258 lines
8.2 KiB
TypeScript
258 lines
8.2 KiB
TypeScript
/// SPDX-License-Identifier: GPL-3.0-or-later
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/// SPDX-FileCopyrightText: Copyright © 2016-2023 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
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import { canonicalString, Dictionary, is, Record, RecordConstructorInfo, Value } from '@preserves/core';
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import { AnyValue, Ref } from './actor.js';
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import * as P from '../gen/dataspacePatterns.js';
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export type Path = Array<AnyValue>;
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export type Shape = string;
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export function classOfValue(v: any): Shape | null {
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if (Record.isRecord(v)) {
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return constructorInfoSignature(Record.constructorInfo(v));
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} else if (Array.isArray(v)) {
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return '' + v.length;
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} else if (Map.isMap(v)) {
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return '{}';
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} else {
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return null;
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}
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}
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export function classOfCtor(v: P.DCompound): Shape {
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switch (v._variant) {
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case 'rec':
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return canonicalString(v.label) + '/' + v.fields.length;
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case 'arr':
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return '' + v.items.length;
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case 'dict':
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return '{}';
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}
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}
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// Called by generated code in addition to functions in this module
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export function constructorInfoSignature(ci: RecordConstructorInfo<Value>): string {
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return canonicalString(ci.label) + '/' + ci.arity;
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}
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export function step(v: AnyValue, index: AnyValue): AnyValue | undefined {
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if (Map.isMap(v)) {
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return v.get(index);
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} else {
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return (v as Array<AnyValue> /* includes Record! */)[index as number];
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}
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}
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export type PatternAnalysis = {
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constPaths: Array<Path>,
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constValues: Array<AnyValue>,
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capturePaths: Array<Path>,
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};
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export function analysePattern(p: P.Pattern): PatternAnalysis {
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const result: PatternAnalysis = {
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constPaths: [],
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constValues: [],
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capturePaths: [],
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};
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const path: Path = [];
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function walkKey(p: P.Pattern, key: AnyValue) {
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path.push(key);
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walk(p);
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path.pop();
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}
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function walk(p: P.Pattern) {
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switch (p._variant) {
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case 'DCompound':
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switch (p.value._variant) {
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case 'rec': p.value.fields.forEach(walkKey); break;
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case 'arr': p.value.items.forEach(walkKey); break;
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case 'dict': p.value.entries.forEach(walkKey); break;
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}
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break;
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case 'DBind':
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result.capturePaths.push(path.slice());
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walk(p.value.pattern);
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break;
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case 'DDiscard':
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break;
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case 'DLit':
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result.constPaths.push(path.slice());
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result.constValues.push(P.fromAnyAtom(p.value.value));
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break;
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}
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}
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walk(p);
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return result;
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}
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export function match(p: P.Pattern, v: AnyValue): Array<AnyValue> | false {
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const captures: Array<AnyValue> = [];
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function walk(p: P.Pattern, v: AnyValue): boolean {
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switch (p._variant) {
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case 'DBind': {
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captures.push(v);
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return walk(p.value.pattern, v);
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}
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case 'DDiscard':
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return true;
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case 'DLit':
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return is(p.value.value, v);
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case 'DCompound': {
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const pcls = classOfCtor(p.value);
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const vcls = classOfValue(v);
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if (pcls !== vcls) return false;
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let items: Array<P.Pattern>;
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switch (p.value._variant) {
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case 'dict':
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for (const [stepIndex, pp] of p.value.entries.entries()) {
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const vv = step(v, stepIndex);
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if (vv === void 0 || !walk(pp, vv)) return false;
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}
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return true;
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case 'rec': items = p.value.fields; break;
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case 'arr': items = p.value.items; break;
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}
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let index = 0;
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for (const pp of items) {
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const vv = step(v, index++);
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if (vv === void 0 || !walk(pp, vv)) return false;
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}
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return true;
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}
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}
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}
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return walk(p, v) ? captures : false;
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}
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export function isCompletelyConcrete(p: P.Pattern): boolean {
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function walk(p: P.Pattern): boolean {
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switch (p._variant) {
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case 'DBind': return false;
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case 'DDiscard': return false;
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case 'DLit': return true;
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case 'DCompound': switch (p.value._variant) {
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case 'rec': return p.value.fields.every(isCompletelyConcrete);
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case 'arr': return p.value.items.every(isCompletelyConcrete);
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case 'dict': {
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for (const pp of p.value.entries.values()) {
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if (!walk(pp)) return false;
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}
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return true;
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}
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}
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}
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}
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return walk(p);
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}
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export function withoutCaptures(p: P.Pattern): P.Pattern {
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function walk(p: P.Pattern): P.Pattern {
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switch (p._variant) {
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case 'DBind': return walk(p.value.pattern);
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case 'DDiscard': return p;
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case 'DLit': return p;
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case 'DCompound':
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switch (p.value._variant) {
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case 'rec':
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return P.Pattern.DCompound(P.DCompound.rec({
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label: p.value.label,
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fields: p.value.fields.map(walk),
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}));
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case 'arr':
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return P.Pattern.DCompound(P.DCompound.arr(p.value.items.map(walk)));
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case 'dict':
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return P.Pattern.DCompound(P.DCompound.dict(p.value.entries.mapEntries(
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e => [e[0], walk(e[1])])));
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}
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}
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}
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return walk(p);
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}
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//---------------------------------------------------------------------------
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// Constructor helpers
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export function bind(p?: P.Pattern): P.Pattern {
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return P.Pattern.DBind(P.DBind(p ?? _));
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}
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export function discard(): P.Pattern {
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return P.Pattern.DDiscard(P.DDiscard());
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}
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export const _ = discard();
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export function lit(v: AnyValue): P.Pattern {
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if (Array.isArray(v)) {
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if ('label' in v) {
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return P.Pattern.DCompound(P.DCompound.rec({
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label: v.label,
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fields: v.map(lit),
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}));
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} else {
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return P.Pattern.DCompound(P.DCompound.arr(v.map(lit)));
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}
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} else if (Map.isMap(v)) {
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return P.Pattern.DCompound(P.DCompound.dict(v.mapEntries(
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e => [e[0], lit(e[1])])));
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} else if (Set.isSet(v)) {
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throw new Error("Cannot express literal set in pattern");
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} else {
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return P.Pattern.DLit(P.DLit(P.asAnyAtom(v)));
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}
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}
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export function drop_lit(p: P.Pattern): AnyValue | null {
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const e = new Error();
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function walk(p: P.Pattern): AnyValue {
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switch (p._variant) {
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case 'DCompound':
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switch (p.value._variant) {
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case 'rec': {
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const v = [] as unknown as Record<AnyValue, AnyValue[], Ref>;
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v.label = p.value.label;
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p.value.fields.forEach(tt => v.push(walk(tt)));
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return v;
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}
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case 'arr':
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return p.value.items.map(walk);
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case 'dict': {
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const v = new Dictionary<Ref, AnyValue>();
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p.value.entries.forEach((pp, key) => v.set(key, walk(pp)));
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return v;
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}
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}
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case 'DLit':
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return P.fromAnyAtom(p.value.value);
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default:
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throw e;
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}
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}
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try {
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return walk(p);
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} catch (ee) {
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if (ee == e) return null;
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throw ee;
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}
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}
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export function rec(label: AnyValue, ... fields: P.Pattern[]): P.Pattern {
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return P.Pattern.DCompound(P.DCompound.rec({ label, fields }));
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}
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export function arr(... patterns: P.Pattern[]): P.Pattern {
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return P.Pattern.DCompound(P.DCompound.arr(patterns));
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}
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export function dict(... entries: [AnyValue, P.Pattern][]): P.Pattern {
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return P.Pattern.DCompound(P.DCompound.dict(new Dictionary<Ref, P.Pattern>(entries)));
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}
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