Ok, I see my mistake. I assumed that let and the rest could create enclosing environments, when only a function call can.
Another example I made of how to use 'up: : (de f () (and 1000 (up 1 @) @)) -> f : (and 10 (f)) -> 10 Thanks for the clarification alex! On Mon, May 24, 2021 at 12:55 AM Alexander Burger <a...@software-lab.de> wrote: > On Sun, May 23, 2021 at 08:44:32PM -0500, polifemo wrote: > > `(let @ 1 (let @ 10 (let @ 20 (up 2 @))))` > > This are two misunderstandings in this example: > > 1. It has not a good idea to bind '@' in a 'let' expression. '@' is set > implicitly by flow- and logic-functions, so a correct usage would be > > (and 1 (or 10 (while 20 (up 2 @)))) > > or - more realistically - > > (and (foo) (or (bar) (while (zup) (up 2 @)))) > > 2. 'up' does not care about 'let', 'use', 'for' etc. They are ignored. An > up > "enclosing environment" always means the enclosing *function* > environment. So > all the above 'let's all run in the same environment. The same rule > applies > to the environment offsets to 'eval' and 'run'. > > > > returns 1, as I expected, if I enclose the 'up expression inside a > function > > This return value of '1' just happens because the environment setup in > bindeng > '@' in 'let' is undefined. > > > Let me try to give an example. > > (when 7 # The result of 'when' is what we are interested in > (extract > '((N) # Here we are in a function > (when (num? N) # 'when' sets '@' > (+ N @) ) ) # so we add the wrong '@' > (1 a 2 b 3))) > -> (2 4 6) > > (when 7 > (extract > '((N) # in a function > (when (num? N) > (+ N (up 1 @)) ) ) # Here we get the '7' > (1 a 2 b 3))) > -> (8 9 10) > > ☺/ A!ex > > -- > UNSUBSCRIBE: mailto:picolisp@software-lab.de?subject=Unsubscribe >
