Re: Augusta: An open source Ada 2012 compiler (someday?)

["Peter C. Chapin" <PChapin@vtc.vsc.edu>]

On 03/27/2014 05:51 PM, Niklas Holsti wrote:

> More interesting to me would be work towards making Ada compiler
> implementation easier. It seems to me that progress in formal methods,
> functional and declarative languages, and computer power, since the
> 80's, should make it possible...

One reason why I choose Scala as an implementation language for Augusta 
is because I wanted to see if I could productively take advantage of 
Scala's functional features when writing a serious compiler. As much as 
I like Ada, I don't think Ada is the most wonderful compiler 
implementation language imaginable.

For example Scala's algebraic data types and pattern matching make 
processing trees quite enjoyable and compilers tend to use a lot of 
trees. Also Scala has good support for creating what the community calls 
"internal domain specific languages." See for example Graph for Scala 
(http://www.scala-graph.org/), a library for manipulating graphs 
(perhaps control flow graphs?) in a arguably elegant way. Finally, of 
course, there might be interesting ways to use higher order functions. I 
won't know until I try.

My intention has also been to use LLVM or something similar (C, the JVM, 
etc) as a back end to reduce the amount of work involved in actually 
getting executable code generated. I understand it is still necessary to 
generate code for whatever target I use, but the targets above are all 
higher level than machine language and so (I anticipate) easier to manage.

Peter