3 Evaluation and Compilation   3.1 Evaluation   3.1.2 The Evaluation Model   3.1.2.1 Form Evaluation

3.1.2.1.2 Conses as Forms

If the car of that compound form is a symbol, that symbol is the name of an operator, and the form is either a special form, a macro form, or a function form, depending on the function binding of the operator in the current lexical environment. If the operator is neither a special operator nor a macro name, it is assumed to be a function name (even if there is no definition for such a function).

If the car of the compound form is not a symbol, then that car must be a lambda expression, in which case the compound form is a lambda form.

How a compound form is processed depends on whether it is classified as a special form, a macro form, a function form, or a lambda form.

3.1.2.1.2.1  Special Forms
3.1.2.1.2.2  Macro Forms
3.1.2.1.2.3  Function Forms
3.1.2.1.2.4  Lambda Forms