The usefullness of EQUALP

[svetlyak40wt]

Among the 4 Lisp’s equality operators equalp may be the least used, but it has some really cool features:

• it matches strings ignoring case (this is well-known, I suppose)
• it also matches structs
• it also matches vectors and arrays
• and it matches hash-tables

The last 3 are really useful because unlike strings and other primitive types, there’s no specialized equality predicates for built-in structural types, so equalp fills this role.

(contributed by @vseloved).
(source: https://lisptips.com/post/53215108902/the-usefullness-of-equalp)