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 cadr)
79 (define let-body cddr)
81 ; (let ([(foo a b) (foo 123 345)]) a)
84 ; (let ([a (foo~0 (foo 123 345)]
85 ; [b (foo~1 (foo 123 345)]) a)
86 (define (expand-pattern-matches x)
87 (define (pattern-match binding)
88 (let ([binding-name (car binding)]
89 [body (cadr binding)])
90 (if (eqv? (ast-type binding-name) 'var)
91 (list (list binding-name body))
92 (let* ([sum-name (car binding-name)]
93 [destructor (lambda (i) (dtor-name sum-name i))])
94 (flat-map (lambda (y i)
95 (pattern-match (list y `(,(destructor i) ,body))))
97 (range 0 (length (cdr binding-name))))))))
99 ['let `(let ,(flat-map pattern-match (let-bindings x))
100 ,@(map expand-pattern-matches (let-body x)))]
101 [else (ast-traverse expand-pattern-matches x)]))
104 (and (list? x) (eq? (car x) 'lambda)))
107 (define (statement-type x)
110 (eqv? (car x) 'data)) 'data]
112 (eqv? (car x) 'define)) 'define]
116 ; (A ((foo (Int Bool))
118 (define (program-data-layouts program)
119 (map (lambda (x) (cons (car x) (cdr x))) ; convert to assoc list
120 (map cdr (filter (lambda (x) (eqv? (statement-type x) 'data))
123 (define (program-defines program)
124 (filter (lambda (x) (eqv? (statement-type x) 'defines))
127 (define (program-map-exprs f program)
129 (case (statement-type x)
134 (define (program-body program)
135 ; hack to have multi-expression bodies
137 ,@(filter (lambda (x) (eqv? (statement-type x) 'expr))
140 ; a data tor is either a constructor or destructor for an ADT
141 ; data-tors returns constructors and destructors for a data-layout
142 ; (data A (foo Int Bool)
146 ; (foo . ((A foo constructor) . (abs Int (abs Bool A))))
147 ; (foo~0 . ((A foo 0) . (abs A Int)))
148 ; (foo~1 . ((A foo 1) . (abs A Bool)))
149 ; (bar . ((A bar constructor) . (abs Bool A)))
150 ; (bar~0 . ((A bar 0) . (abs A Bool)))
151 ; ------+-------------------------------------
154 (define (data-tors data-layout)
155 (define (constructor-type t products)
156 (fold-right (lambda (x acc) `(abs ,x ,acc)) t products))
158 (define (destructor ctor-name prod-type part-type index)
159 (let ([name (dtor-name ctor-name index)])
160 (cons name (cons (list prod-type ctor-name index) `(abs ,prod-type ,part-type)))))
162 (let ([type-name (car data-layout)]
163 [ctors (cdr data-layout)])
166 (let* ([ctor-name (car ctor)]
167 [products (cdr ctor)]
169 [maker (cons ctor-name (cons (list type-name ctor-name 'constructor) (constructor-type type-name products)))]
171 [dtors (map (lambda (t i) (destructor ctor-name type-name t i))
173 (range 0 (length products)))])
174 (cons maker (append dtors acc))))
178 ; creates a type environment for a given adt definition
179 (define (data-tors-type-env data-layout)
180 (map (lambda (x) (cons (car x) (cddr x))) (data-tors data-layout)))
182 (define (dtor-name ctor-name index)
184 (string-append (symbol->string ctor-name)
186 (number->string index))))
188 ; for use in normalized form
189 (define lambda-arg caadr)
191 (define lambda-args cadr)
192 (define lambda-body caddr)
194 (define (references prog)
203 (define (go bs orig-bs)
206 (let* [(bind (car bs))
209 (refs (filter ; only count a reference if its a binding
210 (lambda (x) (assoc x orig-bs))
211 (references (cdr bind))))
212 (edges (map (lambda (x) (cons vert x))
215 (rest (if (null? (cdr bs))
217 (go (cdr bs) orig-bs)))
218 (total-verts (cons vert (car rest)))
219 (total-edges (append edges (cdr rest)))]
220 (cons total-verts total-edges))))
223 (define (successors graph v)
227 (if (eqv? v (caar E))
228 (cons (cdar E) (go v (cdr E)))
232 ; takes in a graph (pair of vertices, edges)
233 ; returns a list of strongly connected components
235 ; ((x y w) . ((x . y) (x . w) (w . x))
245 ; this uses tarjan's algorithm, to get reverse
246 ; topological sorting for free
249 (let* ([indices (make-hash-table)]
250 [lowlinks (make-hash-table)]
251 [on-stack (make-hash-table)]
257 (get-hash-table indices v #f))
259 (get-hash-table lowlinks v #f))
265 (put-hash-table! indices v current)
266 (put-hash-table! lowlinks v current)
267 (set! current (+ current 1))
269 (put-hash-table! on-stack v #t)
273 (if (not (hashtable-contains? indices w))
274 ; successor w has not been visited, recurse
277 (put-hash-table! lowlinks
279 (min (lowlink v) (lowlink w))))
280 ; successor w has been visited
281 (when (get-hash-table on-stack w #f)
282 (put-hash-table! lowlinks v (min (lowlink v) (index w))))))
283 (successors graph v))
285 (when (= (index v) (lowlink v))
288 (let ([w (pop! stack)])
289 (put-hash-table! on-stack w #f)
292 (cons w (new-scc)))))])
293 (set! result (cons scc result))))))])
296 (when (not (hashtable-contains? indices v)) ; v.index == -1
306 (append (range s (- n 1))
307 (list (+ s (- n 1))))))
309 (define (flat-map f . xs) (fold-left append '() (apply map (cons f xs))))
310 (define (repeat x n) (if (<= n 0) '()
311 (cons x (repeat x (- n 1)))))
316 ((_ s x) (set! s (cons x s)))))
320 ((_ s) (let ([x (car s)])