In Scheme and Racket, a symbol is like an immutable string that happens to be interned so that symbols can be compared with eq? (fast, essentially pointer comparison). Symbols and strings are separate data types. One use for symbols is lightweight enumerations. For example, one might say a direction is either ‘north, ‘south, ‘east, or … Read more
PLT Scheme features a built-in, continuation-based web server. Update: PLT Scheme is now called Racket.
CL-PPCRE is often cited as a good example, for good reason. Actually, probably any of Edi Weitz’s libraries will make good reading, but CL-PPCRE is particularly clever and it’s a useful and impressive library. Beyond that a lot of CL implementations are written mostly in CL. It can be pretty productive to pick some part … Read more
Lisp users refer to Lisp as the programmable programming language. It is used for symbolic computing – computing with symbols. Macros are only one way to exploit the symbolic computing paradigm. The broader vision is that Lisp provides easy ways to describe symbolic expressions: mathematical terms, logic expressions, iteration statements, rules, constraint descriptions and more. … Read more
The Lisp community is fragmented, but everything else is too. Why are there so many Linux distributions? Why are there so many BSD variants? OpenBSD, NetBSD, FreeBSD, … even Mac OS X. Why are there so many scripting languages? Ruby, Python, Rebol, TCL, PHP, and countless others. Why are there so many Unix shells? sh, … Read more
I like macros. Here’s code to stuff away attributes for people from LDAP. I just happened to have that code lying around and fiigured it’d be useful for others. Some people are confused over a supposed runtime penalty of macros, so I’ve added an attempt at clarifying things at the end. In The Beginning, There … Read more
Racket has everything that you need. See the Racket web server tutorial and then the documentation. The web server has been around for a while, and it has a lot of features. Probably the only thing that is not included is a mysql interface, but that exists as a package on PLaneT (Racket package distribution … Read more
I would propose reading ‘Practical Common Lisp’, since it already answers some of your questions. There are probably three to four books you should read: Basic introduction to Common Lisp: Common Lisp: A Gentle Introduction to Symbolic Computation Practical introduction to Common Lisp: Practical Common Lisp More advanced Common Lisp: Paradigms of Artificial Intelligence Programming: … Read more
LET itself is not a real primitive in a Functional Programming Language, since it can replaced with LAMBDA. Like this: (let ((a1 b1) (a2 b2) … (an bn)) (some-code a1 a2 … an)) is similar to ((lambda (a1 a2 … an) (some-code a1 a2 … an)) b1 b2 … bn) But (let* ((a1 b1) (a2 … Read more
In Lisp, a linked list element is called a CONS. It is a data structure with two elements, called the CAR and the CDR for historical reasons. (Some Common Lisp programmers prefer to refer to them using the FIRST and REST functions, while others like CAR and CDR because they fit well with the precomposed … Read more