On Wed, Sep 12, 2018 at 4:49 PM Wojciech S. Czarnecki
wrote:
>
> This is not metaprogramming!
>
> Every and each statement is written by the human author in plain Go
> and no code is produced by the program itself.
>
>
The key of metaprogramming is the ability to treat code as data which can
be m
[Bcc: drchase]
On Wed, 12 Sep 2018 10:55:26 +0200
"Wojciech S. Czarnecki" wrote:
> func Min(a, b T) T {
`func Min(a, b type T) type T` of course.
Late correction but needed.
> for type switch {
> case T func(T) Less(T) T:
> return a.Less(b)
> }
> if a < b {
>return a
>
On Thu, 13 Sep 2018 10:29:21 -0700 (PDT)
Manlio Perillo wrote:
> `try` tries each block at compile time, and use the first block that
> compiles successfully.
How the reader of this will know what will compile and what not?
Esp doing "by a finger"/"paper and pencil" codewalk?.
But you just red
On Wednesday, September 12, 2018 at 10:56:04 AM UTC+2, ohir wrote:
>
> On Tue, 11 Sep 2018 18:22:12 -0700
> Patrick Smith > wrote:
>
> > I'm fairly sure there's no way to write Min, but perhaps someone can
> prove
> > me wrong?
>
> Within "Craftsman Go Generics" proposal its trivial:
>
> func
On Wed, 12 Sep 2018 10:05:06 -0700
Ian Lance Taylor wrote:
> a compile-time decision as to which code should be compiled.
Note that this decision making is needed only for outstanding cases
usually in user own code. For many generic implementation a simple
for type contract is enough:
// Sum met
On Wed, 12 Sep 2018 10:05:06 -0700
Ian Lance Taylor wrote:
> I agree that no code is produced by the program, but you're suggesting
> a compile-time decision as to which code should be compiled.
How does it differ from unused code eliding go compiler and linker do
already? Used `for type case`
On Wed, Sep 12, 2018 at 6:34 AM Ian Lance Taylor wrote:
> That said, if we move forward with something like contracts, I think
> that it may be possible to introduce contract adaptors in the future:
> a mechanism that says "if the type argument does not implement
> contract C1, but does implement
Compile-time logic feels like a baby/bathwater issue to me.
With M4 and then CPP on the scene, new kinds of adaptable code became
possible in C. It was such a compelling benefit (I still have the CSTRs)
that it grew to ubiquity and finally to a monsterous horror in C++ that in
recent decades, thro
On Wed, Sep 12, 2018 at 7:49 AM, Wojciech S. Czarnecki wrote:
> On Wed, 12 Sep 2018 06:33:59 -0700
> Ian Lance Taylor wrote:
>
> Addenum:
>
>> You need to have a way to say "compile this code under certain
>> conditions based on the type argument, otherwise compile this code."
>> That is, the co
On Wed, 12 Sep 2018 07:40:37 -0700
Ian Lance Taylor wrote:
> The difference I see is that in one case we write code that can not be
> compiled, and then tell the compiler not to compile it.
> we direct the compiler to automatically insert wrappers that
> make the type fit the contract.
Who is s
On Wed, 12 Sep 2018 06:33:59 -0700
Ian Lance Taylor wrote:
Addenum:
> You need to have a way to say "compile this code under certain
> conditions based on the type argument, otherwise compile this code."
> That is, the compiler is directed, at compile time, as to which code
> should be compiled
On Wed, Sep 12, 2018 at 7:32 AM, Wojciech S. Czarnecki wrote:
> On Wed, 12 Sep 2018 06:33:59 -0700
> Ian Lance Taylor wrote:
>
>> I don't think there is any way to solve this problem as stated without
>> taking a step toward metaprogramming: making decisions at compile time.
>
> Excuse me, how an
On Wed, 12 Sep 2018 06:33:59 -0700
Ian Lance Taylor wrote:
> I don't think there is any way to solve this problem as stated without
> taking a step toward metaprogramming: making decisions at compile time.
Excuse me, how and where below stated artificial "contract adaptors"
are NOT "making decis
On Tue, Sep 11, 2018 at 6:22 PM, Patrick Smith wrote:
>
> This is a hypothetical question. Suppose generics were implemented as in the
> draft proposal, but without contracts. Instead, the rule is that if an
> instantiation of a generic function with a specific type argument doesn't
> compile, the
ISTM that your requirements can't work. 2) and 3) imply that the expression
`x < y` with x,y of type T has to appear at least once in the function
body, which means it can never work for a type that doesn't have it.
I don't think that has anything to do with changing the type-checking rules
though
On Tue, 11 Sep 2018 18:22:12 -0700
Patrick Smith wrote:
> I'm fairly sure there's no way to write Min, but perhaps someone can prove
> me wrong?
Within "Craftsman Go Generics" proposal its trivial:
func Min(a, b T) T {
for type switch {
case T func(T) Less(T) T:
return a.Less(b)
}
This is a hypothetical question. Suppose generics were implemented as in
the draft proposal, but without contracts. Instead, the rule is that if an
instantiation of a generic function with a specific type argument doesn't
compile, then it can't be used.
Under those circumstances, is there any way
17 matches
Mail list logo
