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interpreter.ts
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interpreter.ts
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/**
* This interpreter implements an explicit-control evaluator.
*
* Heavily adapted from https://github.com/source-academy/JSpike/
* and the legacy interpreter at '../interpreter/interpreter'
*/
/* tslint:disable:max-classes-per-file */
import * as es from 'estree'
import { isArray, reverse } from 'lodash'
import { IOptions } from '..'
import { UNKNOWN_LOCATION } from '../constants'
import * as errors from '../errors/errors'
import { RuntimeSourceError } from '../errors/runtimeSourceError'
import { checkEditorBreakpoints } from '../stdlib/inspector'
import { Context, ContiguousArrayElements, Result, Value, type StatementSequence } from '../types'
import * as ast from '../utils/ast/astCreator'
import { filterImportDeclarations } from '../utils/ast/helpers'
import { evaluateBinaryExpression, evaluateUnaryExpression } from '../utils/operators'
import * as rttc from '../utils/rttc'
import * as seq from '../utils/statementSeqTransform'
import { checkProgramForUndefinedVariables } from '../validator/validator'
import Closure from './closure'
import {
Continuation,
isCallWithCurrentContinuation,
makeDummyContCallExpression
} from './continuations'
import * as instr from './instrCreator'
import { Stack } from './stack'
import {
AppInstr,
ArrLitInstr,
AssmtInstr,
BinOpInstr,
BranchInstr,
CSEBreak,
ControlItem,
CseError,
EnvInstr,
ForInstr,
Instr,
InstrType,
UnOpInstr,
WhileInstr
} from './types'
import {
checkNumberOfArguments,
checkStackOverFlow,
createBlockEnvironment,
createEnvironment,
createProgramEnvironment,
currentEnvironment,
declareFunctionsAndVariables,
declareIdentifier,
defineVariable,
envChanging,
getVariable,
handleArrayCreation,
handleRuntimeError,
handleSequence,
hasBreakStatement,
hasContinueStatement,
hasDeclarations,
hasImportDeclarations,
isBlockStatement,
isEnvArray,
isEnvDependent,
isInstr,
isNode,
isSimpleFunction,
isStreamFn,
popEnvironment,
pushEnvironment,
reduceConditional,
setVariable,
valueProducing
} from './utils'
type CmdEvaluator = (
command: ControlItem,
context: Context,
control: Control,
stash: Stash,
isPrelude: boolean
) => void
/**
* The control is a list of commands that still needs to be executed by the machine.
* It contains syntax tree nodes or instructions.
*/
export class Control extends Stack<ControlItem> {
private numEnvDependentItems: number
public constructor(program?: es.Program | StatementSequence) {
super()
this.numEnvDependentItems = 0
// Load program into control stack
program ? this.push(program) : null
}
public canAvoidEnvInstr(): boolean {
return this.numEnvDependentItems === 0
}
// For testing purposes
public getNumEnvDependentItems(): number {
return this.numEnvDependentItems
}
public pop(): ControlItem | undefined {
const item = super.pop()
if (item !== undefined && isEnvDependent(item)) {
this.numEnvDependentItems--
}
return item
}
public push(...items: ControlItem[]): void {
const itemsNew: ControlItem[] = Control.simplifyBlocksWithoutDeclarations(...items)
itemsNew.forEach((item: ControlItem) => {
if (isEnvDependent(item)) {
this.numEnvDependentItems++
}
})
super.push(...itemsNew)
}
/**
* Before pushing block statements on the control stack, we check if the block statement has any declarations.
* If not, the block is converted to a StatementSequence.
* @param items The items being pushed on the control.
* @returns The same set of control items, but with block statements without declarations converted to StatementSequences.
* NOTE: this function handles any case where StatementSequence has to be converted back into BlockStatement due to type issues
*/
private static simplifyBlocksWithoutDeclarations(...items: ControlItem[]): ControlItem[] {
const itemsNew: ControlItem[] = []
items.forEach(item => {
if (isNode(item) && isBlockStatement(item) && !hasDeclarations(item)) {
// Push block body as statement sequence
const seq: StatementSequence = ast.statementSequence(item.body, item.loc)
itemsNew.push(seq)
} else {
itemsNew.push(item)
}
})
return itemsNew
}
public copy(): Control {
const newControl = new Control()
const stackCopy = super.getStack()
newControl.push(...stackCopy)
return newControl
}
}
/**
* The stash is a list of values that stores intermediate results.
