toIntBase10
lib.strings.toIntBase10
Docs pulled from | This Revision | about 1 hour ago
Parse a string as a base 10 int. This supports parsing of zero-padded integers.
Inputs
str- A string to be interpreted as an int.
Type
toIntBase10 :: string -> int
Examples
lib.strings.toIntBase10 usage example
toIntBase10 "1337"
=> 1337
toIntBase10 "-4"
=> -4
toIntBase10 " 123 "
=> 123
toIntBase10 "00024"
=> 24
toIntBase10 "3.14"
=> error: floating point JSON numbers are not supported
Noogle detected
Implementation
The following is the current implementation of this function.
toIntBase10 =
let
matchStripInput = match "[[:space:]]*0*(-?[[:digit:]]+)[[:space:]]*";
matchZero = match "0+";
in
str:
let
# RegEx: Match any leading whitespace, then match any zero padding,
# capture possibly a '-' followed by one or more digits,
# and finally match any trailing whitespace.
strippedInput = matchStripInput str;
# RegEx: Match at least one '0'.
isZero = matchZero (head strippedInput) == [];
# Attempt to parse input
parsedInput = fromJSON (head strippedInput);
generalError = "toIntBase10: Could not convert ${escapeNixString str} to int.";
in
# Error on presence of non digit characters.
if strippedInput == null
then throw generalError
# In the special case zero-padded zero (00000), return early.
else if isZero
then 0
# Error if parse function fails.
else if !isInt parsedInput
then throw generalError
# Return result.
else parsedInput;