Hi Cheer, since you already use the additional function, it worth looking at the 'find' command, which can do all the complicated job which can not be done with simple globbing.
regards, Maxim On Sun, 09 Dec 2012 17:43:59 +0400, Cheer Xiao <xiaqq...@gmail.com> wrote: > Hi all, > > For those not acquainted with zsh: extended globbing is one of the > many features of zsh that allows you to match files satisfying a given > criteria in a inline manner (instead of going through a loop). For > example, "echo abc*(/)" gives you all directories with names starting > with "abc" in current directory, while "rm .*(@)" removes all symlinks > with names starting with ".", etc. It is a useful feature, but I don't > really like the arcane syntax. > > Fish doesn't have extended globbing (which is good actually :-), so > I'm tempted to write this: > > function filter > set predicate $argv[1] > for i in (seq 2 (count $argv)) > test $predicate $argv[$i]; and echo $argv[$i] > end > end > > So now I write "echo (filter -d abc*)" and "rm (filter -L .*)" to > achieve the same effect as "echo abc*(/)" and "rm .*(@)" in zsh. It is > more verbose, but the readability is considerably better; it also > allows you to reuse the knowledge of the "test" builtin. > > This works fine until, of course, you start to encounter file names > containing newlines. Try this: > > cd (mktemp -d) > mkdir 'a > b' > count * > count (filter -d *) > > Clearly, The problem stems from the fact that when fish expands the > command substitution (filter -d *), filenames echo'ed by "filter" run > together before being split on newlines to render the substituted > words. A newline in one of the filenames is then indistinguishable > with two filenames. > > So this leads to my proposal: > > * When evaluating a fish function, maintain an alternative output > buffer besides stdout. The buffer is actually a dynamic-sized list > (std::vector for C++ programmers) of strings. Introduce a new builtin > (say "put") to write to that buffer. > > * Exactly one of the two output buffers (let's call them stdout and > altout) should be active within a function. > > * Within functions, calling "put" activates the altout and closes > stdout. Each invocation of "put" with k arguments appends k new > elements to altout. (The relationship between altout and stdout still > needs some thoughts though.) > > * When command substitution is performed, it is checked which of > stdout and altout is active (the latter is only possible for fish > functions; external commands always have only stdout active). If > altout is active, the elements in altout are substituted directly. If > stdout is active, the content in stdout is split on newlines before > being substituted (as is currently done). > > * When altout is written to when there is no enclosing command > substitution (eg. calling "put" on the prompt), anything written to it > is directed to stdout plus a newline. > > With altout I can write my "filter" by replacing "echo" with "put" and > it's now newline-safe. > > Being able to output arrays of strings can be of many other uses - > actually it enables you to write any array manipulating functions in > an easy way. > > If the newline-in-filenames stuff sounds too invented and unlikely, > consider why shells need real arrays instead of strings joined by > delimiters (be it whitespace or newlines) at all. Actually, one of the > favorite things about fish is its clean array syntax, it is a really > nice thing. I think fish deserves the added expressive power. :) > > > -- > Regards, > Cheer Xiao > > ------------------------------------------------------------------------------ > LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial > Remotely access PCs and mobile devices and provide instant support > Improve your efficiency, and focus on delivering more value-add services > Discover what IT Professionals Know. Rescue delivers > http://p.sf.net/sfu/logmein_12329d2d > _______________________________________________ > Fish-users mailing list > Fish-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/fish-users ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Fish-users mailing list Fish-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/fish-users
