add hw2

node_modules/@chevrotain/gast/lib/src/helpers.js

@@ -0,0 +1,79 @@
+import { every, includes, some } from "lodash-es";
+import { AbstractProduction, Alternation, Alternative, NonTerminal, Option, Repetition, RepetitionMandatory, RepetitionMandatoryWithSeparator, RepetitionWithSeparator, Rule, Terminal, } from "./model.js";
+export function isSequenceProd(prod) {
+    return (prod instanceof Alternative ||
+        prod instanceof Option ||
+        prod instanceof Repetition ||
+        prod instanceof RepetitionMandatory ||
+        prod instanceof RepetitionMandatoryWithSeparator ||
+        prod instanceof RepetitionWithSeparator ||
+        prod instanceof Terminal ||
+        prod instanceof Rule);
+}
+export function isOptionalProd(prod, alreadyVisited = []) {
+    const isDirectlyOptional = prod instanceof Option ||
+        prod instanceof Repetition ||
+        prod instanceof RepetitionWithSeparator;
+    if (isDirectlyOptional) {
+        return true;
+    }
+    // note that this can cause infinite loop if one optional empty TOP production has a cyclic dependency with another
+    // empty optional top rule
+    // may be indirectly optional ((A?B?C?) | (D?E?F?))
+    if (prod instanceof Alternation) {
+        // for OR its enough for just one of the alternatives to be optional
+        return some(prod.definition, (subProd) => {
+            return isOptionalProd(subProd, alreadyVisited);
+        });
+    }
+    else if (prod instanceof NonTerminal && includes(alreadyVisited, prod)) {
+        // avoiding stack overflow due to infinite recursion
+        return false;
+    }
+    else if (prod instanceof AbstractProduction) {
+        if (prod instanceof NonTerminal) {
+            alreadyVisited.push(prod);
+        }
+        return every(prod.definition, (subProd) => {
+            return isOptionalProd(subProd, alreadyVisited);
+        });
+    }
+    else {
+        return false;
+    }
+}
+export function isBranchingProd(prod) {
+    return prod instanceof Alternation;
+}
+export function getProductionDslName(prod) {
+    /* istanbul ignore else */
+    if (prod instanceof NonTerminal) {
+        return "SUBRULE";
+    }
+    else if (prod instanceof Option) {
+        return "OPTION";
+    }
+    else if (prod instanceof Alternation) {
+        return "OR";
+    }
+    else if (prod instanceof RepetitionMandatory) {
+        return "AT_LEAST_ONE";
+    }
+    else if (prod instanceof RepetitionMandatoryWithSeparator) {
+        return "AT_LEAST_ONE_SEP";
+    }
+    else if (prod instanceof RepetitionWithSeparator) {
+        return "MANY_SEP";
+    }
+    else if (prod instanceof Repetition) {
+        return "MANY";
+    }
+    else if (prod instanceof Terminal) {
+        return "CONSUME";
+        /* c8 ignore next 3 */
+    }
+    else {
+        throw Error("non exhaustive match");
+    }
+}
+//# sourceMappingURL=helpers.js.map