make-symbol creates a symbol with a sharpsign, getf fails in accessing it

Asked May 11 '20 at 12:36

Active May 11 '20 at 12:36

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I create a plist with keys that I turn into a symbol from some data with make-symbol:

(defparameter *plist* (list (make-symbol "key") "val"))

It creates the symbol #:|key|: it starts with a sharp sign.

(#:|key| "val")

Using getf mysteriously returns nil:

(getf *plist* :|key|)
NIL

and it is not possible to use #:|key|. This denotes, AFAIK, a variable, which is undefined. I tried a combination of (intern (string (make-symbol… with no success.

Note that the access library works on that structure:

(access:access *plist* :|key|)
"val"
T

What is going on? Is make-symbol appropriate? How can I make getf work?

Thanks

What I am doing is populating an existing plist with user data. New keys can be created on the fly. A plist has been convenient so far. Maybe is there a better suited data structure for this, like a hash-table.

asked May 11 '20 at 12:36

Ehvince

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@sds okay-ish to mark as duplicate… there would still be `:|key|` vs `'key` and `make-symbol` vs `read-from-string` and `getf` vs `access` to discuss, IMO. – Ehvince May 11 '20 at 13:33
So please ask a specific question that is not clear yet. – sds May 11 '20 at 13:49
access compares symbol names (it defines its own equalper, used as a default test) – coredump May 11 '20 at 16:14
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`(eq (intern "key" "KEYWORD") :|key|)` -> T – Rainer Joswig May 12 '20 at 07:07
Generally it's that useful to use an uninterned symbol like `#:|key|` as a key in a property list, since GETF does not support to choose an equality predicate. One would use a replacement for GETF with that feature, then. – Rainer Joswig May 12 '20 at 07:11
1

`#:|foo|` donates an uninterned symbol with a case specific name "foo". – Rainer Joswig May 12 '20 at 07:13
Thank you all for the tips nonetheless. – Ehvince May 12 '20 at 10:03

make-symbol creates a symbol with a sharpsign, getf fails in accessing it

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