* generating SXML trees in guile
@ 2021-01-09 23:50 Matt Wette
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From: Matt Wette @ 2021-01-09 23:50 UTC (permalink / raw)
To: guile-devel
This is a FYI, not saying this is a bug.
I'm digging into the sxml xpath procedures and came across a potential
issue with using sxml in Guile.
I believe I remember that Oleg's SXML code relies on the fact that no
nodes a sxml tree are eq?. For example, in the SXML tree
(define sx1 '(*TOP* (a "1") (a "1)))
node-parent in (sxml xpath) depends on the fact that
(eq? (list-ref sx1 1) (list-ref sx1 2)
=>
#f
But the result, in Guile 3.0.4, is
#t
I'm guessing this is cse optimization at work. I tried this also:
(let* ((sx2 '())
(sx2 (cons '(a "1") sx2))
(sx2 (cons '(a "1") sx2))
(sx2 (cons '*TOP* sx2)))
(eq? (list-ref sx2 1) (list-ref sx2 2)))
=>
#t
In my sandbox, I'm using copy-tree which seems to be changing
the #t to #f, so at least that works.
Matt
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