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%% @author Yariv Sadan <yarivsblog@gmail.com> [http://yarivsblog.com]
%% @copyright Yariv Sadan 2006-2007
%%
%% @doc Smerl: Simple Metaprogramming for Erlang
%%
%% Smerl is an Erlang library
%% that simplifies the creation and manipulation of Erlang modules in
%% runtime.
%%
%% You don't need to know Smerl in order to use ErlyWeb; Smerl
%% is included in ErlyWeb because ErlyWeb uses it internally.
%%
%% Smerl uses Erlang's capabilities for hot code swapping and
%% abstract syntax tree transformations to do its magic. Smerl is inspired by
%% the rdbms_codegen.erl module in the RDBMS application written by
%% Ulf Wiger. RDBMS is part of Jungerl ([http://jungerl.sf.net]).
%%
%% Here's a quick example illustrating how to use Smerl:
%% ```
%% test_smerl() ->
%% M1 = smerl:new(foo),
%% {ok, M2} = smerl:add_func(M1, "bar() -> 1 + 1."),
%% smerl:compile(M2),
%% foo:bar(), % returns 2``
%% smerl:has_func(M2, bar, 0). % returns true
%% '''
%%
%% New functions can be expressed either as strings of Erlang code
%% or as abstract forms. For more information, read the Abstract Format
%% section in the ERTS User's guide
%% ([http://erlang.org/doc/doc-5.5/erts-5.5/doc/html/absform.html#4]).
%%
%% Using the abstract format, the 3rd line of the above example
%% would be written as
%% ```
%% {ok,M2} = smerl:add_func(M1, {function,1,bar,0,
%% [{clause,1,[],[],
%% [{op,1,'+',{integer,1,1},{integer,1,1}}]}]).
%% '''
%%
%% <p>The abstact format may look more verbose in this example, but
%% it's also easier to manipulate in code.</p>
%%
%% Copyright (c) Yariv Sadan 2006-2007
%%
%% Permission is hereby granted, free of charge, to any person
%% obtaining a copy of this software and associated documentation
%% files (the "Software"), to deal in the Software without restriction,
%% including without limitation the rights to use, copy, modify, merge,
%% publish, distribute, sublicense, and/or sell copies of the Software,
%% and to permit persons to whom the Software is furnished to do
%% so, subject to the following conditions:
%%
%% The above copyright notice and this permission notice shall be included
%% in all copies or substantial portions of the Software.
%%
%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
%% EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
%% MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
%% IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
%% CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
%% TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
%% SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
-module(smerl).
-author("Yariv Sadan (yarivsblog@gmail.com, http://yarivsblog.com").
-export([new/1,
for_module/1,
for_module/2,
for_module/3,
for_file/1,
for_file/2,
for_file/3,
get_module/1,
set_module/2,
get_forms/1,
set_forms/2,
get_exports/1,
set_exports/2,
get_export_all/1,
set_export_all/2,
remove_export/3,
get_attribute/2,
add_func/2,
add_func/3,
remove_func/3,
has_func/3,
get_func/3,
replace_func/2,
% replace_func/3,
compile/1,
compile/2,
rename/2,
curry/2,
curry/4,
curry/5,
curry_add/3,
curry_add/4,
curry_add/5,
curry_add/6,
curry_replace/3,
curry_replace/4,
embed_params/2,
embed_params/4,
embed_params/5,
embed_all/2,
extend/2,
extend/3,
extend/4,
to_src/1,
to_src/2
]).
-define(L(Obj), io:format("LOG ~s ~w ~p\n", [?FILE, ?LINE, Obj])).
-define(S(Obj), io:format("LOG ~s ~w ~s\n", [?FILE, ?LINE, Obj])).
-include_lib("kernel/include/file.hrl").
%% @type meta_mod(). A data structure holding the abstract representation
%% for a module.
%% @type func_form(). The abstract form for the function, as described
%% in the ERTS Users' manual.
%% The record type holding the abstract representation for a module.
-record(meta_mod, {module, file, exports = [], forms = [],
export_all = false}).
%% @doc Create a new meta_mod for a module with the given name.
%%
%% @spec new(Module::atom()) -> meta_mod()
new(ModuleName) when is_atom(ModuleName) ->
#meta_mod{module = ModuleName}.
%% @equiv for_module(ModuleName, [])
for_module(ModuleName) ->
for_module(ModuleName, []).
%% @equiv for_module(ModuleName, IncludePaths, [])
for_module(ModuleName, IncludePaths) ->
for_module(ModuleName, IncludePaths, []).
%% @doc Create a meta_mod tuple for an existing module. If ModuleName is a
%% string, it is interpreted as a file name (this is the same as calling
%% @{link smerl:for_file}). If ModuleName is an atom, Smerl attempts to
%% find its abstract represtation either from its source file or from
%% its .beam file directly (if it has been compiled with debug_info).
