String -> Maybe Int
The findIndex function takes a predicate and a list and returns the index of the first element in the list satisfying the predicate, or Nothing if there is no such element.
Ignore an invalid input, substituting nothing in the output.
O(n) The elemIndex function returns the index of the first element in the given ByteString which is equal (by memchr) to the query element, or Nothing if there is no such element.
O(n) The elemIndexEnd function returns the last index of the element in the given ByteString which is equal to the query element, or Nothing if there is no such element. The following holds:
> elemIndexEnd c xs ==
> (-) (length xs - 1) `fmap` elemIndex c (reverse xs)
O(n). length returns the length of a finite list as an Int. It is an instance of the more general Data.List.genericLength, the result type of which may be any kind of number.
error stops execution and displays an error message.
Convert a single digit Char to the corresponding Int. This function fails unless its argument satisfies isHexDigit, but recognises both upper and lower-case hexadecimal digits (i.e. '0'..'9', 'a'..'f', 'A'..'F').
The Prelude.fromEnum method restricted to the type Data.Char.Char.
The elemIndex function returns the index of the first element in the given list which is equal (by ==) to the query element, or Nothing if there is no such element.
Same as getCookie, but tries to read the value to the desired type.
Same as getInput, but tries to read the value to the desired type.
When called, trace outputs the string in its first argument, before returning the second argument as its result. The trace function is not referentially transparent, and should only be used for debugging, or for monitoring execution. Some implementations of trace may decorate the string that's output to indicate that you're tracing. The function is implemented on top of putTraceMsg.
The read function reads input from a string, which must be completely consumed by the input process.
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