%% -*- erlang-indent-level: 4;indent-tabs-mode: nil -*- %% -------------------------------------------------- %% This file is provided to you under the Apache License, %% Version 2.0 (the "License"); you may not use this file %% except in compliance with the License. You may obtain %% a copy of the License at %% %% http://www.apache.org/licenses/LICENSE-2.0 %% %% Unless required by applicable law or agreed to in writing, %% software distributed under the License is distributed on an %% "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY %% KIND, either express or implied. See the License for the %% specific language governing permissions and limitations %% under the License. %% -------------------------------------------------- %% File : parse_trans.erl %% @author : Ulf Wiger %% @end %% Description : %% %% Created : 13 Feb 2006 by Ulf Wiger (then Ericsson) %%%------------------------------------------------------------------- %% @doc Generic parse transform library for Erlang. %% %%

...

%% %% @end -module(parse_trans). -compile({no_auto_import,[error/3]}). -export([plain_transform/2]). -export([ inspect/4, transform/4, depth_first/4, revert/1, revert_form/1, format_exception/2, format_exception/3, return/2 ]). -export([ error/3, format_error/1 ]). -export([ initial_context/2, do_inspect/4, do_transform/4, do_depth_first/4, top/3 ]). -export([do_insert_forms/4, replace_function/4, replace_function/5, export_function/3]). -export([ context/2, get_pos/1, get_file/1, get_module/1, get_attribute/2, get_attribute/3, get_orig_syntax_tree/1, function_exists/3, optionally_pretty_print/3, pp_src/2, pp_beam/1, pp_beam/2 ]). -import(erl_syntax, [atom_value/1, attribute_name/1, attribute_arguments/1, string_value/1, type/1 ]). -ifdef(TEST). -include_lib("eunit/include/eunit.hrl"). -endif. -record(context, {module, function, arity, file, options}). %% Useful macros for debugging and error reporting -define(HERE, {?MODULE, ?LINE}). -define(DUMMY_LINE, 9999). -define(ERROR(R, F, I, Trace), begin rpt_error(R, F, I, Trace), throw({error,get_pos(I),{R, Trace}}) end). -export_type([forms/0]). %% Typedefs -type form() :: any(). -type forms() :: [form()]. -type options() :: [{atom(), any()}]. -type type() :: atom(). -type xform_f_rec() :: fun((type(), form(), #context{}, Acc) -> {form(), boolean(), Acc} | {forms(), form(), forms(), boolean(), Acc}). -type xform_f_df() :: fun((type(), form(), #context{}, Acc) -> {form(), Acc} | {forms(), form(), forms(), Acc}). -type insp_f() :: fun((type(), form(), #context{}, A) -> {boolean(), A}). %%% @spec (Reason, Form, Info) -> throw() %%% Info = [{Key,Value}] %%% %%% @doc %%%

Used to report errors detected during the parse transform.

