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%%%-------------------------------------------------------------------
%%% @author Juan Jose Comellas <juanjo@comellas.org>
%%% @copyright (C) 2009 Juan Jose Comellas
%%% @doc Parses command line options with a format similar to that of GNU getopt.
%%% @end
%%%
%%% This source file is subject to the New BSD License. You should have received
%%% a copy of the New BSD license with this software. If not, it can be
%%% retrieved from: http://www.opensource.org/licenses/bsd-license.php
%%%-------------------------------------------------------------------
-module(getopt).
-author('juanjo@comellas.org').
-export([parse/2, usage/2, usage/3, usage/4, tokenize/1]).
-export([usage_cmd_line/2]).
-define(LINE_LENGTH, 75).
-define(MIN_USAGE_COMMAND_LINE_OPTION_LENGTH, 25).
%% Position of each field in the option specification tuple.
-define(OPT_NAME, 1).
-define(OPT_SHORT, 2).
-define(OPT_LONG, 3).
-define(OPT_ARG, 4).
-define(OPT_HELP, 5).
-define(IS_OPT_SPEC(Opt), (tuple_size(Opt) =:= ?OPT_HELP)).
-define(IS_WHITESPACE(Char), ((Char) =:= $\s orelse (Char) =:= $\t orelse
(Char) =:= $\n orelse (Char) =:= $\r)).
%% Atom indicating the data type that an argument can be converted to.
-type arg_type() :: 'atom' | 'binary' | 'boolean' | 'float' | 'integer' | 'string'.
%% Data type that an argument can be converted to.
-type arg_value() :: atom() | binary() | boolean() | float() | integer() | string().
%% Argument specification.
-type arg_spec() :: arg_type() | {arg_type(), arg_value()} | undefined.
%% Option type and optional default argument.
-type simple_option() :: atom().
-type compound_option() :: {atom(), arg_value()}.
-type option() :: simple_option() | compound_option().
%% Command line option specification.
-type option_spec() :: {
Name :: atom(),
Short :: char() | undefined,
Long :: string() | undefined,
ArgSpec :: arg_spec(),
Help :: string() | undefined
}.
%% Output streams
-type output_stream() :: 'standard_io' | 'standard_error'.
%% For internal use
-type usage_line() :: {OptionText :: string(), HelpText :: string()}.
-type usage_line_with_length() :: {OptionLength :: non_neg_integer(), OptionText :: string(), HelpText :: string()}.
-export_type([arg_type/0, arg_value/0, arg_spec/0, simple_option/0, compound_option/0, option/0, option_spec/0]).
%% @doc Parse the command line options and arguments returning a list of tuples
%% and/or atoms using the Erlang convention for sending options to a
%% function.
-spec parse([option_spec()], string() | [string()]) ->
{ok, {[option()], [string()]}} | {error, {Reason :: atom(), Data :: any()}}.
parse(OptSpecList, CmdLine) when is_list(CmdLine) ->
try
Args = if
is_integer(hd(CmdLine)) -> tokenize(CmdLine);
true -> CmdLine
end,
parse(OptSpecList, [], [], 0, Args)
catch
throw: {error, {_Reason, _Data}} = Error ->
Error
end.
-spec parse([option_spec()], [option()], [string()], integer(), [string()]) ->
{ok, {[option()], [string()]}}.
%% Process the option terminator.
parse(OptSpecList, OptAcc, ArgAcc, _ArgPos, ["--" | Tail]) ->
%% Any argument present after the terminator is not considered an option.
