4GL_metrics
-----------
Purpose : Generate LOC and Cyclomatic-complexity metrics for
	  Informix 4GL modules.
Author  : Renaat.VanHee@vlafo.be
Date    : 1997
Call    : 4GL_metrics UIT module1 module2 module3 ...
	    UIT = csv : generate output as a CSV-file
		  ... : generate output for printer
            module? = 1 or more 4GL-modules to generate
Language : Perl
--------------------------------------------------------------

This PERL-script is my first try at experimenting with metrics. Since
I didn't find any (free) metrics for Informix 4GL on the web a decided
to roll my own.
The PERL script might not be the most perfect written in the world but
it does wat it needs to do for my company.
Here follows a description of the output :


General format of CSV file:

   1         2         3      4    5
FUNC/REP|BLNC_CNT|CMNT_CNT|LN_CNT|V(G)

first column : function name
----------------------------
In the first column you find the function names of the functions in
the evaluated module. The first two are rather special and you will
not find them in your code.
The first "header" contains every line before the first
"Function/Report". This give you an idea about the number of
module-global variables used for the evaluated module.
The second "separator" contains every line between "END
FUNCTION/REPORT" and "FUNCTION/REPORT". Normally this would contain
only blancs or comments.

second column : number of blanc lines
-------------------------------------
I think this is rather self explanatory.

third column : number of comment lines
--------------------------------------

fourth column : total number of lines
-------------------------------------
This equals = blanc + comment + code. This means that you can
determine the number of code lines as total - blanc - comment.

fifth column : cyclomatic complexity.
-------------------------------------
This metric contains the number of decisions in a module + 1. If you
would like more information on this subject I suggest you look it up
on the internet. Suffice is to say that this is a rather important
metric.

Raising of warnings
-------------------
What's the use of these numbers if you can't do anything with them ?
That's why I put certain numbers as a warning in bold in the output generated for the printer.
These warnings aren't based on an empirical study but are based on my
experiences from the last 4 years as a 4GL-programmer, mainly in
maintenance.
The first warning you receive is if the total number of lines for a
function exceeds 250. For most of us it is rather dificult to
understand what the flow of a function is if it exceeds this value.
The second warning you receive is when the V(G) exceeds a value of 10.
This means dat their are more than 10 branching statements
(IF,CASE,...) in a single function. This makes it very difficult to
thoroughly test this function.
When you receive the two warnings for a single function this might
trigger a code review.


Final
-----
If you find this script useful I would like to hear from you. If
you're bussy with experiments regarding metrics on Informix 4GL I also
would like to hear from you.
For the moment I'm bussy making a script to generate an information
flow metric for Informix 4GL.  If you're interested give me a sign.
Last but not least. I'm no expert PERL-programmer so if you want to
modify this script please, by all means, do so. The only thing that I
want in return is that you send a copy of you modifications.


Hope to be of some help,
Renaat.VanHee@vlafo.be
BELGIUM