*/
export class Stash extends Stack<Value> {
public constructor() {
super()
}
public copy(): Stash {
const newStash = new Stash()
const stackCopy = super.getStack()
newStash.push(...stackCopy)
return newStash
}
}
/**
* Function to be called when a program is to be interpreted using
* the explicit control evaluator.
*
* @param program The program to evaluate.
* @param context The context to evaluate the program in.
* @returns The result of running the CSE machine.
*/
export function evaluate(program: es.Program, context: Context, options: IOptions): Value {
try {
checkProgramForUndefinedVariables(program, context)
} catch (error) {
context.errors.push(error)
return new CseError(error)
}
seq.transform(program)
try {
context.runtime.isRunning = true
context.runtime.control = new Control(program)
context.runtime.stash = new Stash()
return runCSEMachine(
context,
context.runtime.control,
context.runtime.stash,
options.envSteps,
options.stepLimit,
options.isPrelude
)
} catch (error) {
return new CseError(error)
} finally {
context.runtime.isRunning = false
}
}
/**
* Function that is called when a user wishes to resume evaluation after
* hitting a breakpoint.
* This should only be called after the first 'evaluate' function has been called so that
* context.runtime.control and context.runtime.stash are defined.
* @param context The context to continue evaluating the program in.
* @returns The result of running the CSE machine.
*/
export function resumeEvaluate(context: Context) {
try {
context.runtime.isRunning = true
return runCSEMachine(context, context.runtime.control!, context.runtime.stash!, -1, -1)
} catch (error) {
return new CseError(error)
} finally {
context.runtime.isRunning = false
}
}
function evaluateImports(program: es.Program, context: Context) {
try {
const [importNodeMap] = filterImportDeclarations(program)
const environment = currentEnvironment(context)
for (const [moduleName, nodes] of importNodeMap) {
const functions = context.nativeStorage.loadedModules[moduleName]
for (const node of nodes) {
for (const spec of node.specifiers) {
declareIdentifier(context, spec.local.name, node, environment)
let obj: any
switch (spec.type) {
case 'ImportSpecifier': {
obj = functions[spec.imported.name]
break
}
case 'ImportDefaultSpecifier': {
obj = functions.default
break
}
case 'ImportNamespaceSpecifier': {
obj = functions
break
}
}
defineVariable(context, spec.local.name, obj, true, node)
}
}
}
} catch (error) {
handleRuntimeError(context, error)
}
}
/**
* Function that returns the appropriate Promise<Result> given the output of CSE machine evaluating, depending
* on whether the program is finished evaluating, ran into a breakpoint or ran into an error.
* @param context The context of the program.
* @param value The value of CSE machine evaluating the program.
* @returns The corresponding promise.
*/
export function CSEResultPromise(context: Context, value: Value): Promise<Result> {
return new Promise((resolve, reject) => {
if (value instanceof CSEBreak) {
resolve({ status: 'suspended-cse-eval', context })
} else if (value instanceof CseError) {
resolve({ status: 'error' })
} else {
resolve({ status: 'finished', context, value })
}
})
}
/**
* The primary runner/loop of the explicit control evaluator.
*
* @param context The context to evaluate the program in.
* @param control Points to the current context.runtime.control
* @param stash Points to the current context.runtime.stash
* @param isPrelude Whether the program we are running is the prelude
* @returns A special break object if the program is interrupted by a breakpoint;
* else the top value of the stash. It is usually the return value of the program.
*/
function runCSEMachine(
context: Context,
control: Control,
stash: Stash,
envSteps: number,
stepLimit: number,
isPrelude: boolean = false
) {
const eceState = generateCSEMachineStateStream(
context,
control,
stash,
envSteps,
stepLimit,
isPrelude
)
// Done intentionally as the state is not needed
// eslint-disable-next-line @typescript-eslint/no-unused-vars
for (const _ of eceState) {
}
return stash.peek()
}
export function* generateCSEMachineStateStream(
context: Context,
control: Control,
stash: Stash,
envSteps: number,
stepLimit: number,
isPrelude: boolean = false
) {
context.runtime.break = false
context.runtime.nodes = []
// steps: number of steps completed
let steps = 0
let command = control.peek()
// Push first node to be evaluated into context.
