18 ('closure 'closure) ; only available in codegen
19 ('static-string 'static-string) ; only available in codegen
21 ((builtin? x) 'builtin)
23 ((integer? x) 'int-literal)
24 ((boolean? x) 'bool-literal)
25 ((string? x) 'string-literal)))
27 (define (ast-traverse f x)
29 ('let `(let ,(map (lambda (x) (list (car x) (f (cadr x))))
31 ,@(map f (let-body x))))
33 ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
34 ('if `(if ,@(map f (cdr x))))
37 (define (ast-collect f x)
38 (define (inner y) (ast-collect f y))
41 (flat-map inner (let-bindings x))
42 (flat-map inner (let-body x)))]
45 ['lambda (append (f x)
46 (inner (lambda-body x)))]
48 (flat-map inner (cdr x)))]
49 ['closure (flat-map inner (caddr x))]
52 (define (ast-find p x)
53 (define (inner y) (ast-find p y))
54 (define (any p x) (fold-left
55 (lambda (acc y) (if acc #t (p y)))
61 (apply either (cdr fs)))))
65 (any inner (let-bindings x))
66 (any inner (let-body x)))]
69 ['lambda (either (p x)
70 (inner (lambda-body x)))]
71 ['if (either (p x) (any inner (cdr x)))]
74 (define (let-bindings e)
75 (define (pattern-match binding body)
76 (if (eqv? (ast-type binding) 'var)
77 (list (cons binding body))
78 (let* ([constructor (car binding)]
79 [destructor (lambda (i) (dtor-name constructor i))])
80 (flat-map (lambda (y i)
81 (pattern-match y `((,(destructor i) ,@body))))
83 (range 0 (length (cdr binding)))))))
84 (flat-map (lambda (x) (pattern-match (car x) (cdr x))) (cadr e)))
85 (define let-body cddr)
88 (and (list? x) (eq? (car x) 'lambda)))
91 (define (statement-type x)
94 (eqv? (car x) 'data)) 'data]
96 (eqv? (car x) 'define)) 'define]
99 (define (program-datas program)
100 (filter (lambda (x) (eqv? (statement-type x) 'data))
103 (define (program-defines program)
104 (filter (lambda (x) (eqv? (statement-type x) 'defines))
107 (define (program-body program)
108 ; hack to have multi-expression bodies
110 ,@(filter (lambda (x) (eqv? (statement-type x) 'expr))
114 ; (A ((foo (Int Bool))
117 (define data-layout cdr)
119 ; gets both constructors and destructors
120 ; (data A (foo Int Bool)
124 ; (foo . (constructor . (abs Int (abs Bool A))))
125 ; (foo~0 . (0 . (abs A Int)))
126 ; (foo~1 . (1 . (abs A Bool)))
127 ; (bar . (constructor . (abs Bool A)))
128 ; (bar~0 . (0 . (abs A Bool)))
130 (define (data-tors data-layout)
131 (define (constructor-type t products)
132 (fold-right (lambda (x acc) `(abs ,x ,acc)) t products))
134 (define (destructor ctor-name prod-type part-type index)
135 (let ([name (dtor-name ctor-name index)])
136 (cons name (cons index `(abs ,prod-type ,part-type)))))
138 (let ([type-name (car data-layout)]
139 [ctors (cdr data-layout)])
142 (let* ([ctor-name (car ctor)]
143 [products (cdr ctor)]
145 [maker (cons ctor-name (cons 'constructor (constructor-type type-name products)))]
147 [dtors (map (lambda (t i) (destructor ctor-name type-name t i))
149 (range 0 (length products)))])
151 (cons maker (append dtors acc))))
155 ; creates a type environment for a given adt definition
156 (define (data-tors-env data-layout)
157 (map (lambda (x) (cons (car x) (cddr x))) (data-tors data-layout)))
159 (define (dtor-name ctor-name index)
161 (string-append (symbol->string ctor-name)
163 (number->string index))))
165 ; for use in normalized form
166 (define lambda-arg caadr)
168 (define lambda-args cadr)
169 (define lambda-body caddr)
171 (define (references prog)
180 (define (go bs orig-bs)
183 (let* [(bind (car bs))
186 (refs (filter ; only count a reference if its a binding
187 (lambda (x) (assoc x orig-bs))
188 (references (cdr bind))))
189 (edges (map (lambda (x) (cons vert x))
192 (rest (if (null? (cdr bs))
194 (go (cdr bs) orig-bs)))
195 (total-verts (cons vert (car rest)))
196 (total-edges (append edges (cdr rest)))]
197 (cons total-verts total-edges))))
200 (define (successors graph v)
204 (if (eqv? v (caar E))
205 (cons (cdar E) (go v (cdr E)))
209 ; takes in a graph (pair of vertices, edges)
210 ; returns a list of strongly connected components
212 ; ((x y w) . ((x . y) (x . w) (w . x))
222 ; this uses tarjan's algorithm, to get reverse
223 ; topological sorting for free
226 (let* ([indices (make-hash-table)]
227 [lowlinks (make-hash-table)]
228 [on-stack (make-hash-table)]
234 (get-hash-table indices v #f))
236 (get-hash-table lowlinks v #f))
242 (put-hash-table! indices v current)
243 (put-hash-table! lowlinks v current)
244 (set! current (+ current 1))
246 (put-hash-table! on-stack v #t)
250 (if (not (hashtable-contains? indices w))
251 ; successor w has not been visited, recurse
254 (put-hash-table! lowlinks
256 (min (lowlink v) (lowlink w))))
257 ; successor w has been visited
258 (when (get-hash-table on-stack w #f)
259 (put-hash-table! lowlinks v (min (lowlink v) (index w))))))
260 (successors graph v))
262 (when (= (index v) (lowlink v))
265 (let ([w (pop! stack)])
266 (put-hash-table! on-stack w #f)
269 (cons w (new-scc)))))])
270 (set! result (cons scc result))))))])
273 (when (not (hashtable-contains? indices v)) ; v.index == -1
283 (append (range s (- n 1))
284 (list (+ s (- n 1))))))
286 (define (flat-map f . xs) (fold-left append '() (apply map (cons f xs))))
287 (define (repeat x n) (if (<= n 0) '()
288 (cons x (repeat x (- n 1)))))
293 ((_ s x) (set! s (cons x s)))))
297 ((_ s) (let ([x (car s)])