%% If the abstract representation can't be found, this function returns
%% an error.
%%
%% The IncludePaths parameter is used when 'ModuleName' is a file name.
%%
%% @spec for_module(ModuleName::atom() | string(), IncludePaths::[string()],
%% Macros::[{atom(), term()}]) ->
%% {ok, meta_mod()} | {error, Error}
for_module(ModuleName, IncludePaths, Macros) when is_list(ModuleName) ->
for_file(ModuleName, IncludePaths, Macros);
for_module(ModuleName, IncludePaths, Macros) when is_atom(ModuleName) ->
[_Exports, _Imports, _Attributes,
{compile, [_Options, _Version, _Time, {source, Path}]}] =
ModuleName:module_info(),
case for_file(Path, IncludePaths, Macros) of
{ok, _Mod} = Res->
Res;
_Err ->
case code:which(ModuleName) of
Path1 when is_list(Path1) ->
case get_forms(ModuleName, Path1) of
{ok, Forms} ->
mod_for_forms(Forms);
_Other ->
{error, {invalid_module, ModuleName}}
end;
_Err ->
{error, {invalid_module, ModuleName}}
end
end.
%% @equiv for_file(SrcFilePath, [])
for_file(SrcFilePath) ->
for_file(SrcFilePath, []).
%% @equiv for_file(SrcFilePath, IncludePaths, [])
for_file(SrcFilePath, IncludePaths) ->
for_file(SrcFilePath, IncludePaths, []).
%% @doc Create a meta_mod for a module from its source file.
%%
%% @spec for_file(SrcFilePath::string(), IncludePaths::[string()],
%% Macros::[{atom(), term()}]) ->
%% {ok, meta_mod()} | {error, invalid_module}
for_file(SrcFilePath, IncludePaths, Macros) ->
case epp:parse_file(SrcFilePath, [filename:dirname(SrcFilePath) |
IncludePaths], Macros) of
{ok, Forms} ->
mod_for_forms(Forms);
_err ->
{error, {invalid_module, SrcFilePath}}
end.
mod_for_forms([{attribute,_,file,{FileName,_FileNum}},
{attribute, _, module, ModuleName}|Forms]) ->
{Exports, OtherForms, ExportAll} =
lists:foldl(
fun({attribute, _, export, ExportList},
{ExportsAcc, FormsAcc, ExportAll}) ->
{ExportList ++ ExportsAcc, FormsAcc, ExportAll};
({attribute, _, compile, export_all},
{ExportsAcc, FormsAcc, _ExportAll}) ->
{ExportsAcc, FormsAcc, true};
({eof, _}, Acc) ->
Acc;
(Form, {ExportsAcc, FormsAcc, ExportAll}) ->
{ExportsAcc, [Form | FormsAcc], ExportAll}
end, {[], [], false}, Forms),
{ok, #meta_mod{module = ModuleName,
file = FileName,
exports = Exports,
forms = OtherForms,
export_all = ExportAll
}};
mod_for_forms(Mod) ->
{error, {invalid_module, Mod}}.
%% @doc Return the module name for the meta_mod.
%%
%% @spec(MetaMod::meta_mod()) -> atom()
get_module(MetaMod) ->
MetaMod#meta_mod.module.
%% @doc Set the meta_mod's module name.
%%
%% @spec set_module(MetaMod::meta_mod(), NewName::atom()) ->
%% NewMod::meta_mod()
set_module(MetaMod, NewName) ->
MetaMod#meta_mod{module = NewName}.
%% @doc Return the list of function forms in the meta_mod.
%%
%% @spec get_forms(MetaMod::meta_mod()) -> [Form]
get_forms(MetaMod) ->
MetaMod#meta_mod.forms.
set_forms(MetaMod, Forms) ->
MetaMod#meta_mod{forms = Forms}.
%% @doc Return the list of exports in the meta_mod.
%%
%% @spec get_exports(MetaMod::meta_mod()) ->
%% [{FuncName::atom(), Arity::integer()}]
get_exports(MetaMod) ->
case MetaMod#meta_mod.export_all of
false ->
MetaMod#meta_mod.exports;
true ->
lists:foldl(
fun({function, _L, Name, Arity, _Clauses}, Exports) ->
[{Name, Arity} | Exports];
(_Form, Exports) ->
Exports
end, [], MetaMod#meta_mod.forms)
end.
%% @doc Set the meta_mod's export list to the new list.
%%
%% @spec set_exports(MetaMod::meta_mod(),
%% Exports::[{FuncName::atom(), Arity::integer()}]) -> NewMod::meta_mod()
set_exports(MetaMod, Exports) ->
MetaMod#meta_mod{exports = Exports}.
