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genieacs/lib/common/expression/synth.ts
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TypeScript

import { espresso, complement, tautology } from "espresso-iisojs";
import { Expression } from "../../types.ts";
import normalize from "./normalize.ts";
import { map, parseLikePattern } from "./parser.ts";
type Minterm = number[];
export abstract class SynthContextBase<
T extends { toString: () => string } = unknown,
U = unknown,
> {
public variables = new Map<string, number>();
protected clauses = new Map<number, U>();
public getVar(c: U): number {
const str = c.toString();
let idx = this.variables.get(str);
if (idx == null) {
idx = this.variables.size;
this.variables.set(str, idx);
this.clauses.set(idx, c);
}
return idx;
}
public getClause(v: number): U {
return this.clauses.get(v);
}
abstract getMinterms(exp: T, res: true | false | null): Minterm[];
abstract getDcSet(minterms: Minterm[]): Minterm[];
// eslint-disable-next-line @typescript-eslint/no-unused-vars
canRaise(idx: number, set: Set<number>): boolean {
return true;
}
// eslint-disable-next-line @typescript-eslint/no-unused-vars
canLower(idx: number, set: Set<number>): boolean {
return true;
}
bias(a: number, b: number): number {
// Bias towards 1 then lower index
return (b ^ 1) - (a ^ 1);
}
sanitizeMinterms(minterms: Minterm[]): Minterm[] {
return minterms;
}
minimize(minterms: Minterm[], dcSet: Minterm[] = []): Minterm[] {
minterms = this.sanitizeMinterms(minterms);
const canRaise = this.canRaise.bind(this);
const canLower = this.canLower.bind(this);
const bias = this.bias.bind(this);
return espresso(
minterms,
[...this.getDcSet([...minterms, ...dcSet]), ...dcSet],
{
canRaise,
canLower,
bias,
},
);
}
}
function* findIsNullDeps(exp: Expression): IterableIterator<Expression> {
if (!Array.isArray(exp)) return;
const op = exp[0];
if (op === "IS NULL" || op === "IS NOT NULL") return;
if (op === "FUNC") {
if (exp[1] === "NOW") {
return;
} else if (exp[1] === "LOWER" || exp[1] === "UPPER") {
yield* findIsNullDeps(exp[2]);
} else if (exp[1] === "ROUND") {
for (const e of exp.slice(2, 4)) yield* findIsNullDeps(e);
return;
}
} else if (op !== "PARAM") {
for (const e of exp.slice(1)) yield* findIsNullDeps(e);
return;
}
yield exp;
}
export abstract class Clause {
private _isNullable: Set<string>;
protected _expression: Expression;
abstract true(context: SynthContextBase<Clause>): Minterm[];
abstract false(context: SynthContextBase<Clause>): Minterm[];
abstract null(context: SynthContextBase<Clause>): Minterm[];
expression(): Expression {
if (this._expression !== undefined) return this._expression;
const context = createSynthContext();
const minterms = this.true(context);
const minimized = context.minimize(minterms);
this._expression = context.toExpression(minimized) as Expression;
return this._expression;
}
isBoolean(): boolean {
return true;
}
isNullable(c: Clause.IsNull): boolean {
if (!this._isNullable) {
this._isNullable = new Set(
[...this.getNullables()].map((n) => n.toString()),
);
}
return this._isNullable.has(c.toString());
}
*getNullables(): IterableIterator<Clause.IsNull> {
const exp = this.expression();
for (const e of findIsNullDeps(exp)) {
if (e === exp) yield new Clause.IsNull(this);
else yield new Clause.IsNull(new Clause.Exp(e));
}
}
toString(): string {
return JSON.stringify(this.expression());
}
}
// eslint-disable-next-line @typescript-eslint/no-namespace
export namespace Clause {
export class Not extends Clause {
constructor(public operand: Clause) {
super();
}
true(context: SynthContextBase<Clause>): Minterm[] {
return this.operand.false(context);
}
false(context: SynthContextBase<Clause>): Minterm[] {
return this.operand.true(context);
}
null(context: SynthContextBase<Clause>): Minterm[] {
return this.operand.null(context);
}
}
export class Or extends Clause {
constructor(public operands: Clause[]) {
super();
}
true(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[] = [];
for (const s of this.operands) {
const m = s.true(context);
if (m.length === 1 && !m[0].length) return [[]];
minterms.push(...m);
}
return minterms;
}
false(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[][] = [];
