Look at AdaScript and BUSH:  <http://www.vaxxine.com/pegasoft/bush-down.html>.

BUSH is an interactive shell for Linux with both Bourne and Ada syntax.
AdaScript is a subset of the Ada 95 language with additional features
specifically for interactive shell sessions.

The BUSH distribution includes the scanner and parser source code.
Whether or not it is based on lex/yacc or alex/ayacc, I don't know.

--
Terry Westley
[log in to unmask]

> -----Original Message-----
> From: Team Ada: Ada Advocacy Issues (83 & 95)
> [mailto:[log in to unmask]]On Behalf Of Sergei Lodyagin
> Sent: Wednesday, December 19, 2001 9:04 AM
> To: [log in to unmask]
> Subject: Generator of parsers for Ada ?
>
>
> Good day to all subscribers.
>
> We would like to implement a small compiler for Ada - like language
> (it will be small Ada language subset with may be some specific extensions).
>
> We are looking for tools like LEX/YACC  which
> can generate Ada lexer/parser. According to our wishes, these tools
> should generate
> GOOD Ada code, i.e. it shouldn't be C code which can be compiled by Ada
> compiler
> but real good style Ada code.
>
> Ideally these tools themselves should be example of good easy-to-support
> Ada code.
>
> Are there such tools ?
>
> Sergei Lodyagin,
> Programmer.