<html><head><meta http-equiv="Content-Type" content="text/html charset=iso-8859-1"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Anton,<div><br></div><div>I've just managed to host much of the ECL Common Lisp code on a C++ core that was built completely from scratch.</div><div>I just got ECL-CLOS and generic function dispatching to compile and run a few days ago.</div><div>I've exposed the LLVM C++ library to Common Lisp and written a new self-hosting compiler in CL.</div><div>I also wrote an S-expression walking CL interpreter to bootstrap the compiler.</div><div><br></div><div>It's taken me about a year working about 8 hours a day. It's my first time and I have no previous experience with Common Lisp.</div><div><br></div><div>Juanjo is absolutely correct, it's the interactions of the CL code with the lower level code that require a lot of time to implement properly. </div><div>This involves a lot of implementation dependent stuff that are not described in the CL standard.</div><div><br></div><div>When I started seriously trying to host the ECL code I had Juanjo's excellent ECL C-code to help me understand what the low-level functionality did. </div><div><br></div><div>Also, very important details like lexical environments are not described at all well in the CL standard and you need to do a lot of code refactoring to get something that works properly in the end.</div><div><br></div><div>Also, tracking down subtle bugs that I introduced because I didn't exactly implement standard Common Lisp behavior the first, second or third time around has taken a lot of my time.</div><div><br></div><div>Best,</div><div><br></div><div>.Chris.</div><div><br></div><div><br></div><div><br><div><div>On Apr 18, 2013, at 9:10 AM, Juan Jose Garcia-Ripoll <<a href="mailto:juanjose.garciaripoll@gmail.com">juanjose.garciaripoll@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Apr 17, 2013 at 9:55 PM, Anton Vodonosov <span dir="ltr"><<a href="mailto:avodonosov@yandex.ru" target="_blank">avodonosov@yandex.ru</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div id=":xh">In theory CL core consists of 25 special operators + build-in data types. Everything else<br>
is a library. So when porting to a new platform, theoretically, all we need to reimplement<br>
is a compiler understanding 25 operators + some build-in functions representing datatypes<br>
(make-array, aref, cons, etc) and some basic reader, allowing to read the source code of the library.<br></div></blockquote><div><br></div><div style="">That is indeed the theory. In practice much of the library deals with operating system stuff: memory allocation, files, etc. That forces a low level implementation of several core structures. Moreover, several functions are critical for performance and are also hard-coded to make bootstrapping faster.</div>
<div> </div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div id=":xh">
How close this theoretical view to practice? We now have several open-source CL implementations.<br>
If one wants to create a Javascript port, what else he must be prepared to solve?<br></div></blockquote></div><br>ECL is pretty well isolated: the C library works like the lisp API and offers a number of functions that one may start with. Many of those functions could _nowadays_ be ported back to Common Lisp, using the fact that the compiler is more efficient. But there are critical things, such as the filesystem, running processes, or I/O operations, that would be hard to implement from scratch.<br>
<br clear="all"><div style="">Perhaps Christian could comment, given that he is using the ECL Common Lisp base to implement a LLVM-based Common Lisp implementation</div><div style=""><br></div><div style="">Juanjo</div><div><br></div>
-- <br>Instituto de Física Fundamental, CSIC<br>c/ Serrano, 113b, Madrid 28006 (Spain) <br><a href="http://juanjose.garciaripoll.googlepages.com/" target="_blank">http://juanjose.garciaripoll.googlepages.com</a>
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