const operands = [...this.operands];
for (const e of operands) {
if (e instanceof Or) {
operands.push(...e.operands);
continue;
}
const m = e.false(context);
if (!m.length) return [];
minterms.push(m);
}
if (!minterms.length) return [[]];
if (minterms.length === 1) return minterms[0];
return complement(minterms.map((m) => complement(m)).flat());
}
null(context: SynthContextBase<Clause>): Minterm[] {
const trueMinterms: Minterm[] = [];
const operands = [...this.operands];
for (const s of operands) {
if (s instanceof Or) {
operands.push(...s.operands);
continue;
}
const t = s.true(context);
if (t.length === 1 && !t[0].length) return [];
trueMinterms.push(...t);
}
const nullMinterms: Minterm[] = [];
for (const s of operands) {
const n = s.null(context);
if (n.length === 1 && !n[0].length && !trueMinterms.length) return [[]];
nullMinterms.push(...n);
}
if (!trueMinterms.length) return nullMinterms;
return complement([...complement(nullMinterms), ...trueMinterms]);
}
}
export class And extends Clause {
constructor(public operands: Clause[]) {
super();
}
true(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[][] = [];
const operands = [...this.operands];
for (const s of operands) {
if (s instanceof And) {
operands.push(...s.operands);
continue;
}
const m = s.true(context);
if (!m.length) return [];
if (m.length === 1 && !m[0].length) continue;
minterms.push(m);
}
if (!minterms.length) return [[]];
if (minterms.length === 1) return minterms[0];
return complement(minterms.map((m) => complement(m)).flat());
}
false(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[] = [];
for (const s of this.operands) {
const m = s.false(context);
if (m.length === 1 && !m[0].length) return [[]];
minterms.push(...m);
}
return minterms;
}
null(context: SynthContextBase<Clause>): Minterm[] {
const falseMinterms: Minterm[] = [];
const operands = [...this.operands];
for (const s of operands) {
if (s instanceof And) {
operands.push(...s.operands);
continue;
}
const f = s.false(context);
if (f.length === 1 && !f[0].length) return [];
falseMinterms.push(...f);
}
const nullMinterms: Minterm[] = [];
for (const s of operands) {
const n = s.null(context);
if (n.length === 1 && !n[0].length && !falseMinterms.length)
return [[]];
nullMinterms.push(...n);
}
if (!falseMinterms.length) return nullMinterms;
return complement([...complement(nullMinterms), ...falseMinterms]);
}
}
export class Case extends Clause {
constructor(public clauses: Clause[]) {
super();
}
true(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[] = [];
const cumulative: Minterm[] = [];
for (let i = 0; i < this.clauses.length; i += 2) {
const w = this.clauses[i].true(context);
const t = this.clauses[i + 1].true(context);
minterms.push(
...complement([...cumulative, ...complement(w), ...complement(t)]),
);
if (i < this.clauses.length - 2) {
cumulative.push(
...complement([
...this.clauses[i].false(context),
...this.clauses[i].null(context),
]),
);
}
}
return minterms;
}
false(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[] = [];
const cumulative: Minterm[] = [];
for (let i = 0; i < this.clauses.length; i += 2) {
const w = this.clauses[i].true(context);
const t = this.clauses[i + 1].false(context);
minterms.push(
...complement([...cumulative, ...complement(w), ...complement(t)]),
);
if (i < this.clauses.length - 2) {
cumulative.push(
...complement([
...this.clauses[i].false(context),
...this.clauses[i].null(context),
]),
);
}
}
return minterms;
}
null(context: SynthContextBase<Clause>): Minterm[] {
const minterms: Minterm[] = [];
const cumulative: Minterm[] = [];
for (let i = 0; i < this.clauses.length; i += 2) {
const w = this.clauses[i].true(context);
const t = this.clauses[i + 1].null(context);
minterms.push(
...complement([...cumulative, ...complement(w), ...complement(t)]),
);
cumulative.push(
...complement([
...this.clauses[i].false(context),
...this.clauses[i].null(context),
]),
);
}
minterms.push(...complement([...cumulative]));
return minterms;
}
expression(): Expression {
if (this._expression != null) return this._expression;
if (this.isBoolean()) {
this._expression = new Clause.Not(new Clause.Not(this)).expression();