{ok, {lists:reverse(append_default_options(OptSpecList, OptAcc)), lists:reverse(ArgAcc, Tail)}};
%% Process long options.
parse(OptSpecList, OptAcc, ArgAcc, ArgPos, ["--" ++ OptArg = OptStr | Tail]) ->
parse_long_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Tail, OptStr, OptArg);
%% Process short options.
parse(OptSpecList, OptAcc, ArgAcc, ArgPos, ["-" ++ ([_Char | _] = OptArg) = OptStr | Tail]) ->
parse_short_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Tail, OptStr, OptArg);
%% Process non-option arguments.
parse(OptSpecList, OptAcc, ArgAcc, ArgPos, [Arg | Tail]) ->
case find_non_option_arg(OptSpecList, ArgPos) of
{value, OptSpec} when ?IS_OPT_SPEC(OptSpec) ->
parse(OptSpecList, add_option_with_arg(OptSpec, Arg, OptAcc), ArgAcc, ArgPos + 1, Tail);
false ->
parse(OptSpecList, OptAcc, [Arg | ArgAcc], ArgPos, Tail)
end;
parse(OptSpecList, OptAcc, ArgAcc, _ArgPos, []) ->
%% Once we have completed gathering the options we add the ones that were
%% not present but had default arguments in the specification.
{ok, {lists:reverse(append_default_options(OptSpecList, OptAcc)), lists:reverse(ArgAcc)}}.
%% @doc Parse a long option, add it to the option accumulator and continue
%% parsing the rest of the arguments recursively.
%% A long option can have the following syntax:
%% --foo Single option 'foo', no argument
%% --foo=bar Single option 'foo', argument "bar"
%% --foo bar Single option 'foo', argument "bar"
-spec parse_long_option([option_spec()], [option()], [string()], integer(), [string()], string(), string()) ->
{ok, {[option()], [string()]}}.
parse_long_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptStr, OptArg) ->
case split_assigned_arg(OptArg) of
{Long, Arg} ->
%% Get option that has its argument within the same string
%% separated by an equal ('=') character (e.g. "--port=1000").
parse_long_option_assigned_arg(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptStr, Long, Arg);
Long ->
case lists:keyfind(Long, ?OPT_LONG, OptSpecList) of
{Name, _Short, Long, undefined, _Help} ->
parse(OptSpecList, [Name | OptAcc], ArgAcc, ArgPos, Args);
{_Name, _Short, Long, _ArgSpec, _Help} = OptSpec ->
%% The option argument string is empty, but the option requires
%% an argument, so we look into the next string in the list.
%% e.g ["--port", "1000"]
parse_long_option_next_arg(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptSpec);
false ->
throw({error, {invalid_option, OptStr}})
end
end.
%% @doc Parse an option where the argument is 'assigned' in the same string using
%% the '=' character, add it to the option accumulator and continue parsing the
%% rest of the arguments recursively. This syntax is only valid for long options.
-spec parse_long_option_assigned_arg([option_spec()], [option()], [string()], integer(),
[string()], string(), string(), string()) ->
{ok, {[option()], [string()]}}.
parse_long_option_assigned_arg(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptStr, Long, Arg) ->
case lists:keyfind(Long, ?OPT_LONG, OptSpecList) of
{_Name, _Short, Long, ArgSpec, _Help} = OptSpec ->
case ArgSpec of
undefined ->
throw({error, {invalid_option_arg, OptStr}});
_ ->
parse(OptSpecList, add_option_with_assigned_arg(OptSpec, Arg, OptAcc), ArgAcc, ArgPos, Args)
end;
false ->
throw({error, {invalid_option, OptStr}})
end.
%% @doc Split an option string that may contain an option with its argument
%% separated by an equal ('=') character (e.g. "port=1000").
-spec split_assigned_arg(string()) -> {Name :: string(), Arg :: string()} | string().
split_assigned_arg(OptStr) ->
split_assigned_arg(OptStr, OptStr, []).
split_assigned_arg(_OptStr, "=" ++ Tail, Acc) ->
{lists:reverse(Acc), Tail};
split_assigned_arg(OptStr, [Char | Tail], Acc) ->
split_assigned_arg(OptStr, Tail, [Char | Acc]);
split_assigned_arg(OptStr, [], _Acc) ->
OptStr.
