3 ms·

I like the idea of the `defer `keyword - you can have automatic cleanup at the end of the scope but you have to make it obvious you are doing so, no hidden exec

by krosaen 11mo ago

I like the idea of the `defer `keyword - you can have automatic cleanup at the end of the scope but you have to make it obvious you are doing so, no hidden execution of anything (unlike c++ destructors).

jibal 11mo ago
Adopted from go, first appeared in D, invented by one of its major developers, Andrei Alexandrescu.
- jibal 11mo ago
  P.S. In D it's `scope(exit)` = defer, `scope(failure)` = Zig's errdefer, and `scope(success)` -- which no one else has and which I have made good use of. e.g., I have a mixin that traces entry and exit from a function, the latter with scope(success). If I use scope(exit) instead then when an exception is thrown all the leave messages are printed and then the stack trace, rather than seeing the stack trace at the point of failure (this baffled me when it first happened).
- fuzztester 11mo ago
  I vaguely remember reading somewhere recently that Andrei left the D community / foundation. Do you know if that is true?
  - jibal 11mo ago
    He's moved on: https://research.nvidia.com/person/andrei-alexandrescu https://research.nvidia.com/person/andrei-alexandrescu
tcfhgj 11mo ago
But you can forget it, unlike C++ destructors
lenkite 11mo ago
I would like a language to support both defer and C++ style destructors / Rust Drop. There are good use-cases for having both. For things like a mutex or straight-forward resource cleanup - having a bunch of brain-dead defer statements adds little value and only bloats unnecessary line count. Let the resource type handle its own release/cleanup at scope close. Code is made sweet, succinct and safe.
- rustacean 11mo ago
  In Rust, there’s a drop guard pattern to do this, which leverages the lazy execution of closure, checkout the scopeguard crate. C++ should be easy to do that too I think
- 1718627440 11mo ago
  GNU C++?
1718627440 11mo ago
The GNU C and C++ dialect also has attribute cleanup. https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-cleanup-variable-attribute https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attribute...
coolThingsFirst 11mo ago
C++ doesn't have hidden execution, you just don't know the language. Once you exit scope destructor is invoked.

by krosaen 11mo ago

jibal 11mo ago

Adopted from go, first appeared in D, invented by one of its major developers, Andrei Alexandrescu.

jibal 11mo ago
P.S. In D it's `scope(exit)` = defer, `scope(failure)` = Zig's errdefer, and `scope(success)` -- which no one else has and which I have made good use of. e.g., I have a mixin that traces entry and exit from a function, the latter with scope(success). If I use scope(exit) instead then when an exception is thrown all the leave messages are printed and then the stack trace, rather than seeing the stack trace at the point of failure (this baffled me when it first happened).
fuzztester 11mo ago
I vaguely remember reading somewhere recently that Andrei left the D community / foundation. Do you know if that is true?
- jibal 11mo ago
  He's moved on: https://research.nvidia.com/person/andrei-alexandrescu https://research.nvidia.com/person/andrei-alexandrescu

tcfhgj 11mo ago

But you can forget it, unlike C++ destructors

lenkite 11mo ago

I would like a language to support both defer and C++ style destructors / Rust Drop. There are good use-cases for having both. For things like a mutex or straight-forward resource cleanup - having a bunch of brain-dead defer statements adds little value and only bloats unnecessary line count. Let the resource type handle its own release/cleanup at scope close. Code is made sweet, succinct and safe.

rustacean 11mo ago
In Rust, there’s a drop guard pattern to do this, which leverages the lazy execution of closure, checkout the scopeguard crate. C++ should be easy to do that too I think
1718627440 11mo ago
GNU C++?

1718627440 11mo ago

The GNU C and C++ dialect also has attribute cleanup. https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html#index-cleanup-variable-attribute https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attribute...

coolThingsFirst 11mo ago

C++ doesn't have hidden execution, you just don't know the language. Once you exit scope destructor is invoked.