return this._expression;
}
const context = createSynthContext();
const cases: { when: Minterm[]; then: Expression }[] = [];
for (let i = 0; i < this.clauses.length; i += 2) {
let minterms = this.clauses[i].true(context);
const then = this.clauses[i + 1].expression();
if (
cases.length &&
JSON.stringify(then) === JSON.stringify(cases[cases.length - 1].then)
)
minterms.push(...cases.pop().when);
minterms = context.minimize(
minterms,
cases.flatMap((c) => c.when),
);
if (!minterms.length) continue;
cases.push({ when: minterms, then });
if (minterms.length === 1 && !minterms[0].length) break;
}
while (cases[cases.length - 1].then == null) cases.pop();
if (!cases.length) return null;
this._expression = [
"CASE",
...cases.flatMap((c) => [context.toExpression(c.when), c.then]),
];
return this._expression;
}
isBoolean(): boolean {
for (let i = 1; i < this.clauses.length; i += 2)
if (!this.clauses[i].isBoolean()) return false;
return true;
}
}
export class IsNull extends Clause {
private _boolean: Clause;
constructor(public operand: Clause) {
super();
this._boolean = new Not(new Not(this));
}
true(context: SynthContextBase<Clause>): Minterm[] {
return this.operand.null(context);
}
false(context: SynthContextBase<Clause>): Minterm[] {
return complement(this.true(context));
}
null(): Minterm[] {
return [];
}
isBoolean(): boolean {
return true;
}
*getNullables(): IterableIterator<IsNull> {
// Never returns null
}
expression(): Expression {
const nullables = [...this.operand.getNullables()];
if (nullables.length === 1 && nullables[0].operand === this.operand)
return ["IS NULL", this.operand.expression()];
return super.expression();
}
}
export class Exp extends Clause {
constructor(public exp: Expression) {
super();
}
true(context: SynthContextBase<Clause>): Minterm[] {
if (Array.isArray(this.exp)) return context.getMinterms(this, true);
if (this.exp) return [[]];
return [];
}
false(context: SynthContextBase<Clause>): Minterm[] {
if (Array.isArray(this.exp)) return context.getMinterms(this, false);
if (!this.exp && this.exp != null) return [[]];
return [];
}
null(context: SynthContextBase<Clause>): Minterm[] {
if (Array.isArray(this.exp)) return context.getMinterms(this, null);
if (this.exp == null) return [[]];
return [];
}
expression(): Expression {
return this.exp;
}
isBoolean(): boolean {
return this.exp === true || this.exp === false || this.exp == null;
}
}
export class Compare extends Clause {
constructor(
public lhs: Clause,
public op: ">" | "<" | "=",
public rhs: boolean | number | string,
) {
super();
}
true(context: SynthContextBase<Clause>): Minterm[] {
return context.getMinterms(this, true);
}
false(context: SynthContextBase<Clause>): Minterm[] {
return context.getMinterms(this, false);
}
null(context: SynthContextBase<Clause>): Minterm[] {
return this.lhs.null(context);
}
*getNullables(): IterableIterator<IsNull> {
yield* this.lhs.getNullables();
}
isBoolean(): boolean {
return true;
}
expression(): Expression {
return [this.op, this.lhs.expression(), this.rhs];
}
}
export class Like extends Clause {
public readonly caseSensitive: boolean;
public readonly contradiction: boolean;
public readonly pattern: string[];
public readonly lhs: Clause;
constructor(
lhs: Clause,
public rhs: string,
public esc?: string,
) {
super();
const exp = lhs.expression();
let caseSensitive = true;
let contradiction = false;
if (Array.isArray(exp)) {
if (exp[0] === "FUNC") {
const func = exp[1];
if (func === "UPPER" || func === "LOWER") {
const p = func === "UPPER" ? rhs.toUpperCase() : rhs.toLowerCase();
if (p === rhs) caseSensitive = false;
else contradiction = true;
lhs = new Exp(exp[2]);
}
}
}
this.lhs = lhs;
this.pattern = parseLikePattern(rhs, esc);
this.caseSensitive = caseSensitive;
this.contradiction = contradiction;
}
true(context: SynthContextBase<Clause>): Minterm[] {
return context.getMinterms(this, true);
}
false(context: SynthContextBase<Clause>): Minterm[] {
return context.getMinterms(this, false);
}
null(context: SynthContextBase<Clause>): Minterm[] {
return this.lhs.null(context);
}
isBoolean(): boolean {
return true;
}
isNullable(c: IsNull): boolean {
return this.lhs.isNullable(c);
}
