Re: Enumap -- a lightweight AA alternative when your keys are enums
On Wednesday, 16 September 2015 at 03:20:28 UTC, SimonN wrote: Yes, the 0.4.x version works with my examples perfectly. Thanks for adding const support! (I haven't tested yet every combination of const/mutable Enumap, const/mutable foraech-value, and direct/ref foreach-value. My examples are exactly what I'd do in normal projects anyway, mapping enum-values to ints.) -- Simon Good to hear! I have a pretty long set of static asserts that tries every (?) operation between mutable/const/immutable enumaps to verify that they do/don't compile as expected, so hopefully that has most situations covered.
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Sunday, 13 September 2015 at 03:33:15 UTC, rcorre wrote: I've released v0.4.0, which implements foreach with ref, and (hopefully) atones for my crimes against const-correctness. You should be able to modify values in a loop and work with const/immutable Enumaps. Thanks for the feedback! Yes, the 0.4.x version works with my examples perfectly. Thanks for adding const support! (I haven't tested yet every combination of const/mutable Enumap, const/mutable foraech-value, and direct/ref foreach-value. My examples are exactly what I'd do in normal projects anyway, mapping enum-values to ints.) -- Simon
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 03:25:58 UTC, SimonN wrote: It doesn't seem to matter whether I put const int, or int, in the foreach statement. What's the idiomatic way to loop over a const Enumap? :-) -- Simon I've released v0.4.0, which implements foreach with ref, and (hopefully) atones for my crimes against const-correctness. You should be able to modify values in a loop and work with const/immutable Enumaps. Thanks for the feedback!
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 08:22:20 UTC, Kagamin wrote:
On Friday, 11 September 2015 at 02:17:25 UTC, rcorre wrote:
@nogc void donFancyHat(Enumap!(Attribute, int) map) {
map.charisma += 1; }
BTW, what this means? Isn't Enumap a value type?
Correct, the parameter should be passed by ref in that example.
Good catch!
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 04:30:31 UTC, SimonN wrote: Since I have been using "ref val" in the first loop, I expected the output to be instead: e1: 101 e2: 102 e3: 103 e1: 104 e2: 105 e3: 106 -- Simon Yep, as I was looking at the constness thing, I realized that ref parameters in foreach are totally broken. I may just have to use opApply instead of opSlice.
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 02:17:25 UTC, rcorre wrote:
@nogc void donFancyHat(Enumap!(Attribute, int) map) {
map.charisma += 1; }
BTW, what this means? Isn't Enumap a value type?
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 04:02:17 UTC, rcorre wrote:
On Friday, 11 September 2015 at 03:25:58 UTC, SimonN wrote:
Hi,
I've ran into a compilation error when iterating over a const
Enumap. In the following code:
Interesting, thanks for pointing that out.
I don't think I did a great job with const-correctness here,
I'll take a look tomorrow.
It should definitely be possible to iterate over (and index,
etc...) a const/immutable Enumset, though you're right that it
doesn't work right now.
No worries, take your time! Thanks for the quick clarification.
I've also tested a couple ways of assigning in a foreach.
Continuing from my code above (struct A { Enumap!(MyEnum, int)
map; /* ... */ }), I've tried this in the main function:
int some_value = 100;
A a;
foreach (MyEnum e, ref val; a.map)
val = ++some_value;
a.mutable_output();
foreach (MyEnum e, ref val; a.map)
a.map[e] = ++some_value;
a.mutable_output();
Output:
e1: 0
e2: 0
e3: 0
e1: 104
e2: 105
e3: 106
Since I have been using "ref val" in the first loop, I expected
the output to be instead:
e1: 101
e2: 102
e3: 103
e1: 104
e2: 105
e3: 106
-- Simon
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 03:25:58 UTC, SimonN wrote:
Hi,
this looks excellent! I've been playing around with it, and am
looking forward to using it regularly.
I've ran into a compilation error when iterating over a const
Enumap. In the following code:
import std.stdio;
import std.conv;
import enumap;
enum MyEnum { e1, e2, e3 }
struct A
{
Enumap!(MyEnum, int) map;
void mutable_output()
{
foreach (MyEnum e, int i; map)
writefln("%s: %d", e.to!string, i);
}
void const_output() const
{
foreach (MyEnum e, const int i; map)
writefln("%s: %d", e.to!string, i);
}
}
...the first method (mutable_output) compiles and works with no
errors. The const method, however, gives:
source/app.d(19,13): Error: invalid foreach aggregate
this.map,
define opApply(), range primitives, or use .tupleof".