%%% @end %%% -spec error(string(), any(), [{any(),any()}]) -> none(). error(R, _F, I) -> ST = erlang:process_info(self(), current_stacktrace), % rpt_error(R, F, I, ST), throw({error,get_pos(I),{R, ST}}). %% @spec plain_transform(Fun, Forms) -> forms() %% Fun = function() %% Forms = forms() %% %% @doc %% Performs a transform of `Forms' using the fun `Fun(Form)'. `Form' is always %% an Erlang abstract form, i.e. it is not converted to syntax_tools %% representation. The intention of this transform is for the fun to have a %% catch-all clause returning `continue'. This will ensure that it stays robust %% against additions to the language. %% %% `Fun(Form)' must return either of the following: %% %% * `NewForm' - any valid form %% * `continue' - dig into the sub-expressions of the form %% * `{done, NewForm}' - Replace `Form' with `NewForm'; return all following %% forms unchanged %% * `{error, Reason}' - Abort transformation with an error message. %% %% Example - This transform fun would convert all instances of `P ! Msg' to %% `gproc:send(P, Msg)': %% 
%% parse_transform(Forms, _Options) ->
%%     parse_trans:plain_transform(fun do_transform/1, Forms).
%%
%% do_transform({'op', L, '!', Lhs, Rhs}) ->
%%      [NewLhs] = parse_trans:plain_transform(fun do_transform/1, [Lhs]),
%%      [NewRhs] = parse_trans:plain_transform(fun do_transform/1, [Rhs]),
%%     {call, L, {remote, L, {atom, L, gproc}, {atom, L, send}},
%%      [NewLhs, NewRhs]};
%% do_transform(_) ->
%%     continue.
%%
%% @end %% plain_transform(Fun, Forms) when is_function(Fun, 1), is_list(Forms) -> plain_transform1(Fun, Forms). plain_transform1(_, []) -> []; plain_transform1(Fun, [F|Fs]) when is_atom(element(1,F)) -> case Fun(F) of skip -> plain_transform1(Fun, Fs); continue -> [list_to_tuple(plain_transform1(Fun, tuple_to_list(F))) | plain_transform1(Fun, Fs)]; {done, NewF} -> [NewF | Fs]; {error, Reason} -> erlang:error(Reason, F, [{form, F}]); NewF when is_tuple(NewF) -> [NewF | plain_transform1(Fun, Fs)] end; plain_transform1(Fun, [L|Fs]) when is_list(L) -> [plain_transform1(Fun, L) | plain_transform1(Fun, Fs)]; plain_transform1(Fun, [F|Fs]) -> [F | plain_transform1(Fun, Fs)]; plain_transform1(_, F) -> F. %% @spec (list()) -> integer() %% %% @doc %% Tries to retrieve the line number from an erl_syntax form. Returns a %% (very high) dummy number if not successful. %% @end %% -spec get_pos(list()) -> erl_anno:location(). get_pos(I) when is_list(I) -> case proplists:get_value(form, I) of undefined -> ?DUMMY_LINE; Form -> Anno = erl_syntax:get_pos(Form), erl_anno:location(Anno) end. %%% @spec (Forms) -> string() %%% @doc %%% Returns the name of the file being compiled. %%% @end %%% -spec get_file(forms()) -> string(). get_file(Forms) -> string_value(hd(get_attribute(file, Forms, [erl_syntax:string("undefined")]))). %%% @spec (Forms) -> atom() %%% @doc %%% Returns the name of the module being compiled. %%% @end %%% -spec get_module([any()]) -> atom(). get_module(Forms) -> atom_value(hd(get_attribute(module, Forms, [erl_syntax:atom(undefined)]))). %%% @spec (A, Forms) -> any() %%% A = atom() %%% %%% @doc %%% Returns the value of the first occurrence of attribute A. %%% @end %%% -spec get_attribute(atom(), [any()]) -> 'none' | [erl_syntax:syntaxTree()]. %% get_attribute(A, Forms) -> get_attribute(A,Forms,[erl_syntax:atom(undefined)]). get_attribute(A, Forms, Undef) -> case find_attribute(A, Forms) of false -> Undef; Other -> Other end. find_attribute(A, [F|Forms]) -> case type(F) == attribute andalso atom_value(attribute_name(F)) == A of true -> attribute_arguments(F); false -> find_attribute(A, Forms) end; find_attribute(_, []) -> false. %% @spec (Fname::atom(), Arity::integer(), Forms) -> boolean() %% %% @doc %% Checks whether the given function is defined in Forms. %% @end %% -spec function_exists(atom(), integer(), forms()) -> boolean(). function_exists(Fname, Arity, Forms) -> Fns = proplists:get_value( functions, erl_syntax_lib:analyze_forms(Forms), []), lists:member({Fname,Arity}, Fns). %%% @spec (Forms, Options) -> #context{} %%% %%% @doc %%% Initializes a context record. When traversing through the form %%% list, the context is updated to reflect the current function and %%% arity. Static elements in the context are the file name, the module %%% name and the options passed to the transform function. %%% @end %%% -spec initial_context(forms(), options()) -> #context{}. initial_context(Forms, Options) -> File = get_file(Forms), Module = get_module(Forms), #context{file = File, module = Module, options = Options}. %%% @spec (Fun, Acc, Forms, Options) -> {TransformedForms, NewAcc} %%% Fun = function() %%% Options = [{Key,Value}] %%% %%% @doc %%% Makes one pass %%% @end -spec transform(xform_f_rec(), Acc, forms(), options()) -> {forms(), Acc} | {error, list()}. transform(Fun, Acc, Forms, Options) when is_function(Fun, 4) -> do(fun do_transform/4, Fun, Acc, Forms, Options). -spec depth_first(xform_f_df(), Acc, forms(), options()) -> {forms(), Acc} | {error, list()}. depth_first(Fun, Acc, Forms, Options) when is_function(Fun, 4) -> do(fun do_depth_first/4, Fun, Acc, Forms, Options). do(Transform, Fun, Acc, Forms, Options) -> Context = initial_context(Forms, Options), File = Context#context.file, try Transform(Fun, Acc, Forms, Context) of {NewForms, Acc1} when is_list(NewForms) -> NewForms1 = optionally_renumber(NewForms, Options), optionally_pretty_print(NewForms1, Options, Context), {NewForms1, Acc1} catch error:Reason:ST -> {error, [{File, [{?DUMMY_LINE, ?MODULE, {Reason, ST}}]}]}; throw:{error, Ln, What} -> {error, [{error, {Ln, ?MODULE, What}}]} end. -spec top(function(), forms(), list()) -> forms() | {error, term()}. top(F, Forms, Options) -> Context = initial_context(Forms, Options), File = Context#context.file, try F(Forms, Context) of {error, Reason} -> {error, Reason}; NewForms when is_list(NewForms) -> NewForms1 = optionally_renumber(NewForms, Options), optionally_pretty_print(NewForms1, Options, Context), NewForms1 catch error:Reason:ST -> {error, [{File, [{?DUMMY_LINE, ?MODULE, {Reason, ST}}]}]}; throw:{error, Ln, What} -> {error, [{File, [{Ln, ?MODULE, What}]}], []} end. replace_function(F, Arity, NewForm, Forms) -> replace_function(F, Arity, NewForm, Forms, []). replace_function(F, Arity, NewForm, Forms, Opts) -> {NewForms, _} = do_transform( fun(function, Form, _Ctxt, Acc) -> case erl_syntax:revert(Form) of {function, _, F, Arity, _} = RevForm -> {[], NewForm, with_original_f(RevForm, Opts), false, Acc}; _ -> {Form, false, Acc} end; (_, Form, _Ctxt, Acc) -> {Form, false, Acc} end, false, Forms, initial_context(Forms, [])), revert(maybe_export_renamed(NewForms, Arity, Opts)). with_original_f({function,_,_,_,_} = Form, Opts) -> case lists:keyfind(rename_original, 1, Opts) of {_, NewName} when is_atom(NewName) -> [setelement(3, Form, NewName)]; _ -> [] end. maybe_export_renamed(Forms, Arity, Opts) -> case lists:keyfind(rename_original, 1, Opts) of {_, NewName} when is_atom(NewName) -> export_function(NewName, Arity, Forms); _ -> Forms end. export_function(F, Arity, Forms) -> do_insert_forms(above, [{attribute, 1, export, [{F, Arity}]}], Forms, initial_context(Forms, [])). -spec do_insert_forms(above | below, forms(), forms(), #context{}) -> forms(). do_insert_forms(above, Insert, Forms, Context) when is_list(Insert) -> {NewForms, _} = do_transform( fun(function, F, _Ctxt, false) -> {Insert, F, [], _Recurse = false, true}; (_, F, _Ctxt, Acc) -> {F, _Recurse = false, Acc} end, false, Forms, Context), NewForms; do_insert_forms(below, Insert, Forms, _Context) when is_list(Insert) -> insert_below(Forms, Insert). insert_below([F|Rest], Insert) -> case type(F) of eof_marker -> %% In the unlikely case someone misused eof_marker Insert ++ [F | Rest]; _ -> [F|insert_below(Rest, Insert)] end. -spec optionally_pretty_print(forms(), options(), #context{}) -> ok. optionally_pretty_print(Result, Options, Context) -> DoPP = option_value(pt_pp_src, Options, Result), DoLFs = option_value(pt_log_forms, Options, Result), File = Context#context.file, if DoLFs -> Out1 = outfile(File, forms), {ok,Fd} = file:open(Out1, [write]), try lists:foreach(fun(F) -> io:fwrite(Fd, "~p.~n", [F]) end, Result) after ok = file:close(Fd) end; true -> ok end, if DoPP -> Out2 = outfile(File, pp), pp_src(Result, Out2), io:fwrite("Pretty-printed in ~p~n", [Out2]); true -> ok end. optionally_renumber(Result, Options) -> case option_value(pt_renumber, Options, Result) of true -> io:fwrite("renumbering...~n", []), Rev = revert(Result), renumber_(Rev); false -> Result end. renumber_(L) when is_list(L) -> {Result, _} = renumber_(L, 1), Result. renumber_(L, Acc) when is_list(L) -> lists:mapfoldl(fun renumber_/2, Acc, L); renumber_(T, Prev) when is_tuple(T) -> case is_form(T) of true -> New = Prev+1, NewE2 = update_line(element(2, T), New), T1 = setelement(2, T, NewE2), {Res, NewAcc} = renumber_(tuple_to_list(T1), New), {list_to_tuple(Res), NewAcc}; false -> L = tuple_to_list(T), {Res, NewAcc} = renumber_(L, Prev), {list_to_tuple(Res), NewAcc} end; renumber_(X, Prev) -> {X, Prev}. is_form(T) when element(1,T)==type -> true; is_form(T) -> try erl_syntax:type(T), true catch error:_ -> false end. update_line(Element2, Line) -> case erl_anno:is_anno(Element2) of true -> erl_anno:set_line(Line, Element2); false -> % location A = erl_anno:new(Element2), NewA = erl_anno:set_line(Line, A), erl_anno:location(NewA) end. option_value(Key, Options, Result) -> case proplists:get_value(Key, Options) of undefined -> case find_attribute(Key,Result) of [Expr] -> type(Expr) == atom andalso atom_value(Expr) == true; _ -> false end; V when is_boolean(V) -> V end. %%% @spec (Fun, Forms, Acc, Options) -> NewAcc %%% Fun = function() %%% @doc %%% Equivalent to do_inspect(Fun,Acc,Forms,initial_context(Forms,Options)). %%% @end %%% -spec inspect(insp_f(), A, forms(), options()) -> A. inspect(F, Acc, Forms, Options) -> Context = initial_context(Forms, Options), do_inspect(F, Acc, Forms, Context). outfile(File, Type) -> "lre." ++ RevF = lists:reverse(File), lists:reverse(RevF) ++ ext(Type). ext(pp) -> ".xfm"; ext(forms) -> ".xforms". %% @spec (Forms, Out::filename()) -> ok %% %% @doc Pretty-prints the erlang source code corresponding to Forms into Out %% -spec pp_src(forms(), string()) -> ok. pp_src(Res, F) -> parse_trans_pp:pp_src(Res, F). %% Str = [io_lib:fwrite("~s~n", %% [lists:flatten([erl_pp:form(Fm) || %% Fm <- revert(Res)])])], %% file:write_file(F, list_to_binary(Str)). %% @spec (Beam::file:filename()) -> string() | {error, Reason} %% %% @doc %% Reads debug_info from the beam file Beam and returns a string containing %% the pretty-printed corresponding erlang source code. %% @end -spec pp_beam(file:filename()) -> ok. pp_beam(Beam) -> parse_trans_pp:pp_beam(Beam). %% @spec (Beam::filename(), Out::filename()) -> ok | {error, Reason} %% %% @doc %% Reads debug_info from the beam file Beam and pretty-prints it as %% Erlang source code, storing it in the file Out. %% @end %% -spec pp_beam(file:filename(), file:filename()) -> ok. pp_beam(F, Out) -> parse_trans_pp:pp_beam(F, Out). %%% @spec (File) -> Forms %%% %%% @doc %%%

