johnbender / unraverl

An erlang module built to provide language features and other operations through manipulation of the abstract form.

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README changes
johnbender (author)
Sat Aug 08 18:38:57 -0700 2009
commit  cc8310fab4538cefd035502f95327bf894130292
tree    6c650a303b615b99e0220b92d9bc8459be6dbc10
parent  f66c0ed3801b3aa8aa34eaaefee06f06086f0744
unraverl / partial_application.erl
100644 53 lines (37 sloc) 1.663 kb
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-module(partial_application).
-export([partial_application/1]).
 
-define(compare_fun, fun({call, _, {atom, _, FuncName}, ArgsList}) ->
			     is_partial(Form, FuncName, ArgsList);
			(_) -> false 
		     end).
 
-define(replace_fun, fun({call, LineNum, {atom, _, FuncName}, ArgsList}) ->
			     RealArity = real_arity(Form, FuncName, ArgsList),
			     ArityDiff = RealArity - length(ArgsList),
			     FunArgList = util:args_list_form(ArityDiff, LineNum, "FunArg"),
			     ?partialy_applied_function
		     end).
 
-define(partialy_applied_function, {'fun',LineNum,
				    {clauses,
				     [{clause,LineNum,
				       FunArgList, %fun arg list [{var,52,'Arg3'}],
				       [], %guards
				       [{call,LineNum,
					 {atom,LineNum,FuncName},
					 ArgsList ++ FunArgList }]}]}}). %Args to pass [{var,52,'Arg1'}]
 
 
%% figure out why least_arity is returning 0			     
 
 
partial_application(Form) ->
    util:replace(Form, ?compare_fun, ?replace_fun).
 
is_partial(Form, FuncName, ArgsList) ->
    Arity = length(ArgsList),
    real_arity(Form, FuncName, ArgsList) > Arity.
 
least_arity(Funcs) ->
    least_arity(Funcs, 0).
 
least_arity([{_, _, _, Arity, _}|T], Max) when Arity >= Max ->
    least_arity(T, Arity);
 
least_arity([{_, _, _, Arity, _}|T], Max) when Arity < Max ->
    least_arity(T, Max);
 
least_arity([], Max) -> Max.
 
real_arity(Form, FuncName, ArgsList) ->	
    least_arity(find_greater_equal_arity(Form, FuncName, length(ArgsList))).		     
     
 
find_greater_equal_arity(Form, Name, Arity) ->
    [{SType, LineNum, SName, SArity, Clauses} || {SType, LineNum, SName, SArity, Clauses} <- Form, Name == SName, Arity =< SArity].