Search found 613 matches

by ramarren
Mon Jan 19, 2009 1:11 am
Forum: Common Lisp
Topic: [newbie] evaluating a list as an expression
Replies: 5
Views: 6021

Re: [newbie] evaluating a list as an expression

However, in the ultimate program, the expressions sent to this function will contain only logical functions (AND, OR, and NOT), so compiling will probably do more harm than good in this case. Is there a way to get this to work without using COMPILE or EVAL? For constricted languages like that an in...
by ramarren
Sun Jan 18, 2009 2:17 am
Forum: Common Lisp
Topic: [newbie] evaluating a list as an expression
Replies: 5
Views: 6021

Re: [newbie] evaluating a list as an expression

First, why are you even trying to do that? It is generally recommended that you don't use EVAL, or for that matter PROGV, unless you know exactly what you are doing. And what are you trying to achieve anyway? PROGV establishes dynamic bindings, and I can't tell if this is what you want... in any cas...
by ramarren
Fri Jan 16, 2009 5:13 am
Forum: Common Lisp
Topic: A "declare" form returned by macro
Replies: 19
Views: 18330

Re: A "declare" form returned by macro

In my opinion, if it is not clear on a glance what arguments the function accepts, then it is either too long or the arguments are badly named. At least for simple types, and more complex things are best put into CLOS objects and operated upon with generic functions, which have something quite close...
by ramarren
Wed Jan 14, 2009 12:49 pm
Forum: Common Lisp
Topic: Implication problem
Replies: 3
Views: 4105

Re: Implication problem

I hear that more and more places are dropping Lisp as a teaching language and replacing it with Python/Ruby, or in the worst case go all Java all the way, although those don't really qualify as computer science in my opinion. I studied physics anyway, and what programming there is is mostly C++/Fort...
by ramarren
Wed Jan 14, 2009 2:16 am
Forum: Common Lisp
Topic: Implication problem
Replies: 3
Views: 4105

Re: Implication problem

This sounds like homework, which I suppose is a good thing because it means that someone somewhere is teaching Lisp ;) Anyway, what you want here is backward chaining . How much Lisp do you know? It is hard to give just a bit of code without giving a full solution, and that is usually counterproduct...
by ramarren
Sun Jan 11, 2009 4:49 am
Forum: Common Lisp
Topic: Crosscompiling Linux->Windows
Replies: 7
Views: 11941

Re: Crosscompiling Linux->Windows

I'm going to do all my development on Linux. I hate working on Windows. Currently, there is only one reason I can't recompile CL code on SBCL running on Windows: I'm unable to install anything using asdf-install on Windows. It just doesn't work (out-of-the-box). Note that asdf-install doesn't reall...
by ramarren
Sun Jan 11, 2009 4:36 am
Forum: The Lounge
Topic: How does defmacro expansion in Scheme and Common Lisp work?
Replies: 2
Views: 4663

Re: How does defmacro expansion in Scheme and Common Lisp work?

First, Scheme, as a language, doesn't have defmacro. I have never really looked into Scheme, but this is usually brought up as one of more important differences between Scheme and CL, that Scheme has a system of pattern substitution hygienic macros, which are more complex, but avoid variable capture...
by ramarren
Sat Jan 03, 2009 10:35 am
Forum: Common Lisp
Topic: Sorting big arrays
Replies: 2
Views: 5968

Re: Sorting big arrays

I would guess that sorting in Perl is implemented in C, so high performance there is not that surprising. I might be wrong, but this seems typical for scripting languages. In any case I believe the problem is the cost of funcalling the predicate, which additionally loses context. That is, note that ...
by ramarren
Wed Dec 31, 2008 4:05 pm
Forum: Common Lisp
Topic: REPL problems in Lisp
Replies: 12
Views: 11447

Re: REPL problems in Lisp

I think SICP (http://mitpress.mit.edu/sicp/full-text/book/book.html) goes a bit into evaluation and quoting... see for example chapter 4.1 The Metacircular Evaluator. Note that SICP uses a variant of Scheme, but concepts are similar.

Happy new year.
by ramarren
Wed Dec 31, 2008 12:51 pm
Forum: Common Lisp
Topic: REPL problems in Lisp
Replies: 12
Views: 11447

Re: REPL problems in Lisp

I say again: by separating the (write (eval (read))) expression by hand you are injecting additional evaluation. (read-from-string "'(a b)") will result in an object whose printable/readable syntax is '(A B), but you cannot just write (eval '(a b)) and expect it to work, because it will be evaluated...