Indeed I have never used predselect. I loved your list. Sounded very similar to the criteria I used to use when deciding whether to do a proposed TOOLSRUN extension (and to some extent, is still used today when contemplating Xagent changes). By the way, MY birthday is November 16 ... ;-)
bc On 10/12/07, Rob van der Heij <[EMAIL PROTECTED]> wrote: > > On 10/12/07, Bob Cronin <[EMAIL PROTECTED]> wrote: > > > some of my pipelines are wondrous to behold, at least to me ;-). Oh, and > if > > what you say were strictly the case, would we really have a SPACE stage? > > Wasn't that done to make it easier to accomplish something that could be > > accomplished with a similar set of somewhat-less-obvious stages? > Where/how > > do you draw the line? > > After 15 years of plumbing, I believe that I think my algorithms in > Pipes (or data flow model) even when I don't implement it as a > pipeline. Writing a sequential program is often harder for me to do. > So I do understand that I'm not the best person to judge whether some > idiom is easy to grasp. But I think that once you master multi-stream > pipelines, the learning is incremental. If you invest part of the time > you saved using Pipes in learning about it, things tend to move pretty > fast. > > It looks like many plumbers master juxtapose, but never used > predselect. That may be because the common reason for destructive > testing (anycase) been built in all stages now. But it's a pity > because predselect is very elegant. I am also a big fan of parcel > (even though some of that is now in deblock). All I can do is show > examples and present about Pipes (when they let me). > > It's the Piper who draws the line. I cannot read his mind, but some of > the things that seem to play a role in that process are: > #1 he needs it himself and does not want to carry around a rexx stage to > do it > #2 It appears to be a common thing and fairly easy to do without > messing things up > #3 it can be generalized to do way more than what was asked for > #4 Melinda convinced him to do it > #5 I asked for it, and it's close to x-mas or my birthday > #6 its on the list of 50 requirements he got for his 50th birthday > And I admit that #4 and #5 do overlap a bit with #6. But there's many > things I have asked for that never happened. > > To build the space function in a generic way is a bit hairy because > you cannot assume there's an unused code position you can use as > end-of-line. You could probably do the basic REXX space() function > with half a dozen stages. But with the generalization that the space > stage has now (pad with strings, and using a set of delimiters) is > pretty powerful and can do many more things (I tend to use space to > remove delimiters from my record, like with "space 0 anyof /:-./" ) > > I am not sure how locating words in a record could be generalized. In > many cases, you would need also the position of the word rather than > just knowing the word is somewhere in the record. And would it be > enough to have the 1st occurrence or would you want all of them. So > maybe a stage that will output a record with the column positions (or > words?). But what words would you want to find? If you must specify it > as an argument, that is very restrictive. But if it reads the words > via a secondary input, then you get very close to what lookup does > now... > > Rob >
