Type of Define expression in Scheme

racket, scheme, types

Solution

In Racket `define` is a special form and not an expression, so it doesn't have a value per-se, if you try to execute something like this you'll get an error:

(display (define x 42))
=>  define: not allowed in an expression context in: (define x 42)

If it were to have a value it'd be something akin to `void`, but that will be dependent on the particular implementation details of the interpreter (I believe I saw one interpreter return `#t` after a `define` was completed)

The constant `#<void>` is returned by most forms and procedures that have a side-effect and no useful result

The specification doesn't go into details on this point, either - reinforcing the statement that it's implementation-dependent.

Problem

To put it simply: My question is whats is the type of a define expression in Scheme? Take for example: ``` (define x 5) ``` or ``` (define x (lambda (n) (* n n))) ``` It's a bit confusing for me. Can anyone help?

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