Re: [Libguestfs] [PATCH v6 2/3] mllib: modify nsplit to take optional noempty and count arguments

On Mon, Jan 30, 2017 at 10:43:15PM +0100, Tomáš Golembiovský wrote: > Added two new optional arguments to nsplit: > > * keep_empty: if set to false empty elements are not stored in the > returned list. The default is to keep the empty elements The ?keep_empty flag is pointless. It's simpler and more clear to write: List.filter ((<>) "") (nsplit ...) when you don't want empty elements.

However the ?count flag is fine, since that's what Perl's split function also does. > - let rec nsplit sep str = > + let rec nsplit ?(keep_empty = true) ?(count = -1) sep str = > let len = length str in > let seplen = length sep in > let i = find str sep in > - if i = -1 then [str] > + if i = -1 || count = 0 then > + if str = "" && not keep_empty then [] else [str] > else ( > let s' = sub str 0 i in > let s'' = sub str (i+seplen) (len-i-seplen) in > - s' :: nsplit sep s'' > + let elem, count = > + if s' = "" && not keep_empty then > + [], count > + else > + [s'], if count > 0 then count-1 else count > + in > + elem @ nsplit ~keep_empty:keep_empty ~count:count sep s'' You can write this line as: elem @ nsplit ~count sep s'' (after dropping keep_empty). Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com libguestfs lets you edit virtual machines. Supports shell scripting, bindings from many languages. http://libguestfs.org