Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

Hi All,

I am considering using D for my latest project and there are a 
few features I would like and am not entirely sure at this point 
whether D has them. They are:


- dynamic creation of classes/structs at runtime (think I can 
emulate this with variants/dynamic)

- dynamic compilation of code files at runtime
- some basic code creation tools

Are the above possible?

Thanks for any help,
Chris Stevens

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Sunday, 6 September 2015 at 14:36:53 UTC, chris stevens wrote:

- dynamic compilation of code files at runtime


I guess I could just invoke the compiler from my code for this? I 
would also like to be able to load this compiled code into the 
current process. This probably can be achieved using a simple 
loadLibrary command right?

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

Thanks so much for your reply.

On Sunday, 6 September 2015 at 14:45:45 UTC, BBasile wrote:
if you mean to generate code as string, writing them to a file, 
of course it will work in D.


I guess you're right it wouldn't be too difficult to do it all 
using strings. The code generation I'd done before in c# I'd used 
some 3rd person library where you build up an object model rather 
than using strings.


Ok, all sounds good. Looks like I'm going to be coding in D.:)

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Sunday, 6 September 2015 at 14:45:45 UTC, BBasile wrote:
You have Object.factory for this. You can also use a custom 
factory based on string comparison. (with some: static 
if(condition) return new This; else static if(otherCondition) 
return new That; etc).


I just had a look at Object.factory and this isn't actually what 
I wanted. I was looking for something that would allow me to 
create new (previously undefined) classes in D at runtime that I 
could then use with Object.factory to create instances of.


I think I can do this with Variants and dynamic, is this 
possible? Or is there another way?

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Monday, 7 September 2015 at 07:57:07 UTC, Kagamin wrote:
On Sunday, 6 September 2015 at 15:15:03 UTC, chris stevens 
wrote:
I guess you're right it wouldn't be too difficult to do it all 
using strings. The code generation I'd done before in c# I'd 
used some 3rd person library where you build up an object 
model rather than using strings.


Maybe with dparse you can construct an AST and later convert it 
to string.


Thanks for the reply Kagamin, just had a quick look at dparse and 
not sure how I could use it in the way you describe. Any examples 
of this?

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Tuesday, 8 September 2015 at 21:51:03 UTC, wobbles wrote:
"Previously undefined". As far as I know, this is impossible in 
D. Thr compiler has to know how much memory to allocate/request 
and it has to know that at compiletime (else it wouldn't be the 
compiler!)


http://wiki.dlang.org/Dynamic_typing

This is what I saw that made me think that I could. Have had 
another closer look and I do believe it's possible.

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Wednesday, 9 September 2015 at 08:24:06 UTC, Kagamin wrote:
As I understand, you wanted to build an AST tree and format it 
to string?


Thanks again. So I can build an AST and convert it to full D 
source from that? I think that's what i'm likely going need to do.

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Wednesday, 9 September 2015 at 09:14:30 UTC, Atila Neves wrote:
So, if your use-case depends on information from the 
file-system, user interaction, networking, etc. then your only 
choice is to generate text files with D code and compile it. 
If, on the other hand, it's all defined by the code you write, 
then D has excellent compile-time code generation tools at your 
disposal.


Thanks for the in depth reply. Unfortunately, yes, my use case 
depends on user input so definitions will not be known at 
compiletime. I'm keen to learn D though so I think I'm going to 
try and make it work with dynamically compiling and loading 
libraries.

Re: Is D suitable for my latest project?

[chris stevens via Digitalmars-d-learn]

On Tuesday, 8 September 2015 at 21:51:03 UTC, wobbles wrote:
"Previously undefined". As far as I know, this is impossible in 
D. Thr compiler has to know how much memory to allocate/request 
and it has to know that at compiletime (else it wouldn't be the 
compiler!)


There was also this:

http://rosettacode.org/wiki/Add_a_variable_to_a_class_instance_at_runtime#D

That made me think I could emulate the functionality I need.