You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: thread.go
    path of file: ./repos/goby/vm
    
    the code of the file until where you have to start completion: package vm

import (
	"fmt"
	"io/ioutil"
	"path/filepath"
	"strings"

	"github.com/goby-lang/goby/compiler"
	"github.com/goby-lang/goby/compiler/bytecode"
	"github.com/goby-lang/goby/compiler/parser"
	"github.com/goby-lang/goby/vm/errors"
)

const mainThreadID = 0

// Thread is the context needed for a single thread of execution
type Thread struct {
	// a stack that holds call frames
	callFrameStack callFrameStack

	// The acall frame currently being executed
	currentFrame callFrame

	// data Stack
	Stack Stack

	// theads have an id so they can be looked up in the vm. The main thread is always 0
	id int64

	vm *VM
}

// VM returns the vm of the thread
func (t *Thread) VM() *VM {
	return t.vm
}

func (t *Thread) isMainThread() bool {
	return t.id == mainThreadID
}

func (t *Thread) getBlock(name string, filename filename
    
func (t *Thread) execFile(fpath string) (err error) {
	file, err := ioutil.ReadFile(fpath)

	if err != nil {
		return
	}

	instructionSets, err := compiler.CompileToInstructions(string(file), parser.NormalMode)

	if err != nil {
		return
	}

	oldMethodTable := isTable{}
	oldClassTable := isTable{}

	// Copy current file's instruction sets.
	for name, is := range t.vm.isTables[bytecode.MethodDef] {
		oldMethodTable[name] = is
	}

	for name, is := range t.vm.isTables[bytecode.ClassDef] {
		oldClassTable[name] = is
	}

	// This creates new execution environments for required file, including new instruction set table.
	// So we need to copy old instruction sets and restore them later, otherwise current program's instruction set would be overwrite.
	t.vm.ExecInstructions(instructionSets, fpath)

	// Restore instruction sets.
	t.vm.isTables[bytecode.MethodDef] = oldMethodTable
	t.vm.isTables[bytecode.ClassDef] = oldClassTable
	return
}