Merge branch 'researchML' into 'dev'

Research ml

See merge request igrannonica/neuronstellar!6

1 files changed, 832 insertions, 0 deletions

diff --git a/sandbox/testAppNevena/Front/node_modules/ajv/lib/compile/codegen/index.ts b/sandbox/testAppNevena/Front/node_modules/ajv/lib/compile/codegen/index.ts
new file mode 100644
index 00000000..9d29055d
--- /dev/null
+++ b/sandbox/testAppNevena/Front/node_modules/ajv/lib/compile/codegen/index.ts
@@ -0,0 +1,832 @@
+import type {ScopeValueSets, NameValue, ValueScope, ValueScopeName} from "./scope"
+import {_, nil, _Code, Code, Name, UsedNames, CodeItem, addCodeArg, _CodeOrName} from "./code"
+import {Scope, varKinds} from "./scope"
+
+export {_, str, strConcat, nil, getProperty, stringify, regexpCode, Name, Code} from "./code"
+export {Scope, ScopeStore, ValueScope, ValueScopeName, ScopeValueSets, varKinds} from "./scope"
+
+// type for expressions that can be safely inserted in code without quotes
+export type SafeExpr = Code | number | boolean | null
+
+// type that is either Code of function that adds code to CodeGen instance using its methods
+export type Block = Code | (() => void)
+
+export const operators = {
+  GT: new _Code(">"),
+  GTE: new _Code(">="),
+  LT: new _Code("<"),
+  LTE: new _Code("<="),
+  EQ: new _Code("==="),
+  NEQ: new _Code("!=="),
+  NOT: new _Code("!"),
+  OR: new _Code("||"),
+  AND: new _Code("&&"),
+  ADD: new _Code("+"),
+}
+
+abstract class Node {
+  abstract readonly names: UsedNames
+
+  optimizeNodes(): this | ChildNode | ChildNode[] | undefined {
+    return this
+  }
+
+  optimizeNames(_names: UsedNames, _constants: Constants): this | undefined {
+    return this
+  }
+
+  // get count(): number {
+  //   return 1
+  // }
+}
+
+class Def extends Node {
+  constructor(private readonly varKind: Name, private readonly name: Name, private rhs?: SafeExpr) {
+    super()
+  }
+
+  render({es5, _n}: CGOptions): string {
+    const varKind = es5 ? varKinds.var : this.varKind
+    const rhs = this.rhs === undefined ? "" : ` = ${this.rhs}`
+    return `${varKind} ${this.name}${rhs};` + _n
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this | undefined {
+    if (!names[this.name.str]) return
+    if (this.rhs) this.rhs = optimizeExpr(this.rhs, names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    return this.rhs instanceof _CodeOrName ? this.rhs.names : {}
+  }
+}
+
+class Assign extends Node {
+  constructor(readonly lhs: Code, public rhs: SafeExpr, private readonly sideEffects?: boolean) {
+    super()
+  }
+
+  render({_n}: CGOptions): string {
+    return `${this.lhs} = ${this.rhs};` + _n
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this | undefined {
+    if (this.lhs instanceof Name && !names[this.lhs.str] && !this.sideEffects) return
+    this.rhs = optimizeExpr(this.rhs, names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    const names = this.lhs instanceof Name ? {} : {...this.lhs.names}
+    return addExprNames(names, this.rhs)
+  }
+}
+
+class AssignOp extends Assign {
+  constructor(lhs: Code, private readonly op: Code, rhs: SafeExpr, sideEffects?: boolean) {
+    super(lhs, rhs, sideEffects)
+  }
+
+  render({_n}: CGOptions): string {
+    return `${this.lhs} ${this.op}= ${this.rhs};` + _n
+  }
+}
+
+class Label extends Node {
+  readonly names: UsedNames = {}
+  constructor(readonly label: Name) {
+    super()
+  }
+
+  render({_n}: CGOptions): string {
+    return `${this.label}:` + _n
+  }
+}
+
+class Break extends Node {
+  readonly names: UsedNames = {}
+  constructor(readonly label?: Code) {
+    super()
+  }
+
+  render({_n}: CGOptions): string {
+    const label = this.label ? ` ${this.label}` : ""
+    return `break${label};` + _n
+  }
+}
+
+class Throw extends Node {
+  constructor(readonly error: Code) {
+    super()
+  }
+
+  render({_n}: CGOptions): string {
+    return `throw ${this.error};` + _n
+  }
+
+  get names(): UsedNames {
+    return this.error.names
+  }
+}
+
+class AnyCode extends Node {
