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# Hypercubed/tvl.ts Created Dec 23, 2017

Three-valued logic (TS)
 export type bool = boolean | null; export type cmpValue = -1 | 0 | 1; export function not(a: bool) { if (a === true) return false; if (a === false) return true; return null; } export function and(lhs: bool, rhs: bool): bool { if (lhs === true) return rhs; if (rhs === true) return lhs; if (lhs === false || rhs === false) return false; return null; } export function nand(lhs: bool, rhs: bool): bool { return not(and(lhs, rhs)); } export function or(lhs: bool, rhs: bool): bool { return nand(not(lhs), not(rhs)); } export function xor(lhs: bool, rhs: bool): bool { return and(or(lhs, rhs), nand(lhs, rhs)); } export function nor(lhs: bool, rhs: bool): bool { return not(or(lhs, rhs)); } export function mimpl(lhs: bool, rhs: bool): bool { return or(not(lhs), rhs); } export function cimpl(lhs: bool, rhs: bool): bool { return or(lhs, not(rhs)); } export function mnonimpl(lhs: bool, rhs: bool): bool { return and(lhs, not(rhs)); } export function cnonimpl(lhs: bool, rhs: bool): bool { return and(not(lhs), rhs); } export function cmp(lhs: bool, rhs: bool): cmpValue { const slhs = sort_order(lhs); const srhs = sort_order(rhs); if (slhs === srhs) return 0; return slhs > srhs ? 1 : -1; } function sort_order(a: bool): cmpValue { if (a === null) return 0; return a ? 1 : -1; }
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