summaryrefslogtreecommitdiff
path: root/util.lisp
blob: 3a5320ddb4f8b34bf1372c0449a1daa9632ff7ca (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
(%defmacro %defun args
  (list '%fset
        (list 'quote (car (cdr (car args))))
        (cons '%lambda (cdr (cdr (car args))))))

(%defun list* args
  (if (null (cdr args))
      (car args)
      (cons (car args)
            (apply 'list* (cdr args)))))

(%defmacro let* args
  (let ((form (car args)))
    (let ((bindings (car (cdr form)))
          (body (cdr (cdr form))))
      (if (null bindings)
          (list* 'let nil body)
          (let ((first-binding (car bindings))
                (rest (cdr bindings)))
            (list 'let
                  (list first-binding)
                  (list* 'let* rest body)))))))

(%defmacro cond args
  (let* ((form (car args))
         (clauses (cdr form))
         (clause (car clauses))
         (rest (cdr clauses)))
    (if (null clauses)
        nil
        (list 'if
              (car clause)
              (cons 'progn (cdr clause))
              (cons 'cond rest)))))

(%defun not args
  (if (null (car args)) t nil))

(%defun make-%defmacro*-body args
  (let ((lambda-list (car args))
        (lambda-list-name (car (cdr args)))
        (body (car (cdr (cdr args)))))
    (cond ((null lambda-list) body)
          ((not (listp lambda-list))
           (list
            (list* 'let
                   (list (list lambda-list lambda-list-name))
                   body)))
          (t (let ((lambda-symbol (car lambda-list))
                   (rest-lambda-list (cdr lambda-list))
                   (rest-name (gensym)))
               (list
                (list* 'let
                       (list (list lambda-symbol
                                   (list 'car lambda-list-name))
                             (list rest-name
                                   (list 'cdr lambda-list-name)))
                       (make-%defmacro*-body (cdr lambda-list)
                                             rest-name
                                             body))))))))

(%defmacro %defmacro* args
  (let* ((form (car args))
         (real-args (cdr form)))
    (let ((name (car real-args))
          (lambda-list (car (cdr real-args)))
          (body (cdr (cdr real-args)))
          (macro-lambda-list-name (gensym))
          (lambda-list-name (gensym)))
      (list '%defmacro
            name
            macro-lambda-list-name
            (list* 'let
                   (list (list lambda-list-name
                               (list 'cdr
                                     (list 'car macro-lambda-list-name))))
                   (make-%defmacro*-body lambda-list lambda-list-name body))))))

(%defmacro %defun* args
  (let* ((form (car args))
         (real-args (cdr form)))
    (let ((name (car real-args))
          (lambda-list (car (cdr real-args)))
          (body (cdr (cdr real-args)))
          (lambda-list-name (gensym)))
      (list* '%defun
             name
             lambda-list-name
             (make-%defmacro*-body lambda-list lambda-list-name body)))))

(%defmacro* and expressions
  (cond ((null expressions) t)
        ((null (cdr expressions)) (car expressions))
        (t (list 'if
                 (car expressions)
                 (cons 'and (cdr expressions))
                 nil))))

(%defmacro* or expressions
  (cond ((null expressions) nil)
        ((null (cdr expressions)) (car expressions))
        (t (let ((expr-sym (gensym)))
             (list 'let
                   (list (list expr-sym (car expressions)))
                   (list 'if
                         expr-sym
                         expr-sym
                         (cons 'or (cdr expressions))))))))

(%defun* %reverse-helper (list stack)
  (if (null list)
      stack
      (%reverse-helper (cdr list) (cons (car list) stack))))

(%defun* reverse (list)
  (%reverse-helper list nil))

(%defun* %append-helper (reversed-list1 list2)
  (if (null reversed-list1)
      list2
      (%append-helper (cdr reversed-list1) (cons (car reversed-list1) list2))))

(%defun* %append-two-lists (list1 list2)
  (%append-helper (reverse list1) list2))

(%defun* %append (lists)
  (if (null (cdr lists))
      (car lists)
      (let ((first-list (car lists))
            (second-list (car (cdr lists)))
            (rest (cdr (cdr lists))))
        (%append (list* (%append-two-lists first-list second-list) rest)))))

(%defun append lists
  (%append lists))

(%defmacro* sys::quasiquote (object)
  (if (not (consp object))
      (list 'quote object)
      (cond ((eq 'sys::unquote (car object)) (car (cdr object)))
            ((eq 'sys::quasiquote (car object)) (list 'quote object))
            ((and (consp (car object))
                  (eq 'sys::unquote-splicing (car (car object))))
             (list 'append
                   (car (cdr (car object)))
                   (list 'sys::quasiquote (cdr object))))
            (t (list 'cons
                     (list 'sys::quasiquote (car object))
                     (list 'sys::quasiquote (cdr object)))))))

(%defun* %member (item list)
  (and list
       (or (and (eq item (car list)) list)
           (%member item (cdr list)))))

(%defmacro* case (object . clauses)
  (let ((this-clause (car clauses))
        (rest (cdr clauses))
        (object-sym (gensym)))
    (if (null clauses)
        nil
        (if (and (null rest)
                 (or (eq (car this-clause) t)
                     (eq (car this-clause) 'otherwise)))
            `(progn ,@(cdr this-clause))
            `(let ((,object-sym ,object))
               (if ,(if (listp (car this-clause))
                        `(%member ,object-sym
                                  (quote ,(car this-clause)))
                        `(eq ,object-sym
                             (quote ,(car this-clause))))
                   (progn ,(cdr this-clause))
                   (case ,object-sym ,@rest)))))))

(%defun* list-eqp (list1 list2)
  "Not really EQUALP (only works on trees of symbols)."
  (if (and (consp list1) (consp list2))
      (and (list-eqp (car list1) (car list2))
           (list-eqp (cdr list1) (cdr list2)))
      (eq list1 list2)))

(%defun* macroexpand (object . rest)
  (let* ((env (if rest (car rest) nil))
         (expansion-1 (macroexpand-1 object env))
         (expansion-2 (macroexpand-1 expansion-1 env)))
    (if (list-eqp expansion-1 expansion-2)
        expansion-1
        (macroexpand expansion-2))))

(%defun* macroexpand-all (object . rest)
  (let* ((env (if rest (car rest) nil)))
    (if (consp object)
        (let ((expansion (macroexpand object env)))
          (cons (macroexpand-all (car expansion))
                (macroexpand-all (cdr expansion))))
        object)))

(%defmacro* unless (test . body)
  `(if (not ,test) (progn ,@body) nil))