Fetches a Syntax Tree representing the code before pre-processing, %%% that is, including record and macro definitions. Note that macro %%% definitions must be syntactically complete forms (this function %%% uses epp_dodger).

%%% @end %%% -spec get_orig_syntax_tree(string()) -> forms(). get_orig_syntax_tree(File) -> case epp_dodger:parse_file(File) of {ok, Forms} -> Forms; Err -> erlang:error(error_reading_file, ?HERE, [{File,Err}]) end. %%% @spec (Tree) -> Forms %%% %%% @doc Reverts back from Syntax Tools format to Erlang forms. %%%

Note that the Erlang forms are a subset of the Syntax Tools %%% syntax tree, so this function is safe to call even on a list of %%% regular Erlang forms.

%%%

Note2: R16B03 introduced a bug, where forms produced by %%% `erl_syntax:revert/1' (specifically, implicit funs) could crash the linter. %%% This function works around that limitation, after first verifying that it's %%% necessary to do so. Use of the workaround can be forced with the help of %%% the `parse_trans' environment variable {revert_workaround, true}. This %%% variable will be removed when R16B03 is no longer 'supported'.

%%% @end %%% -spec revert(forms()) -> forms(). revert(Tree) when is_list(Tree) -> WorkAround = needs_revert_workaround(), [revert_form(T, WorkAround) || T <- lists:flatten(Tree)]. %%% @spec (Tree) -> Form %%% %%% @doc Reverts a single form back from Syntax Tools format to Erlang forms. %%%

`erl_syntax:revert/1' has had a long-standing bug where it doesn't %%% completely revert attribute forms. This function deals properly with those %%% cases.

%%%

Note that the Erlang forms are a subset of the Syntax Tools %%% syntax tree, so this function is safe to call even on a regular Erlang %%% form.

%%%

Note2: R16B03 introduced a bug, where forms produced by %%% `erl_syntax:revert/1' (specifically, implicit funs) could crash the linter. %%% This function works around that limitation, after first verifying that it's %%% necessary to do so. Use of the workaround can be forced with the help of %%% the `parse_trans' environment variable {revert_workaround, true}. This %%% variable will be removed when R16B03 is no longer 'supported'.

%%% @end revert_form(F) -> revert_form(F, needs_revert_workaround()). revert_form(F, W) -> case erl_syntax:revert(F) of {attribute,L,A,Tree} when element(1,Tree) == tree -> {attribute,L,A,erl_syntax:revert(Tree)}; Result -> if W -> fix_impl_fun(Result); true -> Result end end. fix_impl_fun({'fun',L,{function,{atom,_,Fn},{integer,_,Ay}}}) -> {'fun',L,{function,Fn,Ay}}; fix_impl_fun({'fun',L,{function,{atom,_,M},{atom,_,Fn},{integer,_,Ay}}}) -> {'fun',L,{function,M,Fn,Ay}}; fix_impl_fun(T) when is_tuple(T) -> list_to_tuple([fix_impl_fun(F) || F <- tuple_to_list(T)]); fix_impl_fun([H|T]) -> [fix_impl_fun(H) | fix_impl_fun(T)]; fix_impl_fun(X) -> X. needs_revert_workaround() -> case application:get_env(parse_trans,revert_workaround) of {ok, Bool} when is_boolean(Bool) -> Bool; _ -> Res = try lint_reverted() catch error:_ -> true end, application:set_env(parse_trans,revert_workaround,Res), Res end. lint_reverted() -> Ts = [{attribute,1,module,m}, {attribute,2,export,[{f,0}]}, erl_syntax:function(erl_syntax:atom(f), [erl_syntax:clause( [], [erl_syntax:implicit_fun( erl_syntax:atom(f), erl_syntax:integer(0))])])], Rev = erl_syntax:revert_forms(Ts), erl_lint:module(Rev), false. %%% @spec (Forms, Context) -> Forms | {error,Es,Ws} | {warnings,Forms,Ws} %%% %%% @doc Checks the transformed result for errors and warnings %%%

Errors and warnings can be produced from inside a parse transform, with %%% a bit of care. The easiest way is to simply produce an `{error, Err}' or %%% `{warning, Warn}' form in place. This function finds such forms, and %%% removes them from the form list (otherwise, the linter will crash), and %%% produces a return value that the compiler can work with.

%%% %%% The format of the `error' and `warning' "forms" must be %%% `{Tag, {Pos, Module, Info}}', where: %%% %%%

If the error is in the form of a caught exception, `Info' may be produced %%% using the function {@link format_exception/2}.

