On Monday, 11 November 2013 at 08:12:59 UTC, Jacob Carlborg wrote:
On 2013-11-11 08:46, Rikki Cattermole wrote:
One of our targets for AST macros should be the ability to
replicate
roughly linq from c# / .net.
An example syntax for use with AST could be:
auto data = [5, 7, 9];
int[] data2;
query {
from value in data
where value >= 6
add to data2
}
Could be unwrapped to:
auto data = [5, 7, 9];
int[] data2;
foreach(value; data) {
if (value >= 6) data2 ~= value;
}
This isn't a thought out design but it should at least be a
target or a
possibility.
Absolutely. One of my favorite examples is the database query:
auto person = Person.where(e => e.name == "John");
Which translates to the following SQL:
select * from person where name = 'John'
Also c#'s get set should be rather similar as well.
Example:
getset {
public int id;
private bool exit;
}
Would translate to:
private int id;
private bool exit;
@property {
void id(int v) {this.id = v;}
void exit(bool v) { this.exit = v; }
int id() { return this.id; }
bool exit() { return this.exit; }
}
This would definitely open new possibilities up.
Disclaimer I don't like c# or .net but I am partial to these
features.
That's quite similar one of the examples, I like to call it
"property shortcut":
http://wiki.dlang.org/DIP50#Attribute_macros
At current point I think the DIP does have the necessary
features to
implement this. However it would be nice for safety to be able
to get
all scope variables of where the macro was initiated from.
Being able to
check for if a variable exists could provide much needed
compile safety
and better error messages.
Why not? There's quite a lot that is not specified in this DIP.
Mostly because I haven't decided/figured out how it should work
exactly. Of course, any help is always appreciated.
Theres a few other things I think would need to be cleared up.
For example take this code:
shader {
program
vertex {
#version 150
void main() {
}
}
fragment {
#version 150
void main() {
}
}
}
At this point the vertex / fragment segments would be treated as
strings instead of calling their macros. So perhaps a rule to
identify macros inside macros calls? It would save a lot of time
for parsing reasons.
Also can you alias a macro?
alias fragment = tostring;
That would make things a lot simpler creating nice structures of
them.
Perhaps a condition on a macro like the if's we got for templates
would be useful in the sense of being able to say:
if (lexer.compareLine(0, "[a-zA-Z]{1}[a-zA-Z_0-9]*") &&
lexer.isSymbol(1, SymbolTypes.Macro, vertex))
This would require us to develop a lexer library. But if done
right I don't see why it wouldn't be usable for more than just D
macro checks. Preferably also for e.g. c/c++ wink wink for when
D's front end is in D.
