47 lines
1.2 KiB
Racket
47 lines
1.2 KiB
Racket
#lang typed/racket/base
|
|
(require "typed-structs.rkt"
|
|
"helpers.rkt"
|
|
racket/list)
|
|
|
|
(provide find-toplevel-variables)
|
|
|
|
|
|
(: find-toplevel-variables (Expression -> (Listof Symbol)))
|
|
;; Collects the list of toplevel variables we need.
|
|
(define (find-toplevel-variables exp)
|
|
(: loop (Expression -> (Listof Symbol)))
|
|
(define (loop exp)
|
|
(cond
|
|
[(Constant? exp)
|
|
empty]
|
|
|
|
[(Quote? exp)
|
|
empty]
|
|
|
|
[(Var? exp)
|
|
(list (Var-id exp))]
|
|
|
|
[(Assign? exp)
|
|
(loop (Assign-value exp))]
|
|
|
|
[(Def? exp)
|
|
(cons (Def-variable exp)
|
|
(loop (Def-value exp)))]
|
|
|
|
[(Branch? exp)
|
|
(append (loop (Branch-predicate exp))
|
|
(loop (Branch-consequent exp))
|
|
(loop (Branch-alternative exp)))]
|
|
|
|
[(Lam? exp)
|
|
(list-difference (apply append (map loop (Lam-body exp)))
|
|
(Lam-parameters exp))]
|
|
[(Seq? exp)
|
|
(apply append (map loop (Seq-actions exp)))]
|
|
|
|
[(App? exp)
|
|
(append (loop (App-operator exp))
|
|
(apply append (map loop (App-operands exp))))]))
|
|
|
|
(unique (loop exp)))
|
|
|