101 lines
2.9 KiB
TypeScript
101 lines
2.9 KiB
TypeScript
import some from "lodash/some"
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import every from "lodash/every"
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import has from "lodash/has"
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import includes from "lodash/includes"
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import {
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AbstractProduction,
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Alternation,
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Alternative,
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NonTerminal,
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Option,
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Repetition,
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RepetitionMandatory,
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RepetitionMandatoryWithSeparator,
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RepetitionWithSeparator,
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Rule,
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Terminal
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} from "./model"
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import { GAstVisitor } from "./visitor"
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import { IProduction, IProductionWithOccurrence } from "@chevrotain/types"
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export function isSequenceProd(
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prod: IProduction
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): prod is { definition: IProduction[] } & IProduction {
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return (
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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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}
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export function isOptionalProd(
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prod: IProduction,
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alreadyVisited: NonTerminal[] = []
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): boolean {
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const isDirectlyOptional =
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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((<Alternation>prod).definition, (subProd: IProduction) => {
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return isOptionalProd(subProd, alreadyVisited)
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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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} 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(
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(<AbstractProduction>prod).definition,
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(subProd: IProduction) => {
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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(
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prod: IProduction
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): prod is { definition: IProduction[] } & IProduction {
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return prod instanceof Alternation
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}
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export function getProductionDslName(prod: IProductionWithOccurrence): string {
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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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} else if (prod instanceof Option) {
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return "OPTION"
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} else if (prod instanceof Alternation) {
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return "OR"
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} else if (prod instanceof RepetitionMandatory) {
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return "AT_LEAST_ONE"
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} else if (prod instanceof RepetitionMandatoryWithSeparator) {
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return "AT_LEAST_ONE_SEP"
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} else if (prod instanceof RepetitionWithSeparator) {
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return "MANY_SEP"
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} else if (prod instanceof Repetition) {
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return "MANY"
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} else if (prod instanceof Terminal) {
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return "CONSUME"
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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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