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Embedding one language in another

Assembly code can be embedded in C code. Are there examples of a higher level programming language which could embed another high level programming language. HTML and javascipt does not count ;-)

By sudarshan at 2005-03-15 19:24 | LtU Forum | previous forum topic | next forum topic | other blogs | 9164 reads

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C is embedded in my language Kogut similarly to assembler being embedded in C. Example:
http://cvs.sourceforge.net/viewcvs.py/kokogut/kokogut/lib/Network/Network/Sockets/GetAddrInfo.ko?view=markup

By Qrczak at Tue, 2005-03-15 20:00 | login or register to post comments

Inline::*

Perl has a package that handles writing code in another language, calling its compiler/interpreter, and making that code available. I'm pretty sure it's usually used for C.

See here: http://search.cpan.org/~ingy/Inline-0.44/

By joel at Tue, 2005-03-15 20:05 | login or register to post comments

Critcl

Tcl has a similar tool called Critcl:

http://www.equi4.com/critcl.html

http://dedasys.com/davidw/

By David N. Welton at Tue, 2005-03-15 21:30 | login or register to post comments

Ada

Ada is very interesting when it comes to this sort of thing. Here's the RM reference. Other texts give more detailed examples.

By Ehud Lamm at Tue, 2005-03-15 20:28 | login or register to post comments

HTML and javascipt does not count?

Why not? Seems a variation on the theme of Turing completeness: any language that can be represented as text can be emitted from any other language for subsequent execution/interpretation.
I admit with some shame ;) that I've written some ascii-disasters that generated garbled bits of JavaScript and some SQL within VBScript, in the name of spreading the work across client, web-, and database-server.
The J2EE people are embedding a lot of Java in XML, using reflection to skirt the issue that Java is a compiled language, not a scripting language. Ahem.
Conceptually, I think that the latest C++ template metaprogramming developments over on boost.org might be considered to be implementing a functional language within a compiled one, but I'm nowhere near cool enough to grasp the fullness of all that.
Then there is this gem:
fxsl, about which I am highly curious; can anyone relate experience with it?

By Chris at Tue, 2005-03-15 20:31 | login or register to post comments

some work on foreign interfaces

ML

Norman Ramsey: Embedding an Interpreted Language Using Higher-Order Functions and Types

Nick Benton: Embedded Interpreters

PLT Scheme

Eli Barzilay, Dmitry Orlovsky: Foreign Interface for PLT Scheme

Paul Steckler: MysterX: A Scheme Toolkit for Building Interactive Applications with COM

Haskell

Simon Peyton Jones: Tackling the Awkward Squad: Monadic Input/Output, Concurrency, Exceptions, and Foreign-Language Calls in Haskell

More

google://lambda-the-ultimate.org/foreign+interface

By Dave Herman at Tue, 2005-03-15 22:24 | login or register to post comments

A rather obscure example

Do you recall cayenne, the dependently typed programming language? It was implemented in a rather awkward language called Lazy ML or just lml for short. lml was a precursor to Haskell and the hbc compiler used the lml compiler as a backend. Well, you could embed lml into your cayenne code. So that's embedding a very high level language into and even higher level language :-)

By Josef Svenningsson at Tue, 2005-03-15 23:56 | login or register to post comments

Lush

Lush, a Lisp for numerical computing, allows you to mix Lisp and C in functions.

By C Rose at Wed, 2005-03-16 13:02 | login or register to post comments

Interpreters and preprocessors

Naturally, any language can be embedded in any other via one of the following mechanisms:

* Writing an interpreter for the embedded language in the host language. The host language treats the embdded source in the embedded language as data; non-trivial analysis of the embedded code is deferred until the interpreter executes.

* Use of a preprocessor/macro system to translate the embedded language into the host language. This case covers use of standalone preprocessors, macro preprocessors specified by the host language (like C preprocessor), or integrated macro systems (like Lisp/scheme has). SQL used to be done this way. Since we allow use of standalone preprocessors, any language can be obviously metaprogrammed in this fashion.

* Use of directives defined within the host language to embed code fragments of a different language. This is, I suspect, what the original poster meant--the "asm" block is a separate syntactic construct in C, and thus a fundamental part of the language. (Of course, asm directives do very little checking on the specified opcodes, merely passing them down to the assembler).

