Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
Hi, Kevin Cozens [EMAIL PROTECTED] writes: Script-Fu scripts written for GIMP 1.2 won't work under GIMP 2.x without some changes due mainly to differences in the API. In what version of GIMP would it be possible to have the compatibility features of Tiny-Fu removed? The next time we release a version that doesn't guarantee backward compatibility. This will most probably be called GIMP 3.0 then. Sven ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
Hi, Kevin Cozens [EMAIL PROTECTED] writes: I don't really want a compatibility-switch. Instead, old Script-Fu scripts should be updated so they do things the way they are supposed to be done in Scheme rather than how the old SIOD interpreter let script writers get away with some things (ie. not defining variables). It forces a review of the code. For example, I noticed that one script defined an internal routine to compute a least common multiple rather. I deleted the routine and used the standard Scheme routine 'lcm'. I understand your reasons but a compatibility mode (if that is feasible at all) would allow us to ditch Script-Fu in favor of Tiny-Fu. If no such mode is available we will have to continue to ship Script-Fu for quite a while. I don't think we can just tell people that all their scripts won't work any longer when they update GIMP the next time. Sven ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
At 06:00 AM 07/10/2004, Sven wrote: Kevin Cozens [EMAIL PROTECTED] writes: I don't really want a compatibility-switch. Instead, old Script-Fu scripts should be updated so they do things the way they are supposed to be done in Scheme rather than how the old SIOD interpreter let script writers get away with some things (ie. not defining variables). I understand your reasons but a compatibility mode (if that is feasible at all) would allow us to ditch Script-Fu in favor of Tiny-Fu. If no such mode is available we will have to continue to ship Script-Fu for quite a while. Many (most?) of the needed changes between SIOD and TinyScheme could be handled via a set of additional define statements in a separate file included from the main TinyScheme init file. Handling the while loop should be possible but that requires a non-trivial Scheme define. All of these additional defines should be flagged in documentation as deprecated. That just leaves the problem of variables used in a set! statement which are not defined before first use. Tiny-Fu displays an error message stating unbound variable along with the name of the variable when this situation is encountered. The solution is to add a line to the let block with the name of the variable in parenthesis (no initial value is required). A few of the standard Script-Fu scripts had a define that used set! but no let statement so a let had to be added first. I don't see how this can be handled automatically without a change to TinyScheme itself. Script-Fu scripts written for GIMP 1.2 won't work under GIMP 2.x without some changes due mainly to differences in the API. In what version of GIMP would it be possible to have the compatibility features of Tiny-Fu removed? Cheers! Kevin. (http://www.interlog.com/~kcozens/) Owner of Elecraft K2 #2172|What are we going to do today, Borg? E-mail:kcozens at interlog dot com|Same thing we always do, Pinkutus: Packet:[EMAIL PROTECTED]| Try to assimilate the world! #include disclaimer/favourite | -Pinkutus the Borg ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
By using vectors I was able to very quickly update the portion of those scripts which used SIOD array functions. I have not changed the Tiny-Fu marshalling code yet but I will do that soon and release a new tarball. Now since there is essentially a one-to-one correspondence between Tiny-Fu's vectors and Script-Fu's arrays, it might be worth considering adding compatibility definitions to init.scm (similar to gimpcompat.h for plug-ins), that would, depending on a certain compatibility-switch in a configuration file (or in init.scm itself, but I don't know if every user will get a copy or you will install the file in /usr/gimpsomething...), define the current array operations and map them to corresponding vector functions. You could then (depending on said switch) also re-define set! to use define if a variable is not defined?. Markus. ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
At 01:38 PM 07/09/2004, you wrote: Now since there is essentially a one-to-one correspondence between Tiny-Fu's vectors and Script-Fu's arrays, it might be worth considering adding compatibility definitions to init.scm (similar to gimpcompat.h for plug-ins), that would, depending on a certain compatibility-switch in a configuration file (or in init.scm itself, but I don't know if every user will get a copy or you will install the file in /usr/gimpsomething...), define the current array operations and map them to corresponding vector functions. You could then (depending on said switch) also re-define set! to use define if a variable is not defined?. I don't really want a compatibility-switch. Instead, old Script-Fu scripts should be updated so they do things the way they are supposed to be done in Scheme rather than how the old SIOD interpreter let script writers get away with some things (ie. not defining variables). It forces a review of the code. For example, I noticed that one script defined an internal routine to compute a least common multiple rather. I deleted the routine and used the standard Scheme routine 'lcm'. I am planning on putting together a Perl script that will take a Script-Fu script and update as much of it as possible for use with Tiny-Fu. I know of quite a few mappings from SIOD to TinyScheme that can be applied. Pre-defining variables and changing while loops to do loops will still have to be done by hand. Cheers! Kevin. (http://www.interlog.com/~kcozens/) Owner of Elecraft K2 #2172|What are we going to do today, Borg? E-mail:kcozens at interlog dot com|Same thing we always do, Pinkutus: Packet:[EMAIL PROTECTED]| Try to assimilate the world! #include disclaimer/favourite | -Pinkutus the Borg ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