// The typeguard is there to guarantee that we are pushing a node (which should always be the case)
if (command && isNode(command)) {
context.runtime.nodes.unshift(command)
}
while (command) {
// Return to capture a snapshot of the control and stash after the target step count is reached
if (!isPrelude && steps === envSteps) {
yield { stash, control, steps }
return
}
// Step limit reached, stop further evaluation
if (!isPrelude && steps === stepLimit) {
break
}
if (isNode(command) && command.type === 'DebuggerStatement') {
// steps += 1
// Record debugger step if running for the first time
if (envSteps === -1) {
context.runtime.breakpointSteps.push(steps)
}
}
if (!isPrelude && envChanging(command)) {
// command is evaluated on the next step
// Hence, next step will change the environment
context.runtime.changepointSteps.push(steps + 1)
}
control.pop()
if (isNode(command)) {
context.runtime.nodes.shift()
context.runtime.nodes.unshift(command)
checkEditorBreakpoints(context, command)
cmdEvaluators[command.type](command, context, control, stash, isPrelude)
if (context.runtime.break && context.runtime.debuggerOn) {
// We can put this under isNode since context.runtime.break
// will only be updated after a debugger statement and so we will
// run into a node immediately after.
// With the new evaluator, we don't return a break
// return new CSEBreak()
}
} else {
// Command is an instruction
cmdEvaluators[command.instrType](command, context, control, stash, isPrelude)
}
// Push undefined into the stack if both control and stash is empty
if (control.isEmpty() && stash.isEmpty()) {
stash.push(undefined)
}
command = control.peek()
steps += 1
if (!isPrelude) {
context.runtime.envStepsTotal = steps
}
yield { stash, control, steps }
}
}
/**
* Dictionary of functions which handle the logic for the response of the three registers of
* the CSE machine to each ControlItem.
*/
const cmdEvaluators: { [type: string]: CmdEvaluator } = {
/**
* Statements
*/
Program: function (
command: es.BlockStatement,
context: Context,
control: Control,
stash: Stash,
isPrelude: boolean
) {
// After execution of a program, the current environment might be a local one.
// This can cause issues (for example, during execution of consecutive REPL programs)
// This piece of code will reset the current environment to either a global one, a program one or a prelude one.
while (
currentEnvironment(context).name != 'global' &&
currentEnvironment(context).name != 'programEnvironment' &&
currentEnvironment(context).name != 'prelude'
) {
popEnvironment(context)
}
// If the program has outer declarations:
// - Create the program environment (if none exists yet), and
// - Declare the functions and variables in the program environment.
if (hasDeclarations(command) || hasImportDeclarations(command)) {
if (currentEnvironment(context).name != 'programEnvironment') {
const programEnv = createProgramEnvironment(context, isPrelude)
pushEnvironment(context, programEnv)
}
const environment = currentEnvironment(context)
evaluateImports(command as unknown as es.Program, context)
declareFunctionsAndVariables(context, command, environment)
}
if (command.body.length == 1) {
// If program only consists of one statement, evaluate it immediately
const next = command.body[0]
cmdEvaluators[next.type](next, context, control, stash, isPrelude)
} else {
// Push block body as statement sequence
const seq: StatementSequence = ast.statementSequence(command.body, command.loc)
control.push(seq)
}
},
BlockStatement: function (command: es.BlockStatement, context: Context, control: Control) {
// To restore environment after block ends
// If there is an env instruction on top of the stack, or if there are no declarations
// we do not need to push another one
// The no declarations case is handled at the transform stage, so no blockStatement node without declarations should end up here.
const next = control.peek()
// Push ENVIRONMENT instruction if needed - if next control stack item
// exists and is not an environment instruction, OR the control only contains
// environment indepedent items
if (
next &&
!(isInstr(next) && next.instrType === InstrType.ENVIRONMENT) &&
!control.canAvoidEnvInstr()
) {
control.push(instr.envInstr(currentEnvironment(context), command))
}
const environment = createBlockEnvironment(context, 'blockEnvironment')
declareFunctionsAndVariables(context, command, environment)
pushEnvironment(context, environment)
// Push block body as statement sequence
const seq: StatementSequence = ast.statementSequence(command.body, command.loc)
control.push(seq)
},
StatementSequence: function (
command: StatementSequence,
context: Context,
control: Control,
stash: Stash,
isPrelude: boolean
) {
if (command.body.length == 1) {
// If sequence only consists of one statement, evaluate it immediately
const next = command.body[0]
cmdEvaluators[next.type](next, context, control, stash, isPrelude)
} else {
// unpack and push individual nodes in body
control.push(...handleSequence(command.body))
}
return
},
WhileStatement: function (
command: es.WhileStatement,
context: Context,
control: Control,
stash: Stash
) {
if (hasBreakStatement(command.body as es.BlockStatement)) {
control.push(instr.breakMarkerInstr(command))
}
control.push(instr.whileInstr(command.test, command.body, command))
control.push(command.test)
control.push(ast.identifier('undefined', command.loc)) // Return undefined if there is no loop execution
},
ForStatement: function (command: es.ForStatement, context: Context, control: Control) {
// All 3 parts will be defined due to parser rules
const init = command.init!
