digitalmars.D.learn - enum for beginners
- Johannes Totz <johannes jo-t.de> Nov 14 2011
- Timon Gehr <timon.gehr gmx.ch> Nov 14 2011
- Johannes Totz <johannes jo-t.de> Nov 15 2011
- Johannes Totz <johannes jo-t.de> Nov 15 2011
- Johannes Totz <johannes jo-t.de> Nov 15 2011
- Johannes Totz <johannes jo-t.de> Nov 15 2011
- "Steven Schveighoffer" <schveiguy yahoo.com> Nov 15 2011
- "Steven Schveighoffer" <schveiguy yahoo.com> Nov 15 2011
- "Steven Schveighoffer" <schveiguy yahoo.com> Nov 15 2011
- Mike Wey <mike-wey example.com> Nov 15 2011
- Johannes Totz <johannes jo-t.de> Nov 15 2011
- bearophile <bearophileHUGS lycos.com> Nov 15 2011
- Johannes Totz <johannes jo-t.de> Nov 15 2011
Hi!
I'm having trouble with named typed enums.
This works (unnamed):
enum : string
{
a = "a",
b = "b"
}
int main(string[] argv)
{
writeln(a);
return 0;
}
But this does not:
enum X : string
{
a = "a", // Error: Integer constant expression expected
// instead of "a"
b = "b" // Error: Integer constant expression expected
// instead of "b"
}
int main(string[] argv)
{
writeln(X.a);
return 0;
}
What did I miss?
Johannes
Nov 14 2011
On 11/14/2011 11:25 PM, Johannes Totz wrote:Hi! I'm having trouble with named typed enums. This works (unnamed): enum : string { a = "a", b = "b" } int main(string[] argv) { writeln(a); return 0; } But this does not: enum X : string { a = "a", // Error: Integer constan
t expression expected// instead of "a" b = "b" // Error: Integer constant expression expected // instead of "b" } int main(string[] argv) { writeln(X.a); return 0; } What did I miss?
I don't know. It works for me. import std.stdio; enum X : string{ a = "a", b = "b", } int main(string[] argv) { writeln(X.a); return 0; } compiles, runs and prints "a" as expected. Are you using the latest version of the compiler? (DMD v2.056)
Nov 14 2011
On 14/11/2011 22:32, Timon Gehr wrote:On 11/14/2011 11:25 PM, Johannes Totz wrote:Hi! I'm having trouble with named typed enums. This works (unnamed): enum : string { a = "a", b = "b" } int main(string[] argv) { writeln(a); return 0; } But this does not: enum X : string { a = "a", // Error: Integer constan
t expression expected// instead of "a" b = "b" // Error: Integer constant expression expected // instead of "b" } int main(string[] argv) { writeln(X.a); return 0; } What did I miss?
I don't know. It works for me. import std.stdio; enum X : string{ a = "a", b = "b", } int main(string[] argv) { writeln(X.a); return 0; } compiles, runs and prints "a" as expected. Are you using the latest version of the compiler? (DMD v2.056)
I had 2.055 and just upgraded. But this seems to be some issue with VisualD. Compiling on the command line (with 2.056) works fine as expected.
Nov 15 2011
On 15/11/2011 15:43, Johannes Totz wrote:On 14/11/2011 22:32, Timon Gehr wrote:On 11/14/2011 11:25 PM, Johannes Totz wrote:Hi! I'm having trouble with named typed enums. This works (unnamed): enum : string { a = "a", b = "b" } int main(string[] argv) { writeln(a); return 0; } But this does not: enum X : string { a = "a", // Error: Integer constan
t expression expected// instead of "a" b = "b" // Error: Integer constant expression expected // instead of "b" } int main(string[] argv) { writeln(X.a); return 0; } What did I miss?
I don't know. It works for me. import std.stdio; enum X : string{ a = "a", b = "b", } int main(string[] argv) { writeln(X.a); return 0; } compiles, runs and prints "a" as expected. Are you using the latest version of the compiler? (DMD v2.056)
I had 2.055 and just upgraded. But this seems to be some issue with VisualD. Compiling on the command line (with 2.056) works fine as expected.
Ah, when I compile on the command line with: dmd -g -debug main.d main.d(6): Error: enum main.X base type must be of integral type, not char[] main.d(8): Error: cannot implicitly convert expression ("a") of type char[1u] to int main.d(9): Error: cannot implicitly convert expression ("b") of type char[1u] to int
Nov 15 2011
On 15/11/2011 15:56, Steven Schveighoffer wrote:On Tue, 15 Nov 2011 10:55:44 -0500, Steven Schveighoffer <schveiguy yahoo.com> wrote:On Tue, 15 Nov 2011 10:47:22 -0500, Johannes Totz <johannes jo-t.de> wrote:Ah, when I compile on the command line with: dmd -g -debug main.d main.d(6): Error: enum main.X base type must be of integral type, not char[] main.d(8): Error: cannot implicitly convert expression ("a") of type char[1u] to int main.d(9): Error: cannot implicitly convert expression ("b") of type char[1u] to int
dmd must map to a D1 version, where string literals were char[N], not immutable(char)[]. In D1, you could not have enums that were strings.
to check, type dmd without args on the command line, it will tell you the version.
