I'm new to Lisp and I'm currently trying to redo an old UCI Lisp program in Common Lisp. I'm having the following problem when I copy the following code (in funcs.lisp):
;;; HEADER-CD gets the head act of a CD form.
(defun header:cd
(x)
(car x))
The interpreter issues this error:
- READ from #<INPUT BUFFERED FILE-STREAM CHARACTER #P"funcs.lisp" @11>: there is no package
with name "HEADER"
I do not understand the purpose for the colon in the code but I am guessing it's to specify the type of acceptable input since there is another function called "header:pair".
I'm not sure how to resolve this. Perhaps I could move to UCI lisp but I can't find its compiler/interpreter. Kindly help.
I don't think the colon in UCI Lisp for header:cd has any specific technical meaning. It's just an identifier and identifiers in UCI Lisp probably can (could -> it's a Lisp from the 70s which is no longer in use) use most of the ASCII character set, including the colon :. Here it might be a coding convention.
In Common Lisp the colon character has a special technical meaning in identifiers: it separates the package name from the symbol name. Note that UCI Lisp had no such feature as symbol packages.
Thus, I would simply translate an UCI-Lisp-identifier header:cd to header-cd in Common Lisp.
A slightly less useful way is to translate the UCI-Lisp-identifier header:cd to |HEADER:CD| or HEADER\:CD in Common Lisp. The vertical bars escape the symbol. The backslash escapes a single character in a symbol.
CL-USER 3 > '|HEADER:CD|
HEADER\:CD
CL-USER 4 > (symbol-name '|HEADER:CD|)
"HEADER:CD"