Re: Calling a function with undefined symbol

[Jean Abou Samra]

> Le 31 oct. 2022 à 09:59, Heime <heimeborgia@protonmail.com> a écrit :
> 
> Yes, I have got really confused about what symbols are exactly.  Even
> after reading several times.  I have never seen anybody make a symbol,
> only variables.  So, what is a symbol?



Imagine parents who are planning to have a child and decide they will call it, 
say Deborah. They will say things like “I like the name Deborah better than 
Mary”. Those are sentences about the names themselves, not some children. The 
names don’t need children in order to exist as words. Then, the child is born 
and sentences like “Deborah weighs 3kg” (referring to the child named Deborah) 
start to make sense.

When you do 'symbol in Lisp, this gives you a bare name, or a “symbol”. With 
symbol-value, you get what value is associated with this symbol, if any (the 
child with that name). But you don’t need a value bound to the symbol (a child 
called Deborah) before you start using the symbol itself (the name “Deborah”).