There is a 1.071 version somewhere in the path... C:\Users\...>dmd DMD32 D Compiler v1.071 But if I do... C:\Users\...>C:\D\dmd2\windows\bin\dmd.exe -g -debug main.d main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" However... C:\Users\...>C:\D\dmd2\windows\bin\dmd.exe main.d C:\Users\...>main.exe a Getting rid of 1.071... C:\Users\...>dmd DMD32 D Compiler v2.056 C:\Users\...>dmd -g -debug main.d main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b"
Nov 15 2011
Johannes Totz <johannes jo-t.de> On 15/11/2011 16:30, Steven Schveighoffer wrote:On Tue, 15 Nov 2011 11:15:01 -0500, Johannes Totz <johannes jo-t.de> wrote:On 15/11/2011 15:56, Steven Schveighoffer wrote:On Tue, 15 Nov 2011 10:55:44 -0500, Steven Schveighoffer <schveiguy yahoo.com> wrote:On Tue, 15 Nov 2011 10:47:22 -0500, Johannes Totz <johannes jo-t.de> wrote:Ah, when I compile on the command line with: dmd -g -debug main.d main.d(6): Error: enum main.X base type must be of integral type, not char[] main.d(8): Error: cannot implicitly convert expression ("a") of type char[1u] to int main.d(9): Error: cannot implicitly convert expression ("b") of type char[1u] to int
dmd must map to a D1 version, where string literals were char[N], not immutable(char)[]. In D1, you could not have enums that were strings.
to check, type dmd without args on the command line, it will tell you the version.
There is a 1.071 version somewhere in the path... C:\Users\...>dmd DMD32 D Compiler v1.071 But if I do... C:\Users\...>C:\D\dmd2\windows\bin\dmd.exe -g -debug main.d main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" However... C:\Users\...>C:\D\dmd2\windows\bin\dmd.exe main.d C:\Users\...>main.exe a Getting rid of 1.071... C:\Users\...>dmd DMD32 D Compiler v2.056 C:\Users\...>dmd -g -debug main.d main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b"
Don't have a windows box handy, but this works on Linux: steves steve-laptop:~/testd$ cat testenum.d import std.stdio; enum X : string { a = "a", b = "b", } void main() { writeln(X.b); } steves steve-laptop:~/testd$ ~/dmd-2.056/linux/bin32/dmd -g -debug testenum.d steves steve-laptop:~/testd$ ./testenum b Can you post your exact code that doesn't work with dmd 2.056? This is all I have from your previous post. I can't see why it wouldn't work.
-g is what makes it fail, -debug is fine. ---------------------------------------- module main; import std.stdio; enum X : string { a = "a", b = "b" } int main(string[] argv) { writeln(X.a); return 0; } ----------------------------------------
Nov 15 2011
On Tue, 15 Nov 2011 10:47:22 -0500, Johannes Totz <johannes jo-t.de> wrote:On 15/11/2011 15:43, Johannes Totz wrote:On 14/11/2011 22:32, Timon Gehr wrote:On 11/14/2011 11:25 PM, Johannes Totz wrote:Hi! I'm having trouble with named typed enums. This works (unnamed): enum : string { a = "a", b = "b" } int main(string[] argv) { writeln(a); return 0; } But this does not: enum X : string { a = "a", // Error: Integer constan
t expression expected// instead of "a" b = "b" // Error: Integer constant expression expected // instead of "b" } int main(string[] argv) { writeln(X.a); return 0; } What did I miss?
I don't know. It works for me. import std.stdio; enum X : string{ a = "a", b = "b", } int main(string[] argv) { writeln(X.a); return 0; } compiles, runs and prints "a" as expected. Are you using the latest version of the compiler? (DMD v2.056)
I had 2.055 and just upgraded. But this seems to be some issue with VisualD. Compiling on the command line (with 2.056) works fine as expected.
Ah, when I compile on the command line with: dmd -g -debug main.d main.d(6): Error: enum main.X base type must be of integral type, not char[] main.d(8): Error: cannot implicitly convert expression ("a") of type char[1u] to int main.d(9): Error: cannot implicitly convert expression ("b") of type char[1u] to int
dmd must map to a D1 version, where string literals were char[N], not immutable(char)[]. In D1, you could not have enums that were strings. -Steve
Nov 15 2011
On Tue, 15 Nov 2011 10:55:44 -0500, Steven Schveighoffer <schveiguy yahoo.com> wrote:On Tue, 15 Nov 2011 10:47:22 -0500, Johannes Totz <johannes jo-t.de> wrote:Ah, when I compile on the command line with: dmd -g -debug main.d main.d(6): Error: enum main.X base type must be of integral type, not char[] main.d(8): Error: cannot implicitly convert expression ("a") of type char[1u] to int main.d(9): Error: cannot implicitly convert expression ("b") of type char[1u] to int
dmd must map to a D1 version, where string literals were char[N], not immutable(char)[]. In D1, you could not have enums that were strings.
