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Fix #227

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Wen Kokke 2019-11-29 13:16:07 +00:00
parent 88ce889159
commit 32a626789b
1 changed files with 8 additions and 9 deletions
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11
src/plfa/part1/Lists.lagda.md
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@ -115,12 +115,11 @@ _++_ : ∀ {A : Set} → List A → List A → List A
[] ++ ys = ys [] ++ ys = ys
(x ∷ xs) ++ ys = x ∷ (xs ++ ys) (x ∷ xs) ++ ys = x ∷ (xs ++ ys)
``` ```
The type `A` is an implicit argument to append, making it a The type `A` is an implicit argument to append, making it a _polymorphic_
_polymorphic_ function (one that can be used at many types). The function (one that can be used at many types). A list appended to the empty list
empty list appended to another list yields the other list. A yields the list itself. A list appended to a non-empty list yields a list with
non-empty list appended to another list yields a list with head the the head the same as the head of the non-empty list, and a tail the same as the
same as the head of the first list and tail the same as the tail of other list appended to tail of the non-empty list.
the first list appended to the second list.
Here is an example, showing how to compute the result Here is an example, showing how to compute the result
of appending two lists: of appending two lists: