gleam/iodata
Types
Iodata
Iodata is a type used for efficiently building strings.
When we append one string to another the strings must be copied to a new location in memory so that they can sit together. This behaviour enables efficient reading of the string but copying can be expensive, especially if we want to join many strings together.
Iodata is different in that it can be joined together in constant time
using minimal memory, and then can be efficiently converted to a string
using the to_string function.
pub external type Iodata
Functions
append
pub external fn append(to: Iodata, suffix: String) -> Iodata
Append a String onto the end of some Iodata.
Runs in constant time.
append_iodata
pub external fn append_iodata( to: Iodata, suffix: Iodata, ) -> Iodata
Append some Iodata onto the end of another.
Runs in constant time.
concat
pub external fn concat(List(Iodata)) -> Iodata
Joins a list of iodata into a single iodata.
Runs in constant time.
from_float
pub external fn from_float(Float) -> Iodata
Creates textual representation of the given float as iodata.
from_strings
pub external fn from_strings(List(String)) -> Iodata
Convert a list of strings into iodata.
Runs in constant time.
is_empty
pub external fn is_empty(Iodata) -> Bool
Inspect some iodata to determine if it is equivalent to an empty string.
Examples
> new("ok") |> is_empty
False
> new("") |> is_empty
True
> from_strings([]) |> is_empty
True
is_equal
pub external fn is_equal(Iodata, Iodata) -> Bool
Compare two pieces of iodata to determine if they have the same textual content.
Comparing two iodata using the == operator may return False even if they
have the same content as they may have been build in different ways, so
using this function is often preferred.
Examples
> from_strings(["a", "b"]) == new("ab")
False
> is_equal(from_strings(["a", "b"]), new("ab"))
True
lowercase
pub external fn lowercase(Iodata) -> Iodata
Converts Iodata to a new Iodata where valid UTF-8 string data is lowercased.
prepend
pub external fn prepend(to: Iodata, prefix: String) -> Iodata
Prepend a String onto the start of some Iodata.
Runs in constant time.
prepend_iodata
pub external fn prepend_iodata( to: Iodata, prefix: Iodata, ) -> Iodata
Prepend some Iodata onto the start of another.
Runs in constant time.
replace
pub fn replace( in iodata: Iodata, each pattern: String, with substitute: String, ) -> Iodata
Replaces all instances of a pattern with a given string substitute.
reverse
pub external fn reverse(Iodata) -> Iodata
Converts Iodata to a new Iodata where valid UTF-8 string data is reversed.
split
pub fn split(iodata: Iodata, on pattern: String) -> List(Iodata)
Splits iodata on a given pattern into a list of iodata.
to_string
pub external fn to_string(Iodata) -> String
Turns an Iodata into a String
This function is implemented natively by the virtual machine and is highly optimised.
uppercase
pub external fn uppercase(Iodata) -> Iodata
Converts Iodata to a new Iodata where valid UTF-8 string data is uppercased.