Adding syntacti sugar for simple "readonly" attribute ?
Hello everyone i am new to the D community and i really enjoy
programming in D,
i haven't done anything significant so far. but being a very lazy
person,
when writing a bit of code i noticed that maybe for such a simple
thing we could have a shorter syntax.
i don't know if this is the correct way to suggest enhancement to
D,
and i am sorry if this is already in the language.
so maybe we could add syntactic sugar for "readonly" attributes.
here is simple example, where the following code
---
class Foo
{
@readonly int bar = 12; // or maybe "@directread" ?
this(string baz)
{
this.bar = baz;
}
}
---
would be the same as
---
class Foo
{
private string bar_;
this(string baz)
{
this.bar_ = baz;
}
@property string bar()
{
return this.bar_;
}
}
Re: Adding syntacti sugar for simple "readonly" attribute ?
On Thursday, 26 October 2017 at 21:19:28 UTC, LunaticWare wrote:
[snip]
You can use string mixins.
template GenGetterSetter(string Type, string Name)
{
const char[] GenGetterSetter = "private " ~ Type ~ " " ~
Name ~ "_;\n" ~
"this(" ~ Type ~ " x)\n" ~
"{\n" ~
"" ~ Name ~ "_ = x;\n"
~
"}\n" ~
"@property " ~ Type ~ " "
~ Name ~ "()\n" ~
"{\n" ~
"return " ~ Name ~
"_;\n" ~
"}";
}
class Foo
{
mixin(GenGetterSetter!("string", "bar"));
}
void main()
{
import std.stdio : writeln;
Foo foo = new Foo("bar");
writeln(foo.bar);
}
Re: Adding syntacti sugar for simple "readonly" attribute ?
On 10/26/2017 02:19 PM, LunaticWare wrote:
> i don't know if this is the correct way to suggest enhancement to D,
Improvement proposals are handled through DIPs here:
https://github.com/dlang/DIPs
> so maybe we could add syntactic sugar for "readonly" attributes.
There is the following project that comes close:
http://forum.dlang.org/thread/zdcrkrktfsmvghmid...@forum.dlang.org
class WithAccessors
{
@Read @Write
private int num_;
mixin(GenerateFieldAccessors);
}
Ali
Re: Adding syntacti sugar for simple "readonly" attribute ?
On Thursday, 26 October 2017 at 21:19:28 UTC, LunaticWare wrote:
Hello everyone i am new to the D community and i really enjoy
programming in D,
i haven't done anything significant so far. but being a very
lazy person,
when writing a bit of code i noticed that maybe for such a
simple
thing we could have a shorter syntax.
i don't know if this is the correct way to suggest enhancement
to D,
and i am sorry if this is already in the language.
so maybe we could add syntactic sugar for "readonly" attributes.
here is simple example, where the following code
---
class Foo
{
@readonly int bar = 12; // or maybe "@directread" ?
this(string baz)
{
this.bar = baz;
}
}
---
would be the same as
---
class Foo
{
private string bar_;
this(string baz)
{
this.bar_ = baz;
}
@property string bar()
{
return this.bar_;
}
}
The first example would not equal the second, because you could
set bar from anywhere within the module.
Immutable will already do your behavior.
class Foo
{
immutable string bar;
this(string baz)
{
bar = baz;
}
}
...
auto foo = new Foo("hello");
foo.bar ~= " World!"; // Error.
string bar = foo.bar; // Okay.
bar ~= " World!"; // Okay, because "bar" is not immutable, nor is
it referring to foo.bar.
Re: Adding syntacti sugar for simple "readonly" attribute ?
On 2017-10-27 01:04, bauss wrote:
The first example would not equal the second, because you could set bar
from anywhere within the module.
Immutable will already do your behavior.
class Foo
{
immutable string bar;
this(string baz)
{
bar = baz;
}
}
That only works for primitive types. For anything else (like a class or
struct) you won't be able to modify the internal state. While with the
with the initial example you can.
--
/Jacob Carlborg
Re: Adding syntacti sugar for simple "readonly" attribute ?
On Friday, 27 October 2017 at 06:49:47 UTC, Jacob Carlborg wrote:
On 2017-10-27 01:04, bauss wrote:
The first example would not equal the second, because you
could set bar from anywhere within the module.
Immutable will already do your behavior.
class Foo
{
immutable string bar;
this(string baz)
{
bar = baz;
}
}
That only works for primitive types. For anything else (like a
class or struct) you won't be able to modify the internal
state. While with the with the initial example you can.
Ahh yeah, that's true. I wasn't thinking that far
Re: Adding syntacti sugar for simple "readonly" attribute ?
On 2017-10-27 11:06, bauss wrote: Ahh yeah, that's true. I wasn't thinking that far I think head const [1] is what he's looking for. Similar to "final" in Java. [1] https://dlang.org/const-faq.html#head-const -- /Jacob Carlborg
