World: r3wp
[Red] Red language group
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Kaj 17-Jun-2011 [2038x2] | input-next may have the same problem, but did you try it? |
Strings are terminated properly with gets/input-line but you must allocate an unknown storage size, which is warned for in the source of the binding | |
Kaj 18-Jun-2011 [2040x3] | The binaries Red generates with a binding are now ten times as big as a few weeks ago, because it now generates code for #import definitions. Is that correct? |
When I have a struct! as a local variable, is only the pointer to the struct reserved on the stack, not the struct itself? | |
When I make a STRUCT for a local variable within a function, is it created on the heap, so that I need to free it? | |
Dockimbel 18-Jun-2011 [2043x5] | Bigger binaries: yes, it is caused by #import bindings and by runtime message strings. |
Local struct variable: that is correct, only the pointer is stored in the stack frame. | |
STRUCT is used to declare literal structures. As all literals, it is stored in the data segment of the executable image, you don't need to free it as it is not allocated with a malloc() call. | |
Kaj: have you found the "struct [...]" construction somehow misleading? I am asking this because there is a discussion about that on the mailing-list and I need to decide this weekend if I keep pointer/struct literal declarations as-is or change it. | |
Any feedback on this topic (and other opened questions on the ML and issue tracker) will be appreciated. | |
Kaj 18-Jun-2011 [2048x8] | I've been thinking about it, but the reason it is misleading is basically that it's defined at the C level. You have to flip flop your mind between low level C thinking and high level REBOL thinking |
I suppose this is inherent in the concept of Red/System, and I think it's mainly a matter of learning the new language | |
However, my own preference is to make concepts higher level if it doesn't compromise performance | |
It now dawns on me that I mixed up STRUCT and ALLOCATE. I hit these issues last night and went to bad because I was tired and pretty sure that I would be able to see it more clearly today, but I had already formulated the questions in my head :-) | |
to bed | |
The fact that I needed to allocate a local struct was pointed out to me by the new initialisation checks in Red, so that's pretty good | |
It would be nice to be able to use SIZE? on a datatype, instead of an actually existing data value: | |
size? integer! | |
Dockimbel 18-Jun-2011 [2056x2] | That might only be useful with integer! as it should be extended to 64-bit when Red/System will be ported to 64-bit platforms. But I think that a specific macro would be more appropriate (something like integer-size?). |
or rather: get-integer-size | |
Kaj 18-Jun-2011 [2058] | No, I simplified the example. I actually wanted to get sizes of structs without allocating one |
Dockimbel 18-Jun-2011 [2059] | Try with an alias (untested). |
Kaj 18-Jun-2011 [2060] | Doesn't it get the size of the pointer then? |
Dockimbel 18-Jun-2011 [2061x4] | Let me try... |
SIZE? doesn't seem to recognize the alias. | |
An alias is an abstract definition, it doesn't allocated anything. So we can decide that the size of an alias is the whole struct size. | |
allocated => allocate | |
Kaj 18-Jun-2011 [2065x7] | Yes, that's what I would like |
In the runtime, there's now a new generic pointer type defined: | |
#define byte-ptr! c-string! | |
However, it's type incompatible with the previous definition, which NULL still uses: | |
null: pointer [integer!] ;-- null pointer declaration | |
The documentation specifies a third definition, namely integer! | |
This comes back to the lack of a void pointer type again | |
Dockimbel 18-Jun-2011 [2072] | There is a ticket about null: https://github.com/dockimbel/Red/issues/96 |
Kaj 18-Jun-2011 [2073x2] | Failing that, I think these definitions should use the same type |
The new ALLOCATE and FREE use c-string! which makes using them on generic byte arrays, and comparisons with NULL, confusing | |
Dockimbel 18-Jun-2011 [2075] | NULL will be adapted to cop with that (either using polymorphism or by replacing it by a NULL? macro). |
Kaj 18-Jun-2011 [2076x2] | I find ALLOCATE and FREE using c-string! unintuitive |
Other types need to be cast to use these functions | |
Dockimbel 18-Jun-2011 [2078] | Same as malloc() with C void pointers. |
Kaj 18-Jun-2011 [2079] | Still, why do we have now have three different definitions of a generic pointer? |
Dockimbel 18-Jun-2011 [2080] | There is no such thing as a generic pointer in Red/System. |
Kaj 18-Jun-2011 [2081] | I know, but I #define it as handle! like we talked about before, but there's now no way to define handle! in such a way that it works everywhere |
Dockimbel 18-Jun-2011 [2082] | Have you tried with defining it as integer!? |
Kaj 18-Jun-2011 [2083] | I once did, but I doubt it will now compensate for c-string! and NULL |
Dockimbel 18-Jun-2011 [2084] | Integer! is conceptually the closest type to handle!. |
Kaj 18-Jun-2011 [2085] | Yes, so why not define NULL and byte-ptr! as integer? |
Dockimbel 18-Jun-2011 [2086] | About NULL, please read the ticket on github I have posted above. NULL will be changed. |
Kaj 18-Jun-2011 [2087] | Sure, but why not fix this inconvenience right now? |
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