2.4 Programming Types

There are two general categories of types in Emacs Lisp: those having to do with Lisp programming, and those having to do with editing. The former exist in many Lisp implementations, in one form or another. The latter are unique to Emacs Lisp.

• Integer Type		Numbers without fractional parts.
• Floating-Point Type		Numbers with fractional parts and with a large range.
• Character Type		The representation of letters, numbers and control characters.
• Symbol Type		A multi-use object that refers to a function, variable, or property list, and has a unique identity.
• Sequence Type		Both lists and arrays are classified as sequences.
• Cons Cell Type		Cons cells, and lists (which are made from cons cells).
• Array Type		Arrays include strings and vectors.
• String Type		An (efficient) array of characters.
• Vector Type		One-dimensional arrays.
• Char-Table Type		One-dimensional sparse arrays indexed by characters.
• Bool-Vector Type		One-dimensional arrays of t or nil.
• Hash Table Type		Super-fast lookup tables.
• Function Type		A piece of executable code you can call from elsewhere.
• Macro Type		A method of expanding an expression into another expression, more fundamental but less pretty.
• Primitive Function Type		A function written in C, callable from Lisp.
• Byte-Code Type		A function written in Lisp, then compiled.
• Record Type		Compound objects with programmer-defined types.
• Type Descriptors		Objects holding information about types.
• Autoload Type		A type used for automatically loading seldom-used functions.
• Finalizer Type		Runs code when no longer reachable.