CODEWITHSUNDEEP
lispcommon-lisp
Eli Schneider
Eli Schneider

Reputation: 4955

Common Lisp: Why not the array literal evaluate arguments?

Why is it that the Common Lisp array syntax is not evaluating its arguments:

(let ((a 1)) #2A((a 2) (3 4)))
=> #2A((A 2) (3 4))

I would have guessed it was #2A((1 2) (3 4)). Is this because A is not available at reader time?

Upvotes: 6

Views: 876

Answers (1)

Svante
Svante

Reputation: 51511

In short, yes.

#2A((A 2) (3 4)) is not an abbreviation ("syntactic sugar") for (make-array '(2 2) :initial-contents (list (list a 2) (list 3 4))). If anything, it could be rationalized as (make-array '(2 2) :initial-contents (quote ((A 2) (3 4)))), but this would be a bit misleading as the array construction already happens at read-time.

Upvotes: 5

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