const test = command.test!
const update = command.update!
// Loop control variable present
// Refer to Source §3 specifications https://docs.sourceacademy.org/source_3.pdf
if (init.type === 'VariableDeclaration' && init.kind === 'let') {
const id = init.declarations[0].id as es.Identifier
const valueExpression = init.declarations[0].init!
control.push(
ast.blockStatement(
[
init,
ast.forStatement(
ast.assignmentExpression(id, valueExpression, command.loc),
test,
update,
ast.blockStatement(
[
ast.variableDeclaration(
[
ast.variableDeclarator(
ast.identifier(`_copy_of_${id.name}`, command.loc),
ast.identifier(id.name, command.loc),
command.loc
)
],
command.loc
),
ast.blockStatement(
[
ast.variableDeclaration(
[
ast.variableDeclarator(
ast.identifier(id.name, command.loc),
ast.identifier(`_copy_of_${id.name}`, command.loc),
command.loc
)
],
command.loc
),
command.body
],
command.loc
)
],
command.loc
),
command.loc
)
],
command.loc
)
)
} else {
if (hasBreakStatement(command.body as es.BlockStatement)) {
control.push(instr.breakMarkerInstr(command))
}
control.push(instr.forInstr(init, test, update, command.body, command))
control.push(test)
control.push(instr.popInstr(command)) // Pop value from init assignment
control.push(init)
control.push(ast.identifier('undefined', command.loc)) // Return undefined if there is no loop execution
}
},
IfStatement: function (
command: es.IfStatement,
context: Context,
control: Control,
stash: Stash
) {
control.push(...reduceConditional(command))
},
ExpressionStatement: function (
command: es.ExpressionStatement,
context: Context,
control: Control,
stash: Stash,
isPrelude: boolean
) {
// Fast forward to the expression
// If not the next step will look like it's only removing ';'
cmdEvaluators[command.expression.type](command.expression, context, control, stash, isPrelude)
},
DebuggerStatement: function (command: es.DebuggerStatement, context: Context) {
context.runtime.break = true
},
VariableDeclaration: function (
command: es.VariableDeclaration,
context: Context,
control: Control
) {
const declaration: es.VariableDeclarator = command.declarations[0]
const id = declaration.id as es.Identifier
// Parser enforces initialisation during variable declaration
const init = declaration.init!
control.push(instr.popInstr(command))
control.push(instr.assmtInstr(id.name, command.kind === 'const', true, command))
control.push(init)
},
FunctionDeclaration: function (
command: es.FunctionDeclaration,
context: Context,
control: Control
) {
// Function declaration desugared into constant declaration.
const lambdaExpression: es.ArrowFunctionExpression = ast.blockArrowFunction(
command.params as es.Identifier[],
command.body,
command.loc
)
const lambdaDeclaration: es.VariableDeclaration = ast.constantDeclaration(
command.id!.name,
lambdaExpression,
command.loc
)
control.push(lambdaDeclaration)
},
ReturnStatement: function (command: es.ReturnStatement, context: Context, control: Control) {
// Push return argument onto control as well as Reset Instruction to clear to ignore all statements after the return.