%% @doc Get the export_all value for the module.
%%
%% @spec get_export_all(MetaMod::meta_mod) -> true | false
get_export_all(MetaMod) ->
MetaMod#meta_mod.export_all.
%% @doc Set the export_all value for the module.
%%
%% @spec set_export_all(MetaMod::meta_mod(), Val::true | false) ->
%% NewMetaMod::meta_mod()
set_export_all(MetaMod, Val) ->
MetaMod#meta_mod{export_all = Val}.
%% @doc Remove the export from the list of exports in the meta_mod.
%%
%% @spec remove_export(MetaMod::meta_mod(), FuncName::atom(),
%% Arity::integer()) -> NewMod::meta_mod()
remove_export(MetaMod, FuncName, Arity) ->
MetaMod#meta_mod{exports =
lists:delete({FuncName, Arity},
MetaMod#meta_mod.exports)}.
%% @doc Get the value a the module's attribute.
%%
%% @spec get_attribute(MetaMod::meta_mod(), AttName::atom()) ->
%% {ok, Val} | error
get_attribute(MetaMod, AttName) ->
case lists:keysearch(AttName, 3, get_forms(MetaMod)) of
{value, {attribute,_,_,Val}} ->
{ok, Val};
_ -> error
end.
%% Get the abstract representation, if available, for the module.
%%
%% Strategy:
%% 1) Try to get the abstract code from the module if it's compiled
%% with debug_info.
%% 2) Look for the source file in the beam file's directory.
%% 3) If the file's directory ends with 'ebin', then search in
%% [beamdir]/../src
get_forms(Module, Path) ->
case beam_lib:chunks(Path, [abstract_code]) of
{ok, {_, [{abstract_code, {raw_abstract_v1, Forms}}]}} ->
{ok, Forms};
_Err ->
case filename:find_src(Module, [{"ebin", "src"}]) of
{error, _} = Err ->
get_forms_from_binary(Module, Err);
{SrcPath, _} ->
Filename = SrcPath ++ ".erl",
epp:parse_file(Filename, [filename:dirname(Filename)], [])
end
end.
get_dirs_in_dir(Dir) ->
case file:list_dir(Dir) of
{error, _} ->
undefined;
{ok, Listing} ->
lists:foldl(
fun (Name, Acc) ->
Path = Dir ++ "/" ++ Name,
case file:read_file_info(Path) of
{ok, #file_info{type=directory}} -> [Path | Acc];
_ -> Acc
end
end, [], Listing)
end.
%% @doc Try to infer module source files from the beam code path.
get_forms_from_binary(Module, OrigErr) ->
Ret =
case code:where_is_file(atom_to_list(Module) ++ ".beam") of
non_existing ->
OrigErr;
Filename ->
%% We could automatically obtain a list of all dirs under this dir, but we just do
%% a hack for now.
Basedir = filename:dirname(Filename),
Lastdir = filename:basename(Basedir),
if Lastdir == "ebin" ->
Rootdir = filename:dirname(Basedir),
DirList = [Rootdir ++ "/src"],
get_forms_from_file_list(Module, Rootdir,
DirList ++ get_dirs_in_dir(Rootdir ++ "/src"));
true ->
DirList = [Basedir],
get_forms_from_file_list(Module, Basedir, DirList)
end
end,
if Ret == [] -> OrigErr;
true -> Ret
end.
get_forms_from_file_list(_Module, _Basedir, []) ->
[];
get_forms_from_file_list(Module, Basedir, [H|T]) ->
Filename = H ++ "/" ++ atom_to_list(Module) ++ ".erl",
case file:read_file_info(Filename) of
{ok, #file_info{type=regular}} ->
epp:parse_file(Filename, [filename:dirname(Filename)], []);
_ ->
get_forms_from_file_list(Module, Basedir, T)
end.
%% @doc Add a new function to the meta_mod and return the resulting meta_mod.
%% This function calls add_func(MetaMod, Form, true).
%%
%% @spec add_func(MetaMod::meta_mod(), Form::func_form() | string()) ->
%% {ok, NewMod::meta_mod()} | {error, parse_error}
add_func(MetaMod, Form) ->
add_func(MetaMod, Form, true).
%% @doc Add a new function to the meta_mod and return the new MetaMod
%% record. Export is a boolean variable indicating if the function should
%% be added to the module's exports.
