Types

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# XCX 3.0 Data Types

Simple Types

Symbol Type Default Example
i / int Integer 0 42, -7, 0
f / float Float 0.0 3.14, -0.5, 2.0
s / str String "" "hello", ""
b / bool Boolean false true, false
date Date 1970-01-01 date("2024-12-25")
json JSON Object null <<< {"key": "value"} >>>

Complex Types

Symbol Type Declaration Example
array:i Array of integers array:i: nums {1, 2, 3}
array:f Array of floats array:f: vals {1.0, 2.5}
array:s Array of strings array:s: words {"a", "b"}
array:b Array of booleans array:b: flags {true, false}
array:json Array of JSON objects array:json: items
set:N Set of Natural numbers set:N: s {1,,10}
set:Z Set of Integers set:Z: s {-2, 0, 2}
set:Q Set of Rational (float) set:Q: s {0.5, 1.0, 1.5}
set:S Set of Strings set:S: s {"a", "b"}
set:B Set of Booleans set:B: s {true, false}
set:C Set of Characters set:C: s {"A",,"Z"}
map Key-Value Map map: m { schema = [s <-> i] data = [...] }
table Relational Table table: t { columns = [...] rows = [...] }
database: Database Connection database: db { engine = "sqlite", path = "app.db" }
fiber:T Typed Fiber fiber:b: f = my_fiber(arg)
fiber: Void Fiber fiber: f = my_void_fiber(arg)

array:json

array:json is an array storing elements of type json. Used primarily when working with HTTP responses that return arrays of JSON objects.

--- Declare an empty JSON array
array:json: items;

--- Iterate over a JSON array (e.g. from a network response)
i: size = resp.body.size();
i: idx = 0;
while (idx < size) do;
    json: item = resp.body.get(idx);
    s: name; item.bind("name", name);
    >! name;
    idx = idx + 1;
end;

--- Add an element
json: obj <<< {"key": "value"} >>>;
items.push(obj);

Methods on array:json are identical to other array types (.push(), .pop(), .get(i), .size(), etc.).

database:

database: represents a connection to a relational database. Declared with a configuration block and used through its built-in methods. See Database Documentation for the full API.

database: app {
    engine = "sqlite",
    path   = "app.db"
};

yield app.sync(users);
table: all = yield app.fetch(users);

Default Values

int:   def_int;     --- 0 (alias for i)
float: def_float;   --- 0.0 (alias for f)
str:   def_str;     --- "" (alias for s)
bool:  def_bool;    --- false (alias for b)

Type Casting

f: x = 3.7;
i: n = i(x);       --- 3 (truncate toward zero)

i: m = 42;
f: y = f(m);       --- 42.0

i: num = 99;
s: str = s(num);   --- "99"

[!NOTE] b → i conversion is intentionally blocked. true + 1 is a type error to prevent logical bugs common in C-family languages.

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