Giter Club home page Giter Club logo

Comments (5)

bethebunny avatar bethebunny commented on June 24, 2024

init_pointee_move treats the input as "uninit", which means it won't call the destructor on whatever data is in the pointer already, whereas move_pointee_into will call the destructor of the old data before the move.

from mojo.

soraros avatar soraros commented on June 24, 2024

@bethebunny So s.move_pointee_into(t) is t.init_pointee_move(s.take_pointee())?

from mojo.

bethebunny avatar bethebunny commented on June 24, 2024

s.move_pointee_into(t) should be equivalent to

_ = t.take_pointee()
t.init_pointee_move(s.take_pointee())

from mojo.

soraros avatar soraros commented on June 24, 2024

But the doctoring of move_pointee_into says that dst is assumed to be uninitialised, so it doesn't run the destructor.

If it calls the destructor of the old data, why can't we write

t[] = s[]^

from mojo.

soraros avatar soraros commented on June 24, 2024

The really difference seems to be that t.init_pointee_move(s.take_pointee()) calls moveinit twice.

struct S:
  var data: Float64

  fn __init__(inout self, data: Float64):
    self.data = data

  fn __copyinit__(inout self, other: S):
    print("  copyinit", other.data)
    self.data = other.data

  fn __moveinit__(inout self, owned other: S):
    print("  moveinit", other.data)
    self.data = other.data

  fn __del__(owned self):
    print("  del", self.data)

fn move_pointee_into():
  print("move_pointee_into:")
  var v = S(10)
  var t = UnsafePointer[S].alloc(1)
  var s = UnsafePointer.address_of(v)
  s.move_pointee_into(t)
  print()
  _ = v

fn init_pointee_move():
  print("init_pointee_move:")
  var v = S(20)
  var t = UnsafePointer[S].alloc(1)
  var s = UnsafePointer.address_of(v)
  t.init_pointee_move(s.take_pointee())
  print()
  _ = v

fn main():
  move_pointee_into()
  print()
  init_pointee_move()

Result:

move_pointee_into:
  moveinit 10.0

  del 10.0

init_pointee_move:
  moveinit 20.0
  moveinit 20.0

  del 20.0

from mojo.

Related Issues (20)

Recommend Projects

  • React photo React

    A declarative, efficient, and flexible JavaScript library for building user interfaces.

  • Vue.js photo Vue.js

    🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.

  • Typescript photo Typescript

    TypeScript is a superset of JavaScript that compiles to clean JavaScript output.

  • TensorFlow photo TensorFlow

    An Open Source Machine Learning Framework for Everyone

  • Django photo Django

    The Web framework for perfectionists with deadlines.

  • D3 photo D3

    Bring data to life with SVG, Canvas and HTML. 📊📈🎉

Recommend Topics

  • javascript

    JavaScript (JS) is a lightweight interpreted programming language with first-class functions.

  • web

    Some thing interesting about web. New door for the world.

  • server

    A server is a program made to process requests and deliver data to clients.

  • Machine learning

    Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.

  • Game

    Some thing interesting about game, make everyone happy.

Recommend Org

  • Facebook photo Facebook

    We are working to build community through open source technology. NB: members must have two-factor auth.

  • Microsoft photo Microsoft

    Open source projects and samples from Microsoft.

  • Google photo Google

    Google ❤️ Open Source for everyone.

  • D3 photo D3

    Data-Driven Documents codes.