std/conv

Converting values to and from their string forms. Import with import "std/conv";. Available everywhere.

Functions

to_string

string to_string<T>(v: T)

Converts any supported value to its string form. The type argument is required, since Kora does not infer type arguments from the call.

conv.to_string::<int>(42)       # "42"
conv.to_string::<bool>(true)    # "true"
conv.to_string::<char>('A')     # "A"
conv.to_string::<Money>(m)      # whatever Money's __str__ returns

What each type produces:

T	Result
int	decimal, with a leading - if negative
real	decimal with up to six fractional digits, trailing zeros trimmed (at least one digit always remains). Non-finite values become "nan", "inf", or "-inf"
bool	"true" or "false"
char	a one-character string
string	the value unchanged
a struct	whatever its string __str__(self) method returns

conv.to_string::<int>(-7)         # "-7"
conv.to_string::<real>(3.14)      # "3.14"
conv.to_string::<real>(2.0)       # "2.0"
conv.to_string::<real>(1.0/3.0)   # "0.333333"

Any other T is an error at the call site, reported as a missing __str__ method on the type.

string_to_int

int? string_to_int(s: string)

Parses s as a decimal integer: an optional leading + or -, then digits. Returns none if s is empty or contains anything else, including whitespace.

conv.string_to_int("42")     # 42
conv.string_to_int("-13")    # -13
conv.string_to_int("4x")     # none
conv.string_to_int(" 42")    # none (no whitespace allowed)

A typical use, defaulting on bad input:

let parsed = conv.string_to_int(text);
let port = 80;
if (parsed != none) { port = parsed!; }