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fixpoint algorithm: parameterize the Map to use

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This commit is contained in:
Joeri Exelmans 2025-05-22 14:31:26 +02:00
parent ea878975be
commit 47786ae792
3 changed files with 58 additions and 10 deletions
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12
tests/fixpoint.js
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@ -1,4 +1,6 @@
import { compareStrings } from "../lib/compare/primitives.js";
import { fixer } from "../lib/util/fixpoint.js";
import { MutableRBTree } from "../lib/util/rbtree_wrapper.js";
const booleanLattice = {
isMaximal: (value) => value,
@ -7,7 +9,7 @@ const booleanLattice = {
};
const nullable = grammar => nonterminal => request => {
console.log(nonterminal);
console.log(nonterminal);
const f = nt => {
return {
Epsilon: () => true,
@ -15,7 +17,7 @@ const nullable = grammar => nonterminal => request => {
NT: () => request(nt.nt),
Seq: () => f(nt.l) && f(nt.r),
Alt: () => f(nt.l) || f(nt.r),
}[nt.kind]();
}[nt.kind]();
}
return f(grammar[nonterminal]);
}
@ -65,8 +67,10 @@ const exampleGrammar = {
// B is nullable because B → A C, and both A and C are nullable.
// S is nullable because S → A B C, and A, B, and C are all nullable.
const isNullable = fixer(nullable(exampleGrammar), booleanLattice);
const isNullable = fixer(
nullable(exampleGrammar), // eqs
() => MutableRBTree.new((a,b) => compareStrings(a)(b)), // dict to use
booleanLattice);
console.log(isNullable("S"));
console.log(isNullable("A"));