132 lines
5.3 KiB
TypeScript
132 lines
5.3 KiB
TypeScript
import { stringify } from '@preserves/core';
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import * as M from './meta';
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export function checkSchema(schema: M.Schema): (
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{ ok: true, schema: M.Schema } | { ok: false, problems: Array<string> })
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{
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const checker = new Checker();
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schema.definitions.forEach(checker.checkDefinition.bind(checker));
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if (checker.problems.length > 0) {
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return { ok: false, problems: checker.problems };
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} else {
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return { ok: true, schema };
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}
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}
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enum ValueAvailability {
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AVAILABLE,
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NOT_AVAILABLE,
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};
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class Checker {
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problems: Array<string> = [];
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recordProblem(context: string, detail: string): void {
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this.problems.push(`${detail} in ${context}`);
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}
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checkBinding(scope: Set<string>, sym: symbol, context: string): void {
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const name = sym.description!;
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if (scope.has(name)) {
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this.recordProblem(context, `duplicate binding named ${JSON.stringify(name)}`);
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}
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if (!M.isValidToken(name)) {
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this.recordProblem(context, `invalid binding name ${JSON.stringify(name)}`);
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}
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scope.add(name);
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}
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checkDefinition(def: M.Definition, name: symbol): void {
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switch (def._variant) {
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case 'or': {
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const labels = new Set<string>();
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[def.pattern0, def.pattern1, ... def.patternN].forEach(({ variantLabel, pattern }) => {
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const context = `variant ${variantLabel} of ${name.description!}`;
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if (labels.has(variantLabel)) {
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this.recordProblem(context, `duplicate variant label`);
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}
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if (!M.isValidToken(variantLabel)) {
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this.recordProblem(context, `invalid variant label`);
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}
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labels.add(variantLabel);
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this.checkPattern(new Set(), pattern, context, ValueAvailability.AVAILABLE);
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});
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break;
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}
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case 'and': {
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const ps = [def.pattern0, def.pattern1, ... def.patternN];
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const scope = new Set<string>();
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ps.forEach((p) => this.checkNamedPattern(scope, p, name.description!));
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break;
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}
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case 'Pattern':
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this.checkPattern(
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new Set(), def.value, name.description!, ValueAvailability.AVAILABLE);
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break;
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}
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}
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checkNamedPattern(scope: Set<string>, p: M.NamedPattern, context: string): void
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{
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switch (p._variant) {
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case 'named': {
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this.checkBinding(scope, p.value.name, context);
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this.checkPattern(scope,
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M.Pattern.SimplePattern(p.value.pattern),
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`${JSON.stringify(p.value.name.description!)} of ${context}`,
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ValueAvailability.AVAILABLE);
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break;
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}
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case 'anonymous':
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this.checkPattern(scope, p.value, context, ValueAvailability.NOT_AVAILABLE);
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break;
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}
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}
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checkPattern(scope: Set<string>,
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p: M.Pattern,
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context: string,
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availability: ValueAvailability): void
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{
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switch (p._variant) {
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case 'SimplePattern':
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if (p.value._variant !== 'lit' && availability === ValueAvailability.NOT_AVAILABLE) {
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this.recordProblem(context, 'cannot recover serialization of non-literal pattern');
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}
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if (p.value._variant === 'Ref' &&
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!(M.isValidToken(p.value.value.name.description!) &&
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p.value.value.module.every(n => M.isValidToken(n.description!))))
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{
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this.recordProblem(context, 'invalid reference name');
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}
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break;
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case 'CompoundPattern':
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((p: M.CompoundPattern): void => {
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switch (p._variant) {
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case 'rec':
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this.checkNamedPattern(scope, p.label, `label of ${context}`);
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this.checkNamedPattern(scope, p.fields, `fields of ${context}`);
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break;
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case 'tuple':
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p.patterns.forEach((pp, i) =>
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this.checkNamedPattern(scope, pp, `item ${i} of ${context}`));
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break;
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case 'tuplePrefix':
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p.fixed.forEach((pp, i) =>
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this.checkNamedPattern(scope, pp, `item ${i} of ${context}`));
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this.checkNamedPattern(
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scope, M.promoteNamedSimplePattern(p.variable), `tail of ${context}`);
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break;
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case 'dict':
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p.entries.forEach((np, key) =>
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this.checkNamedPattern(
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scope,
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M.promoteNamedSimplePattern(np),
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`entry ${stringify(key)} in dictionary in ${context}`));
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break;
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}
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})(p.value);
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}
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}
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}
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