+  constructor(private code: SafeExpr) {
+    super()
+  }
+
+  render({_n}: CGOptions): string {
+    return `${this.code};` + _n
+  }
+
+  optimizeNodes(): this | undefined {
+    return `${this.code}` ? this : undefined
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this {
+    this.code = optimizeExpr(this.code, names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    return this.code instanceof _CodeOrName ? this.code.names : {}
+  }
+}
+
+abstract class ParentNode extends Node {
+  constructor(readonly nodes: ChildNode[] = []) {
+    super()
+  }
+
+  render(opts: CGOptions): string {
+    return this.nodes.reduce((code, n) => code + n.render(opts), "")
+  }
+
+  optimizeNodes(): this | ChildNode | ChildNode[] | undefined {
+    const {nodes} = this
+    let i = nodes.length
+    while (i--) {
+      const n = nodes[i].optimizeNodes()
+      if (Array.isArray(n)) nodes.splice(i, 1, ...n)
+      else if (n) nodes[i] = n
+      else nodes.splice(i, 1)
+    }
+    return nodes.length > 0 ? this : undefined
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this | undefined {
+    const {nodes} = this
+    let i = nodes.length
+    while (i--) {
+      // iterating backwards improves 1-pass optimization
+      const n = nodes[i]
+      if (n.optimizeNames(names, constants)) continue
+      subtractNames(names, n.names)
+      nodes.splice(i, 1)
+    }
+    return nodes.length > 0 ? this : undefined
+  }
+
+  get names(): UsedNames {
+    return this.nodes.reduce((names: UsedNames, n) => addNames(names, n.names), {})
+  }
+
+  // get count(): number {
+  //   return this.nodes.reduce((c, n) => c + n.count, 1)
+  // }
+}
+
+abstract class BlockNode extends ParentNode {
+  render(opts: CGOptions): string {
+    return "{" + opts._n + super.render(opts) + "}" + opts._n
+  }
+}
+
+class Root extends ParentNode {}
+
+class Else extends BlockNode {
+  static readonly kind = "else"
+}
+
+class If extends BlockNode {
+  static readonly kind = "if"
+  else?: If | Else
+  constructor(private condition: Code | boolean, nodes?: ChildNode[]) {
+    super(nodes)
+  }
+
+  render(opts: CGOptions): string {
+    let code = `if(${this.condition})` + super.render(opts)
+    if (this.else) code += "else " + this.else.render(opts)
+    return code
+  }
+
+  optimizeNodes(): If | ChildNode[] | undefined {
+    super.optimizeNodes()
+    const cond = this.condition
+    if (cond === true) return this.nodes // else is ignored here
+    let e = this.else
+    if (e) {
+      const ns = e.optimizeNodes()
+      e = this.else = Array.isArray(ns) ? new Else(ns) : (ns as Else | undefined)
+    }
+    if (e) {
+      if (cond === false) return e instanceof If ? e : e.nodes
+      if (this.nodes.length) return this
+      return new If(not(cond), e instanceof If ? [e] : e.nodes)
+    }
+    if (cond === false || !this.nodes.length) return undefined
+    return this
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this | undefined {
+    this.else = this.else?.optimizeNames(names, constants)
+    if (!(super.optimizeNames(names, constants) || this.else)) return
+    this.condition = optimizeExpr(this.condition, names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    const names = super.names
+    addExprNames(names, this.condition)
+    if (this.else) addNames(names, this.else.names)
+    return names
+  }
+
+  // get count(): number {
+  //   return super.count + (this.else?.count || 0)
+  // }
+}
+
+abstract class For extends BlockNode {
+  static readonly kind = "for"
+}
+
+class ForLoop extends For {
+  constructor(private iteration: Code) {
+    super()
+  }
+
+  render(opts: CGOptions): string {
+    return `for(${this.iteration})` + super.render(opts)
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this | undefined {
+    if (!super.optimizeNames(names, constants)) return
+    this.iteration = optimizeExpr(this.iteration, names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    return addNames(super.names, this.iteration.names)
+  }
+}
+
