On Sun, Nov 11, 2018 at 09:49:09PM +0200, megane wrote:
> The second example is correct but maybe not too well stated. Maybe if it
> said:
> "(forall (a) ('a -> a)) is _also_ translated to (forall (a) (a -> a))"
>
> So if there's an explicit forall with a typevar "a" adding the apostrophe has
> no effect.Thanks for clarifying. Here's a signed-off copy of the patch with NEWS entry and improved wording in the manual. Cheers, Peter
From 1dc2ba7a0e967e45449460ebffce81cabc3937e6 Mon Sep 17 00:00:00 2001
From: Peter Bex <pe...@more-magic.net>
Date: Sun, 11 Nov 2018 20:56:10 +0100
Subject: [PATCH] Add quoted symbols as shorthand for forall
---
NEWS | 7 +++++++
manual/Types | 10 ++++++++++
scrutinizer.scm | 10 ++++++++++
tests/typematch-tests.scm | 21 +++++++++++++++++++++
4 files changed, 48 insertions(+)
diff --git a/NEWS b/NEWS
index 18eefd7f..31fded0f 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,10 @@
+5.0.1
+
+- Type system
+ - It is now possible to quote free variables in type declarations,
+ which acts as shorthand for `forall' (thanks to "megane")
+
+
5.0.0
- Runtime system
diff --git a/manual/Types b/manual/Types
index c87ea431..587cdaa5 100644
--- a/manual/Types
+++ b/manual/Types
@@ -161,6 +161,16 @@ or {{:}} should follow the syntax given below:
(*) Note: no type-variables are bound inside {{(not TYPE)}}.
+You can use a shorthand {{'SYMBOL}} for introducing free variables in
+{{forall}} types, for example:
+
+ ('a -> 'a) is translated to (forall (a) (a -> a))
+
+If a {{forall}} already exists, quotes around the free variables
+introduced by it will be stripped:
+
+ (forall (a) ('a -> a)) is translated to (forall (a) (a -> a))
+
Note that type-variables in {{forall}} types may be given "constraint" types, i.e.
(: sort (forall (e (s (or (vector-of e) (list-of e))))
diff --git a/scrutinizer.scm b/scrutinizer.scm
index 8209ae38..0349e136 100644
--- a/scrutinizer.scm
+++ b/scrutinizer.scm
@@ -1972,6 +1972,16 @@
(second t))
constraints))
(validate (third t) rec)))))
+ ((and (eq? 'quote (car t))
+ (pair? (cdr t))
+ (symbol? (second t))
+ (null? (cddr t))
+ (second t))
+ =>
+ (lambda (v)
+ (unless (memq v typevars)
+ (set! typevars (cons v typevars)))
+ v))
((eq? 'or (car t))
(and (list? t)
(let ((ts (map validate (cdr t))))
diff --git a/tests/typematch-tests.scm b/tests/typematch-tests.scm
index 4d8f40cd..97b83289 100644
--- a/tests/typematch-tests.scm
+++ b/tests/typematch-tests.scm
@@ -255,6 +255,7 @@
(infer (forall (a) (procedure (#!rest a) a)) +)
(infer (list fixnum) '(1))
+(define something)
(infer port (open-input-string "foo"))
(infer input-port (open-input-string "bar"))
@@ -398,4 +399,24 @@
(length a) ; refine (or pair null) with list (= (list-of *))
(infer list a))
+
+(assert
+ (compiler-typecase 1
+ ('a #t)))
+
+(assert
+ (compiler-typecase (the (list fixnum string string) something)
+ ((list 'a 'a 'b) #f)
+ ((list 'a 'b 'b) #t)))
+
+(assert
+ (compiler-typecase (the (list fixnum string string) something)
+ ((forall (a) (list a 'a 'b)) #f)
+ ((forall (b) (list 'a 'b b)) #t)))
+
+(assert
+ (compiler-typecase (the (list string (list string fixnum)) something)
+ ((list 'a (forall (a) (list 'b a))) #f)
+ ((list 'b (forall (b) (list b 'a))) #t)))
+
(test-exit)
--
2.11.0
signature.asc
Description: PGP signature
_______________________________________________ Chicken-hackers mailing list Chicken-hackers@nongnu.org https://lists.nongnu.org/mailman/listinfo/chicken-hackers
