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author | Xander <xander@biltopia.org> | 2023-08-17 22:08:21 +0200 |
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committer | Xander <xander@biltopia.org> | 2023-08-17 22:08:21 +0200 |
commit | d177285a761de33b86fcbde72fd718137bfa6f86 (patch) | |
tree | 3a880d6df65418ea591be69cf36fd3da8e679f07 /lib | |
parent | e2d7deb82cd25b47cbccda0c48ab39e17c5c536d (diff) | |
download | ats-os-d177285a761de33b86fcbde72fd718137bfa6f86.tar.xz ats-os-d177285a761de33b86fcbde72fd718137bfa6f86.zip |
Add valid/unvalid type, replacement of optional
Diffstat (limited to 'lib')
-rw-r--r-- | lib/DATS/valid.dats | 15 | ||||
-rw-r--r-- | lib/SATS/valid.sats | 18 |
2 files changed, 33 insertions, 0 deletions
diff --git a/lib/DATS/valid.dats b/lib/DATS/valid.dats new file mode 100644 index 0000000..f4ea0aa --- /dev/null +++ b/lib/DATS/valid.dats @@ -0,0 +1,15 @@ +#define ATS_DYNLOADFLAG 0 +staload "lib/SATS/valid.sats" + +assume valid(a:t@ype,b:bool) = (a,bool b) + +implement{a} create_valid(value : a) = (value,true) + +// Create unvalid value by casting null pointer to type. +implement{a} create_unvalid() = let + staload UN = "prelude/SATS/unsafe.sats" +in + ($UN.ptr0_get<a>(the_null_ptr),false) //UNSAFE: +end + +implement{a} unwrap_valid(v) = v.0 diff --git a/lib/SATS/valid.sats b/lib/SATS/valid.sats new file mode 100644 index 0000000..e3841e0 --- /dev/null +++ b/lib/SATS/valid.sats @@ -0,0 +1,18 @@ + +// implement a type that can be unvalid or valid. +// It's a replacement of Optional, but can be allocated on stack, so no heap allocaton needed. +// When unvalid, it should be not possible to get unvalid value, thats why abstract type is used. +// bool b: true means valid, false unvalid +abst@ype valid(a:t@ype,b:bool) = (a,bool b) + +typedef Valid(a:t@ype) = [b : bool] valid(a,b) + +// Wraps valid value. +fn {a:t@ype} create_valid(value : a) : valid(a,true) + +// Creates unvalid type. +fn {a:t@ype} create_unvalid() : valid(a,false) + +// Only function that allows getting value. Only accepts valid values. +fn {a:t@ype} unwrap_valid(valid(a,true)) : a + |