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author | Jakob Kaivo <jkk@ung.org> | 2022-03-04 12:32:20 -0500 |
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committer | Jakob Kaivo <jkk@ung.org> | 2022-03-04 12:32:20 -0500 |
commit | 55f277e77428d7423ae906a8e1f1324d35b07a7d (patch) | |
tree | 5c1c04703dff89c46b349025d2d3ec88ea9b3819 /miralib/ex/stack.m |
import Miranda 2.066 from upstream
Diffstat (limited to 'miralib/ex/stack.m')
-rw-r--r-- | miralib/ex/stack.m | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/miralib/ex/stack.m b/miralib/ex/stack.m new file mode 100644 index 0000000..d7a1af2 --- /dev/null +++ b/miralib/ex/stack.m @@ -0,0 +1,19 @@ +||This script defines stack, as an abstract data type based on lists. +||Note that there is a show function for stacks, causing them to print +||in a sensible way. + +abstype stack * +with empty::stack *; push::*->stack *->stack *; + pop::stack *->stack *; top::stack *->*; isempty::stack *->bool; + showstack::(*->[char])->stack *->[char] + +stack * == [*] +empty = [] +push a x = a:x +pop(a:x) = x +top(a:x) = a +isempty x = (x=[]) +showstack f [] = "empty" +showstack f (a:x) = "(push " ++ f a ++ " " ++ showstack f x ++ ")" + +teststack = push 1(push 2(push 3 empty)) |