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digitalmars.D - Various documentation questions

reply Bernard Helyer <b.helyer gmail.com> writes:
I may be trying to write a D2 compiler in D2 (you can't prove 
anything!), it's early days, but I've run into a few things I'd like 
clarification on. This won't be the last of these posts, I'm sure of it! *g*

I'm not sure what are bugs, in documentation, in DMD, and in my 
understanding.


---

http://www.digitalmars.com/d/2.0/module.html#ModuleDeclaration

"module (system) ModuleFullyQualifiedName ;"

This syntax is not accepted by DMD.

---

http://www.digitalmars.com/d/2.0/module.html#ImportDeclaration

"static import ImportList ;"

is listed specifically, but static can be found under

http://www.digitalmars.com/d/2.0/attribute.html#AttributeSpecifier

which can have a DeclarationBlock afterward, which would include a 
single import statement, so surely the former is tautological?

---

http://www.digitalmars.com/d/2.0/lex.html#keyword

where do the  keywords fall?

---

http://www.digitalmars.com/d/2.0/lex.html#tokens

There is no '**' token listed. I assume this is an omission (and lex it 
as a separate token in SDC, and not two '*'s).

---

http://www.digitalmars.com/d/2.0/expression.html#PostfixExpression

"PostfixExpression . NewExpression"

Where is that valid?

---

http://www.digitalmars.com/d/2.0/expression.html#UnaryExpression

"( Type ) . Identifier"

why is that significant?

---
Jun 05 2010
next sibling parent reply bearophile <bearophileHUGS lycos.com> writes:
Bernard Helyer Wrote:


 I may be trying to write a D2 compiler in D2 (you can't prove 
 anything!), it's early days,


:-)



 http://www.digitalmars.com/d/2.0/lex.html#tokens
 
 There is no '**' token listed. I assume this is an omission (and lex it 
 as a separate token in SDC, and not two '*'s).


What is ** for?

Bye,
bearophile
Jun 05 2010
parent Bernard Helyer <b.helyer gmail.com> writes:
On 06/06/10 01:27, bearophile wrote:

 Bernard Helyer Wrote:


 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!), it's early days,


 :-)



 http://www.digitalmars.com/d/2.0/lex.html#tokens

 There is no '**' token listed. I assume this is an omission (and lex it
 as a separate token in SDC, and not two '*'s).


 What is ** for?

 Bye,
 bearophile


Sorry, thinking in python. :o
Jun 05 2010
prev sibling next sibling parent Bernard Helyer <b.helyer gmail.com> writes:
On 06/06/10 01:22, Bernard Helyer wrote:

 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!), it's early days, but I've run into a few things I'd like
 clarification on. This won't be the last of these posts, I'm sure of it!
 *g*

 I'm not sure what are bugs, in documentation, in DMD, and in my
 understanding.


 ---

 http://www.digitalmars.com/d/2.0/lex.html#tokens

 There is no '**' token listed. I assume this is an omission (and lex it
 as a separate token in SDC, and not two '*'s).

 ---


I was thinking Python. The exponentiation operator is '^^' and is also 
not listed as its own token (I made the same mistake in my lexer as I 
did in the post! I've got to fix it now! :D).
Jun 05 2010
prev sibling parent reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 06/05/2010 08:22 AM, Bernard Helyer wrote:

 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!),


ditto, except mine is in java

it's early days, but I've run into a few things I'd like

 clarification on. This won't be the last of these posts, I'm sure of it!
 *g*

 I'm not sure what are bugs, in documentation, in DMD, and in my
 understanding.


 ---

 http://www.digitalmars.com/d/2.0/module.html#ModuleDeclaration

 "module (system) ModuleFullyQualifiedName ;"

 This syntax is not accepted by DMD.

 ---

 http://www.digitalmars.com/d/2.0/module.html#ImportDeclaration

 "static import ImportList ;"

 is listed specifically, but static can be found under

 http://www.digitalmars.com/d/2.0/attribute.html#AttributeSpecifier

 which can have a DeclarationBlock afterward, which would include a
 single import statement, so surely the former is tautological?


from my reading, I don't think this is the case in dmd. It does 
literally parse 'static import'. same with static if, static assert, and 
maybe some others. I don't know, but I suspect that stuff like

static public import blah;

wouldn't give you a static import. I also don't know whether it would be 
reasonable to make it work like that. The trouble is static means 
something else for other declarations.

Something like

static:
...
import blah;

In the parser that I currently have, it would be rather obnoxious to 
tell the difference between that and 'static import blah;'. Well, maybe not.


 ---

 http://www.digitalmars.com/d/2.0/lex.html#keyword

 where do the  keywords fall?


' ' is a token which should be followed by an identifier


 ---

 http://www.digitalmars.com/d/2.0/lex.html#tokens

 There is no '**' token listed. I assume this is an omission (and lex it
 as a separate token in SDC, and not two '*'s).

 ---

 http://www.digitalmars.com/d/2.0/expression.html#PostfixExpression

 "PostfixExpression . NewExpression"

 Where is that valid?


I remember thinking the same thing.

class A{
     class B{
         string s;
     }
     int i;
}

void main(){
     //A.B b = new A.B; //Error: outer class A 'this' needed to 'new' 
nested class B
     A a = new A;
     A.B b = a.new B;
}


 ---

 http://www.digitalmars.com/d/2.0/expression.html#UnaryExpression

 "( Type ) . Identifier"

 why is that significant?

