Type System

Hush is strongly dynamically typed, which means all values have a well formed type, but variables are untyped. Therefore, you may assign values of distinct types to a given variable. Python, Ruby, and Lua are also dynamically typed languages, in case you’re familiar with any of them.

As in Lua, Hush proposes only a handful of built-in types, and no user-defined types. This makes the type system extremely simple, and yet still it remains quite expressive. The following types are available:

• nil: the unit type, usually for representing missing values.
• bool: the boolean type.
• int: a 64 bit integer type.
• float: a 64 bit floating point type.
• char: a C-like unsigned char type, 0-255.
• string: a char-array like immutable string.
• array: a heterogeneous array, 0-indexed (unlike in Lua).
• dict: a heterogeneous hash map.
• function: a callable function.
• error: a special error type, to ease distinction of errors from other values. This type can only be instantiated by the built-in std.error function.

Although it may seem like a limitation to only have a handful of types, Hush provides facilities that enable these types to be extremely flexible. We’ll get more in depth about that in practice on the Paradigms section.