%%
%% @spec add_func(MetaMod::meta_mod(), Func::func_form() | string(),
%% Export::boolean()) ->
%% {ok, NewMod::meta_mod()} | {error, parse_error}
add_func(MetaMod, Func, Export) when is_list(Func) ->
case parse_func_string(Func) of
{ok, Form} ->
add_func(MetaMod, Form, Export);
Err ->
Err
end;
add_func(MetaMod, {function, _Line, FuncName, Arity, _Clauses} = Form,
true) ->
Foo = {ok, MetaMod#meta_mod{
exports = [{FuncName, Arity} | MetaMod#meta_mod.exports],
forms = [Form | MetaMod#meta_mod.forms]
}},
Foo;
add_func(MetaMod, {function, _Line, _FuncName, _Arity, _Clauses} = Form,
false) ->
{ok, MetaMod#meta_mod{forms = [Form | MetaMod#meta_mod.forms]}};
%%add_func(MetaMod, Name, Fun) when is_function(Fun) ->
%% add_func(MetaMod, Name, Fun, true);
add_func(_, _, _) ->
{error, parse_error}.
%% add_func(MetaMod, Name, Fun, Export) when is_function(Fun) ->
%% case form_for_fun(Name, Fun) of
%% {ok, Form} ->
%% add_func(MetaMod, Form, Export);
%% Err ->
%% Err
%% end.
%% form_for_fun(Name, Fun) ->
%% Line = 999,
%% Info = erlang:fun_info(Fun),
%% case Info of
%% [{module, _ModName}, _FuncName, _Arity, _Env, {type, external}] ->
%% {error, cant_add_external_funcs};
%% [_Pid, _Module, _NewIdx, _NewUniq, _Index, _Uniq, _Name,
%% {arity, Arity},
%% {env, [Vars, _Unknown1, _Unknown2, Clauses]},
%% {type, local}] ->
%% EnvVars = lists:map(
%% fun({VarName, Val}) ->
%% {match,Line,{var,Line,VarName},
%% erl_parse:abstract(Val)}
%% end, Vars),
%% NewClauses = lists:map(
%% fun({clause, Line1, Params, Guards, Exprs}) ->
%% {clause, Line1, Params, Guards,
%% EnvVars ++ Exprs}
%% end, Clauses),
%% {ok, {function, Line, Name, Arity, NewClauses}};
%% _Other ->
%% {error, bad_fun}
%% end.
parse_func_string(Func) ->
case erl_scan:string(Func) of
{ok, Toks, _} ->
case erl_parse:parse_form(Toks) of
{ok, _Form} = Res ->
Res;
_Err ->
{error, parse_error}
end;
_Err ->
{error, parse_error}
end.
%% @doc Try to remove the function from the meta_mod.
%% If the function exists, the new meta_mod is returned. Otherwise,
%% original meta_mod is returned.
%%
%% @spec remove_func(MetaMod::meta_mod(), FuncName::string(), Arity::integer())
%% -> NewMod::meta_mod()
%%
remove_func(MetaMod, FuncName, Arity) ->
MetaMod#meta_mod{forms =
lists:filter(
fun({function, _Line, FuncName1, Arity1, _Clauses})
when FuncName1 =:= FuncName, Arity =:= Arity1->
false;
(_) ->
true
end, MetaMod#meta_mod.forms),
exports =
lists:filter(
fun({FuncName1, Arity1})
when FuncName1 =:= FuncName,
Arity1 =:= Arity ->
false;
(_) ->
true
end, MetaMod#meta_mod.exports)
}.
%% @doc Check whether the meta_mod has a function with the given name
%% and arity.
%% @spec has_func(MetaMod::meta_mod(), FuncName::atom(), Arity::integer()) ->
%% bool()
has_func(MetaMod, FuncName, Arity) ->
lists:any(fun({function, _Line, FuncName1, Arity1, _Clauses})
when FuncName1 == FuncName, Arity1 == Arity ->
true;
(_) ->
false
end, MetaMod#meta_mod.forms).
%% @doc Get the form for the function with the specified arity in the
%% meta_mod.
%%
%% @spec get_func(MetaMod::meta_mod() | atom(),
%% FuncName::atom(), Arity::integer()) ->
%% {ok, func_form()} | {error, Err}
get_func(Module, FuncName, Arity) when is_atom(Module) ->
case smerl:for_module(Module) of
{ok, C1} ->
get_func(C1, FuncName, Arity);
Err ->
Err
end;
get_func(MetaMod, FuncName, Arity) ->
get_func2(MetaMod#meta_mod.forms, FuncName, Arity).
get_func2([], FuncName, Arity) ->
{error, {function_not_found, {FuncName, Arity}}};
get_func2([{function, _Line, FuncName, Arity, _Clauses} = Form | _Rest],
FuncName, Arity) ->
{ok, Form};
get_func2([_Form|Rest], FuncName, Arity) ->
get_func2(Rest, FuncName, Arity).
%% @doc
%% Replace an existing function with the new one. If the function doesn't exist
%% the new function is added to the meta_mod.
%% This is tantamount to calling smerl:remove_func followed by smerl:add_func.
