I am reading SICP recently to learn lisp programming.
There is an example in the book to make a high level function sum as below.
(define (sum term a next b) ... (term a) ... (next a) ...
In this function, term and next are functions.
I want to write the same function in elisp like this.
(defun sum (term a next b) .... (funcall term a) ... (func next a) ....
Then I define some test functions to test sum
(defun inc-test (x) (+ x 1)) sum inc-test 1 inc-test 10
but it show errors like this: Invalid function: inc-test
As I am new to elisp, can anyone call tell me how to fix it? very appreciate
inc-testin your last example is used as a variable, but is not defined as a variable (it is a function). You need to pass either a symbol or a function reference to
funcall. Hence one way of fixing your code is to pass it
inc-test(note the quote).