Definitions - Revised(5) Scheme

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5.2 Definitions

Definitions are valid in some, but not all, contexts where expressions are allowed. They are valid only at the top level of a <program> and at the beginning of a <body>.

A definition should have one of the following forms:

(define <variable> <expression>)
(define (<variable> <formals>) <body>)
<Formals> should be either a sequence of zero or more variables, or a sequence of one or more variables followed by a space-delimited period and another variable (as in a lambda expression). This form is equivalent to
```
          
          (define <variable>
            (lambda (<formals>) <body>)).
          
     
```

(define (<variable> . <formal>) <body>)

<Formal> should be a single variable. This form is equivalent to

          
          (define <variable>
            (lambda <formal> <body>)).