+class ForRange extends For {
+  constructor(
+    private readonly varKind: Name,
+    private readonly name: Name,
+    private readonly from: SafeExpr,
+    private readonly to: SafeExpr
+  ) {
+    super()
+  }
+
+  render(opts: CGOptions): string {
+    const varKind = opts.es5 ? varKinds.var : this.varKind
+    const {name, from, to} = this
+    return `for(${varKind} ${name}=${from}; ${name}<${to}; ${name}++)` + super.render(opts)
+  }
+
+  get names(): UsedNames {
+    const names = addExprNames(super.names, this.from)
+    return addExprNames(names, this.to)
+  }
+}
+
+class ForIter extends For {
+  constructor(
+    private readonly loop: "of" | "in",
+    private readonly varKind: Name,
+    private readonly name: Name,
+    private iterable: Code
+  ) {
+    super()
+  }
+
+  render(opts: CGOptions): string {
+    return `for(${this.varKind} ${this.name} ${this.loop} ${this.iterable})` + super.render(opts)
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this | undefined {
+    if (!super.optimizeNames(names, constants)) return
+    this.iterable = optimizeExpr(this.iterable, names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    return addNames(super.names, this.iterable.names)
+  }
+}
+
+class Func extends BlockNode {
+  static readonly kind = "func"
+  constructor(public name: Name, public args: Code, public async?: boolean) {
+    super()
+  }
+
+  render(opts: CGOptions): string {
+    const _async = this.async ? "async " : ""
+    return `${_async}function ${this.name}(${this.args})` + super.render(opts)
+  }
+}
+
+class Return extends ParentNode {
+  static readonly kind = "return"
+
+  render(opts: CGOptions): string {
+    return "return " + super.render(opts)
+  }
+}
+
+class Try extends BlockNode {
+  catch?: Catch
+  finally?: Finally
+
+  render(opts: CGOptions): string {
+    let code = "try" + super.render(opts)
+    if (this.catch) code += this.catch.render(opts)
+    if (this.finally) code += this.finally.render(opts)
+    return code
+  }
+
+  optimizeNodes(): this {
+    super.optimizeNodes()
+    this.catch?.optimizeNodes() as Catch | undefined
+    this.finally?.optimizeNodes() as Finally | undefined
+    return this
+  }
+
+  optimizeNames(names: UsedNames, constants: Constants): this {
+    super.optimizeNames(names, constants)
+    this.catch?.optimizeNames(names, constants)
+    this.finally?.optimizeNames(names, constants)
+    return this
+  }
+
+  get names(): UsedNames {
+    const names = super.names
+    if (this.catch) addNames(names, this.catch.names)
+    if (this.finally) addNames(names, this.finally.names)
+    return names
+  }
+
+  // get count(): number {
+  //   return super.count + (this.catch?.count || 0) + (this.finally?.count || 0)
+  // }
+}
+
+class Catch extends BlockNode {
+  static readonly kind = "catch"
+  constructor(readonly error: Name) {
+    super()
+  }
+
+  render(opts: CGOptions): string {
+    return `catch(${this.error})` + super.render(opts)
+  }
+}
+
+class Finally extends BlockNode {
+  static readonly kind = "finally"
+  render(opts: CGOptions): string {
+    return "finally" + super.render(opts)
+  }
+}
+
+type StartBlockNode = If | For | Func | Return | Try
+
+type LeafNode = Def | Assign | Label | Break | Throw | AnyCode
+
+type ChildNode = StartBlockNode | LeafNode
+
+type EndBlockNodeType =
+  | typeof If
+  | typeof Else
+  | typeof For
+  | typeof Func
+  | typeof Return
+  | typeof Catch
+  | typeof Finally
+
+type Constants = Record<string, SafeExpr | undefined>
+
+export interface CodeGenOptions {
+  es5?: boolean
+  lines?: boolean
+  ownProperties?: boolean
+}
+
+interface CGOptions extends CodeGenOptions {
+  _n: "\n" | ""
+}
+
+export class CodeGen {
+  readonly _scope: Scope
+  readonly _extScope: ValueScope
+  readonly _values: ScopeValueSets = {}
+  private readonly _nodes: ParentNode[]
+  private readonly _blockStarts: number[] = []
+  private readonly _constants: Constants = {}
+  private readonly opts: CGOptions
+
