Parsing inbound strings with delimiters

[edwardewilliams]

very, very simple task - take inbound data coming in on a com port, parse various things out of the string, display the parsed output...

Here's the code:

global string datain = ""
global string site = ""
global string date = ""
global string time = ""
global string chan = ""
global string val = ""

?"SEQUENCE START"


while(1)
   try()
      ?"WAITING INSIDE WHILE"
      device.COM5.Purge()
      datain = ""
      datain = device.COM5.ReadUntil(10)
      site = parse(datain,0,"@")
      date = parse(datain,1,"@")
      time = parse(datain,2,"@")
      chan = parse(datain,3,"@")
      val = parse(datain,4,"@")

      ?"Datain: " + datain
      ?"Site: " + site
      ?"Date: " + date
      ?"Time: " + time
      ?"Channel: " + chan
      ?"Reading: " + val
   catch()
      ?strlasterror
   endcatch
endwhile

I'm using global variables just so I can access them from the command alert window for testing - they'll normally be private variables - just FYI.

example of an inbound string:

TEST UNIT@11/06/08@21:00:25@ A1@     16.94/013/010
(pay no attention to the wrong direction slashes on the line termination
characters - the board apparently doesn't like backslashes in posts...)

The issue is this - I see the deata coming in on Com 5 just fine in both the direct port monitor and the docking window. The "datain" string gets stored, but then the parse commands don't actually seem to be parsing and I can't figure out why.

I've also tried the codee this way:

      datain = parse((device.COM5.ReadUntil(10)),-1,"@")
      site = datain[0]
      date = datain[1]
      time = datain[2]
      chan = datain[3]
      val = datain[4]

and in this case, when I display datain, which should be an array, all I get back is the raw string as opposed to something more like {"TEST UNIT","11/06/08","21:00:25", etc...}), thus I have no array to go through in the subsequent calls.

I'm clearly missing something simple - and after you stare at code for hours, you go a little funny in the eyes, so I'm sure it's an obvious and simple error.

Help?

[AzeoTech]

This is because DAQFactory's multi-lingual features are getting in the way. The @ sign as the first character of a string means that you want the string to be translatable and the @ is stripped. As it explains in the manual under creating multilingual apps, to create a string that starts with @, you must put to @@ signs.

Also, you might look into the parse() function passing -1 as the index. It returns an array of strings which is faster than parsing 5 times.

(Am I really that picky on these forums that you defend all the little things like global vs private and the / vs \? )

[edwardewilliams]

OK, educate me on the following method:

      device.COM5.Purge()
      datain = ""
      datain = device.COM5.ReadUntil(10)
      ?datain
      PString = parse(datain,-1,",")
      ?PString[0]
      ?PString[1]
      ?PString[2]
      ?PString[3]
      ?PString[4]
      site = PString[0]
      date = PString[1]
      time = PString[2]
      chan = PString[3]
      val = PString[4]

The "PString" array is created ok, and the ?PString[x] statements output the values in the array.

Clearly, however, I'm not assigning the variables correctly from that array (site = PString[0], etc) because those variables do not get populated, and in fact the while loops hangs just after that last ?PString[x] statement...

The software guys across the way are going to love it when I tell them that they're going to need a different sting delimiter than "@" if we're going to make our new box work with DF. Oh well, they'll get over it.

- and no, pickiness is not the issue - I'm trying not to look COMPLETELY dumb...

[AzeoTech]

There doesn't appear to be anything wrong with the script. I wonder if "site" has some issue. Try assigning it a constant.

There is no reason you can't use @ as a delimiter. Just use "@@" instead of "@" in your parse statement. The first @ is removed leaving just a single @. @ as a language specifier only gets stripped if it is the very first character of a string.

That said, I must say that @ is a weird delimiter to use, especially in the internet age where @ is used in email addresses. Same goes for <, >, and &

[edwardewilliams]

Ah, now I get it on the "@" character.

As for the sequence, it finally turned out that DF apparently didn't like "TIME" as a variable name for some reason. Once I replaced that variable with "TM" instead, everything works fine.

Odd.

I also had a great deal of trouble getting changes to take effect while editing the sequence. I couldn't just do "apply and compile" then hit "restart sequence". I had to stop the sequence, apply and compile, save the file, then hit "start sequence" in debug - otherwise my new edits would not be run. Something to do with still having the serial port open perhaps??

Anyway, main issue solved for now. Thanks for the pointers.

[AzeoTech]

Time is a reserved word. Think about the graph: you use Time usually for the X axis. Of course it only really means anything in a graph, but it still ends up as a global reserved word.

As for the restart: try just using F5. This is the quick way to stop, apply and restart a sequence.