Hi Joachim, Nice to hear from you again. On 22/05/2012, at 12:16, Joachim Schimpf wrote: > Paulo Moura wrote: >> Hi, >> I'm using ECLiPSe 6.1#112 on Windows 7 64 bits. The built-in predicate canonical_path_bug/2 always seem to return the wrong path when the first argument is an absolute path such as 'C:/Users/' or 'C:\\Users\\'. The returned path always have the current working directory as a prefix. Moreover, if the first argument starts with an environment variable, the variable is not expanded and again the returned path have the current working directory as a prefix. I reported this bug (which was fixed on 5.x) on July 13, 2006. > > Hi Paulo, > > You have overlooked that ECLiPSe internally uses an OS-independent path > name syntax which employs no separator characters apart from the "/". > In this syntax, absolute paths always start with a /. > > The ONLY predicate that understands OS-specific path names is > os_file_name(?EclipseName, ?OSName), which converts between operating > system syntax and internal Eclipse syntax. For example, on Windows, > os_file_name("//C/a/b", "C:\\a\\b") is true. ALL other built-in > predicates that accept/return path names, expect/produce the > simplified internal form. If you have path names that come in > OS syntax, you will have to convert them once. > > This is an old (but clean) design decision dating back to the first > Windows-port of ECLiPSe in the 90s, when there was still much confusion > about file name syntax in different operating systems. The kind of "fix" > you have in mind would break the design. I find the design sound. In fact, it's a design also adapted by other Prolog compilers. For example, SWI-Prolog provides a similar prolog_to_os_filename/2 built-in predicate (which I use). The only possible issue when using this conversion predicates is when you receive a path, e.g. from a consult/compile/load predicate call, where the user may pass either an operating-system path or a Prolog "internal" path. In my limited test with ECLiPSe 6.1#112, the os_file_name/2 predicate seems behave correctly when the the second argument already uses the internal syntax. I'm redesigning the Logtalk code that handles operating-system paths to follow more closely this design (the main issue being that only some Prolog compilers provide these conversion predicates). > However, I'm open to suggestions > of how to make things more intuitive and/or nore compatible with other > systems. As you know, dealing with file-system is a portability nightmare, specially when considering both POSIX and Windows. The only practical solution will likely be to provide a library that forgoes the native support (from the point-of-view of interface) and provides a portability layer. I have something along these lines in Logtalk: http://trac.logtalk.org/browser/trunk/examples/cc/osp.lgt http://trac.logtalk.org/browser/trunk/examples/cc/os.lgt You may remember contributing to this code in the past. But, currently, the above code is provided as an example of using conditional compilation directives and not as a standard library (this may change on Logtalk 3.x, under development, however). The main reasons are comprehensive testing (specially on Windows), the lack (of up-to-date) binary distributions of the Prolog compilers (e.g. ECLiPSe itself on MacOS X or XSB on Windows), unexpected incompatible changes (e.g. absolute_file_name/2-3 on recent SWI-Prolog and YAP versions), and the commercial nature of some Prolog compilers (I refuse to buy copies given all the work I do for Prolog standardization and to make Logtalk compatible with those compilers). Summarizing what is starting to sound like a rant, such a portable library would need to be actively maintained by the Prolog vendors themselves. I'm skeptical that that will happen any time soon. Thanks for your support. Cheers, Paulo ----------------------------------------------------------------- Paulo Jorge Lopes de Moura, PhD Assistant Professor Dep. of Computer Science, University of Beira Interior 6201-001 Covilhã, Portugal Office 3.18 Ext. 3276 Phone: +351 275 242081 Fax: +351 275 319899 Email: <mailto:pmoura_at_...16...> Home page: <http://www.di.ubi.pt/~pmoura> Research: <http://logtalk.org/> Blog: <http://blog.logtalk.org/> -----------------------------------------------------------------Received on Tue May 22 2012 - 13:15:49 CEST
This archive was generated by hypermail 2.3.0 : Tue Apr 16 2024 - 09:13:20 CEST