%%
%% @spec replace_func(MetaMod::meta_mod(), Function::string() | func_form()) ->
%% {ok, NewMod::meta_mod()} | {error, Error}
replace_func(MetaMod, Function) when is_list(Function) ->
case parse_func_string(Function) of
{ok, Form} ->
replace_func(MetaMod, Form);
Err ->
Err
end;
replace_func(MetaMod, {function, _Line, FuncName, Arity, _Clauses} = Form) ->
Mod1 = remove_func(MetaMod, FuncName, Arity),
add_func(Mod1, Form);
replace_func(_MetaMod, _) ->
{error, parse_error}.
%% %% @doc Simliar to replace_func/2, but accepts a function
%% %% name + fun expression.
%% %%
%% %% @spec replace_func(MetaMod::meta_mod(), Name::atom(), Fun::function()) ->
%% %% {ok, NewMod::meta_mod()} | {error, Error}
%% replace_func(MetaMod, Name, Fun) when is_function(Fun) ->
%% case form_for_fun(Name, Fun) of
%% {ok, Form} ->
%% replace_func(MetaMod, Form);
%% Err ->
%% Err
%% end.
%% @doc Compile the module represented by the meta_mod and load the
%% resulting BEAM into the emulator. This function calls
%% compile(MetaMod, [report_errors, report_warnings]).
%%
%% @spec compile(MetaMod::meta_mod()) -> ok | {error, Error}
compile(MetaMod) ->
compile(MetaMod, undefined).
%% @doc Compile the module represented by the meta_mod and load the
%% resulting BEAM into the emulator. 'Options' is a list of options as
%% described in the 'compile' module in the Erlang documentation.
%%
%% If the 'outdir' option is provided,
%% the .beam file is written to the destination directory.
%%
%% @spec compile(MetaMod::meta_mod(), Options::[term()]) -> ok | {error, Error}
compile(MetaMod, undefined) ->
compile(MetaMod, [report_errors, report_warnings,
return_errors]);
compile(MetaMod, Options) ->
Forms = [{attribute, 2, module, MetaMod#meta_mod.module},
{attribute, 3, export, get_exports(MetaMod)}],
FileName =
case MetaMod#meta_mod.file of
undefined -> atom_to_list(get_module(MetaMod));
Val -> Val
end,
Forms1 = [{attribute, 1, file, {FileName, 1}} | Forms],
Forms2 = Forms1 ++ lists:reverse(MetaMod#meta_mod.forms),
case compile:forms(Forms2, Options) of
{ok, Module, Bin} ->
Res =
case lists:keysearch(outdir, 1, Options) of
{value, {outdir, OutDir}} ->
file:write_file(
OutDir ++
['/' | atom_to_list(MetaMod#meta_mod.module)] ++
".beam", Bin);
false -> ok
end,
case Res of
ok ->
code:purge(Module),
case code:load_binary(
Module,
atom_to_list(Module) ++ ".erl", Bin) of
{module, _Module} ->
ok;
Err ->
Err
end;
Err ->
Err
end;
Err ->
Err
end.
%% @doc Change the name of the function represented by the form.
%%
%% @spec rename(Form::func_form(), NewName::atom()) ->
%% {ok, NewForm::func_form()} | {error, Err}
rename({function, Line, _Name, Arity, Clauses}, NewName) ->
{function, Line, NewName, Arity, Clauses}.
%% @doc Get the curried form for the function and parameter(s). Currying
%% involves replacing one or more of the function's leading parameters
%% with predefined values.
%%
%% @spec curry(Form::func_form(), Param::term() | [term()]) ->
%% {ok, NewForm::func_form()} | {error, Err}
curry(Form, Param) when not is_list(Param) ->
curry(Form, [Param]);
curry({function, _Line, _Name, Arity, _Clauses}, Params)
when length(Params) > Arity ->
{error, too_many_params};
curry({function, Line, Name, Arity, Clauses}, NewParams) ->
NewClauses =
lists:foldl(
fun(Clause, Clauses1) ->
[curry_clause(Clause, NewParams) | Clauses1]
end, [], Clauses),
{ok, {function, Line, Name, Arity-length(NewParams), NewClauses}}.
curry_clause({clause, L1, ExistingParams, Guards, _Exprs} = Clause,
NewParams) ->
{FirstParams, LastParams} =
lists:split(length(NewParams), ExistingParams),
%% Matches =
%% lists:foldl(
%% fun({Var, NewVal}, Acc) ->
%% [{match, 1, Var, erl_parse:abstract(NewVal)} | Acc]
%% end, [], lists:zip(FirstParams, NewParams)),
%% {clause, L1, LastParams, Guards, Matches ++ Exprs}.
