Wednesday, 19 September 2012

Splitting long lines of code

In javascript, for example, white space is pretty much ignored by the interpretor.  You can spread your code over as many lines as you think makes it more readable, just don't forget to indicate the end of the line with a semi-colon.  However, Uniface doesn't allow this, it uses the carriage return as the end of line character.  So what do you do if you have a really long line of code?

Well, for me, I tend to just leave it as a very long line of code.  If it gets too long, I'll ask my boss for an even bigger monitor :) 

I suffer a little with this practice when I'm developing on my laptop though, as I was yesterday.  This reminded me about something that I've seen used before, and that's using a Uniface feature that allows you to split a single line of code over multiple lines, like this...

  if ( value != "1" & value != "2" & value != "3" & %\
       value != "4" & value != "5" & value != "6" & %\
       value != "7" & value != "8" & value != "9" )
    value = "0"

I'm sure this is something that's documented, but what do you search for to find it?  I certainly couldn't find anything.  So here's a little tip for you, if you prefer to keep those lines a little shorter.  

One situation I have used it in before is with a long SQL command or selectdb statement, as it can help to format it in a similar way to how you might write the SQL in your favourite database tool.  For example...

  selectdb max(field6) from "entity" u_where ( %\
    (field1 = value1) & %\
    (field2 = value2) & %\
    (field3 = value3) & %\
    (field4 = value4) & %\
    (field5 = value5)) to (value6)

EDIT:  Uniface calls this the "Line Continuation Marker" and it is documented as such. 
If anyone knows where this is in the manuals, please leave a comment and let me know.

Summary: It is possible to split a single line of code over multiple lines in Uniface, but you have to do it explicitly.  


  1. Hey Rik, enjoying the blog - thanks for writing this stuff down.

    It's worth noting that splitting a string over multiple lines can cause problems.

    vLongList = "a;b;c;d; %\

    I believe this will result in 'e' having a lot of leading white space and a carriage return before it. It's obvious when you look at it, but it can trip people up.

    1. The continuation marker is the first thing that is processed, so you won't get a carriage return in the string, but you will get any spaces that appear either side of it (end of the first line, or beginning of the second line).

    2. And thank you, I'm glad you're enjoying the my blog :)