Demo files: set-var-by-name-v4 and set-var-by-name-md5
This is a quick follow up to last December’s Set Variable By Name Revisited, and to avoid repetition will assume the reader is familiar with the material that was presented in that article. But to briefly recap:
1. FileMaker does not provide an obvious way to programatically name a variable.
Update 19 Aug 2021: demo file has been superseded by the one available in Set Variable By Name Re-Revisited
You’ve probably heard the old joke that goes…
Patient: Doc, it hurts when I do this.
Doctor: Don’t do that.
Perhaps you’re also familiar with the FileMaker equivalent?
Developer: It hurts when I try to assign certain variable names.
FileMaker: Don’t do that.
Demo file: virtual-list-simplified.zip
Note 1: The example in today’s article/demo is intentionally very basic.
Note 2: The demo is self-populating to keep the data current, so the values you see in the screen shots will not exactly match those you encounter in the demo.
Recently I had the pleasure of discussing virtual list with Paul Jansen and Jeremy Brown on The Context podcast. One consequence of having written so much on the subject over a period of many years, is that information has been spread across many articles. Another consequence is that my thinking re: certain implementation specifics has changed over time.
At the risk of stating the obvious, there are many, many ways to skin the virtual list cat, and the purpose of today’s article is not to say “this is the best way”, or imply that other approaches are flawed, but simply to propose one particular approach you might take — especially if you are either: a) new to virtual list, or b) already using virtual list, but aren’t completely happy with your current implementation.
At any rate, my aim today is to gather some useful insights from earlier articles into a single document (with an occasional new idea thrown in as well), and some of what follows has been recycled from those earlier articles. Continue reading “Virtual List Simplified”
28 Dec 2020: for further thoughts on this subject see Set Variable By Name Revisited.
6 Apr 2016: A “SetVarByName” custom function can make things a whole lot easier. For details, see Set Variable by Name.
31 Oct 2014: This was originally embedded inside another article, but I now realize it should have been a standalone post, so I am belatedly taking corrective action and making it so.
Although FileMaker provides a “Set Field By Name” script step, it does not provide a direct method to dynamically declare the name of a variable.
Note that I said there isn’t a “direct” method to accomplish this… but it can be done indirectly.
Creating Variables on the Fly
There’s something cool and slightly miraculous about being able to dynamically name and populate variables at runtime. In the code below we don’t care about $x at all — it’s just a convenient way to access the calculation engine so we can invoke the Evaluate and Let functions.
We’ll come back to that in a minute, but first let’s consider a much simpler example. If we know the name of the variable we want to declare, but want to specify the repetition dynamically, it can be accomplished in a very straight-forward manner, like so:
This gives us a variable named $array_01[x] where “x” represents whatever number is currently in the $rep variable.
The following also achieves the same result, but normally we wouldn’t bother since it’s more work with no additional benefit. But it does show that a variable can be defined via Let, with the rep specified dynamically — in this example, via a variable, $rep, but Get(RecordNumber) or any calculated expression would work.
However, the technique breaks down if we try to dynamically specify the name of the variable itself. In the above example, we’re telling FileMaker to define a variable named $array_01 with whatever repetition number happens to be sitting in the $rep variable.
But we want to declare a variable named $array_xx where “xx” could be anything from “00” to “12” and is based on the value sitting in the $column variable (padded with a leading zero where appropriate), and to pull that off we need to bring out the heavy artillery, i.e., Evaluate.
It makes my head hurt, but it actually works.
Editor’s note: for additional thoughts on this subject see Fast Summaries Revisited and Fast Summaries Re-revisited.
Have you ever wished you could pull the values from a summary report, and use them in a script or a calculation? Back in the FileMaker 6 days, Mikhail Edoshin introduced a technique to do just that.
He called the technique Fast Summaries, and I came to employ it extensively in my own solutions. Continue reading “Fast Summaries”
This morning I was doing some maintenance on an old solution when I ran into this ungrammatical dialog. “I’d like to give a piece of my mind to the lazy slob who wrote that”, I said to myself smugly, followed a few seconds later by, “Uh, whoops, the slob was me.” Normally, I’m pretty good about making sure my dialog text is correct with regard to plural or singular, but in this case I must’ve been feeling particularly lazy (or overly confident that users would never export only a single record).