const next = control.peek()
if (next && isInstr(next) && next.instrType === InstrType.MARKER) {
control.pop()
} else {
control.push(instr.resetInstr(command))
}
if (command.argument) {
control.push(command.argument)
}
},
ContinueStatement: function (
command: es.ContinueStatement,
context: Context,
control: Control,
stash: Stash
) {
control.push(instr.contInstr(command))
},
BreakStatement: function (
command: es.BreakStatement,
context: Context,
control: Control,
stash: Stash
) {
control.push(instr.breakInstr(command))
},
ImportDeclaration: function () {},
/**
* Expressions
*/
Literal: function (command: es.Literal, context: Context, control: Control, stash: Stash) {
stash.push(command.value)
},
AssignmentExpression: function (
command: es.AssignmentExpression,
context: Context,
control: Control
) {
if (command.left.type === 'MemberExpression') {
control.push(instr.arrAssmtInstr(command))
control.push(command.right)
control.push(command.left.property)
control.push(command.left.object)
} else if (command.left.type === 'Identifier') {
const id = command.left
control.push(instr.assmtInstr(id.name, false, false, command))
control.push(command.right)
}
},
ArrayExpression: function (command: es.ArrayExpression, context: Context, control: Control) {
const elems = command.elements as ContiguousArrayElements
reverse(elems)
const len = elems.length
control.push(instr.arrLitInstr(len, command))
for (const elem of elems) {
control.push(elem)
}
},
MemberExpression: function (
command: es.MemberExpression,
context: Context,
control: Control,
stash: Stash
) {
control.push(instr.arrAccInstr(command))
control.push(command.property)
control.push(command.object)
},
ConditionalExpression: function (
command: es.ConditionalExpression,
context: Context,
control: Control,
stash: Stash
) {
control.push(...reduceConditional(command))
},
Identifier: function (command: es.Identifier, context: Context, control: Control, stash: Stash) {
stash.push(getVariable(context, command.name, command))
},
UnaryExpression: function (command: es.UnaryExpression, context: Context, control: Control) {
control.push(instr.unOpInstr(command.operator, command))
control.push(command.argument)
},
BinaryExpression: function (command: es.BinaryExpression, context: Context, control: Control) {
control.push(instr.binOpInstr(command.operator, command))
control.push(command.right)
control.push(command.left)
},
LogicalExpression: function (command: es.LogicalExpression, context: Context, control: Control) {
if (command.operator === '&&') {
control.push(
ast.conditionalExpression(command.left, command.right, ast.literal(false), command.loc)
)
} else {
control.push(
ast.conditionalExpression(command.left, ast.literal(true), command.right, command.loc)
)
}
},
ArrowFunctionExpression: function (
command: es.ArrowFunctionExpression,
context: Context,
control: Control,
stash: Stash,
isPrelude: boolean
) {
const closure: Closure = Closure.makeFromArrowFunction(
command,
currentEnvironment(context),
context,
true,
isPrelude
)
stash.push(closure)
},
CallExpression: function (command: es.CallExpression, context: Context, control: Control) {
// Push application instruction, function arguments and function onto control.
control.push(instr.appInstr(command.arguments.length, command))
for (let index = command.arguments.length - 1; index >= 0; index--) {
control.push(command.arguments[index])
}
control.push(command.callee)
},
/**
* Instructions
*/
[InstrType.RESET]: function (command: Instr, context: Context, control: Control, stash: Stash) {
// Keep pushing reset instructions until marker is found.
const cmdNext: ControlItem | undefined = control.pop()
if (cmdNext && (isNode(cmdNext) || cmdNext.instrType !== InstrType.MARKER)) {
control.push(instr.resetInstr(command.srcNode))
}
},
[InstrType.WHILE]: function (
command: WhileInstr,
context: Context,
control: Control,
stash: Stash
) {
const test = stash.pop()
// Check if test condition is a boolean
const error = rttc.checkIfStatement(command.srcNode, test, context.chapter)
if (error) {
handleRuntimeError(context, error)
}
if (test) {
control.push(command)
control.push(command.test)
if (hasContinueStatement(command.body as es.BlockStatement)) {
control.push(instr.contMarkerInstr(command.srcNode))
}
if (!valueProducing(command.body)) {
// if loop body is not value-producing, insert undefined expression statement
control.push(ast.identifier('undefined', command.body.loc))
}
control.push(command.body)
control.push(instr.popInstr(command.srcNode)) // Pop previous body value
}
},
[InstrType.FOR]: function (command: ForInstr, context: Context, control: Control, stash: Stash) {