%%% @end return(Forms, Context) -> JustForms = plain_transform( fun({error,_}) -> skip; ({warning,_}) -> skip; (_) -> continue end, Forms), File = case Context of #context{file = F} -> F; _ -> "parse_transform" end, case {find_forms(Forms, error), find_forms(Forms, warning)} of {[], []} -> JustForms; {[], Ws} -> {warnings, JustForms, [{File, [W || {warning,W} <- Ws]}]}; {Es, Ws} -> {error, [{File, [E || {error,E} <- Es]}], [{File, [W || {warning,W} <- Ws]}]} end. find_forms([H|T], Tag) when element(1, H) == Tag -> [H|find_forms(T, Tag)]; find_forms([H|T], Tag) when is_tuple(H) -> find_forms(tuple_to_list(H), Tag) ++ find_forms(T, Tag); find_forms([H|T], Tag) when is_list(H) -> find_forms(H, Tag) ++ find_forms(T, Tag); find_forms([_|T], Tag) -> find_forms(T, Tag); find_forms([], _) -> []. -define(LINEMAX, 5). -define(CHAR_MAX, 60). %%% @spec (Class, Reason) -> String %%% @equiv format_exception(Class, Reason, 4) format_exception(Class, Reason) -> format_exception(Class, Reason, 4). %%% @spec (Class, Reason, Lines) -> String %%% Class = error | throw | exit %%% Reason = term() %%% Lines = integer() | infinity %%% %%% @doc Produces a few lines of user-friendly formatting of exception info %%% %%% This function is very similar to the exception pretty-printing in the shell, %%% but returns a string that can be used as error info e.g. by error forms %%% handled by {@link return/2}. By default, the first 4 lines of the %%% pretty-printed exception info are returned, but this can be controlled %%% with the `Lines' parameter. %%% %%% Note that a stacktrace is generated inside this function. %%% @end format_exception(Class, Reason, Lines) -> {current_stacktrace, ST} = erlang:process_info(self(), current_stacktrace), PrintF = fun(Term, I) -> io_lib_pretty:print( Term, I, columns(), ?LINEMAX, ?CHAR_MAX, record_print_fun()) end, StackF = fun(_, _, _) -> false end, lines(Lines, erl_error:format_exception( 1, Class, Reason, ST, StackF, PrintF)). columns() -> case io:columns() of {ok, N} -> N; _-> 80 end. lines(infinity, S) -> S; lines(N, S) -> [L1|Ls] = re:split(iolist_to_binary([S]), <<"\n">>, [{return,list}]), [L1|["\n" ++ L || L <- lists:sublist(Ls, 1, N-1)]]. record_print_fun() -> fun(_,_) -> no end. %%% @spec (Attr, Context) -> any() %%% Attr = module | function | arity | options %%% %%% @doc %%% Accessor function for the Context record. %%% @end -spec context(atom(), #context{}) -> term(). context(module, #context{module = M} ) -> M; context(function, #context{function = F}) -> F; context(arity, #context{arity = A} ) -> A; context(file, #context{file = F} ) -> F; context(options, #context{options = O} ) -> O. -spec do_inspect(insp_f(), term(), forms(), #context{}) -> term(). do_inspect(F, Acc, Forms, Context) -> F1 = fun(Form, Acc0) -> Type = type(Form), {Recurse, Acc1} = apply_F(F, Type, Form, Context, Acc0), if_recurse( Recurse, Form, _Else = Acc1, fun(ListOfLists) -> lists:foldl( fun(L, AccX) -> do_inspect( F, AccX, L, update_context(Form, Context)) end, Acc1, ListOfLists) end) end, lists:foldl(F1, Acc, Forms). if_recurse(true, Form, Else, F) -> recurse(Form, Else, F); if_recurse(false, _, Else, _) -> Else. recurse(Form, Else, F) -> case erl_syntax:subtrees(Form) of [] -> Else; [_|_] = ListOfLists -> F(ListOfLists) end. -spec