diff options
| -rw-r--r-- | Generics/generics.b | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/Generics/generics.b b/Generics/generics.b index f46b95c..75bc9e8 100644 --- a/Generics/generics.b +++ b/Generics/generics.b @@ -14,12 +14,24 @@ Generics: module { init: fn(nil: ref Draw->Context, nil: list of string); }; +# Polymorphic type Rd: adt[T] { t: ref Iobuf; ws: fn(rd: self ref Rd[T]): int; }; -# Polymorphic type +Num: adt { + pick { + String => + s: string; + Int => + d: int; + } + + stringify: fn(v: self ref Num): string; +}; + +# Polymorphic and pick-tagged type Word: adt[T] { w: T; @@ -50,12 +62,18 @@ init(nil: ref Draw->Context, nil: list of string) { c := rd.ws(); print("Broke on '%c'\n", c); + d := ref Num.Int(5); + s := ref Num.String("Five"); + + print("%s\n", d.stringify()); + print("%s\n", s.stringify()); + words: list of ref Word[Int].String; smiley := "☺"; frowny := ":("; - sword := ref Word[Int].String(Int(5), smiley); + sword := ref Word[Int].String(Int(9), smiley); # Format is: Adt[Type].PickTag(fields...) words = sword :: words; @@ -80,6 +98,17 @@ Word[T].eq(a, b: ref Word): int return a.w == b.w; # This is a shallow comparison, don't rely on this } +Num.stringify(v: self ref Num): string { + pick xv := v { + String => + return xv.s; + Int => + return string xv.d; + * => + raise "type error"; + } +} + # Matches whitespace characters isspace(c: int): int { return c == ' ' || c == '\r' || c == '\t' || c == '\n'; |