18 ('closure 'closure) ; only available in codegen
19 ('static-string 'static-string) ; only available in codegen
20 ('stack 'stack) ; only available in codegen (tag that value is passed via stack)
22 ((builtin? x) 'builtin)
24 ((integer? x) 'int-literal)
25 ((boolean? x) 'bool-literal)
26 ((string? x) 'string-literal)))
28 (define (ast-traverse f x)
30 ('let `(let ,(map (lambda (x) (list (car x) (f (cadr x))))
32 ,@(map f (let-body x))))
34 ('lambda `(lambda ,(lambda-args x) ,(f (lambda-body x))))
35 ('if `(if ,@(map f (cdr x))))
36 ('stack `(stack ,(cadr x) ,(map f (caddr x))))
39 (define (ast-collect f x)
40 (define (inner y) (ast-collect f y))
43 (flat-map inner (let-bindings x))
44 (flat-map inner (let-body x)))]
47 ['lambda (append (f x)
48 (inner (lambda-body x)))]
50 (flat-map inner (cdr x)))]
55 (define (ast-find p x)
56 (define (inner y) (ast-find p y))
57 (define (any p x) (fold-left
58 (lambda (acc y) (if acc #t (p y)))
64 (apply either (cdr fs)))))
68 (any inner (let-bindings x))
69 (any inner (let-body x)))]
72 ['lambda (either (p x)
73 (inner (lambda-body x)))]
74 ['if (either (p x) (any inner (cdr x)))]
75 ['stack (either (p x) (inner (caddr x)))]
78 (define (let-bindings e)
79 (define (pattern-match binding body)
80 (if (eqv? (ast-type binding) 'var)
81 (list (cons binding body))
82 (let* ([constructor (car binding)]
83 [destructor (lambda (i) (dtor-name constructor i))])
84 (flat-map (lambda (y i)
85 (pattern-match y `((,(destructor i) ,@body))))
87 (range 0 (length (cdr binding)))))))
88 (flat-map (lambda (x) (pattern-match (car x) (cdr x))) (cadr e)))
89 (define let-body cddr)
92 (and (list? x) (eq? (car x) 'lambda)))
95 (define (statement-type x)
98 (eqv? (car x) 'data)) 'data]
100 (eqv? (car x) 'define)) 'define]
104 ; (A ((foo (Int Bool))
106 (define (program-data-layouts program)
107 (map (lambda (x) (cons (car x) (cdr x))) ; convert to assoc list
108 (map cdr (filter (lambda (x) (eqv? (statement-type x) 'data))
111 (define (program-defines program)
112 (filter (lambda (x) (eqv? (statement-type x) 'defines))
115 (define (program-body program)
116 ; hack to have multi-expression bodies
118 ,@(filter (lambda (x) (eqv? (statement-type x) 'expr))
123 ; gets both constructors and destructors
124 ; (data A (foo Int Bool)
128 ; (foo . (constructor . (abs Int (abs Bool A))))
129 ; (foo~0 . (0 . (abs A Int)))
130 ; (foo~1 . (1 . (abs A Bool)))
131 ; (bar . (constructor . (abs Bool A)))
132 ; (bar~0 . (0 . (abs A Bool)))
134 (define (data-tors data-layout)
135 (define (constructor-type t products)
136 (fold-right (lambda (x acc) `(abs ,x ,acc)) t products))
138 (define (destructor ctor-name prod-type part-type index)
139 (let ([name (dtor-name ctor-name index)])
140 (cons name (cons index `(abs ,prod-type ,part-type)))))
142 (let ([type-name (car data-layout)]
143 [ctors (cdr data-layout)])
146 (let* ([ctor-name (car ctor)]
147 [products (cdr ctor)]
149 [maker (cons ctor-name (cons 'constructor (constructor-type type-name products)))]
151 [dtors (map (lambda (t i) (destructor ctor-name type-name t i))
153 (range 0 (length products)))])
154 (cons maker (append dtors acc))))
158 ; creates a type environment for a given adt definition
159 (define (data-tors-env data-layout)
160 (map (lambda (x) (cons (car x) (cddr x))) (data-tors data-layout)))
162 (define (dtor-name ctor-name index)
164 (string-append (symbol->string ctor-name)
166 (number->string index))))
168 ; for use in normalized form
169 (define lambda-arg caadr)
171 (define lambda-args cadr)
172 (define lambda-body caddr)
174 (define (references prog)
183 (define (go bs orig-bs)
186 (let* [(bind (car bs))
189 (refs (filter ; only count a reference if its a binding
190 (lambda (x) (assoc x orig-bs))
191 (references (cdr bind))))
192 (edges (map (lambda (x) (cons vert x))
195 (rest (if (null? (cdr bs))
197 (go (cdr bs) orig-bs)))
198 (total-verts (cons vert (car rest)))
199 (total-edges (append edges (cdr rest)))]
200 (cons total-verts total-edges))))
203 (define (successors graph v)
207 (if (eqv? v (caar E))
208 (cons (cdar E) (go v (cdr E)))
212 ; takes in a graph (pair of vertices, edges)
213 ; returns a list of strongly connected components
215 ; ((x y w) . ((x . y) (x . w) (w . x))
225 ; this uses tarjan's algorithm, to get reverse
226 ; topological sorting for free
229 (let* ([indices (make-hash-table)]
230 [lowlinks (make-hash-table)]
231 [on-stack (make-hash-table)]
237 (get-hash-table indices v #f))
239 (get-hash-table lowlinks v #f))
245 (put-hash-table! indices v current)
246 (put-hash-table! lowlinks v current)
247 (set! current (+ current 1))
249 (put-hash-table! on-stack v #t)
253 (if (not (hashtable-contains? indices w))
254 ; successor w has not been visited, recurse
257 (put-hash-table! lowlinks
259 (min (lowlink v) (lowlink w))))
260 ; successor w has been visited
261 (when (get-hash-table on-stack w #f)
262 (put-hash-table! lowlinks v (min (lowlink v) (index w))))))
263 (successors graph v))
265 (when (= (index v) (lowlink v))
268 (let ([w (pop! stack)])
269 (put-hash-table! on-stack w #f)
272 (cons w (new-scc)))))])
273 (set! result (cons scc result))))))])
276 (when (not (hashtable-contains? indices v)) ; v.index == -1
286 (append (range s (- n 1))
287 (list (+ s (- n 1))))))
289 (define (flat-map f . xs) (fold-left append '() (apply map (cons f xs))))
290 (define (repeat x n) (if (<= n 0) '()
291 (cons x (repeat x (- n 1)))))
296 ((_ s x) (set! s (cons x s)))))
300 ((_ s) (let ([x (car s)])