3. The method of claim 2 , further comprising: detecting a selection of at least two layer files by the user; and merging the at least two layer files to generate a new layer file comprising a new abstract syntax tree corresponding to the at least two layer files.
2. The method of claim 1 , where retrieving the main program from the memory comprises: retrieving at least one layer file associated with the main program from the memory; displaying program code corresponding to the at least one layer file and the main program; and further comprising: determining whether to hide the program code corresponding to at least one of the at least one layer file in response to a detected user input from a user; and where initiating the layer representing the portion of the main program for editing on the display comprises initiating the layer based upon the determination of whether to hide the program code corresponding to the at least one of the at least one layer file.