• Andrey (10/50) Oct 08 2017 Hello, I'm trying to figure it out how dmd compiler is working
• Andrey (2/2) Oct 08 2017 I understood, I need to read the op field from expression and
• Jacob Carlborg (7/11) Oct 09 2017 You can have a look here [1]. This looks for the @selector("foo") UDA on...

Andrey <andrey kabylin.ru> writes:

Hello, I'm trying to figure it out how dmd compiler is working 
and using his parser and tools for my little utility, I learned 
how to parse a file and working with parsed data via visitor, I 
wrote this:
 class CollectVisitor : TransitiveVisitor {
     override void visit(ASTBase.Import imp) {
         writeln();
         writeln("visit import");
     }
 
     override void visit(ASTBase.StructDeclaration d) {
         writeln();
         writeln("visit struct");
     }
 
     override void visit(ASTBase.UserAttributeDeclaration d) {
         writeln();
         writeln("visit attribute");
         writeln("attributes:");
 
         foreach (a; *d.atts) {
             // How can I here read data from a?
         }
 
         writeln("declarations:");
         foreach (s; *d.decl) {
             writeln("  ", s.ident.toString());
         }
     }
 }

I'm trying to parse this file:
  Tag
  Tag1
 struct A {
     void greet() {
         writeln("Hello world!");
     }
 }
 
  Tag
 struct B {
     void greet() {
         writeln("Hello world!");
     }
 }

I can parse it, and read some data from structs (so far only 
name), but how can I retrieve some info from UDAs? e.g. name? 
atts is array of expressions, but I don't understand how retrieve 
something from expression (I need name of attribute and its 
parameters).

Andrey <andrey kabylin.ru> writes:

I understood, I need to read the op field from expression and 
cast to needed expression type

Jacob Carlborg <doob me.com> writes:

On 2017-10-08 10:12, Andrey wrote:

 I can parse it, and read some data from structs (so far only name), but 
 how can I retrieve some info from UDAs? e.g. name? atts is array of 
 expressions, but I don't understand how retrieve something from 
 expression (I need name of attribute and its parameters).

You can have a look here [1]. This looks for the  selector("foo") UDA on 
a method declaration, extracts the string "foo" and stores it for later 
processing.

[1] https://github.com/dlang/dmd/blob/master/src/ddmd/objc.d#L199

-- 
/Jacob Carlborg