+  constructor(extScope: ValueScope, opts: CodeGenOptions = {}) {
+    this.opts = {...opts, _n: opts.lines ? "\n" : ""}
+    this._extScope = extScope
+    this._scope = new Scope({parent: extScope})
+    this._nodes = [new Root()]
+  }
+
+  toString(): string {
+    return this._root.render(this.opts)
+  }
+
+  // returns unique name in the internal scope
+  name(prefix: string): Name {
+    return this._scope.name(prefix)
+  }
+
+  // reserves unique name in the external scope
+  scopeName(prefix: string): ValueScopeName {
+    return this._extScope.name(prefix)
+  }
+
+  // reserves unique name in the external scope and assigns value to it
+  scopeValue(prefixOrName: ValueScopeName | string, value: NameValue): Name {
+    const name = this._extScope.value(prefixOrName, value)
+    const vs = this._values[name.prefix] || (this._values[name.prefix] = new Set())
+    vs.add(name)
+    return name
+  }
+
+  getScopeValue(prefix: string, keyOrRef: unknown): ValueScopeName | undefined {
+    return this._extScope.getValue(prefix, keyOrRef)
+  }
+
+  // return code that assigns values in the external scope to the names that are used internally
+  // (same names that were returned by gen.scopeName or gen.scopeValue)
+  scopeRefs(scopeName: Name): Code {
+    return this._extScope.scopeRefs(scopeName, this._values)
+  }
+
+  scopeCode(): Code {
+    return this._extScope.scopeCode(this._values)
+  }
+
+  private _def(
+    varKind: Name,
+    nameOrPrefix: Name | string,
+    rhs?: SafeExpr,
+    constant?: boolean
+  ): Name {
+    const name = this._scope.toName(nameOrPrefix)
+    if (rhs !== undefined && constant) this._constants[name.str] = rhs
+    this._leafNode(new Def(varKind, name, rhs))
+    return name
+  }
+
+  // `const` declaration (`var` in es5 mode)
+  const(nameOrPrefix: Name | string, rhs: SafeExpr, _constant?: boolean): Name {
+    return this._def(varKinds.const, nameOrPrefix, rhs, _constant)
+  }
+
+  // `let` declaration with optional assignment (`var` in es5 mode)
+  let(nameOrPrefix: Name | string, rhs?: SafeExpr, _constant?: boolean): Name {
+    return this._def(varKinds.let, nameOrPrefix, rhs, _constant)
+  }
+
+  // `var` declaration with optional assignment
+  var(nameOrPrefix: Name | string, rhs?: SafeExpr, _constant?: boolean): Name {
+    return this._def(varKinds.var, nameOrPrefix, rhs, _constant)
+  }
+
+  // assignment code
+  assign(lhs: Code, rhs: SafeExpr, sideEffects?: boolean): CodeGen {
+    return this._leafNode(new Assign(lhs, rhs, sideEffects))
+  }
+
+  // `+=` code
+  add(lhs: Code, rhs: SafeExpr): CodeGen {
+    return this._leafNode(new AssignOp(lhs, operators.ADD, rhs))
+  }
+
+  // appends passed SafeExpr to code or executes Block
+  code(c: Block | SafeExpr): CodeGen {
+    if (typeof c == "function") c()
+    else if (c !== nil) this._leafNode(new AnyCode(c))
+    return this
+  }
+
+  // returns code for object literal for the passed argument list of key-value pairs
+  object(...keyValues: [Name | string, SafeExpr | string][]): _Code {
+    const code: CodeItem[] = ["{"]
+    for (const [key, value] of keyValues) {
+      if (code.length > 1) code.push(",")
+      code.push(key)
+      if (key !== value || this.opts.es5) {
+        code.push(":")
+        addCodeArg(code, value)
+      }
+    }
+    code.push("}")
+    return new _Code(code)
+  }
+
+  // `if` clause (or statement if `thenBody` and, optionally, `elseBody` are passed)
+  if(condition: Code | boolean, thenBody?: Block, elseBody?: Block): CodeGen {
+    this._blockNode(new If(condition))
+
+    if (thenBody && elseBody) {
+      this.code(thenBody).else().code(elseBody).endIf()
+    } else if (thenBody) {
+      this.code(thenBody).endIf()
+    } else if (elseBody) {
+      throw new Error('CodeGen: "else" body without "then" body')
+    }
+    return this
+  }
+
+  // `else if` clause - invalid without `if` or after `else` clauses
+  elseIf(condition: Code | boolean): CodeGen {
+    return this._elseNode(new If(condition))
+  }
+
+  // `else` clause - only valid after `if` or `else if` clauses
