Re: if procedure

[Anders Eriksson]

On 2019-11-27 14:20, Freeman Gilmore wrote:

> From Extending Lilypond:
>
> guile> (define a 3)
> guile> (define b 5)
> guile> (if (> a b) "a is greater than b" "a is not greater than b")
> "a is not greater than b"
>
> Note missing ")".
>     
    No, it's not missing any ")"
> In Frescobaldi i tried:
>
> \version "2.19.83"
> #(define a 3)
> #(define b 5)
> #(display (if (> a b) "a is greater than b" "a is not greater than b")
> "a is not greater than b"))
>
>
>     
    What is the code suppose to do?
      You define two variables, a and b, and give them a value.
      You then compare a and b and if a is greater than b then you write
      out a text "a is greater than b" if not then you write out a
      different text "a is not greater than b".
      
      Scheme is a Lisp based language and uses parentheses to group
      statements.
      The number of left parentheses should be the same as the number of
      right parentheses!!!
      
      Your problem is the line
    
#(display (if (> a b) "a is greater than b" "a is not greater than b")
    
      It has 3 left parentheses and 2 right parentheses.
      Frescobaldi is helpful and shows the matched parentheses when you
      put the cursor on a a parentheses.
      Using this help you soon will find the the first left parentheses
      has no right parentheses.
      
      The error will disappear if you add a right parentheses last on
      the line
      #(display (if (> a b) "a is greater than b" "a is not greater
      than b"))
      
      // Anders