please help me

[mhbpxy]

dear ddd member:

how do you do!
excuse me that I have to interrupt your work,because I have a  
question to ask about ddd
Now I worked in linux system,I have a project about ddd's  
development,I have no idea,because I am not familar with ddd,I don't 
konw ddd software's development structure;
I have saw some code about ddd,can you answer me some question 
below?thank you for your help.please
 1. *.vsl file's function
 2. ddd software were written in c/c++ language?include the GUI(graph 
user interface)?
 if not,which language did you use? and where is the GUI part's  code?
3.the relation between ddd and gdb(system's gdb),If I delete system's  
gdb or change other's version gdb,ddd can work exactly?
 
I'm sorry to interrupt your job,but please help me,Thank for your help very much!
                            your sincerely

                             stiwen