getNullables(): IterableIterator<IsNull> {
return this.lhs.getNullables();
}
expression(): Expression {
let lhs = this.lhs.expression();
if (this.contradiction) {
if (this.rhs === this.rhs.toLocaleUpperCase())
lhs = ["FUNC", "LOWER", lhs];
else lhs = ["FUNC", "UPPER", lhs];
} else if (!this.caseSensitive) {
if (this.rhs === this.rhs.toLocaleUpperCase())
lhs = ["FUNC", "UPPER", lhs];
else lhs = ["FUNC", "LOWER", lhs];
}
return ["LIKE", lhs, this.rhs, ...(this.esc ? [this.esc] : [])];
}
}
export function fromExpression(exp: Expression): Clause {
const res = map(exp, (e) => {
if (!Array.isArray(e)) return new Clause.Exp(e);
let op = e[0];
let negate = true;
if (op === "NOT LIKE") op = "LIKE";
else if (op === "IS NOT NULL") op = "IS NULL";
else if (op === "<>") op = "=";
else if (op === ">=") op = "<";
else if (op === "<=") op = ">";
else negate = false;
let clause: Clause;
if (op === "IS NULL") {
clause = new Clause.IsNull(e[1]);
} else if (op === "NOT") {
clause = new Clause.Not(e[1]);
} else if (op === "OR") {
clause = new Clause.Or(e.slice(1));
} else if (op === "AND") {
clause = new Clause.And(e.slice(1));
} else if (op === "CASE") {
clause = new Clause.Case(e.slice(1));
} else if (op === "LIKE") {
const rhs = e[2] instanceof Exp ? e[2].expression() : null;
const esc = e[3] instanceof Exp ? e[3].expression() : null;
if (typeof rhs === "string" && typeof esc === "string")
clause = new Clause.Like(e[1], rhs, esc);
else if (typeof rhs === "string" && esc == null)
clause = new Clause.Like(e[1], rhs);
} else if (op === ">" || op === "<" || op === "=") {
const rhs = e[2] instanceof Exp ? e[2].expression() : null;
if (["boolean", "number", "string"].includes(typeof rhs)) {
clause = new Clause.Compare(
e[1],
op,
rhs as boolean | number | string,
);
}
}
if (!clause) {
const args = e.slice(1).map((a) => (a as Clause).expression());
clause = new Clause.Exp([op, ...args]);
}
if (negate) clause = new Clause.Not(clause);
return clause;
});
return res;
}
}
function groupBy<T, K>(
input: T[],
callback: (item: T) => K,
): Iterable<[K, T[]]> {
const groups = new Map<K, T[]>();
for (const item of input) {
const key = callback(item);
let arr = groups.get(key);
if (!arr) groups.set(key, (arr = []));
arr.push(item);
}
return groups.entries();
}
export class SynthContext extends SynthContextBase<Clause, Clause> {
constructor() {
super();
}
getMinterms(clause: Clause, res: true | false | null): number[][] {
const v = this.getVar(clause);
if (res === true) return [[(v << 2) ^ 3]];
else if (res === false) return [[(v << 2) ^ 1]];
else return [[v << 2, (v << 2) ^ 2]];
}
getDcSet(minterms: Minterm[]): number[][] {
const dcSet: number[][] = [];
const whitelist = new Set([...minterms.flat()].map((v) => v >> 2));
const allClauses = [...whitelist].map((v) => this.getClause(v));
const comparisons = allClauses.filter(
(c) => c instanceof Clause.Compare,
) as Clause.Compare[];
// Comparisons
for (const [, clauses] of groupBy(comparisons, (c) =>
JSON.stringify(c.lhs),
)) {
const lhs = clauses[0].lhs;
const values = new Set(clauses.map((c) => c.rhs));
const valuesSorted = [...values].sort((a, b) => {
const ta = typeof a;
const tb = typeof b;
if (ta === tb) return a > b ? 1 : -1;
else if (ta === "string") return 1;
else if (tb === "string") return -1;
return +a - +b;
});
for (const [i, v] of valuesSorted.entries()) {
const eq = this.getVar(new Clause.Compare(lhs, "=", v));
const gt = this.getVar(new Clause.Compare(lhs, ">", v));
const lt = this.getVar(new Clause.Compare(lhs, "<", v));
dcSet.push([(eq << 2) ^ 3, (gt << 2) ^ 3]);
dcSet.push([(lt << 2) ^ 3, (gt << 2) ^ 3]);
dcSet.push([(lt << 2) ^ 3, (eq << 2) ^ 3]);
dcSet.push([(lt << 2) ^ 1, (eq << 2) ^ 1, (gt << 2) ^ 1]);
const negEquivOp = [lt, eq, gt].filter((o) => !whitelist.has(o));
if (negEquivOp.length === 1) whitelist.add(negEquivOp[0]);
for (let j = 0; j < i; j++) {
const eq2 = this.getVar(
new Clause.Compare(lhs, "=", valuesSorted[j]),
);
const gt2 = this.getVar(
new Clause.Compare(lhs, ">", valuesSorted[j]),
);
const lt2 = this.getVar(
new Clause.Compare(lhs, "<", valuesSorted[j]),
);
// This is the minimum clauses required if all relavent vars
// were included in the DC set.
