create Erlang Modules

ast.erl

-define(A(A), erl_syntax:atom(A)).                                   
-define(I(I), erl_syntax:integer(I)).                                
-define(S(S), erl_syntax:string(S)).                                 
-define(V(V), erl_syntax:variable(V)).                               
                                                                     
s_f(N, P, B) -> erl_syntax:function(N, erl_syntax:clause(P, [], B)). 
                                                                     
s_c(M, F, A) -> [erl_syntax:application(?A(M), ?A(F), [A])].         
                                                                     
s_m(M) -> s_d(module, [?A(M)]).                                      
                                                                     
s_i(P) -> s_d(include, [?S(P)]).                                     
                                                                     
s_e(E) ->                                                            
  Exports = [erl_syntax:arity_qualifier(?A(F), ?I(A)) || {F,A} <- E],
  s_d(export, [erl_syntax:list(Exports)]).                           
                                                                     
s_d(K, V) -> erl_syntax:attribute(?A(K), V).                         
                                                                     
s_c(C) -> erl_syntax:comment(C).                                     
                                                                     
pretty_print(ST) ->                                                  
  {text, S} = erl_prettypr:best(ST),                                 
  S.