Re: D 2.066 new behavior
On Friday, 22 August 2014 at 02:26:38 UTC, safety0ff wrote: On Friday, 22 August 2014 at 01:54:55 UTC, Paul D Anderson wrote: Is this expected behavior that has never been enforced before, or is it something new? And is anyone else having the same problem? Paul Looks like a regression, I've filed it here: https://issues.dlang.org/show_bug.cgi?id=13351 Seems to be a duplicate of bug 13294: https://issues.dlang.org/show_bug.cgi?id=13294
D 2.066 new behavior
In all previous versions through 2.066 beta 5, the following code
compiled and ran correctly:
import std.stdio;
T add(T)(in T x, in T y)
{
T z;
z = x + y;
return z;
}
void main()
{
const double a = 1.0;
const double b = 2.0;
double c;
c = add(a,b);
writefln(c = %s, c);// 3.0
c = 1.0;
writefln(c = %s, c);// 1.0
}
From beta 6 onward it no longer compiles. The problem seems to be
const qualifiers being carried into the template type. Since a
and b are const double, the function template parameter T is
const double. So x and y are const, no problem, but z is now
const also. The following error message is given.
T add(T)(in T x, in T y)
{
T z;
z = x + y; // Error: Can't modify const expression z
return z;
}
The same problem shows up elsewhere as 'cannot implicitly convert
const x to x'
and 'none of the overloads are callable using argument types (x)
const'.
Is this expected behavior that has never been enforced before, or
is it something new?
And is anyone else having the same problem?
Paul
Re: Decimal Numbers
On Tuesday, 8 July 2014 at 08:15:28 UTC, Sönke Ludwig wrote: Am 07.07.2014 23:15, schrieb Paul D Anderson: On Monday, 7 July 2014 at 03:26:54 UTC, Poyeyo wrote: Can you add a dub.json and submit it to the dub registry? etcimon generated a dub.json file which I've merged into github. Thanks. However, I am unable to register the package because it requires a version number, which I don't know how to add. I've used git tag and edited dub.selections.json, but neither seems to be the answer. Can someone enlighten me? Paul git tag v0.9.0 git push --tags should do the trick (as well as any other version instead of 0.9.0, of course). Thanks. That did it.
Re: Decimal Numbers
On Monday, 7 July 2014 at 03:26:54 UTC, Poyeyo wrote: Can you add a dub.json and submit it to the dub registry? etcimon generated a dub.json file which I've merged into github. Thanks. However, I am unable to register the package because it requires a version number, which I don't know how to add. I've used git tag and edited dub.selections.json, but neither seems to be the answer. Can someone enlighten me? Paul
Re: Decimal Numbers
On Monday, 7 July 2014 at 03:26:54 UTC, Poyeyo wrote: Can you add a dub.json and submit it to the dub registry? I can do that but I want to get the 32-, 64- and 128-bit structs in place first. Probably by midweek (July 9).
Re: Decimal Numbers
On Friday, 4 July 2014 at 06:43:15 UTC, Iain Buclaw via Digitalmars-d-announce wrote: 6) Rename the file decimal.d to package.d, and module eris.decimal.decimal to eris.decimal Thanks, will do. Paul
Re: Decimal Numbers
Sorry for the unusual formatting. Paul
Decimal Numbers
A candidate implementation of decimal numbers (arbitrary-precision floating-point numbers) is available for review at https://github.com/andersonpd/eris/tree/master/eris/decimal. This is a substantial rework of an earlier implementation which was located at https://github.com/andersonpd/decimal. This is a D language implementation of the General Decimal Arithmetic Specification (http://www.speleotrove.com/decimal/decarith.pdf), which is compliant with IEEE-754 and other standards as noted in the specification. The current implementation is not complete; there are a lot of TODOs and NOTEs scattered throughout the code, but all the arithmetic and miscellaneous operations listed in the spec are working, along with decimal versions of most of the functions and constants in std.math. I think it is far enough along for effective review. Briefly, this software adds the capability of properly rounded arbitrary-precision floating-point arithmetic to the D language. All arithmetic operations are governed by a context, which specifies the precision (number of decimal digits) and rounding mode for the operations. This same functionality exists in most modern computer languages (for example, java.math.BigDecimal). Unlike Java, however, which uses function syntax for arithmetic ops (add(BigDecimal, BigDecimal), etc.), in D the same arithmetic operators that work for floats or doubles work for decimal numbers. (Of course!) In this implementation decimal numbers having different contexts are different types. The types are specified using template parameters for the precision, maximum exponent value and rounding mode. This means that Decimal!(9,99,Rounding.HALF_EVEN) is a different type than Decimal!(19,199,Rounding.HALF_DOWN). They are largely interoperable, however. Different decimal types can be cast to and from each other. There are three standard decimal structs which fit into 32-, 64- and 128-bits of memory, with 7, 16 and 34 digit precision, respectively. These are used for compact storage; they are converted to their corresponding decimal numbers for calculation. They bear the same relation to decimal numbers as Walter's half-float type does to floats. (http://www.drdobbs.com/cpp/implementing-half-floats-in-d/240146674). Implementation of these still needs a little work, and will be added to github very shortly. Major TODO items: 1) The current underlying integer type uses my own big integer struct (eris.integer.extended) rather than std.bigint. This was mainly due to problems with constness and CTFE of BigInts. These problems have since been resolved, but I didn't want to switch over to BigInts until everything was working for fear of introducing new bugs. 2) Integration of Decimal32, Decimal64 and Decimal128 structs are not complete. (See above.) 3) Conversion to and from floats, doubles and reals is currently working but it is slow. (Conversion is through strings: double to string to decimal and vice versa.) 4) Still incomplete implementations of some functions in decimal.math: expm1, acosh, atanh, possibly others. 5) More unit tests (always!).
Re: core.checkedint added to druntime
Will this be in the 2.066 Beta? On Wednesday, 18 June 2014 at 01:26:16 UTC, Walter Bright wrote: https://github.com/D-Programming-Language/druntime/pull/839 While being a very modest piece of code in and of itself, I believe this offers a significant opportunity that both D compilers and user defined types can exploit. Not only can it be used to create an efficient safeint data type, it can be used to implement multi-precision integer arithmetic types. I'd also like to see it used to replace the various ad-hoc schemes currently in use. It should also be used in dmd itself for things like detecting array size overflows, which is currently done ad-hoc, and detecting overflows in CTFE. For background information and rationale, see http://blog.regehr.org/archives/1139
