How is it, that in
`(1 ,(+ 1 1) (- 4 1) 4) ; '(1 2 (- 4 1) 4)
the minus sign (“-“) is not treated as an operator (but as a symbol; ‘- instead of #’- – correct?) (This part I think I understand.)
But why is it, that the third left parenthesis is indeed evaluated to '( -> (list … (That is, a list/expression delimiter and not just a literal like the ‘- above?) Does the interpreter “peek ahead” for the closing delimiter or does it simply say, “OK, this should be a list. If there is no delimiter to the right the expression is not valid and that’s not my problem.”?
Sorry for a confusing question; to boil it down, I guess my question is: how does the interpreter step by step evaluate the above list correctly? (Also feel free to correct terminology.)
i’m trying to imagine what you are thinking that is causing the confusion. i guess that the problem is:
if that is what you are asking, then the answer (roughly – people like rainer know a lot more about lisp than me) that quoting isn’t as simple as you think. when the code is read by lisp, it is processed by a thing called “the reader”. that turns the code into a syntax tree – a bunch of lists that form a tree that contains the program.
quoting is just an instruction to the reader that says something like:
and comma works something like
i don’t know if that helps. if i am contradicting rainer then he (i assume it’s a male name?) wins. i am just trying to get more inside your head.
oh – one more thing. quoting doesn’t make things “text”. it makes words atoms (and brackets lists). so it’s really not as simple as “make this text”.