Using make-symbol, boundp and symbol-value to reference a variable whose name is made from a string

Question

When I run the following three lines with eval-region

(defcustom custom-var "some-custom-value" "for testing only")
(setq indirectRef (make-symbol "custom-var"))
(message "ref=%s, is bound=%s" indirectRef (boundp indirectRef))

the output is

`ref=custom-var, is bound=nil`

Why does boundp not return t?

Answer 1

You're mixing up a few things.

• Your (defcustom...) is essentially irrelevant to the rest, except that it sets the value of variable custom-var to a given string.
• You need to C-h f make-symbol and C-h f intern. And see (elisp) Creating Symbols.

---

make-symbol is a built-in function in ‘C source code’.

(make-symbol NAME)

Return a newly allocated uninterned symbol whose name is NAME.

Its value is void, and its function definition and property list are nil.

---

intern is a built-in function in ‘C source code’.

(intern STRING &optional OBARRAY)

Return the canonical symbol whose name is STRING.

If there is none, one is created by this function and returned.

A second optional argument specifies the obarray to use; it defaults to the value of obarray.

(boundp 'custom-var)                ; => t, since you did the `defcustom`.
(boundp (intern "custom-var"))      ; => t, since `intern` returns the same symbol.
(boundp (make-symbol "custom-var")) ; => nil. `make-symbol` returns an uninterned symbol.

More succinctly:

(eq (intern "custom-var") (make-symbol "custom-var"))      ; => nil.
(eq (make-symbol "custom-var") (make-symbol "custom-var")) ; => nil.
(eq (intern "custom-var") (intern "custom-var"))           ; => t.