Types

Kiwi supports the following builtin types. To build your own type, see Structs.

---

Type	Description	Documentation
boolean	A true or false value.	See below for an example.
bytes	A byte array.	See below for an example.
date	A date-time object.	See Dates.
float	A floating point number.	See below for an example.
generator	A lazy sequence produced by a generator function.	See Generators.
hashmap	A dictionary of key-value pairs.	See Hashmaps.
integer	A 64-bit integer.	See below for an example.
lambda	An anonymous function.	See lambdas.
list	A list of values.	See Lists.
none	A null value.	See below for an example.
object	An instance of a struct.	See Structs and Abstract Structs.
pointer	A pointer to a managed reference.	See example below.
string	A sequence of characters.	See Strings.

---

boolean

A true or false value.

# A value indicating true or false.
enabled = true

println(enabled) # prints: true

---

bytes

A byte array.

ascii_chars = [33..126].to_bytes()

println ascii_chars.to_string() 

/# prints:
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
#/

---

date

Represents a date and time. See Dates.

dt = "2023-01-02".to_date()

println(dt) # prints: 1/2/2023 12:00:00 AM

---

float

A floating point number.

# A real number.
pi = 3.14159
tau = pi * 2

println(tau) # prints: 6.28318

---

generator

A lazy sequence produced by a generator function — a function that contains one or more yield statements. Calling a generator function does not execute its body; instead it returns a generator object that produces values on demand when iterated with for.

fn countdown(n)
  while n >= 0 do
    yield n
    n -= 1
  end
end

for x in countdown(3) do
  print "${x} "
end
# 3 2 1 0

# typeof returns "generator"
g = countdown(5)
println typeof(g)   # generator

---

hashmap

A dictionary of key-value pairs. See Hashmaps.

# A simple hashmap with a single key `language`.
hashmap = { "language": "kiwi" }

println(hashmap) # prints: {"language": "kiwi"}
println(hashmap.language) # prints: kiwi

---

integer

A 64-bit integer.

# A whole number.
number = 5
number += 5

println(number) # prints: 10

---

lambda

An anonymous function. Lambdas can be assigned identifiers for code reuse. See lambdas.

# Define a reusable lambda called `puts` which accepts a parameter called `s` and prints its value.
puts = with (s) do
  println(s)
end

puts("Hello, World!") # prints: Hello, World!

---

list

A list of values. See Lists.

# A list of values.
list = [1, 2, 3, 4, 5]
println(list) # prints: [1, 2, 3, 4, 5]

---

none

A null value. A value that points to nothing.

# Define a hashmap, `c`, with null values.
c = { "a": null, "b": null }
println(c) # prints: {"a": null, "b": null}

# Deserializing a JSON string with "null" values into a hashmap.
d = deserialize('{"a": null, "b": null}')
println(d) # prints: {"a": null, "b": null}

# Set the hashmap key values of `a` and `b` to non-null values.
d.a = false
d.b = 'hello'
println(d) # prints: {"a": false, "b": "hello"}

# Set the hashmap key values of `a` and `b` to null values.
d.a = null
d.b = null
println(d) # prints: {"a": null, "b": null}

# Set `d` to a null value.
d = null
println(d) # prints: null

# Explicitly checking if `d` is null.
if d == null
  println "d is null" # prints: d is null
end

# Set `d` to a non-null value.
d = 0

# Explicitly checking if `d` is non-null.
if d != null
  println "d is not null" # prints: d is not null
end

# Type coercion of null to a Boolean.
if !null
  println "hello world" # prints: hello world
end

---

object

An instance of a struct. See Structs and Abstract Structs.

# Define an empty struct called `MyStruct`
struct MyStruct end

# Create an instance of `MyStruct`
inst = MyStruct.new()
println(inst)
# prints: [Object(struct=MyStruct, identifier=inst)]

pointer

A pointer to a managed reference. For internal use only.

cap = 3
chan = __chan_create__(cap)
__chan_send__(chan, "hello")
println __chan_recv__(chan) # prints hello
__chan_close__(chan)

---

string

Represents text data. See Strings.

# A string of text.
hello = "Hello, World!"

println(hello) # prints: Hello, World!