It doesn't seem to matter whether I put const int, or int, in
the foreach statement.
What's the idiomatic way to loop over a const Enumap? :-)
-- Simon
Interesting, thanks for pointing that out.
I don't think I did a great job with const-correctness here, I'll
take a look tomorrow.
It should definitely be possible to iterate over (and index,
etc...) a const/immutable Enumset, though you're right that it
doesn't work right now.
Re: Enumap -- a lightweight AA alternative when your keys are enums
On Friday, 11 September 2015 at 02:17:25 UTC, rcorre wrote:
I frequently find myself needing a data structure that maps
each member of an enum to a value;
something similar what Java calls an EnumMap
(http://docs.oracle.com/javase/7/docs/api/java/util/EnumMap.html).
I couldn't find any D implementation out there, so I wrote a
little module for it.
Enumap is available on Github (https://github.com/rcorre/enumap)
and via dub (http://code.dlang.org/packages/enumap).
Docs are hosted at http://rcorre.github.io/enumap/.
Hi,
this looks excellent! I've been playing around with it, and am
looking forward to using it regularly.
I've ran into a compilation error when iterating over a const
Enumap. In the following code:
import std.stdio;
import std.conv;
import enumap;
enum MyEnum { e1, e2, e3 }
struct A
{
Enumap!(MyEnum, int) map;
void mutable_output()
{
foreach (MyEnum e, int i; map)
writefln("%s: %d", e.to!string, i);
}
void const_output() const
{
foreach (MyEnum e, const int i; map)
writefln("%s: %d", e.to!string, i);
}
}
...the first method (mutable_output) compiles and works with no
errors. The const method, however, gives:
source/app.d(19,13): Error: invalid foreach aggregate
this.map,
define opApply(), range primitives, or use .tupleof".
It doesn't seem to matter whether I put const int, or int, in the
foreach statement.
What's the idiomatic way to loop over a const Enumap? :-)
-- Simon
Enumap -- a lightweight AA alternative when your keys are enums
I frequently find myself needing a data structure that maps each
member of an enum to a value;
something similar what Java calls an EnumMap
(http://docs.oracle.com/javase/7/docs/api/java/util/EnumMap.html).
I couldn't find any D implementation out there, so I wrote a
little module for it.
Enumap is available on Github (https://github.com/rcorre/enumap)
and via dub (http://code.dlang.org/packages/enumap).
Docs are hosted at http://rcorre.github.io/enumap/.
An Enumap is basically a thin wrapper that makes a static array
look like an associative array:
---
enum Attribute {
strength, dexterity, constitution, wisdom, intellect, charisma
}
Enumap!(Attribute,int) attributes;
attributes[Attribute.strength] = 10;
---
However, you might prefer an Enumap to an associative array if:
You like syntactic sugar:
---
// Boring!
if (hero.attributes[Attribute.wisdom] < 5)
hero.drink(unidentifiedPotion);
// Fun! And Concise!
if (hero.attributes.wisdom < 5) hero.drink(unidentifiedPotion);
---
You like ranges:
---
// roll for stats!
attributes = generate!(() => uniform!"[]"(1, 20)).take(6);
---
You like default values:
---
int[Attribute] aa;
Enumap!(Attribute, int) em;
aa[Attribute.strength]; // Range violation!
em.strength;// 0
---
You like array-wise operations:
---
// note the convenient constructor function:
auto bonus = enumap(Attribute.charisma, 2, Attribute.wisdom, 1);
// level up! adds 2 to charisma and 1 to wisdom.
hero.attributes += bonus;
---
You dislike garbage day:
---
void donFancyHat(int[Attribute] aa) {
aa[Attribute.charisma] += 1; }
@nogc void donFancyHat(Enumap!(Attribute, int) map) {
map.charisma += 1; }
---
Check it out, report bugs and all that!
P.S.
The above example used to read:
attributes = sequence!((a,n) => uniform!"[]"(1, 20)).take(6);
before Gary's recently posted article at
http://nomad.so/2015/08/more-hidden-treasure-in-the-d-standard-library/ made me realize generate existed.
