+(require 'alist)
+
+(defvar calist-package-alist nil)
+(defvar calist-field-match-method-obarray nil)
+
+(defun find-calist-package (name)
+ "Return a calist-package by NAME."
+ (cdr (assq name calist-package-alist)))
+
+(defun define-calist-field-match-method (field-type function)
+ "Set field-match-method for FIELD-TYPE to FUNCTION."
+ (fset (intern (symbol-name field-type) calist-field-match-method-obarray)
+ function))
+
+(defun use-calist-package (name)
+ "Make the symbols of package NAME accessible in the current package."
+ (mapatoms (lambda (sym)
+ (if (intern-soft (symbol-name sym)
+ calist-field-match-method-obarray)
+ (signal 'conflict-of-calist-symbol
+ (list (format "Conflict of symbol %s")))
+ (if (fboundp sym)
+ (define-calist-field-match-method
+ sym (symbol-function sym))
+ )))
+ (find-calist-package name)))
+
+(defun make-calist-package (name &optional use)
+ "Create a new calist-package."
+ (let ((calist-field-match-method-obarray (make-vector 7 0)))
+ (set-alist 'calist-package-alist name
+ calist-field-match-method-obarray)
+ (use-calist-package (or use 'standard))
+ calist-field-match-method-obarray))
+
+(defun in-calist-package (name)
+ "Set the current calist-package to a new or existing calist-package."
+ (setq calist-field-match-method-obarray
+ (or (find-calist-package name)
+ (make-calist-package name))))
+
+(in-calist-package 'standard)
+
+(defun calist-default-field-match-method (calist field-type field-value)
+ (let ((s-field (assoc field-type calist)))
+ (cond ((null s-field)
+ (cons (cons field-type field-value) calist)
+ )
+ ((eq field-value t)
+ calist)
+ ((equal (cdr s-field) field-value)
+ calist))))
+
+(define-calist-field-match-method t (function calist-default-field-match-method))
+
+(defsubst calist-field-match-method (field-type)
+ (symbol-function
+ (or (intern-soft (if (symbolp field-type)
+ (symbol-name field-type)
+ field-type)
+ calist-field-match-method-obarray)
+ (intern-soft "t" calist-field-match-method-obarray))))
+
+(defsubst calist-field-match (calist field-type field-value)
+ (funcall (calist-field-match-method field-type)
+ calist field-type field-value))
+