tfunctions.lisp - clic - Clic is an command line interactive client for gopher written in Common LISP
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tfunctions.lisp (6645B)
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1 (in-package :alexandria)
2
3 ;;; To propagate return type and allow the compiler to eliminate the IF when
4 ;;; it is known if the argument is function or not.
5 (declaim (inline ensure-function))
6
7 (declaim (ftype (function (t) (values function &optional))
8 ensure-function))
9 (defun ensure-function (function-designator)
10 "Returns the function designated by FUNCTION-DESIGNATOR:
11 if FUNCTION-DESIGNATOR is a function, it is returned, otherwise
12 it must be a function name and its FDEFINITION is returned."
13 (if (functionp function-designator)
14 function-designator
15 (fdefinition function-designator)))
16
17 (define-modify-macro ensure-functionf/1 () ensure-function)
18
19 (defmacro ensure-functionf (&rest places)
20 "Multiple-place modify macro for ENSURE-FUNCTION: ensures that each of
21 PLACES contains a function."
22 `(progn ,@(mapcar (lambda (x) `(ensure-functionf/1 ,x)) places)))
23
24 (defun disjoin (predicate &rest more-predicates)
25 "Returns a function that applies each of PREDICATE and MORE-PREDICATE
26 functions in turn to its arguments, returning the primary value of the first
27 predicate that returns true, without calling the remaining predicates.
28 If none of the predicates returns true, NIL is returned."
29 (declare (optimize (speed 3) (safety 1) (debug 1)))
30 (let ((predicate (ensure-function predicate))
31 (more-predicates (mapcar #'ensure-function more-predicates)))
32 (lambda (&rest arguments)
33 (or (apply predicate arguments)
34 (some (lambda (p)
35 (declare (type function p))
36 (apply p arguments))
37 more-predicates)))))
38
39 (defun conjoin (predicate &rest more-predicates)
40 "Returns a function that applies each of PREDICATE and MORE-PREDICATE
41 functions in turn to its arguments, returning NIL if any of the predicates
42 returns false, without calling the remaining predicates. If none of the
43 predicates returns false, returns the primary value of the last predicate."
44 (if (null more-predicates)
45 predicate
46 (lambda (&rest arguments)
47 (and (apply predicate arguments)
48 ;; Cannot simply use CL:EVERY because we want to return the
49 ;; non-NIL value of the last predicate if all succeed.
50 (do ((tail (cdr more-predicates) (cdr tail))
51 (head (car more-predicates) (car tail)))
52 ((not tail)
53 (apply head arguments))
54 (unless (apply head arguments)
55 (return nil)))))))
56
57
58 (defun compose (function &rest more-functions)
59 "Returns a function composed of FUNCTION and MORE-FUNCTIONS that applies its
60 arguments to to each in turn, starting from the rightmost of MORE-FUNCTIONS,
61 and then calling the next one with the primary value of the last."
62 (declare (optimize (speed 3) (safety 1) (debug 1)))
63 (reduce (lambda (f g)
64 (let ((f (ensure-function f))
65 (g (ensure-function g)))
66 (lambda (&rest arguments)
67 (declare (dynamic-extent arguments))
68 (funcall f (apply g arguments)))))
69 more-functions
70 :initial-value function))
71
72 (define-compiler-macro compose (function &rest more-functions)
73 (labels ((compose-1 (funs)
74 (if (cdr funs)
75 `(funcall ,(car funs) ,(compose-1 (cdr funs)))
76 `(apply ,(car funs) arguments))))
77 (let* ((args (cons function more-functions))
78 (funs (make-gensym-list (length args) "COMPOSE")))
79 `(let ,(loop for f in funs for arg in args
80 collect `(,f (ensure-function ,arg)))
81 (declare (optimize (speed 3) (safety 1) (debug 1)))
82 (lambda (&rest arguments)
83 (declare (dynamic-extent arguments))
84 ,(compose-1 funs))))))
85
86 (defun multiple-value-compose (function &rest more-functions)
87 "Returns a function composed of FUNCTION and MORE-FUNCTIONS that applies
88 its arguments to each in turn, starting from the rightmost of
89 MORE-FUNCTIONS, and then calling the next one with all the return values of
90 the last."
91 (declare (optimize (speed 3) (safety 1) (debug 1)))
92 (reduce (lambda (f g)
93 (let ((f (ensure-function f))
94 (g (ensure-function g)))
95 (lambda (&rest arguments)
96 (declare (dynamic-extent arguments))
97 (multiple-value-call f (apply g arguments)))))
98 more-functions
99 :initial-value function))
100
101 (define-compiler-macro multiple-value-compose (function &rest more-functions)
102 (labels ((compose-1 (funs)
103 (if (cdr funs)
104 `(multiple-value-call ,(car funs) ,(compose-1 (cdr funs)))
105 `(apply ,(car funs) arguments))))
106 (let* ((args (cons function more-functions))
107 (funs (make-gensym-list (length args) "MV-COMPOSE")))
108 `(let ,(mapcar #'list funs args)
109 (declare (optimize (speed 3) (safety 1) (debug 1)))
110 (lambda (&rest arguments)
111 (declare (dynamic-extent arguments))
112 ,(compose-1 funs))))))
113
114 (declaim (inline curry rcurry))
115
116 (defun curry (function &rest arguments)
117 "Returns a function that applies ARGUMENTS and the arguments
118 it is called with to FUNCTION."
119 (declare (optimize (speed 3) (safety 1)))
120 (let ((fn (ensure-function function)))
121 (lambda (&rest more)
122 (declare (dynamic-extent more))
123 ;; Using M-V-C we don't need to append the arguments.
124 (multiple-value-call fn (values-list arguments) (values-list more)))))
125
126 (define-compiler-macro curry (function &rest arguments)
127 (let ((curries (make-gensym-list (length arguments) "CURRY"))
128 (fun (gensym "FUN")))
129 `(let ((,fun (ensure-function ,function))
130 ,@(mapcar #'list curries arguments))
131 (declare (optimize (speed 3) (safety 1)))
132 (lambda (&rest more)
133 (declare (dynamic-extent more))
134 (apply ,fun ,@curries more)))))
135
136 (defun rcurry (function &rest arguments)
137 "Returns a function that applies the arguments it is called
138 with and ARGUMENTS to FUNCTION."
139 (declare (optimize (speed 3) (safety 1)))
140 (let ((fn (ensure-function function)))
141 (lambda (&rest more)
142 (declare (dynamic-extent more))
143 (multiple-value-call fn (values-list more) (values-list arguments)))))
144
145 (define-compiler-macro rcurry (function &rest arguments)
146 (let ((rcurries (make-gensym-list (length arguments) "RCURRY"))
147 (fun (gensym "FUN")))
148 `(let ((,fun (ensure-function ,function))
149 ,@(mapcar #'list rcurries arguments))
150 (declare (optimize (speed 3) (safety 1)))
151 (lambda (&rest more)
152 (declare (dynamic-extent more))
153 (multiple-value-call ,fun (values-list more) ,@rcurries)))))
154
155 (declaim (notinline curry rcurry))
156
157 (defmacro named-lambda (name lambda-list &body body)
158 "Expands into a lambda-expression within whose BODY NAME denotes the
159 corresponding function."
160 `(labels ((,name ,lambda-list ,@body))
161 #',name))