At 08:09 PM 07/07/2004, Markus Triska wrote: I also opt for vector because apart from being the natural Scheme equivalent to PDB's one-dimensional arrays, it makes writing plug-ins easier for people that have no to little practice in converting common for/while loops using tail-recursion, and current scripts would work practically unmodified, without explicit conversions list-vector that would only cost time (with everybody ending up calling these instead of working on lists most of the time). By using vectors I was able to very quickly update the portion of those scripts which used SIOD array functions. I have not changed the Tiny-Fu marshalling code yet but I will do that soon and release a new tarball. Cheers! Kevin. (http://www.interlog.com/~kcozens/) Owner of Elecraft K2 #2172|What are we going to do today, Borg? E-mail:kcozens at interlog dot com|Same thing we always do, Pinkutus: Packet:[EMAIL PROTECTED]| Try to assimilate the world! #include disclaimer/favourite | -Pinkutus the Borg ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
On Wednesday 07 July 2004 05:05, Kevin Cozens wrote: On Tue, 2004-07-06 at 19:45, Sven Neumann wrote: The fact that the PDB uses arrays doesn't necessarily mean that a language binding such as Tiny-Fu needs to represent them as arrays. One of the most annoying bits of Script-Fu is that it forces you to work with arrays even though the natural choice for a scheme dialekt would be lists. If Tiny-Fu cannot provide backward-compatibility, then it should overcome this mistake and map the PDB API to lists. Tiny-Fu makes no attempt to provide backwards compatability with the SIOD Scheme interpreter way of doing things. It expects scripts to follow the current Scheme standard as defined in the R5RS document. Since the R5RS does not define an array type, any script which uses arrays either internally or when dealing with PDB calls needs to be modified to use a list. The marshalling code of Tiny-Fu converts between PDB *ARRAY and Scheme lists as needed. The alternative would be to use a Scheme vector but instead of a list. Using a list seemed like the simplest approach. Are you sure using lists instead of vectors is the right thing to do? Lists are linked lists and as such accessing the i'th element is O(i). In vectors it is O(1). This can cause an order of complexity increase in handling them. Are you certain that all the scripts initialize the arrays, one element after another in sequential order? Or are there scripts with random access? In any case, this may not be an issue, because a programmer can temporarily use a vector, and convert it to a list before calling the PDB entries. (It reminds me that in Visual Basic the built-in array is implemented as a linked list, and so random access to it is slow as hell. What serious programmers do is implement the array logic in C and bind it to their VB programs) Regards, Shlomi Fish -- - Shlomi Fish [EMAIL PROTECTED] Homepage:http://shlomif.il.eu.org/ Knuth is not God! It took him two days to build the Roman Empire. ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
At 05:17 AM 07/07/2004, Shlomi Fish wrote: Are you sure using lists instead of vectors is the right thing to do? Lists are linked lists and as such accessing the i'th element is O(i). In vectors it is O(1). This can cause an order of complexity increase in handling them. No, I'm not sure. For the few scripts I looked at (and for ease of implementation), using a list was the easier route to have something functional during the early development stages. Using vectors instead of a simple list would mean the ability to use functions which would provide rough equivalents to the SIOD interpreters array manipulation functions. In any case, this may not be an issue, because a programmer can temporarily use a vector, and convert it to a list before calling the PDB entries. Conversion is simple through the use of vector-list and list-vector. I will take a closer look at using vectors. It will simplify the work needed to update old Script-Fu scripts for use with Tiny-Fu. I will start by converting between list and vector. If the approach works well, I will bit the bullet and update the marshalling code to use vectors for the *ARRAY types. Cheers! Kevin. (http://www.interlog.com/~kcozens/) Owner of Elecraft K2 #2172|What are we going to do today, Borg? E-mail:kcozens at interlog dot com|Same thing we always do, Pinkutus: Packet:[EMAIL PROTECTED]| Try to assimilate the world! #include disclaimer/favourite | -Pinkutus the Borg ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
Re: Lists, Arrays and Vectors [was Re: [Gimp-developer] Re: Tiny-Fu: A new plug-in for GIMP]
Are you sure using lists instead of vectors is the right thing to do? Lists are linked lists and as such accessing the i'th element is O(i). In vectors it is O(1). This can cause an order of complexity increase in handling them. This is true, but not much of a problem, since most scripts only use either the first 1 or 2 elements of arrays or work on typically very short arrays, or want to pass a (short) array to PDB, where there is no difference between list-construction and setting every element of a vector explicitly (the latter possibly being even more inefficient). No, I'm not sure. For the few scripts I looked at (and for ease of implementation), using a list was the easier route to have something functional during the early development stages. Using vectors instead of a simple list would mean the ability to use functions which would provide rough equivalents to the SIOD interpreters array manipulation functions. As I understand it, there are even *exact* equivalents to the current array type. No wonder, since a Lisp vector is a special case of an array (one-dimensional). In Script-Fu, arrays are indeed vectors. I will take a closer look at using vectors. It will simplify the work needed to update old Script-Fu scripts for use with Tiny-Fu. I will start by converting between list and vector. If the approach works well, I will bit the bullet and update the marshalling code to use vectors for the *ARRAY types. I also opt for vector because apart from being the natural Scheme equivalent to PDB's one-dimensional arrays, it makes writing plug-ins easier for people that have no to little practice in converting common for/while loops using tail-recursion, and current scripts would work practically unmodified, without explicit conversions list-vector that would only cost time (with everybody ending up calling these instead of working on lists most of the time). Markus. ___ Gimp-developer mailing list [EMAIL PROTECTED] http://lists.xcf.berkeley.edu/mailman/listinfo/gimp-developer
