On Thursday, 18 December 2014 at 23:06:12 UTC, ketmar via
Digitalmars-d wrote:
On Thu, 18 Dec 2014 22:46:04 +0000
Jonathan Marler via Digitalmars-d <[email protected]>
wrote:
What are peoples thoughts on having an inferred type for
"cast"? Good/Bad idea? If good, how helpful would this be?
Would this break existing code somehow? I think this feature
would be a nice added convenience. Not super helpful but nice
to have.
Here's the details
-------------------
Typed Cast: cast(T)v
try to cast v to T
Type Inferred Cast: cast(auto)v
try to cast v to whatever type is required in the current
context
void foo(string s)
{
// ...
}
void main()
{
const(char)[] s = "hello";
foo(cast(string)s); // Current
foo(cast(auto) s); // The type of the cast is inferred
to be a string
foo(cast() s); // Another possible syntax
}
This would help refactoribility. If a function argument
changes it's type, and the caller is using a cast, then the
caller's cast type will be updated automatically. Note that
if it changes to an invalid type, the cast will still fail
like normal.
using casts is a bad practice. and "auto casts" is... i can't
even find
a word. the only thing this will help is to hide bugs, i
believe.
please, don't.
nothing personal, i'm just terrified by the idea.
Performing a grep on phobos reveals there are currently almost
3,000 casts. I never like to use casts but they are a necessary
evil. I think anything D can do to help the programmer get their
job done is a win. The initial "pro" I saw for this idea was
improving refactoribility. I see this as a huge win. You claim
it will hide bugs? Could you give an example?
When I requested other people to chime in on this idea I was more
looking for data/examples. Maybe someone will think of an
example that shows this idea could encourage bad coding
practices? Maybe it will hide bugs? My point is, I don't want
to discourage you from providing your opinion, but I would
really like to understand where your opinion comes from. I hope
that wasn't harsh, I've read other posts you've made on the
forums and although I don't agree with everything you say I would
value your assessment. Thanks.