const test = stash.pop()
// Check if test condition is a boolean
const error = rttc.checkIfStatement(command.srcNode, test, context.chapter)
if (error) {
handleRuntimeError(context, error)
}
if (test) {
control.push(command)
control.push(command.test)
control.push(instr.popInstr(command.srcNode)) // Pop value from update
control.push(command.update)
if (hasContinueStatement(command.body as es.BlockStatement)) {
control.push(instr.contMarkerInstr(command.srcNode))
}
if (!valueProducing(command.body)) {
// if loop body is not value-producing, insert undefined expression statement
control.push(ast.identifier('undefined', command.body.loc))
}
control.push(command.body)
control.push(instr.popInstr(command.srcNode)) // Pop previous body value
}
},
[InstrType.ASSIGNMENT]: function (
command: AssmtInstr,
context: Context,
control: Control,
stash: Stash
) {
command.declaration
? defineVariable(
context,
command.symbol,
stash.peek(),
command.constant,
command.srcNode as es.VariableDeclaration
)
: setVariable(
context,
command.symbol,
stash.peek(),
command.srcNode as es.AssignmentExpression
)
},
[InstrType.UNARY_OP]: function (
command: UnOpInstr,
context: Context,
control: Control,
stash: Stash
) {
const argument = stash.pop()
const error = rttc.checkUnaryExpression(
command.srcNode,
command.symbol as es.UnaryOperator,
argument,
context.chapter
)
if (error) {
handleRuntimeError(context, error)
}
stash.push(evaluateUnaryExpression(command.symbol as es.UnaryOperator, argument))
},
[InstrType.BINARY_OP]: function (
command: BinOpInstr,
context: Context,
control: Control,
stash: Stash
) {
const right = stash.pop()
const left = stash.pop()
const error = rttc.checkBinaryExpression(
command.srcNode,
command.symbol as es.BinaryOperator,
context.chapter,
left,
right
)
if (error) {
handleRuntimeError(context, error)
}
stash.push(evaluateBinaryExpression(command.symbol as es.BinaryOperator, left, right))
},
[InstrType.POP]: function (command: Instr, context: Context, control: Control, stash: Stash) {
stash.pop()
},
[InstrType.APPLICATION]: function (
command: AppInstr,
context: Context,
control: Control,
stash: Stash
) {
checkStackOverFlow(context, control)
// Get function arguments from the stash
const args: Value[] = []
for (let index = 0; index < command.numOfArgs; index++) {
args.unshift(stash.pop())
}
// Get function from the stash
const func: Closure | Function = stash.pop()
if (!(func instanceof Closure || func instanceof Function)) {
handleRuntimeError(context, new errors.CallingNonFunctionValue(func, command.srcNode))
}
if (isCallWithCurrentContinuation(func)) {
// Check for number of arguments mismatch error
checkNumberOfArguments(context, func, args, command.srcNode)
// generate a continuation here
const contControl = control.copy()
const contStash = stash.copy()
const contEnv = context.runtime.environments.slice()
// at this point, the extra CALL instruction
// has been removed from the control stack.
// additionally, the single closure argument has been
// removed (as the parameter of call/cc) from the stash
// and additionally, call/cc itself has been removed from the stash.
// as such, there is no further need to modify the
// copied C, S and E!
const continuation = new Continuation(contControl, contStash, contEnv)
// Get the callee
const cont_callee: Value = args[0]
const dummyFCallExpression = makeDummyContCallExpression('f', 'cont')
// Prepare a function call for the continuation-consuming function
control.push(instr.appInstr(command.numOfArgs, dummyFCallExpression))
// push the argument (the continuation caller) back onto the stash
stash.push(cont_callee)
// finally, push the continuation onto the stash
stash.push(continuation)
return
}
if (func instanceof Continuation) {
// Check for number of arguments mismatch error
checkNumberOfArguments(context, func, args, command.srcNode)
// const dummyContCallExpression = makeDummyContCallExpression('f', 'cont')
// // Restore the state of the stash,
// // but replace the function application instruction with
// // a resume continuation instruction
// stash.push(func)
// // we need to push the arguments back onto the stash
// // as well
// stash.push(...args)
// control.push(instr.resumeContInstr(command.numOfArgs, dummyContCallExpression))
// get the C, S, E from the continuation
const contControl = func.getControl()
const contStash = func.getStash()
const contEnv = func.getEnv()
// update the C, S, E of the current context
control.setTo(contControl)
stash.setTo(contStash)
context.runtime.environments = contEnv
// push the arguments back onto the stash
stash.push(...args)
return
}
if (func instanceof Closure) {