uniform-utilities

The library aims to provide a uniform way of getting things done in Common Lisp. Unlike its alpha-variant (digikar-utiliites), this does not modify the readtable, and has a single goal.

Towards this, it defines:

• getv
• getv-chained
• defdpar
• dlet*

and borrows from and iterate. (iterate is available separately on quicklisp.)

There also exists access which might be considered more uniform that getv below; however, it has a significant runtime overhead (factor of 10) and type checking seems to be at issue.

Further, there is also metabang-bind, which isn't perfect - neither is this library though.

getv

(getv object key &optional intended-type-of-object)

getv provides a uniform interface to strings, vectors, hash-tables, arrays, lists, standard objects as well as structs. On specifying intended-type-of-object, there is no runtime overhead, along with type safety of the specialized functions assocated with the data types - this is achieved using compiler-macros.

There also exists (setf getv). This, too, has compiler macros.

getv-chained

(getv-chained object &rest keys)

This allows for chaining the accessors:

CL-USER> (let ((a '((1 2 3) (4 5 6)))) 
           (getv-chained a 0 2))
3

However, unlike getv, this does not allow for any type specifiers. (There arises ambiguity with multidimensional array syntax.)

This, too, has (setf getv-chained).

Reader macros for getv-chained

Example:

(named-readtables:in-readtable uniform-utilities:getv-chained)
(defdpar str '("hello"))
[str 0 2] ; => #\l
(setf [str 0 2] #\d)
str ; => ("hedlo")

Caution: in-readtable does not seem very reliable. For instance, the following does not work as expected:

(named-readtables:in-readtable uniform-utilities:getv-chained) ; [str 0 2] works
(named-readtables:in-readtable :standard)                      ; does not work
(named-readtables:in-readtable uniform-utilities:getv-chained) ; does not work

defdpar

(defdpar &rest vars-and-val)

Example:

(flet ((foo () (values '(1 2) 3)))
   (defdpar b c (foo))      ; b is '(1 2), c is 3
   (defdpar (d e) (foo))    ; d is 1, e is 2
   (defdpar f (car (foo)))) ; f is 1

This provides a combination of destructuring with defparameter. However, lambda lists are not supported in the general case - the support is only restricted for destructuring coupled with multiple-values.

dlet*

(dlet* bindings &body body)

Example:

(dlet* (((a c) b (values '(1 3) 2))
        (d e f (values 1 2))
        ((a b) '(4 5))) 
  (list a b c d e f))
;; => (4 5 3 1 2 NIL)

Testing

(ql:quickload :uniform-utilities-test)
(prove:run-test-package :uniform-utilities-test)