// dcSet.push([(eq << 2) ^ 3, (eq2 << 2) ^ 3]);
// dcSet.push([(lt << 2) ^ 1, (gt2 << 2) ^ 1]);
// But we use non-minimal set because intermediate vars
// between any two may not be present in the DC set.
dcSet.push([(gt2 << 2) ^ 1, (lt << 2) ^ 1]);
dcSet.push([(eq2 << 2) ^ 3, (lt << 2) ^ 1]);
dcSet.push([(lt2 << 2) ^ 3, (lt << 2) ^ 1]);
dcSet.push([(gt2 << 2) ^ 1, (gt << 2) ^ 3]);
dcSet.push([(gt2 << 2) ^ 1, (eq << 2) ^ 3]);
dcSet.push([(eq2 << 2) ^ 3, (gt << 2) ^ 3]);
dcSet.push([(eq2 << 2) ^ 3, (eq << 2) ^ 3]);
dcSet.push([(lt2 << 2) ^ 3, (gt << 2) ^ 3]);
dcSet.push([(lt2 << 2) ^ 3, (eq << 2) ^ 3]);
}
}
}
// LIKE
const likes = allClauses.filter(
(c) => c instanceof Clause.Like,
) as Clause.Like[];
for (const [, clauses] of groupBy(likes, (c) => JSON.stringify(c.lhs))) {
for (let i1 = 0; i1 < clauses.length; ++i1) {
const l1 = clauses[i1];
if (l1.contradiction) {
dcSet.push([(this.getVar(l1) << 2) ^ 3]);
continue;
}
for (let i2 = i1 + 1; i2 < clauses.length; ++i2) {
const l2 = clauses[i2];
if (l2.contradiction) continue;
let p1 = l1.pattern;
let p2 = l2.pattern;
if (!l1.caseSensitive || !l2.caseSensitive) {
p1 = p1.map((c) => c.toLowerCase());
p2 = p2.map((c) => c.toLowerCase());
}
if (likeDisjoint(p1, p2)) {
dcSet.push([
(this.getVar(l1) << 2) ^ 3,
(this.getVar(l2) << 2) ^ 3,
]);
} else if (
(!l1.caseSensitive || l2.caseSensitive) &&
likeImplies(p1, p2)
) {
dcSet.push([
(this.getVar(l1) << 2) ^ 2,
(this.getVar(l2) << 2) ^ 3,
]);
dcSet.push([
(this.getVar(l1) << 2) ^ 1,
(this.getVar(l2) << 2) ^ 0,
]);
} else if (
(!l2.caseSensitive || l1.caseSensitive) &&
likeImplies(p2, p1)
) {
dcSet.push([
(this.getVar(l1) << 2) ^ 3,
(this.getVar(l2) << 2) ^ 2,
]);
dcSet.push([
(this.getVar(l1) << 2) ^ 0,
(this.getVar(l2) << 2) ^ 1,
]);
}
}
}
}
for (const v of whitelist) {
const clause = this.getClause(v);
const nullables = [...clause.getNullables()].map((c) => this.getVar(c));
if (nullables.length) {
dcSet.push([
...nullables.map((n) => (n << 2) ^ 2),
(v << 2) ^ 0,
(v << 2) ^ 2,
]);
for (const n of nullables) {
dcSet.push([(n << 2) ^ 3, (v << 2) ^ 1]);
dcSet.push([(n << 2) ^ 3, (v << 2) ^ 3]);
whitelist.add(n);
}
}
if (clause instanceof Clause.IsNull) {
const str = clause.operand.toString();
if (str === '["PARAM","DeviceID.ID"]' || str === '["PARAM","_id"]')
dcSet.push([(v << 2) ^ 3]);
}
}
return dcSet.filter((m) => m.every((v) => whitelist.has(v >> 2)));
}
canRaise(idx: number, set: Set<number>): boolean {
const clause = this.getClause(idx >> 2);
if (clause instanceof Clause.IsNull) {
for (const i of set) {
if (i === idx || i & 1) continue;
const c = this.getClause(i >> 2);
if (c.isNullable(clause)) return false;
}
return true;
}
return !(idx & 1) || !set.has(idx ^ 3);
}
canLower(idx: number, set: Set<number>): boolean {
if (idx & 1) return true;
const clause = this.getClause(idx >> 2);
if (clause instanceof Clause.IsNull) return true;
return set.has(idx ^ 3) || set.has(idx ^ 1);
}
bias(a: number, b: number): number {
// Bias towards 1 then true
return ((b & 3) ^ 3) - ((a & 3) ^ 3);
}
sanitizeMinterms(minterms: Minterm[]): Minterm[] {