to check, type dmd without args on the command line, it will tell you the version. -Steve
Nov 15 2011
On Tue, 15 Nov 2011 11:15:01 -0500, Johannes Totz <johannes jo-t.de> wrote:On 15/11/2011 15:56, Steven Schveighoffer wrote:On Tue, 15 Nov 2011 10:55:44 -0500, Steven Schveighoffer <schveiguy yahoo.com> wrote:On Tue, 15 Nov 2011 10:47:22 -0500, Johannes Totz <johannes jo-t.de> wrote:Ah, when I compile on the command line with: dmd -g -debug main.d main.d(6): Error: enum main.X base type must be of integral type, not char[] main.d(8): Error: cannot implicitly convert expression ("a") of type char[1u] to int main.d(9): Error: cannot implicitly convert expression ("b") of type char[1u] to int
dmd must map to a D1 version, where string literals were char[N], not immutable(char)[]. In D1, you could not have enums that were strings.
to check, type dmd without args on the command line, it will tell you the version.
There is a 1.071 version somewhere in the path... C:\Users\...>dmd DMD32 D Compiler v1.071 But if I do... C:\Users\...>C:\D\dmd2\windows\bin\dmd.exe -g -debug main.d main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" However... C:\Users\...>C:\D\dmd2\windows\bin\dmd.exe main.d C:\Users\...>main.exe a Getting rid of 1.071... C:\Users\...>dmd DMD32 D Compiler v2.056 C:\Users\...>dmd -g -debug main.d main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b" main.d(8): Error: Integer constant expression expected instead of "a" main.d(9): Error: Integer constant expression expected instead of "b"
Don't have a windows box handy, but this works on Linux: steves steve-laptop:~/testd$ cat testenum.d import std.stdio; enum X : string { a = "a", b = "b", } void main() { writeln(X.b); } steves steve-laptop:~/testd$ ~/dmd-2.056/linux/bin32/dmd -g -debug testenum.d steves steve-laptop:~/testd$ ./testenum b Can you post your exact code that doesn't work with dmd 2.056? This is all I have from your previous post. I can't see why it wouldn't work. -Steve
Nov 15 2011
On 11/14/2011 11:25 PM, Johannes Totz wrote:Hi! I'm having trouble with named typed enums. This works (unnamed): enum : string { a = "a", b = "b" } int main(string[] argv) { writeln(a); return 0; } But this does not: enum X : string { a = "a", // Error: Integer constant expression expected // instead of "a" b = "b" // Error: Integer constant expression expected // instead of "b" } int main(string[] argv) { writeln(X.a); return 0; } What did I miss? Johannes
It's a bug: string enums don't work with -g compiler switch. http://d.puremagic.com/issues/show_bug.cgi?id=5168 -- Mike Wey
Nov 15 2011
On 15/11/2011 20:37, Mike Wey wrote:On 11/14/2011 11:25 PM, Johannes Totz wrote:Hi! I'm having trouble with named typed enums. This works (unnamed): enum : string { a = "a", b = "b" } int main(string[] argv) { writeln(a); return 0; } But this does not: enum X : string { a = "a", // Error: Integer constant expression expected // instead of "a" b = "b" // Error: Integer constant expression expected // instead of "b" } int main(string[] argv) { writeln(X.a); return 0; } What did I miss? Johannes
It's a bug: string enums don't work with -g compiler switch. http://d.puremagic.com/issues/show_bug.cgi?id=5168
Ah thanks! I've added my case... How would i go about using a custom class for the enum-type? Various combinations of the snippet below lead to errors. class EnumType { int x; alias x this; this(int i) { x = i; } void opCall(int i) { } } enum X : EnumType { a = EnumType(1), b = 2 } Errors range are always variations of main.d(16): Error: function main.EnumType.opCall need 'this' to access member opCall main.d(23): called from here: opCall(1) main.d(23): Error: cannot implicitly convert expression (opCall(1)) of type void to main.EnumType main.d(24): Error: cannot implicitly convert expression (2) of type int to main.EnumType
Nov 15 2011
Johannes Totz:class EnumType { int x; alias x this; this(int i) { x = i; } void opCall(int i) { } } enum X : EnumType { a = EnumType(1), b = 2 } Errors range are always variations of main.d(16): Error: function main.EnumType.opCall need 'this' to access member opCall
The error message suggests you to use a static opCall. And are you sure you want a class instead of a struct? Bye, bearophile
Nov 15 2011
On 15/11/2011 22:56, bearophile wrote:Johannes Totz:class EnumType { int x; alias x this; this(int i) { x = i; } void opCall(int i) { } } enum X : EnumType { a = EnumType(1), b = 2 } Errors range are always variations of main.d(16): Error: function main.EnumType.opCall need 'this' to access member opCall
The error message suggests you to use a static opCall. And are you sure you want a class instead of a struct?
struct works, thanks! No need for class.
Nov 15 2011