79 lines
2.7 KiB
JavaScript
79 lines
2.7 KiB
JavaScript
import { every, includes, some } from "lodash-es";
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import { AbstractProduction, Alternation, Alternative, NonTerminal, Option, Repetition, RepetitionMandatory, RepetitionMandatoryWithSeparator, RepetitionWithSeparator, Rule, Terminal, } from "./model.js";
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export function isSequenceProd(prod) {
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return (prod instanceof Alternative ||
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prod instanceof Option ||
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prod instanceof Repetition ||
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prod instanceof RepetitionMandatory ||
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prod instanceof RepetitionMandatoryWithSeparator ||
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prod instanceof RepetitionWithSeparator ||
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prod instanceof Terminal ||
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prod instanceof Rule);
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}
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export function isOptionalProd(prod, alreadyVisited = []) {
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const isDirectlyOptional = prod instanceof Option ||
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prod instanceof Repetition ||
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prod instanceof RepetitionWithSeparator;
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if (isDirectlyOptional) {
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return true;
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}
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// note that this can cause infinite loop if one optional empty TOP production has a cyclic dependency with another
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// empty optional top rule
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// may be indirectly optional ((A?B?C?) | (D?E?F?))
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if (prod instanceof Alternation) {
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// for OR its enough for just one of the alternatives to be optional
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return some(prod.definition, (subProd) => {
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return isOptionalProd(subProd, alreadyVisited);
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});
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}
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else if (prod instanceof NonTerminal && includes(alreadyVisited, prod)) {
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// avoiding stack overflow due to infinite recursion
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return false;
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}
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else if (prod instanceof AbstractProduction) {
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if (prod instanceof NonTerminal) {
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alreadyVisited.push(prod);
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}
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return every(prod.definition, (subProd) => {
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return isOptionalProd(subProd, alreadyVisited);
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});
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}
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else {
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return false;
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}
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}
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export function isBranchingProd(prod) {
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return prod instanceof Alternation;
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}
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export function getProductionDslName(prod) {
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/* istanbul ignore else */
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if (prod instanceof NonTerminal) {
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return "SUBRULE";
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}
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else if (prod instanceof Option) {
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return "OPTION";
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}
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else if (prod instanceof Alternation) {
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return "OR";
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}
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else if (prod instanceof RepetitionMandatory) {
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return "AT_LEAST_ONE";
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}
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else if (prod instanceof RepetitionMandatoryWithSeparator) {
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return "AT_LEAST_ONE_SEP";
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}
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else if (prod instanceof RepetitionWithSeparator) {
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return "MANY_SEP";
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}
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else if (prod instanceof Repetition) {
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return "MANY";
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}
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else if (prod instanceof Terminal) {
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return "CONSUME";
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/* c8 ignore next 3 */
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}
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else {
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throw Error("non exhaustive match");
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}
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}
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//# sourceMappingURL=helpers.js.map
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