const res = [] as number[][];
loop: for (const m of minterms) {
const merged: Map<number, number> = new Map();
for (const i of m)
merged.set(i >> 2, (merged.get(i >> 2) || 0) | (1 << (i & 3)));
const minterm: number[] = [];
const perms: number[][] = [];
for (const [k, v] of merged) {
if ((v & 0b0011) === 0b0011) continue loop;
if ((v & 0b1100) === 0b1100) continue loop;
const clause = this.clauses.get(k);
if (!clause) throw new Error("Invalid literal");
if (clause instanceof Clause.IsNull) {
if (v === 0b0100) minterm.push((k << 2) ^ 2);
else if (v === 0b1000) minterm.push((k << 2) ^ 3);
else throw new Error("Invalid literal");
continue;
}
if ((v & 0b1010) === 0b1010) continue loop;
const isNullVars = [...clause.getNullables()].map((c) =>
this.getVar(c),
);
const t = k << 2;
if (v === 0b0101) {
if (isNullVars.length === 1) minterm.push((isNullVars[0] << 2) ^ 3);
else perms.push(isNullVars.map((n) => (n << 2) ^ 3));
} else if (v === 0b0001) {
perms.push([...isNullVars.map((n) => (n << 2) ^ 3), t ^ 3]);
} else if (v === 0b0100) {
perms.push([...isNullVars.map((n) => (n << 2) ^ 3), t ^ 1]);
} else if (v & 0b1000) {
minterm.push(t ^ 3);
} else if (v & 0b0010) {
minterm.push(t ^ 1);
}
}
let ms = [minterm];
while (perms.length) {
const newMs: number[][] = [];
const perm = perms.pop();
for (const p of perm) newMs.push(...ms.map((mm) => [...mm, p]));
ms = newMs;
}
res.push(...ms);
}
return res;
}
toExpression(sop: number[][]): Expression {
if (!sop.length) return false;
const res: Expression[] = [];
for (const s of sop) {
if (!s.length) return true;
const conjs: Expression[] = [];
for (const i of s) {
const clause = this.getClause(i >>> 2);
if (!clause) throw new Error("Invalid literal");
if (clause instanceof Clause.IsNull) {
if (!(i & 2)) throw new Error("Invalid literal");
} else if (!(i & 1)) {
// Should never be reached if minimized correctly
const isNullVars = [...clause.getNullables()].map((c) =>
this.getVar(c),
);
conjs.push(
this.toExpression([
[i ^ 3],
...isNullVars.map((n) => [(n << 2) ^ 3]),
]),
);
continue;
}
let expr = clause.expression() as Expression;
if (!(i & 1) !== !(i & 2)) expr = ["NOT", expr];
if (
Array.isArray(expr) &&
expr[0] === "NOT" &&
Array.isArray(expr[1])
) {
const e: Expression[] = expr[1];
if (e[0] === "IS NULL") expr = ["IS NOT NULL", ...e.slice(1)];
else if (e[0] === "LIKE") expr = ["NOT LIKE", ...e.slice(1)];
else if (e[0] === "=") expr = ["<>", ...e.slice(1)];
else if (e[0] === "<>") expr = ["=", ...e.slice(1)];
else if (e[0] === ">") expr = ["<=", ...e.slice(1)];
else if (e[0] === ">=") expr = ["<", ...e.slice(1)];
else if (e[0] === "<") expr = [">=", ...e.slice(1)];
else if (e[0] === "<=") expr = [">", ...e.slice(1)];
else if (e[0] === "NOT") expr = e[1];
}
conjs.push(expr);
}
if (conjs.length > 1) res.push(["AND", ...conjs]);
else res.push(conjs[0]);
}
if (res.length > 1) return ["OR", ...res];
return res[0];
}
}
// Classes aren't hoisted in JS but functions are. This function is used to
// create a new SynthContext instance from inside the Clause class.