+  else(): CodeGen {
+    return this._elseNode(new Else())
+  }
+
+  // end `if` statement (needed if gen.if was used only with condition)
+  endIf(): CodeGen {
+    return this._endBlockNode(If, Else)
+  }
+
+  private _for(node: For, forBody?: Block): CodeGen {
+    this._blockNode(node)
+    if (forBody) this.code(forBody).endFor()
+    return this
+  }
+
+  // a generic `for` clause (or statement if `forBody` is passed)
+  for(iteration: Code, forBody?: Block): CodeGen {
+    return this._for(new ForLoop(iteration), forBody)
+  }
+
+  // `for` statement for a range of values
+  forRange(
+    nameOrPrefix: Name | string,
+    from: SafeExpr,
+    to: SafeExpr,
+    forBody: (index: Name) => void,
+    varKind: Code = this.opts.es5 ? varKinds.var : varKinds.let
+  ): CodeGen {
+    const name = this._scope.toName(nameOrPrefix)
+    return this._for(new ForRange(varKind, name, from, to), () => forBody(name))
+  }
+
+  // `for-of` statement (in es5 mode replace with a normal for loop)
+  forOf(
+    nameOrPrefix: Name | string,
+    iterable: Code,
+    forBody: (item: Name) => void,
+    varKind: Code = varKinds.const
+  ): CodeGen {
+    const name = this._scope.toName(nameOrPrefix)
+    if (this.opts.es5) {
+      const arr = iterable instanceof Name ? iterable : this.var("_arr", iterable)
+      return this.forRange("_i", 0, _`${arr}.length`, (i) => {
+        this.var(name, _`${arr}[${i}]`)
+        forBody(name)
+      })
+    }
+    return this._for(new ForIter("of", varKind, name, iterable), () => forBody(name))
+  }
+
+  // `for-in` statement.
+  // With option `ownProperties` replaced with a `for-of` loop for object keys
+  forIn(
+    nameOrPrefix: Name | string,
+    obj: Code,
+    forBody: (item: Name) => void,
+    varKind: Code = this.opts.es5 ? varKinds.var : varKinds.const
+  ): CodeGen {
+    if (this.opts.ownProperties) {
+      return this.forOf(nameOrPrefix, _`Object.keys(${obj})`, forBody)
+    }
+    const name = this._scope.toName(nameOrPrefix)
+    return this._for(new ForIter("in", varKind, name, obj), () => forBody(name))
+  }
+
+  // end `for` loop
+  endFor(): CodeGen {
+    return this._endBlockNode(For)
+  }
+
+  // `label` statement
+  label(label: Name): CodeGen {
+    return this._leafNode(new Label(label))
+  }
+
+  // `break` statement
+  break(label?: Code): CodeGen {
+    return this._leafNode(new Break(label))
+  }
+
+  // `return` statement
+  return(value: Block | SafeExpr): CodeGen {
+    const node = new Return()
+    this._blockNode(node)
+    this.code(value)
+    if (node.nodes.length !== 1) throw new Error('CodeGen: "return" should have one node')
+    return this._endBlockNode(Return)
+  }
+
+  // `try` statement
+  try(tryBody: Block, catchCode?: (e: Name) => void, finallyCode?: Block): CodeGen {
+    if (!catchCode && !finallyCode) throw new Error('CodeGen: "try" without "catch" and "finally"')
+    const node = new Try()
+    this._blockNode(node)
+    this.code(tryBody)
+    if (catchCode) {
+      const error = this.name("e")
+      this._currNode = node.catch = new Catch(error)
+      catchCode(error)
+    }
+    if (finallyCode) {
+      this._currNode = node.finally = new Finally()
+      this.code(finallyCode)
+    }
+    return this._endBlockNode(Catch, Finally)
+  }
+
+  // `throw` statement
+  throw(error: Code): CodeGen {
+    return this._leafNode(new Throw(error))
+  }
+
+  // start self-balancing block
+  block(body?: Block, nodeCount?: number): CodeGen {
+    this._blockStarts.push(this._nodes.length)
+    if (body) this.code(body).endBlock(nodeCount)
+    return this
+  }
+
+  // end the current self-balancing block
+  endBlock(nodeCount?: number): CodeGen {
+    const len = this._blockStarts.pop()
+    if (len === undefined) throw new Error("CodeGen: not in self-balancing block")
+    const toClose = this._nodes.length - len
+    if (toClose < 0 || (nodeCount !== undefined && toClose !== nodeCount)) {
