In the first version (+ 1 2 3) is raw code, whereas in the second version it is data. By assuming the truth of this statement it can be argued that Lisp isn’t even homiconic. The code has the same representation as data in the sense that they are both lists/trees/S-expressions. But the fact that … Read more
It means “code as data” which is a general characteristic of Lisp family. (add 2 3) Just like above string, which is both a list and also a function call. The “Homo” prefix stands for this characteristic.
In the words of Bill Clinton, “It depends upon what the meaning of the word ‘is’ is”. Well, ok, not really, but it does depend on what the meaning of the word “homoiconic” is. This term is sufficiently controversial that we no longer say that Julia is homoiconic – so you can decide for yourself whether … 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
To give the short answer, macros are used for defining language syntax extensions to Common Lisp or Domain Specific Languages (DSLs). These languages are embedded right into the existing Lisp code. Now, the DSLs can have syntax similar to Lisp (like Peter Norvig’s Prolog Interpreter for Common Lisp) or completely different (e.g. Infix Notation Math … Read more