compiling pattern matching to point-free combinators sequence

Cyrille Duret <[email protected]> Wed, 30 Apr 2014 09:04:36 +0200
Newsgroups gmane.comp.lang.concatenative
Message-ID <CALk5yVdmzsvpMLUH7f3ng+tbLDBLUPoCsdBv3R=scyGk9ZUs9Q@mail.gmail.com>
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Content-Type: text/plain; charset=UTF-8

hello,
I have good interest in postfix concatenative languages for some years now,
I discover the postfix notation with forth and saw the beauty of joy and
now I try to experiment the benefit of a concatenative language for
distributed application, user interface ( I am thinking of a visual touch
based programming environment a bit like hopscotch
https://www.gethopscotch.com/) , etc..

My language of prototyping is javascript and my language of choice for
implementation is ATS2 (http://www.ats-lang.org/)

I have already done a conventional implementation of a very basic language
here https://github.com/cduret/stk.js , but I want to go further.
At the time I read this paper (
http://mitarbeiter.hs-heilbronn.de/~herzberg/Publications/ICSOFT.2009.pdf),
I saw the power and simplicity of a concatenative language based on a
rewriting system.

So I began my implementation of a basic rewrite system :
The words can be defined with pattern matching as follow :

x dup => x x.
x y swap => y x.
[x_] call => x_.
...

Rewriting system is powerful and can compute symbolic expression as well
but the explosion of rewriting steps can lead to slow execution time.
That's why I try to think about a compiler that would transform the
rule-based program into a stack oriented bytecode.

My first problem is to find a way of rewriting a rule with named parameters
into a point-free word (in a forth or factor meaning).

How I could compile the rule :

a b toto => a a * 3 b * +.

into

toto => 3 * swap dup * +.


I am looking for such an algorithm if you have some advices..

thank you very much ;-)

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      <p><div dir=3D"ltr">hello,<div>I have good interest in postfix concat=
enative languages for some years now, I discover the postfix notation with =
forth and saw the beauty of joy and now I try to experiment the benefit of =
a concatenative language for distributed application, user interface ( I am=
 thinking of a visual touch based programming environment a bit like hopsco=
tch <a href=3D"https://www.gethopscotch.com/">https://www.gethopscotch.com/=
</a>) , etc..</div>
<div><br></div><div>My language of prototyping is javascript and my languag=
e of choice for implementation is ATS2 (<a href=3D"http://www.ats-lang.org/=
">http://www.ats-lang.org/</a>)</div><div><br></div><div>I have already don=
e a conventional implementation of a very basic language here=C2=A0<a href=
=3D"https://github.com/cduret/stk.js">https://github.com/cduret/stk.js</a> =
, but I want to go further.</div>
<div>At the time I read this paper (<a href=3D"http://mitarbeiter.hs-heilbr=
onn.de/~herzberg/Publications/ICSOFT.2009.pdf">http://mitarbeiter.hs-heilbr=
onn.de/~herzberg/Publications/ICSOFT.2009.pdf</a>), I saw the power and sim=
plicity of a concatenative language based on a rewriting system.</div>
<div><br></div><div>So I began my implementation of a basic rewrite system =
:</div><div>The words can be defined with pattern matching as follow :</div=
><div><br></div><div><div style=3D"margin:0px;padding:0px;vertical-align:ba=
seline;font-family:Arial,Helvetica,sans-serif;font-size:13px;">
<div style=3D"margin:0px;padding:0px;vertical-align:baseline;">x dup =3D&gt=
; x x.</div></div><div style=3D"margin:0px;padding:0px;vertical-align:basel=
ine;font-family:Arial,Helvetica,sans-serif;font-size:13px;">
x y swap =3D&gt; y x.<br></div><div style=3D"margin:0px;padding:0px;vertica=
l-align:baseline;font-family:Arial,Helvetica,sans-serif;font-size:13px;">[x=
_] call =3D&gt; x_.</div></div><div style=3D"margin:0px;padding:0px;vertica=
l-align:baseline;font-family:Arial,Helvetica,sans-serif;font-size:13px;">
...</div><div style=3D"margin:0px;padding:0px;vertical-align:baseline;font-=
family:Arial,Helvetica,sans-serif;font-size:13px;"><br></div><div style=3D"=
margin:0px;padding:0px;vertical-align:baseline;font-family:Arial,Helvetica,=
sans-serif;font-size:13px;">
Rewriting system is powerful and can compute symbolic expression as well bu=
t the explosion of rewriting steps can lead to slow execution time.</div><d=
iv style=3D"margin:0px;padding:0px;vertical-align:baseline;font-family:Aria=
l,Helvetica,sans-serif;font-size:13px;">
That&#39;s why I try to think about a compiler that would transform the rul=
e-based program into a stack oriented bytecode.</div><div style=3D"margin:0=
px;padding:0px;vertical-align:baseline;font-family:Arial,Helvetica,sans-ser=
if;font-size:13px;">
<br></div><div style=3D"margin:0px;padding:0px;vertical-align:baseline;font=
-family:Arial,Helvetica,sans-serif;font-size:13px;">My first problem is to =
find a way of rewriting a rule with named parameters into a point-free word=
 (in a forth or factor meaning).</div>
<div style=3D"margin:0px;padding:0px;vertical-align:baseline;font-family:Ar=
ial,Helvetica,sans-serif;font-size:13px;"><br></div><div style=3D"margin:0p=
x;padding:0px;vertical-align:baseline;font-family:Arial,Helvetica,sans-seri=
f;font-size:13px;">
How I could compile the rule :</div><div style=3D"margin:0px;padding:0px;ve=
rtical-align:baseline;font-family:Arial,Helvetica,sans-serif;font-size:13px=
;"><br></div><div style=3D"margin:0px;padding:0px;vertical-align:baseline;f=
ont-family:Arial,Helvetica,sans-serif;font-size:13px;">
a b toto =3D&gt; a a * 3 b * +.=C2=A0<br></div><div style=3D"margin:0px;pad=
ding:0px;vertical-align:baseline;font-family:Arial,Helvetica,sans-serif;fon=
t-size:13px;"><br></div><div style=3D"margin:0px;padding:0px;vertical-align=
:baseline;font-family:Arial,Helvetica,sans-serif;font-size:13px;">
into=C2=A0</div><div style=3D"margin:0px;padding:0px;vertical-align:baselin=
e;font-family:Arial,Helvetica,sans-serif;font-size:13px;"><br></div><div st=
yle=3D"margin:0px;padding:0px;vertical-align:baseline;font-family:Arial,Hel=
vetica,sans-serif;font-size:13px;">
toto =3D&gt; 3 * swap dup * +.<br></div><div style=3D"margin:0px;padding:0p=
x;vertical-align:baseline;font-family:Arial,Helvetica,sans-serif;font-size:=
13px;"><br></div><div style=3D"margin:0px;padding:0px;vertical-align:baseli=
ne;font-family:Arial,Helvetica,sans-serif;font-size:13px;">
<br></div><div style=3D"margin:0px;padding:0px;vertical-align:baseline;font=
-family:Arial,Helvetica,sans-serif;font-size:13px;">I am looking for such a=
n algorithm if you have some advices..</div><div style=3D"margin:0px;paddin=
g:0px;vertical-align:baseline;font-family:Arial,Helvetica,sans-serif;font-s=
ize:13px;">
<br></div><div style=3D"margin:0px;padding:0px;vertical-align:baseline;font=
-family:Arial,Helvetica,sans-serif;font-size:13px;">thank you very much ;-)=
</div></div>
</p>

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