 ---


I suppose it's a bid to reduce the amount of incorrect parsing that 
would result from

Type . Identifier

And to its credit, I don't think I have come across any trouble with it.
Jun 05 2010
parent reply Bernard Helyer <b.helyer gmail.com> writes:
On 06/06/10 03:26, Ellery Newcomer wrote:

 On 06/05/2010 08:22 AM, Bernard Helyer wrote:

 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!),


 ditto, except mine is in java


Awesome! :)



 http://www.digitalmars.com/d/2.0/module.html#ImportDeclaration

 "static import ImportList ;"

 is listed specifically, but static can be found under

 http://www.digitalmars.com/d/2.0/attribute.html#AttributeSpecifier

 which can have a DeclarationBlock afterward, which would include a
 single import statement, so surely the former is tautological?


 from my reading, I don't think this is the case in dmd. It does
 literally parse 'static import'. same with static if, static assert, and
 maybe some others. I don't know, but I suspect that stuff like

 static public import blah;

 wouldn't give you a static import. I also don't know whether it would be
 reasonable to make it work like that. The trouble is static means
 something else for other declarations.

 Something like

 static:
 ...
 import blah;

 In the parser that I currently have, it would be rather obnoxious to
 tell the difference between that and 'static import blah;'. Well, maybe
 not.


Okay, I see.



 ---

 http://www.digitalmars.com/d/2.0/lex.html#keyword

 where do the  keywords fall?


 ' ' is a token which should be followed by an identifier


I did not know that. Thanks!



 http://www.digitalmars.com/d/2.0/expression.html#PostfixExpression

 "PostfixExpression . NewExpression"

 Where is that valid?


 I remember thinking the same thing.

 class A{
 class B{
 string s;
 }
 int i;
 }

 void main(){
 //A.B b = new A.B; //Error: outer class A 'this' needed to 'new' nested
 class B
 A a = new A;
 A.B b = a.new B;
 }


Funky. Thank you for the example.


 ---

 http://www.digitalmars.com/d/2.0/expression.html#UnaryExpression

 "( Type ) . Identifier"

 why is that significant?

 ---


 I suppose it's a bid to reduce the amount of incorrect parsing that
 would result from

 Type . Identifier

 And to its credit, I don't think I have come across any trouble with it.


Maybe I'm having a slow morning, but I can't really grok that. Could you 
elaborate? Speak slowly. :)
Jun 05 2010
parent reply Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 06/05/2010 08:16 PM, Bernard Helyer wrote:

 On 06/06/10 03:26, Ellery Newcomer wrote:

 On 06/05/2010 08:22 AM, Bernard Helyer wrote:

 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!),


 ditto, except mine is in java


 Awesome! :)


No. Java isn't. :)

Although the jvm talk bearophile linked to suggested that the jvm would 
be relatively easy to generate machine code for.


 ---

 http://www.digitalmars.com/d/2.0/expression.html#UnaryExpression

 "( Type ) . Identifier"

 why is that significant?

 ---


 I suppose it's a bid to reduce the amount of incorrect parsing that
 would result from

 Type . Identifier

 And to its credit, I don't think I have come across any trouble with it.


 Maybe I'm having a slow morning, but I can't really grok that. Could you
 elaborate? Speak slowly. :)


expressions and types are ambiguous, so any place where both can appear 
will be trouble. Consider the token string

Identifier [ Identifier ] . Identifier

does the part before the dot represent a type, or an expression? It's 
impossible to say at parse time (in the general case), and the 
programmer will have cause to use both fairly often.

And yes,

( Identifier [ Identifier ] ) . Identifier

is just as ambiguous, but I think

( Expression ) . Identifier

is much less common than

Expression . Identifier

Ugh. I suppose I'm going to have to write a Type -> Expression routine 
sometime soon.
Jun 05 2010
parent reply retard <re tard.com.invalid> writes:
Sat, 05 Jun 2010 23:03:34 -0500, Ellery Newcomer wrote:


 On 06/05/2010 08:16 PM, Bernard Helyer wrote:

 On 06/06/10 03:26, Ellery Newcomer wrote:

 On 06/05/2010 08:22 AM, Bernard Helyer wrote:

 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!),


 ditto, except mine is in java


 Awesome! :)


 
 No. Java isn't. :)


Why didn't you use some modern JVM language like Clojure or Scala? You 
hate D's competitors more than Java?
Jun 06 2010
parent Ellery Newcomer <ellery-newcomer utulsa.edu> writes:
On 06/06/2010 03:15 AM, retard wrote:

 Sat, 05 Jun 2010 23:03:34 -0500, Ellery Newcomer wrote:


 On 06/05/2010 08:16 PM, Bernard Helyer wrote:

 On 06/06/10 03:26, Ellery Newcomer wrote:

 On 06/05/2010 08:22 AM, Bernard Helyer wrote:

 I may be trying to write a D2 compiler in D2 (you can't prove
 anything!),


 ditto, except mine is in java


 Awesome! :)


 No. Java isn't. :)


 Why didn't you use some modern JVM language like Clojure or Scala? You
 hate D's competitors more than Java?


I've thought about using Clojure. I suppose I've just been too lazy to 
bother learning it. Come to think of it though, it would make things 
much less painful, and I have been wishing for a pattern matching syntax 
forever.

Maybe I will when I have some time.
Jun 06 2010