Expressions not valid in hash-set creation

[mx]

Looks like #{...} can often only accept immediate values. For example:

$ sbcl
* (require :reader)
NIL
* (require :hash-set)
NIL
* (reader:enable-reader-syntax 'get-val 'hash-table 'not 'string 'describe 'array 'set 'run-program)
#<READTABLE {100261DBA3}>
* (defvar x #{(cons 1 2)})

debugger invoked on a TYPE-ERROR @536416CB in thread
#<THREAD "main thread" RUNNING {1004DC81F3}>:
  The value
    2
  is not of type
    LIST

;; ...

* (defvar s #{:a 1 :b 2})
S

[digikar99]

While #{...} can handle non-immediate-value expressions, hash set does handle lists in an unexpected manner.

CL-USER> (let ((reader:*set-function* 'hash-set:list-to-hs)) ; hash-set:list-to-hs converts lists to hash-sets
           (hash-set:dohashset (x (eval (read-from-string "#{(list 1 2)}")))
             (princ x)))
#<HASH-SET of count: 2 {1042E1B5C3}>
NIL
CL-USER> (let ((reader:*set-function* 'hash-set:list-to-hs)) ; #{...} can handle non-immediate values
           (hash-set:dohashset (x (eval (read-from-string "#{(+ 2 3)}")))
             (princ x)))
5
NIL

One could write their own function that behaves as expected:

CL-USER> (defun our-list-to-hash-set (list &key test)
           (declare (ignore test))
           (let ((hs (hash-set:make-hash-set)))
             (loop :for item :in list
                   :do (hash-set:hs-ninsert hs item))
             hs))
OUR-LIST-TO-HASH-SET
CL-USER> (let ((reader:*set-function* 'our-list-to-hash-set))
           (hash-set:dohashset (x (eval (read-from-string "#{(list 1 2)}")))
             (princ x)))
(1 2)
NIL

[mx]

With the latest commit removing the hash-set dependency, I suppose this issue is now obsolete.

That said, before closing it, since you already went through the work of writing a version that works. I'm wondering if it makes sense to you to add a contrib/ directory, with a system for hash-set, that you include/use when you want to use hash-set with this library. Then pull requests could be made similarly for adding systems for fset and whatever other data structure libraries the user cares for.

[digikar99]

Before adding a contrib, I'd want to evaluate cl-syntax to see if reader can be merged into it. The original cl-syntax has been archived by the author, so a maintainer (someone who has already invested time in it and uses it actively) for cl-syntax is remaining.