digitalmars.D.bugs - [Issue 4111] New: Foreach ranges accept floating-point extrema
- d-bugmail puremagic.com (32/32) Apr 21 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4111
- Aelxx (7/11) Apr 21 2010 I'd like MATLAB style more:
- bearophile (5/18) Apr 22 2010 If you have comments on a bug report, it's quite better if you write the...
- d-bugmail puremagic.com (18/18) Apr 22 2010 http://d.puremagic.com/issues/show_bug.cgi?id=4111
http://d.puremagic.com/issues/show_bug.cgi?id=4111 Summary: Foreach ranges accept floating-point extrema Product: D Version: future Platform: All OS/Version: All Status: NEW Keywords: accepts-invalid Severity: normal Priority: P2 Component: DMD AssignedTo: nobody puremagic.com ReportedBy: bearophile_hugs eml.cc This D2 code works with dmd 2.043, it shows that foreach accepts floating point extrema too. But I think it's safer/tidier to accept only ranges with integral extrema (in Python too the range/xrange expects integers). FP approximations can cause problems here. import std.stdio; import std.math: nextUp; void main() { foreach(i; 2.1 .. 4.10001) { writeln(typeid(typeof(i))); // Output: double break; } foreach(i; 2.1 .. nextUp(4.1)) write(i, " "); // Output: 2.1 3.1 4.1 } -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 21 2010
foreach(i; 2.1 .. 4.10001) { writeln(typeid(typeof(i))); // Output: double break; }I'd like MATLAB style more: foreach (f; linspace (0.0, 1.0, 100)) {...} here f gets values 0, 0.0101.., 0.0202..., ..., 0.98989..., 1.0 foreach (f; logspace (1.0, 1e6, 7)) {...} here f gets values 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6.
Apr 21 2010
Aelxx:If you have comments on a bug report, it's quite better if you write them in Bugzilla, because here they will probably be lost/ignored. Phobos has iota() that's similar to what you ask, a FP version is easy to create. Bye, bearophileforeach(i; 2.1 .. 4.10001) { writeln(typeid(typeof(i))); // Output: double break; }I'd like MATLAB style more: foreach (f; linspace (0.0, 1.0, 100)) {...} here f gets values 0, 0.0101.., 0.0202..., ..., 0.98989..., 1.0 foreach (f; logspace (1.0, 1e6, 7)) {...} here f gets values 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6.
Apr 22 2010
http://d.puremagic.com/issues/show_bug.cgi?id=4111 Aelxx (aelxx at yandex dot ru) suggests: I'd like MATLAB style more: foreach (f; linspace (0.0, 1.0, 100)) {...} here f gets values 0, 0.0101.., 0.0202..., ..., 0.98989..., 1.0 foreach (f; logspace (1.0, 1e6, 7)) {...} here f gets values 1e0, 1e1, 1e2, 1e3, 1e4, 1e5, 1e6. ------------------------ My answer: Phobos has iota() that's similar to what you ask, a FP version is easy to create. With iota even the current interval syntax becomes less useful. See also bug 4112. -- Configure issuemail: http://d.puremagic.com/issues/userprefs.cgi?tab=email ------- You are receiving this mail because: -------
Apr 22 2010