tvl-depot/third_party/lisp/alexandria/symbols.lisp

65 lines
2.4 KiB
Common Lisp

(in-package :alexandria)
(declaim (inline ensure-symbol))
(defun ensure-symbol (name &optional (package *package*))
"Returns a symbol with name designated by NAME, accessible in package
designated by PACKAGE. If symbol is not already accessible in PACKAGE, it is
interned there. Returns a secondary value reflecting the status of the symbol
in the package, which matches the secondary return value of INTERN.
Example:
(ensure-symbol :cons :cl) => cl:cons, :external
"
(intern (string name) package))
(defun maybe-intern (name package)
(values
(if package
(intern name (if (eq t package) *package* package))
(make-symbol name))))
(declaim (inline format-symbol))
(defun format-symbol (package control &rest arguments)
"Constructs a string by applying ARGUMENTS to string designator CONTROL as
if by FORMAT within WITH-STANDARD-IO-SYNTAX, and then creates a symbol named
by that string.
If PACKAGE is NIL, returns an uninterned symbol, if package is T, returns a
symbol interned in the current package, and otherwise returns a symbol
interned in the package designated by PACKAGE."
(maybe-intern (with-standard-io-syntax
(apply #'format nil (string control) arguments))
package))
(defun make-keyword (name)
"Interns the string designated by NAME in the KEYWORD package."
(intern (string name) :keyword))
(defun make-gensym (name)
"If NAME is a non-negative integer, calls GENSYM using it. Otherwise NAME
must be a string designator, in which case calls GENSYM using the designated
string as the argument."
(gensym (if (typep name '(integer 0))
name
(string name))))
(defun make-gensym-list (length &optional (x "G"))
"Returns a list of LENGTH gensyms, each generated as if with a call to MAKE-GENSYM,
using the second (optional, defaulting to \"G\") argument."
(let ((g (if (typep x '(integer 0)) x (string x))))
(loop repeat length
collect (gensym g))))
(defun symbolicate (&rest things)
"Concatenate together the names of some strings and symbols,
producing a symbol in the current package."
(let* ((length (reduce #'+ things
:key (lambda (x) (length (string x)))))
(name (make-array length :element-type 'character)))
(let ((index 0))
(dolist (thing things (values (intern name)))
(let* ((x (string thing))
(len (length x)))
(replace name x :start1 index)
(incf index len))))))