lib/compile/codegen/index.ts
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})`
}