Vals =
lists:foldl(
fun({{var,_,Name}, NewVal}, Acc) ->
[{Name, erl_parse:abstract(NewVal)} | Acc];
(_, Acc) ->
Acc
end, [], lists:zip(FirstParams, NewParams)),
NewExprs = replace_vars(Clause, Vals),
{clause, L1, LastParams, Guards, NewExprs}.
replace_vars(Clause, Vals) ->
Tree =
erl_syntax_lib:map(
fun({var,_L2,Name} = Expr) ->
case proplists:lookup(Name, Vals) of
none ->
Expr;
{_, Val} ->
Val
end;
(Expr) ->
Expr
end, Clause),
{clause, _, _, _, NewExprs} = erl_syntax:revert(Tree),
NewExprs.
%% @doc Curry the function from the module with the given param(s)
%%
%% @spec curry(ModName::atom(), Name::atom(), Arity::integer(),
%% Params::term() | [term()]) ->
%% {ok, NewForm} | {error, Err}
curry(ModName, Name, Arity, Params) when is_atom(ModName) ->
case for_module(ModName) of
{ok, MetaMod} ->
curry(MetaMod, Name, Arity, Params);
Err ->
Err
end;
%% @doc Curry the function from the meta_mod with
%% the given param(s)
%%
%% @spec curry(MetaMod::meta_mod(), Name::atom(), arity::integer(),
%% Params::term() | [terms()]) ->
%% {ok, NewForm} | {error, Err}
curry(MetaMod, Name, Arity, Params) ->
case get_func(MetaMod, Name, Arity) of
{ok, Form} ->
curry(Form, Params);
Err ->
Err
end.
%% @doc Curry the function from the module or meta_mod
%% with the param(s), and return its renamed form.
%%
%% @spec curry(Module::atom() | meta_mod(), Name::atom(), Arity::integer(),
%% Params::term() | [terms()], NewName::atom()) ->
%% {ok, NewForm} | {error, Err}
curry(Module, Name, Arity, Params, NewName) ->
case curry(Module, Name, Arity, Params) of
{ok, NewForm} ->
{ok, rename(NewForm, NewName)};
Err ->
Err
end.
%% @doc Add the curried form of the function in the meta_mod
%% with its curried form.
%%
%% @spec curry_add(MetaMod::meta_mod(), Form::func_form(),
%% Params::term() | [term()]) ->
%% {ok, NewMetaMod::meta_mod()} | {error, Err}
curry_add(MetaMod, {function, _Line, Name, Arity, _Clauses}, Params) ->
curry_add(MetaMod, Name, Arity, Params).
%% @doc Add the curried form of the function
%% in the meta_mod with its curried form.
%%
%% @spec curry_add(MetaMod::meta_mod(), Name::atom(), Arity::integer(),
%% Params::term() | [term()]) ->
%% {ok, NewMetaMod::meta_mod()} | {error, Err}
curry_add(MetaMod, Name, Arity, Params) ->
curry_change(MetaMod, Name, Arity, Params, false).
%% @doc Curry the function form from the meta_mod, then add it
%% to the other meta_mod with a new name.
%%
%% @spec curry_add(MetaMod::meta_mod(), Name::atom(), Arity::integer(),
%% Params::[term()], NewName::atom()) -> {ok, NewMod::meta_mod()} |
%% {error, Err}
curry_add(MetaMod, Name, Arity, Params, NewName) ->
curry_add(MetaMod, MetaMod, Name, Arity, Params, NewName).
%% @doc Curry the function in the module, rename the curried form, and
%% add it to the meta_mod.
%%
%% @spec curry_add(MetaMod::meta_mod(), Module::atom() | meta_mod(),
%% Name::atom(), Arity::integer(), Params::term() | [term()],
%% NewName::atom()) ->
%% {ok, NewMod::meta_mod()} | {error, Error}
curry_add(MetaMod, Module, Name, Arity, Params, NewName) ->
case curry(Module, Name, Arity, Params, NewName) of
{ok, Form} ->
add_func(MetaMod, Form);
Err ->
Err
end.
curry_change(MetaMod, Name, Arity, Params, Remove) ->
case get_func(MetaMod, Name, Arity) of
{ok, OldForm} ->
case curry(OldForm, Params) of
{ok, NewForm} ->
MetaMod1 =
case Remove of
true ->
remove_func(MetaMod, Name, Arity);
false ->
MetaMod
end,
add_func(MetaMod1, NewForm);
Err ->
Err
end;
Err ->
Err
end.
%% @doc Replace the function in the meta_mod with
%% its curried form.
%%
%% @spec curry_replace(MetaMod::meta_mod(), Form::func_form(),
%% Params::term() | [term()]) ->
%% {ok, NewMetaMod::meta_mod()} | {error, Err}
curry_replace(MetaMod, {function, _Line, Name, Arity, _Clauses}, Params) ->
curry_replace(MetaMod, Name, Arity, Params).