export function createSynthContext(): SynthContext {
return new SynthContext();
}
export function likeImplies(pat1: string[], pat2: string[]): boolean {
let backtrack: [number, number] = null;
for (let i1 = 0, i2 = 0; ; ++i1, ++i2) {
while (i1 < pat1.length && pat1[i1] === "\\%") backtrack = [i1++, i2];
if (i2 >= pat2.length) return i1 >= pat1.length;
const c = i1 < pat1.length ? pat1[i1] : null;
if (c !== pat2[i2] && c !== "\\_") {
if (!backtrack) return false;
[i1, i2] = backtrack;
++backtrack[1];
}
}
}
export function likeDisjoint(pat1: string[], pat2: string[]): boolean {
const left1Idx = pat1.indexOf("\\%");
const left2Idx = pat2.indexOf("\\%");
const right1Idx = pat1.lastIndexOf("\\%");
const right2Idx = pat2.lastIndexOf("\\%");
const left1 = pat1.slice(0, left1Idx !== -1 ? left1Idx : pat1.length);
const left2 = pat2.slice(0, left2Idx !== -1 ? left2Idx : pat2.length);
const right1 = pat1.slice(right1Idx !== -1 ? right1Idx + 1 : 0).reverse();
const right2 = pat2.slice(right2Idx !== -1 ? right2Idx + 1 : 0).reverse();
for (let i = 0; i < Math.min(left1.length, left2.length); ++i) {
if (left1[i] !== left2[i] && left1[i] !== "\\_" && left2[i] !== "\\_")
return true;
}
for (let i = 0; i < Math.min(right1.length, right2.length); ++i) {
if (right1[i] !== right2[i] && right1[i] !== "\\_" && right2[i] !== "\\_")
return true;
}
if (pat1.length === left1.length)
return pat2.filter((c) => c !== "\\%").length > pat1.length;
else if (pat2.length === left2.length)
return pat1.filter((c) => c !== "\\%").length > pat2.length;
return false;
}
export function minimize(expr: Expression, boolean = false): Expression {
let synth = Clause.fromExpression(normalize(expr));
if (boolean) synth = new Clause.Not(new Clause.Not(synth));
return synth.expression();
}
export function unionDiff(
expr1: Expression,
expr2: Expression,
): [Expression, Expression] {
expr2 = normalize(expr2);
if (!expr2) return [expr1, false];
const synth2 = Clause.fromExpression(expr2);
if (!expr1) {
const e = synth2.expression();
return [e, e];
}
expr1 = normalize(expr1);
const synth1 = Clause.fromExpression(expr1);
const context = new SynthContext();
const expr2Minterms = synth2.true(context);
const expr1Minterms = synth1.true(context);
const union = context.minimize([...expr1Minterms, ...expr2Minterms]);
const diff = context.minimize(
complement([...expr1Minterms, ...complement(expr2Minterms)]),
);
return [context.toExpression(union), context.toExpression(diff)];
}
export function covers(expr1: Expression, expr2: Expression): boolean {
expr2 = normalize(expr2);
if (!expr2) return true;
expr1 = normalize(expr1);
if (!Array.isArray(expr1)) return !!expr1;
const synt1 = Clause.fromExpression(expr1);
const synt2 = Clause.fromExpression(expr2);
const context = new SynthContext();
const expr1Minterms = synt1.true(context);
const expr2Minterms = synt2.true(context);
return tautology([
...context.sanitizeMinterms(complement(expr2Minterms)),
...context.getDcSet([...expr2Minterms, ...expr1Minterms]),
...context.sanitizeMinterms(expr1Minterms),
]);
}