fm2x clients often create forms or questionnaires of considerable logical complexity (sample logic table). It is not unusual for the logic presented to be incomplete or incorrect. Network graphs are a convenient way of presenting logic back to clients for verification and validation.

Graphviz is open source software for generating diagrams of abstract graphs and networks. Although there is a python library, using it through dot, a command line generator, is simpler and easier to test. Here is how fm2x interfaced its tabular logic generator to create a network logic diagram:

#Typical dot syntax where question numbers are preceded with Q 
#Q1->Q2  [style=bold,fontsize=10]; Q1->Q2  [label="Q6=='1'"fontsize=10];
#Q1->Q3A [label="Q6=='2'",fontsize=10]; Q1->Q4  [label="Q6=='3'",fontsize=10];
#Q2->Q4  [style=bold]; Q3A->Q4 [style=bold]; Q4->Q8  [style=bold];
t="";
for type,name,qnid,prompt,code in r:
    code=code.replace('r','').replace(';','');
    if type<>'page':continue;
    lines=code.split("");
    for line in lines:
        code1=line.split("page=");
        code1[0]=code1[0].replace("'","'");
        if code1[0]=="" and len(lines)>1:code1[0]="Default"
        try: t+='''%s->%s [label="%s",fontsize=10];'''%(name,code1[1],code1[0]);
        except: pass
dot='''digraph hierarchy {bgcolor=lightgoldenrod1; %s } '''%(t);
pngfile='/imgs/medixdat/logic.png';
dotfile='/imgs/medixdat/logic.dot';
f=open(dotfile,'w'); f.write(dot);
command = '''echo '%s' |dot -Tpng -o %s '''%(dot,pngfile);
os.system(command);