%% @doc Replace the function in the meta_mod with
%% its curried form.
%%
%% @spec curry_replace(MetaMod::meta_mod(), Name::atom(),
%% Arity::integer(), Params::term() | list()) ->
%% {ok, NewMetaMod::meta_mod()} | {error, Err}
curry_replace(MetaMod, Name, Arity, Params) ->
curry_change(MetaMod, Name, Arity, Params, true).
%% @doc This function takes a function form and list of name/value pairs,
%% and replaces all the function's parameters that whose names match an
%% element from the list with the predefined value.
%%
%% @spec embed_params(Func::func_form(),
%% Vals::[{Name::atom(), Value::term()}]) -> NewForm::func_form()
embed_params({function, L, Name, Arity, Clauses}, Vals) ->
NewClauses =
lists:map(
fun({clause, L1, Params, Guards, _Exprs} = Clause) ->
{EmbeddedVals, OtherParams} =
lists:foldr(
fun({var,_, VarName} = Param, {Embedded, Rest}) ->
case proplists:lookup(VarName, Vals) of
none ->
{Embedded, [Param | Rest]};
{_, Val} ->
{[{VarName, erl_parse:abstract(Val)} |
Embedded], Rest}
end;
(Param, {Embedded, Rest}) ->
{Embedded, [Param | Rest]}
end, {[], []}, Params),
NewExprs = replace_vars(Clause, EmbeddedVals),
{clause, L1, OtherParams, Guards, NewExprs}
%% {Params1, Matches1, _RemainingVals} =
%% lists:foldl(
%% fun({var, _L2, ParamName} = Param,
%% {Params2, Matches2, Vals1}) ->
%% case lists:keysearch(ParamName, 1, Vals1) of
%% {value, {_Name, Val} = Elem} ->
%% Match = {match, L1, Param,
%% erl_parse:abstract(Val)},
%% {Params2, [Match | Matches2],
%% lists:delete(Elem, Vals1)};
%% false ->
%% {[Param | Params2], Matches2, Vals1}
%% end;
%% (Param, {Params2, Matches2, Vals1}) ->
%% {[Param | Params2], Matches2, Vals1}
%% end, {[], [], Vals}, Params),
%% [{clause, L1, lists:reverse(Params1), Guards,
%% lists:reverse(Matches1) ++ Exprs} | Clauses1]
end, Clauses),
NewArity =
case NewClauses of
[{clause, _L2, Params, _Guards, _Exprs}|_] ->
length(Params);
_ ->
Arity
end,
{function, L, Name, NewArity, NewClauses}.
%% @doc Apply {@link embed_params/2} to a function from the meta_mod and
%% add the resulting function to the meta_mod, and return the resulting
%% meta_mod.
%%
%% @spec embed_params(MetaMod::meta_mod(), Name::atom(), Arity::integer(),
%% Values::proplist()) -> {ok, NewMetaMod::meta_mod()} | {error, Err}
embed_params(MetaMod, Name, Arity, Values) ->
embed_params(MetaMod, Name, Arity, Values, Name).
%% @doc Apply embed_params/2 to the function from the meta_mod and
%% add the resulting function to the meta_mod after renaming the function.
%%
%% @spec embed_params(MetaMod::meta_mod(), Name::atom(), Arity::integer(),
%% Values::proplist(), NewName::atom()) ->
%% {ok, NewMetaMod::meta_mod()} | {error, Err}
embed_params(MetaMod, Name, Arity, Values, NewName) ->
case get_func(MetaMod, Name, Arity) of
{ok, Form} ->
NewForm = embed_params(Form, Values),
add_func(MetaMod, rename(NewForm, NewName));
Err ->
Err
end.
%% @doc Apply the embed_params function with the list of {Name, Value}
%% pairs to all forms in the meta_mod. Exports
%% for functions whose arities change due to the embedding are preserved.
%%
%% @spec embed_all(MetaMod::meta_mod(), Vals::[{Name::atom(),
%% Value::term()}]) -> NewMetaMod::meta_mod()
embed_all(MetaMod, Vals) ->
Forms = get_forms(MetaMod),
Exports = get_exports(MetaMod),
{NewForms, Exports3, NewExports} =
lists:foldl(
fun({function, _L, Name, Arity, _Clauses} = Form,
{Forms1, Exports1, NewExports1}) ->
{function, _, _, NewArity, _} = NewForm =
embed_params(Form, Vals),
Exports2 = lists:delete({Name, Arity}, Exports1),
NewExports2 =
case length(Exports2) == length(Exports1) of
true ->
NewExports1;
false ->
[{Name, NewArity} | NewExports1]
end,
{[NewForm | Forms1], Exports2, NewExports2};
(Form, {Forms1, Exports1, NewExports1}) ->
{[Form | Forms1], Exports1, NewExports1}
end, {[], Exports, []}, Forms),
#meta_mod{module = get_module(MetaMod),
exports = Exports3 ++ NewExports,
forms = lists:reverse(NewForms),
export_all = get_export_all(MetaMod)}.
