Hi Arie,
> Playing around I got this surprise:
> I wanted to set variable x to value '(1 2 3 4):
> 1. first try (without RTFM):
> ...
> 2. second try (superficially RTFM)
> ...
> 3. third try (now RTFM)
Yeah, as you see, PicoLisp is radically different both from CL and Scheme :)
> : (de x . '(1 2 3 4))
> : x
> -> '(1 2 3 4)
>
> Bingo! I now can see a master plan to keep the number of
> functions limited, but more versatile.
1. Note that normally you set a symbol value with either 'setq' or 'let'.
: (setq x (1 2 3 4))
-> (1 2 3 4)
: x
-> (1 2 3 4)
2. Also, are you sure you want the quote here? As can be seen above, lists
starting with a number don't need to be quoted at all.
But as 'de' does not evaluate its arguments, what you actually did was
setting 'x' to the 5-element list (quote 1 2 3 4).
3. A dot followed by a list is just a list:
: (de x . (1 2 3 4))
is the same as
: (de x 1 2 3 4)
In both cases:
: x
-> (1 2 3 4)
4. 'de' is basically like a non-evaluating 'setq' with checks for changes:
: (de x 5 6 7) # Changed value!
# x redefined # gives a redefined message
-> x
: x
-> (5 6 7)
I hope this clears up things a little ;)
♪♫ Alex
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