information about compiler internals

Hi again,

> Is there any more documentation/information or can anybody give me
> more detailed information about the compiler (plugins)?

Some information about the compiler I found in
http://infoscience.epfl.ch/record/64423/files/ScalableComponent.pdf

Cheers,
Thomas

Thomas,

There is little documentation available in general on the compiler, but you
may find the following useful: these are two recordings of code
walk-through sessions that Martin did some time back.

http://www.scala-lang.org/sites/default/files/martin_ordersky_scala_inte...
http://www.scala-lang.org/sites/default/files/martin_ordersky_scala_inte...

The video quality is not excellent, but the information should be of use.
Hope this helps!
Toni

Thomas Pawlitzki wrote:
> Hi again,
>
>> Is there any more documentation/information or can anybody give me
>> more detailed information about the compiler (plugins)?
>
> Some information about the compiler I found in
> http://infoscience.epfl.ch/record/64423/files/ScalableComponent.pdf
>
> Cheers,
> Thomas
>

Hi Toni,

> There is little documentation available in general on the compiler, but you
> may find the following useful: these are two recordings of code walk-through
> sessions that Martin did some time back.
>
> http://www.scala-lang.org/sites/default/files/martin_ordersky_scala_inte...
> http://www.scala-lang.org/sites/default/files/martin_ordersky_scala_inte...

Thank you for this links.
I will have a look at them.

Cheers,
Thomas

Hi Thomas,
I found another link: http://lamp.epfl.ch/~emir/bqbase/2005/06/02/nscTutorial.html

Cheers, Daniel

On Fri, Jan 16, 2009 at 8:04 AM, Thomas Pawlitzki <thomas.pawlitzki@gmail.com> wrote:

Hi Toni,

> There is little documentation available in general on the compiler, but you
> may find the following useful: these are two recordings of code walk-through
> sessions that Martin did some time back.
>
> http://www.scala-lang.org/sites/default/files/martin_ordersky_scala_internals_2008-10-29.avi
> http://www.scala-lang.org/sites/default/files/martin_ordersky_scala_internals_2008-11-05.avi

Thank you for this links.
I will have a look at them.

Cheers,
Thomas

Hello Daniel,
hello all,

> I found another link:
> http://lamp.epfl.ch/~emir/bqbase/2005/06/02/nscTutorial.html

Thanks for this link.
This text contains really useful information.

I think that after reading the texts and looking at the source code I
have a dim idea of the compiler internals.

But I still miss a possibility to adapt/extend the syntax. I found the
location where the parsing is done:
compiler/scala/tools/nsc/ast/parser/Parsers
So I still don't know what to do if I want to add (for instance) a new
TopStatSeq.
I think I have to
- register a new keyword
- register a new token to the new keyword (ScannerConfiguration)
- define a new match in the Parser.topStatSeq() method to create a new AST-Node
- do my own checks and transforms with my new AST-Node

But how can I do this in a compiler plugin without hacking the
compiler sources? I think here is my gap in my moderate scala
knowledge.
I read about implicit declarations [1] but I guess this that this
would not solve my problem as with implicit I can not override
existing methods, right?

Perhaps there is someone here who can give me some concrete
information about my problem.

Thanks in advance.

Cheers,
Thomas

[1] http://www.scala-lang.org/node/114

Thomas Pawlitzki wrote:

a4df10ce0901220243k5b2cbe68u84f2c5c06fc2564e [at] mail [dot] gmail [dot] com" type="cite">

But I still miss a possibility to adapt/extend the syntax. I found the
location where the parsing is done:
compiler/scala/tools/nsc/ast/parser/Parsers
So I still don't know what to do if I want to add (for instance) a new
TopStatSeq.
I think I have to
 - register a new keyword
 - register a new token to the new keyword (ScannerConfiguration)
 - define a new match in the Parser.topStatSeq() method to create a new AST-Node
 - do my own checks and transforms with my new AST-Node

But how can I do this in a compiler plugin without hacking the
compiler sources? 

It is not presently possible to write a compiler plugin that will extend the syntax of the language.   It may be possible in the future to replace the parser phase, but for performance reasons I doubt the default parser will ever provide hooks for the kind of extension you want.  I recall someone writing a plugin that sort of works around this using XML for their syntax, but I cannot remember enough about it to find it in the mailing list archives.

-- 
[ Geoff Washburn 
| geoffrey.washburn@epfl.ch 
| http://lamp.epfl.ch/~washburn/ ]

I believe this is the thread you're talking about:

http://www.nabble.com/-scala--Extending-Scala-to15856708.html#a15856708

--j

On Thu, Jan 22, 2009 at 2:53 AM, Geoffrey Alan Washburn <geoffrey.washburn@epfl.ch> wrote:

Thomas Pawlitzki wrote:

But I still miss a possibility to adapt/extend the syntax. I found the
location where the parsing is done:
compiler/scala/tools/nsc/ast/parser/Parsers
So I still don't know what to do if I want to add (for instance) a new
TopStatSeq.
I think I have to
 - register a new keyword
 - register a new token to the new keyword (ScannerConfiguration)
 - define a new match in the Parser.topStatSeq() method to create a new AST-Node
 - do my own checks and transforms with my new AST-Node

But how can I do this in a compiler plugin without hacking the
compiler sources? 

It is not presently possible to write a compiler plugin that will extend the syntax of the language.   It may be possible in the future to replace the parser phase, but for performance reasons I doubt the default parser will ever provide hooks for the kind of extension you want.  I recall someone writing a plugin that sort of works around this using XML for their syntax, but I cannot remember enough about it to find it in the mailing list archives.

-- 
[ Geoff Washburn 
| geoffrey.washburn@epfl.ch 
| http://lamp.epfl.ch/~washburn/ ]