Two other common ways of mixing code (whether these constitute "embedding", as the source written in different languages is segregated in these last cases) are:

* Use of foreign function interfaces--whether simple things like extern "C" or JNI, or complicated beasts like RMI

* Use of compenent frameworks/architectures designed for inter-language use.

By Scott Johnson at Wed, 2005-03-16 20:02 | login or register to post comments

Quines and polyglots

Somewhat related topics are quines (programs that output themselves) and polyglots (programs that behave observationally identically in different PLs).

By Andris Birkmanis at Thu, 2005-03-17 12:20 | login or register to post comments

Not to be a wet blanket...

...but is there any real importance to quines and polyglots, or are tese in the category of amusing/cool hacks that are otherwise uninteresting from a theoretical and/or practical viewpoint? Especially for PL designers?

By Scott Johnson at Thu, 2005-03-17 20:58 | login or register to post comments

Well, if your PL that you designed is HQ9+

then quines are a large consideration. :-)

Personally I'd rather see an eval/apply contest wherein the source code becomes self compiling.

By Chris Rathman at Thu, 2005-03-17 21:17 | login or register to post comments

Metaprogramming

I think of quines as a kind of fixed points of meta-programming.

Both them and polyglots are good for exploring the PL in a bit unusual perspective, but that's a personal opinion. I don't see any formal importance, but then again I don't believe in the ideal of pure formality.

By Andris Birkmanis at Fri, 2005-03-18 09:39 | login or register to post comments

Sort of

Polyglots are primarily a curio, although they *may* be instructive with regards to ways of embedding one language inside another.

Quines, on the other hand, give some insight into the metaprogramming ability of a language. It is no coincidence that lisp (or, in fact, lambda calculus) has one of the smallest quines around:
((LAMBDA (X) `(,X ',X)) '(LAMBDA (X) `(,X ',X)))

By Marcin Tustin at Fri, 2005-03-18 14:06 | login or register to post comments

Biology

...is there any real importance to quines and polyglots...

The best example of a quine I can think of is the DNA program running on your personal "cell" hardware. And I suppose a cross-species virus is somewhat similar to a polyglot.

By Greg Buchholz at Tue, 2005-03-22 16:08 | login or register to post comments

There are real uses...

I actually did a quine that had a real, practical use. I was writing a script that performed a random drawing of people to win a prize. In order to create a paper trail and make sure that everything was above-board, I had the program print itself out as part of the listing.

By Jonathan Tang at Wed, 2005-03-23 20:57 | login or register to post comments

Linking to Quines and polyglots

Hi Andreas,

Just a note: best to link to Wikipedia itself, not a syndicate like answers.com unless you have a particular reason. So Quines and polyglots, version #2.

By Charles A Stewart at Fri, 2005-03-18 23:00 | login or register to post comments

Metaprogramming example

http://dslengine.sourceforge.net/

http://arxiv.org/abs/cs.PL/0409016

By Mauhuur at Wed, 2005-03-23 17:34 | login or register to post comments

Another example

Oracle preprocessors like Pro*C, Pro*Fortran, ...

By Mauhuur at Thu, 2005-03-24 15:05 | login or register to post comments

Embedding one language in another

Is this related to integration between langauges in different language "paradigms"?

An example of integrating a functional language to a logical language is the programming language Mercury. Mercury achieves this by being a logical language at base, and providing a little sugaring that gives a functional notation that exhibits indeed functional semantics.

An opposite approach seems possible, althogh perhaps not so easy, of having a language be functional at base and implementing logic within it and providing any syntactic sugaring that would be necessary to make the logic convenient to write in.

Is there any reason to prefer the approach that puts functional programming at the base over the approach that puts logic programming at the base?

Would an integration where each language thinks it is simulating the other be a worthwhile goal? Would achieving it require a conceptual infinite tower of interpreters?

By Jack Waugh at Thu, 2005-03-24 15:50 | login or register to post comments

Functional/Logic integration

Is there any reason to prefer the approach that puts functional programming at the base over the approach that puts logic programming at the base?

The fact that functional programs are relational but relational programs aren't functional. But there are functional logic languages that emphasize the functional aspect over the logic aspect, e.g. Curry

Would an integration where each language thinks it is simulating the other be a worthwhile goal?

Probably not, I don't see what it buys the user. A language where there doesn't appear to be two (or more) languages seems more worthwhile.

Would achieving it require a conceptual infinite tower of interpreters?

Refci!

By Derek Elkins at Thu, 2005-03-24 19:10 | login or register to post comments