suzanne.soy/racket
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Added comments to explain TR's type on subprocess and friends.

Browse Source
This commit is contained in:
Eric Dobson 2011-09-14 22:17:43 -07:00 committed by Sam Tobin-Hochstadt
parent 7fcf28bef2
commit 1f3d68e55e
1 changed files with 27 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
collects/typed-racket/base-env/base-env.rkt
View File

@ -1522,10 +1522,25 @@
;Section 14.4 (Processes)
;; Subprocces has 3 arguments and 3 return values which are either ports
;; or false. There is a relation that if a port argument is false, then
;; the corresponding return value is a port, and if it is a port the return
;; value is false. process/ports and process*/ports have a similar behavior.
;; This behavior is encoded in the type system as each possible combination
;; of port arguments being one case of a case-> type. There is also a
;; final case where the unions are preserved because TR currently can
;; not deal with applying a case lambda to union types, and ensure that
;; while no one branch covers every union, every union is covered by a branch.
;; There is also twice as many cases to deal with the 'exact behavior for windows.
[subprocess
(let* ((make-opt-in-port (lambda (port) (if port -Input-Port (-val #f))))
(make-opt-out-port (lambda (port) (if port -Output-Port (-val #f))))
(ret-type (-values (list -Subprocess (-opt -Input-Port) (-opt -Output-Port) (-opt -Input-Port))))
;; out, in, err, and exact are all booleans and correspond to
;; whether or not the argument is a port (#t) or #f (#f).
;; The return value is the function type that is one branch
;; of the case lambda.
(make-specific-case (lambda (out in err exact)
(let ((arg-out (make-opt-out-port out))
(arg-in (make-opt-in-port in))
@ -1605,6 +1620,12 @@
(-> (-val 'kill) -Void)))
(make-opt-in-port (lambda (port) (if port -Input-Port (-val #f))))
(make-opt-out-port (lambda (port) (if port -Output-Port (-val #f))))
;; out, in, and exact are all booleans and correspond to
;; whether or not the argument is a port (#t) or #f (#f).
;; err is either a boolean or 'stdout where 'stdout corresponds
;; to the input being the value 'stdout.
;; The return value is the function type that is one branch
;; of the case lambda.
(make-specific-case (lambda (out in err)
(-> (make-opt-out-port out)
(make-opt-in-port in)
@ -1638,6 +1659,12 @@
(-> (-val 'kill) -Void)))
(make-opt-in-port (lambda (port) (if port -Input-Port (-val #f))))
(make-opt-out-port (lambda (port) (if port -Output-Port (-val #f))))
;; out, in, and exact are all booleans and correspond to
;; whether or not the argument is a port (#t) or #f (#f).
;; err is either a boolean or 'stdout where 'stdout corresponds
;; to the input being the value 'stdout.
;; The return value is the function type that is one branch
;; of the case lambda.
(make-specific-case (lambda (out in err exact)
(let ((arg-out (make-opt-out-port out))
(arg-in (make-opt-in-port in))