do_transform(xform_f_rec(), term(), forms(), #context{}) -> {forms(), term()}. do_transform(F, Acc, Forms, Context) -> Rec = fun do_transform/4, % this function F1 = fun(Form, Acc0) -> {Before1, Form1, After1, Recurse, Acc1} = this_form_rec(F, Form, Context, Acc0), if Recurse -> {NewForm, NewAcc} = enter_subtrees(Form1, F, update_context(Form1, Context), Acc1, Rec), {Before1, NewForm, After1, NewAcc}; true -> {Before1, Form1, After1, Acc1} end end, mapfoldl(F1, Acc, Forms). -spec do_depth_first(xform_f_df(), term(), forms(), #context{}) -> {forms(), term()}. do_depth_first(F, Acc, Forms, Context) -> Rec = fun do_depth_first/4, % this function F1 = fun(Form, Acc0) -> {NewForm, NewAcc} = enter_subtrees(Form, F, Context, Acc0, Rec), this_form_df(F, NewForm, Context, NewAcc) end, mapfoldl(F1, Acc, Forms). enter_subtrees(Form, F, Context, Acc, Recurse) -> case erl_syntax:subtrees(Form) of [] -> {Form, Acc}; [_|_] = ListOfLists -> {NewListOfLists, NewAcc} = mapfoldl( fun(L, AccX) -> Recurse(F, AccX, L, Context) end, Acc, ListOfLists), NewForm = erl_syntax:update_tree( Form, NewListOfLists), {NewForm, NewAcc} end. this_form_rec(F, Form, Context, Acc) -> Type = type(Form), case apply_F(F, Type, Form, Context, Acc) of {Form1x, Rec1x, A1x} -> {[], Form1x, [], Rec1x, A1x}; {_Be1, _F1, _Af1, _Rec1, _Ac1} = Res1 -> Res1 end. this_form_df(F, Form, Context, Acc) -> Type = type(Form), case apply_F(F, Type, Form, Context, Acc) of {Form1x, A1x} -> {[], Form1x, [], A1x}; {_Be1, _F1, _Af1, _Ac1} = Res1 -> Res1 end. apply_F(F, Type, Form, Context, Acc) -> try F(Type, Form, Context, Acc) catch error:Reason:ST -> ?ERROR(Reason, ?HERE, [{type, Type}, {context, Context}, {acc, Acc}, {apply_f, F}, {form, Form}, {stack, ST}], ST) end. update_context(Form, Context0) -> case type(Form) of function -> {Fun, Arity} = erl_syntax_lib:analyze_function(Form), Context0#context{function = Fun, arity = Arity}; _ -> Context0 end. %%% Slightly modified version of lists:mapfoldl/3 %%% Here, F/2 is able to insert forms before and after the form %%% in question. The inserted forms are not transformed afterwards. mapfoldl(F, Accu0, [Hd|Tail]) -> {Before, Res, After, Accu1} = case F(Hd, Accu0) of {Be, _, Af, _} = Result when is_list(Be), is_list(Af) -> Result; {R1, A1} -> {[], R1, [], A1} end, {Rs, Accu2} = mapfoldl(F, Accu1, Tail), {Before ++ [Res| After ++ Rs], Accu2}; mapfoldl(F, Accu, []) when is_function(F, 2) -> {[], Accu}. rpt_error(_Reason, _Fun, _Info, _Trace) -> %% Fmt = lists:flatten( %% ["*** ERROR in parse_transform function:~n" %% "*** Reason = ~p~n", %% "*** Location: ~p~n", %% "*** Trace: ~p~n", %% ["*** ~10w = ~p~n" || _ <- Info]]), %% Args = [Reason, Fun, Trace | %% lists:foldr( %% fun({K,V}, Acc) -> %% [K, V | Acc] %% end, [], Info)], %%io:format(Fmt, Args), ok. -spec format_error({atom(), term()}) -> iolist(). format_error({E, [{M,F,A}|_]} = Error) -> try lists:flatten(io_lib:fwrite("~p in ~s:~s/~s", [E, atom_to_list(M), atom_to_list(F), integer_to_list(A)])) catch error:_ -> format_error_(Error) end; format_error(Error) -> format_error_(Error). format_error_(Error) -> lists:flatten(io_lib:fwrite("~p", [Error])). %% EUnit -ifdef(TEST). format_exeption_test() -> [_,_,_] = format_exception(error, {error, foo}, 3), ok. -endif.