%% @doc extend/2
%% Add all the parent module's functions that are missing from the child
%% module to the child module. The new functions in the child module are
%% shallow: they have the name and arity as their corresponding functions in
%% the parent meta_mod, but instead of implementing their logic they call
%% the parent module's functions.
%%
%% @spec extend(Parent::atom() | meta_mod(), Child::atom() | meta_mod()) ->
%% NewChildMod::meta_mod()
extend(Parent, Child) ->
extend(Parent, Child, 0).
%% @doc Similar to extend/2, with the addition of the 'ArityDiff' parameter,
%% which indicates the difference
%% in arities Smerl should use when figuring out which functions to
%% generate based on the modules' exports. This is sometimes
%% useful when calling extend() followed by embed_all().
%%
%% @spec extend(Parent::atom() | meta_mod(), Child::atom() | meta_mod(),
%% ArityDiff::integer()) ->
%% NewChildMod::meta_mod()
extend(Parent, Child, ArityDiff) ->
extend(Parent, Child, ArityDiff, []).
extend(Parent, Child, ArityDiff, Options) ->
{{ParentName, ParentExports, ParentMod}, ChildMod} =
get_extend_data(Parent, Child),
ChildExports = get_exports(ChildMod),
ChildExports1 = [{ExportName, ExportArity + ArityDiff} ||
{ExportName, ExportArity} <-
ChildExports],
ExportsDiff = ParentExports -- ChildExports1,
NewChild =
lists:foldl(
fun({FuncName, Arity}, ChildMod1) ->
Func =
case lists:member(copy, Options) of
true ->
{ok, ParentFunc} =
smerl:get_func(ParentMod, FuncName, Arity),
ParentFunc;
_ ->
Params = get_params(
ParentMod, FuncName, Arity),
Clause1 =
{clause,1,Params,[],
[{call,1,
{remote,1,{atom,1,ParentName},
{atom,1,FuncName}},
Params}]},
{function,1,FuncName,Arity, [Clause1]}
end,
{ok, ChildMod2} = add_func(ChildMod1, Func),
ChildMod2
end, ChildMod, ExportsDiff),
NewChild.
get_extend_data(Parent, Child) when is_atom(Parent) ->
[{exports, Exports} |_] = Parent:module_info(),
Exports1 = Exports -- [{module_info, 0}],
Exports2 = Exports1 -- [{module_info, 1}],
ParentMod = case smerl:for_module(Parent) of
{ok, M} -> M;
{error, _} -> undefined
end,
get_extend_data({Parent, Exports2, ParentMod}, Child);
get_extend_data(Parent, Child) when is_record(Parent, meta_mod) ->
get_extend_data({get_module(Parent),
get_exports(Parent),
Parent}, Child);
get_extend_data(Parent, Child) when is_list(Parent) ->
case for_file(Parent) of
{ok, M1} ->
get_extend_data(M1, Child);
Err ->
Err
end;
get_extend_data({_,_,_} = ParentData, Child) when is_atom(Child);
is_list(Child) ->
case for_module(Child) of
{ok, MetaMod} ->
{ParentData, MetaMod};
Err ->
Err
end;
get_extend_data(ParentData, Child) when is_record(Child, meta_mod) ->
{ParentData, Child}.
get_params(_, _, 0) -> [];
get_params(undefined, _FuncName, Arity) ->
[{var,1,list_to_atom("P" ++ integer_to_list(Num))}
|| Num <- lists:seq(1, Arity)];
get_params(ParentMod, FuncName, Arity) ->
{ok, {function, _L, _Name, _Arity,
[{clause,_,Params,_Guards,_Exprs} | _]}} =
get_func(ParentMod, FuncName, Arity),
Params.
%% @doc Return the pretty-printed source code for the module.
%%
%% @spec to_src(MetaMod::meta_mod()) -> string()
to_src(MetaMod) ->
ExportsForm =
{attribute,1,export,get_exports(MetaMod)},
AllForms = [{attribute,1,module,get_module(MetaMod)}, ExportsForm |
get_forms(MetaMod)],
erl_prettypr:format(erl_syntax:form_list(AllForms)).
%% @doc Write the pretty printed source code for the module
%% to the file with the given file name.
%%
%% @spec to_src(MetaMod::meta_mod(), FileName::string()) ->
%% ok | {error, Error}
to_src(MetaMod, FileName) ->
Src = to_src(MetaMod),
file:write_file(FileName, list_to_binary(Src)).