[added printf example
mail@stefanwehr.de**20050528085605] {
hunk ./PhracPrelude.phc 12
+-- maybe the most inefficient implementation of converting an Int to a string...
+showInt :: Int -> List Char;
+showInt i = if i == -9 then "-9" else (
+            if i == -8 then "-8" else (
+            if i == -7 then "-7" else (
+            if i == -6 then "-6" else (
+            if i == -5 then "-5" else (
+            if i == -4 then "-4" else (
+            if i == -3 then "-3" else (
+            if i == -2 then "-2" else (
+            if i == -1 then "-1" else (
+            if i == 0 then "0" else (
+            if i == 1 then "1" else (
+            if i == 2 then "2" else (
+            if i == 3 then "3" else (
+            if i == 4 then "4" else (
+            if i == 5 then "5" else (
+            if i == 6 then "6" else (
+            if i == 7 then "7" else (
+            if i == 8 then "8" else (
+            if i == 9 then "9" else (
+            let x = i % 10;
+                y = i / 10;
+            in showInt y ++ showInt x
+            )))))))))))))))))));
+
+class Show __a where {
+    show :: __a -> List Char;
+}
+
+instance Show Int where {
+    show i = showInt i;
+}
+
+instance Show Char where {
+    show c = Cons c Nil;
+}
+
addfile ./tests/examples/Printf.out
hunk ./tests/examples/Printf.out 1
+sprintf :: forall fmt[1] . Format fmt[1] => fmt[1] -> Sprintf fmt[1]
+formatSpec :: S (I (S (C (List Char))))
addfile ./tests/examples/Printf.phc
hunk ./tests/examples/Printf.phc 1
+data I f   = I f;
+data C f   = C f;
+data S f   = S (List Char) f;
+
+class Format fmt where {
+  type Sprintf fmt;
+  sprintf' :: List Char -> fmt -> Sprintf fmt;
+}
+
+instance Format (List Char) where {
+  type Sprintf (List Char) = List Char;
+  sprintf' prefix str = prefix ++ str;
+}
+
+instance Format a => Format (I a) where {
+  type Sprintf (I a) = Int -> Sprintf a;
+  sprintf' prefix i = case i of I a -> (\j -> sprintf' (prefix ++ show j) a);;
+}
+
+instance Format a => Format (C a) where {
+  type Sprintf (C a) = Char -> Sprintf a;
+  sprintf' prefix c = case c of C a -> (\d -> sprintf' (prefix ++ show d) a);;
+}
+
+instance Format a => Format (S a) where {
+  type Sprintf (S a) = Sprintf a;
+  sprintf' prefix s = case s of S str a -> sprintf' (prefix ++ str) a;;
+}
+
+sprintf :: Format fmt => fmt -> Sprintf fmt;
+sprintf = sprintf' "";
+
+formatSpec = S "Int: " (I (S ", Char: " (C ".")));
}