Crystal provides several literals for creating values of some basic types.
| Literal | Sample values |
|---|---|
| Nil | nil |
| Bool |
true, false
|
| Integers |
18, -12, 19_i64, 14_u32,64_u8
|
| Floats |
1.0, 1.0_f32, 1e10, -0.5
|
| Char |
'a', '\n', 'あ'
|
| String |
"foo\tbar", %("あ"), %q(foo #{foo})
|
| Symbol |
:symbol, :"foo bar"
|
| Array |
[1, 2, 3], [1, 2, 3] of Int32, %w(one two three)
|
| Array-like | Set{1, 2, 3} |
| Hash |
{"foo" => 2}, {} of String => Int32
|
| Hash-like | MyType{"foo" => "bar"} |
| Range |
1..9, 1...10, 0..var
|
| Regex |
/(foo)?bar/, /foo #{foo}/imx, %r(foo/)
|
| Tuple | {1, "hello", 'x'} |
| NamedTuple |
{name: "Crystal", year: 2011}, {"this is a key": 1}
|
| Proc | ->(x : Int32, y : Int32) { x + y } |
| Command |
`echo foo` , %x(echo foo)
|
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https://crystal-lang.org/docs/syntax_and_semantics/literals.html