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Re: Gurus? Care to re-explain the absense of gh_set_x() for me?
From: |
Miroslav Silovic |
Subject: |
Re: Gurus? Care to re-explain the absense of gh_set_x() for me? |
Date: |
16 Jul 2001 00:01:47 +0200 |
Sam Tregar <address@hidden> writes:
> > Hmmm... not sure what the implications of directly changing the SCM
> > struct contents would be, and whether this might break things in
> > Guile.
>
> This is roughly what I was expecting the non-existent gh_set_x() to do -
> change the value stored in an SCM without otherwise disturbing its
> identity.
Actually gh_set_x changes the _binding_ of a variable, rather than
modifying the value it's bound to. Basically, a variable in Scheme is
simply a name for a particular writable cell that contains one SCM,
and SCM itself is _not_ a cell (in particular, integers in Guile are
not represented by pointers to a box, they're recognised by a
particular bit-pattern of a SCM value).
So basically you just can't change a value of a SCM without changing
its identity. :)
--
How to eff the ineffable?
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, (continued)
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Sam Tregar, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Alex Shinn, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Sam Tregar, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Alex Shinn, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Sam Tregar, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Eric E Moore, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Rob Browning, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Miroslav Silovic, 2001/07/15
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Rob Browning, 2001/07/16
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Neil Jerram, 2001/07/14
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?,
Miroslav Silovic <=
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Neil Jerram, 2001/07/16
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Miroslav Silovic, 2001/07/15
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Matthias Koeppe, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Sam Tregar, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Brett Viren, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Sam Tregar, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, tom, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Matthias Koeppe, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Sam Tregar, 2001/07/13
- Re: Gurus? Care to re-explain the absense of gh_set_x() for me?, Matthias Koeppe, 2001/07/13