Type.Entity('tt:contact'));
        await typeCheckFilter(permissionRule.principal, null, scope, schemas, {}, getMeta);
    }

    {
        const scope = new Scope();
        await typecheckPermissionFunction(permissionRule.query, scope, schemas, getMeta);
        scope.$has_event = true;
        await typecheckPermissionFunction(permissionRule.action, scope, schemas, getMeta);
    }
}

async function typeCheckDataset(dataset, schemas, classes, getMeta = false) {
    for (let ex of dataset.examples)
        await typeCheckExample(ex, schemas, classes, getMeta);
}

async function typeCheckMeta(meta, schemas, getMeta = false) {
    const classes = {};
    for (let klass of meta.classes) {
        await typeCheckClass(klass, schemas, classes, getMeta, true);
        classes[klass.name] = klass;
    }
    for (let dataset of meta.datasets)
        await typeCheckDataset(dataset, schemas, classes, getMeta);
}

async function typeCheckBookkeeping(intent, schemas, getMeta = false) {
    if (intent.isSpecial) {
        if (Ast.BookkeepingSpecialTypes.indexOf(intent.type) < 0)
            throw new TypeError(`Invalid special ${intent.type}`);
    } else if (intent.isCommandList) {
        const valueType = await typeCheckValue(intent.device, new Scope, schemas, {}, getMeta);
        if (!Type.isAssignable(valueType, Type.Entity('tt:device'), {}, true))
            throw new TypeError('Invalid device parameter');
    }
}

module.exports = {
    typeCheckBookkeeping,
    typeCheckProgram,
    typeCheckDialogue,
    typeCheckFilter,
    typeCheckPermissionRule,
    typeCheckMeta,
    typeCheckClass,
    typeCheckExample
};

stanford-oval / thingtalk / 870

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