+      throw new Error(`CodeGen: wrong number of nodes: ${toClose} vs ${nodeCount} expected`)
+    }
+    this._nodes.length = len
+    return this
+  }
+
+  // `function` heading (or definition if funcBody is passed)
+  func(name: Name, args: Code = nil, async?: boolean, funcBody?: Block): CodeGen {
+    this._blockNode(new Func(name, args, async))
+    if (funcBody) this.code(funcBody).endFunc()
+    return this
+  }
+
+  // end function definition
+  endFunc(): CodeGen {
+    return this._endBlockNode(Func)
+  }
+
+  optimize(n = 1): void {
+    while (n-- > 0) {
+      this._root.optimizeNodes()
+      this._root.optimizeNames(this._root.names, this._constants)
+    }
+  }
+
+  private _leafNode(node: LeafNode): CodeGen {
+    this._currNode.nodes.push(node)
+    return this
+  }
+
+  private _blockNode(node: StartBlockNode): void {
+    this._currNode.nodes.push(node)
+    this._nodes.push(node)
+  }
+
+  private _endBlockNode(N1: EndBlockNodeType, N2?: EndBlockNodeType): CodeGen {
+    const n = this._currNode
+    if (n instanceof N1 || (N2 && n instanceof N2)) {
+      this._nodes.pop()
+      return this
+    }
+    throw new Error(`CodeGen: not in block "${N2 ? `${N1.kind}/${N2.kind}` : N1.kind}"`)
+  }
+
+  private _elseNode(node: If | Else): CodeGen {
+    const n = this._currNode
+    if (!(n instanceof If)) {
+      throw new Error('CodeGen: "else" without "if"')
+    }
+    this._currNode = n.else = node
+    return this
+  }
+
+  private get _root(): Root {
+    return this._nodes[0] as Root
+  }
+
+  private get _currNode(): ParentNode {
+    const ns = this._nodes
+    return ns[ns.length - 1]
+  }
+
+  private set _currNode(node: ParentNode) {
+    const ns = this._nodes
+    ns[ns.length - 1] = node
+  }
+
+  // get nodeCount(): number {
+  //   return this._root.count
+  // }
+}
+
+function addNames(names: UsedNames, from: UsedNames): UsedNames {
+  for (const n in from) names[n] = (names[n] || 0) + (from[n] || 0)
+  return names
+}
+
+function addExprNames(names: UsedNames, from: SafeExpr): UsedNames {
+  return from instanceof _CodeOrName ? addNames(names, from.names) : names
+}
+
+function optimizeExpr<T extends SafeExpr | Code>(expr: T, names: UsedNames, constants: Constants): T
+function optimizeExpr(expr: SafeExpr, names: UsedNames, constants: Constants): SafeExpr {
+  if (expr instanceof Name) return replaceName(expr)
+  if (!canOptimize(expr)) return expr
+  return new _Code(
+    expr._items.reduce((items: CodeItem[], c: SafeExpr | string) => {
+      if (c instanceof Name) c = replaceName(c)
+      if (c instanceof _Code) items.push(...c._items)
+      else items.push(c)
+      return items
+    }, [])
+  )
+
+  function replaceName(n: Name): SafeExpr {
+    const c = constants[n.str]
+    if (c === undefined || names[n.str] !== 1) return n
+    delete names[n.str]
+    return c
+  }
+
+  function canOptimize(e: SafeExpr): e is _Code {
+    return (
+      e instanceof _Code &&
+      e._items.some(
+        (c) => c instanceof Name && names[c.str] === 1 && constants[c.str] !== undefined
+      )
+    )
+  }
+}
+
+function subtractNames(names: UsedNames, from: UsedNames): void {
+  for (const n in from) names[n] = (names[n] || 0) - (from[n] || 0)
+}
+
+export function not<T extends Code | SafeExpr>(x: T): T
+export function not(x: Code | SafeExpr): Code | SafeExpr {
+  return typeof x == "boolean" || typeof x == "number" || x === null ? !x : _`!${par(x)}`
+}
+
+const andCode = mappend(operators.AND)
+
+// boolean AND (&&) expression with the passed arguments
+export function and(...args: Code[]): Code {
+  return args.reduce(andCode)
+}
+
+const orCode = mappend(operators.OR)
+
+// boolean OR (||) expression with the passed arguments
+export function or(...args: Code[]): Code {
+  return args.reduce(orCode)
+}
+
+type MAppend = (x: Code, y: Code) => Code
+
+function mappend(op: Code): MAppend {
+  return (x, y) => (x === nil ? y : y === nil ? x : _`${par(x)} ${op} ${par(y)}`)
+}
+
+function par(x: Code): Code {
+  return x instanceof Name ? x : _`(${x})`
+}