labs/lib/src/numbers/default.nix

70 lines
1.9 KiB
Nix

lib: {
numbers = {
into = {
## Convert a number into a string.
##
## @type Int | Float -> String
string = value:
if builtins.isInt value
then builtins.toString value
else builtins.toJSON value;
## Convert a number into a list of digits in the given base.
##
## @type Int -> Int -> List Int
base = base: target: let
process = value: let
r = value - ((value / base) * base);
q = (value - r) / base;
in
if value < base
then [value]
else [r] ++ process q;
result = process target;
in
assert lib.errors.trace (builtins.isInt base) "Base must be an integer.";
assert lib.errors.trace (builtins.isInt target) "Target must be an integer.";
assert lib.errors.trace (base >= 2) "Base must be at least 2.";
assert lib.errors.trace (target >= 0) "Target cannot be negative.";
lib.lists.reverse result;
## Convert a number into a hexadecimal string.
##
## @type Int -> String
hex = value: let
serialize = part:
if part < 10
then builtins.toString part
else if part == 10
then "A"
else if part == 11
then "B"
else if part == 12
then "C"
else if part == 13
then "D"
else if part == 14
then "E"
else if part == 15
then "F"
else builtins.throw "Invalid hex digit.";
in
lib.strings.concatMap
serialize
(lib.numbers.into.base 16 value);
};
## Compare two numbers. When the first number is less than the second, -1
## is returned. When the first number is greater than the second, 1 is
## returned. When the numbers are equal, 0 is returned.
##
## @type Int -> Int -> Int
compare = a: b:
if a < b
then -1
else if a > b
then 1
else 0;
};
}