%% @doc Retrieve the argument for an option from the next string in the list of
%% command-line parameters or set the value of the argument from the argument
%% specification (for boolean and integer arguments), if possible.
parse_long_option_next_arg(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, {Name, _Short, _Long, ArgSpec, _Help} = OptSpec) ->
ArgSpecType = arg_spec_type(ArgSpec),
case Args =:= [] orelse is_implicit_arg(ArgSpecType, hd(Args)) of
true ->
parse(OptSpecList, add_option_with_implicit_arg(OptSpec, OptAcc), ArgAcc, ArgPos, Args);
false ->
[Arg | Tail] = Args,
try
parse(OptSpecList, [{Name, to_type(ArgSpecType, Arg)} | OptAcc], ArgAcc, ArgPos, Tail)
catch
error:_ ->
throw({error, {invalid_option_arg, {Name, Arg}}})
end
end.
%% @doc Parse a short option, add it to the option accumulator and continue
%% parsing the rest of the arguments recursively.
%% A short option can have the following syntax:
%% -a Single option 'a', no argument or implicit boolean argument
%% -a foo Single option 'a', argument "foo"
%% -afoo Single option 'a', argument "foo"
%% -abc Multiple options: 'a'; 'b'; 'c'
%% -bcafoo Multiple options: 'b'; 'c'; 'a' with argument "foo"
%% -aaa Multiple repetitions of option 'a' (only valid for options with integer arguments)
-spec parse_short_option([option_spec()], [option()], [string()], integer(), [string()], string(), string()) ->
{ok, {[option()], [string()]}}.
parse_short_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptStr, OptArg) ->
parse_short_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptStr, first, OptArg).
parse_short_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptStr, OptPos, [Short | Arg]) ->
case lists:keyfind(Short, ?OPT_SHORT, OptSpecList) of
{Name, Short, _Long, undefined, _Help} ->
parse_short_option(OptSpecList, [Name | OptAcc], ArgAcc, ArgPos, Args, OptStr, first, Arg);
{_Name, Short, _Long, ArgSpec, _Help} = OptSpec ->
%% The option has a specification, so it requires an argument.
case Arg of
[] ->
%% The option argument string is empty, but the option requires
%% an argument, so we look into the next string in the list.
parse_short_option_next_arg(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, OptSpec, OptPos);
_ ->
case is_valid_arg(ArgSpec, Arg) of
true ->
parse(OptSpecList, add_option_with_arg(OptSpec, Arg, OptAcc), ArgAcc, ArgPos, Args);
_ ->
NewOptAcc = case OptPos of
first -> add_option_with_implicit_arg(OptSpec, OptAcc);
_ -> add_option_with_implicit_incrementable_arg(OptSpec, OptAcc)
end,
parse_short_option(OptSpecList, NewOptAcc, ArgAcc, ArgPos, Args, OptStr, next, Arg)
end
end;
false ->
throw({error, {invalid_option, OptStr}})
end;
parse_short_option(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, _OptStr, _OptPos, []) ->
parse(OptSpecList, OptAcc, ArgAcc, ArgPos, Args).
%% @doc Retrieve the argument for an option from the next string in the list of
%% command-line parameters or set the value of the argument from the argument
%% specification (for boolean and integer arguments), if possible.
parse_short_option_next_arg(OptSpecList, OptAcc, ArgAcc, ArgPos, Args, {Name, _Short, _Long, ArgSpec, _Help} = OptSpec, OptPos) ->
case Args =:= [] orelse is_implicit_arg(ArgSpec, hd(Args)) of
true when OptPos =:= first ->
parse(OptSpecList, add_option_with_implicit_arg(OptSpec, OptAcc), ArgAcc, ArgPos, Args);
true ->
parse(OptSpecList, add_option_with_implicit_incrementable_arg(OptSpec, OptAcc), ArgAcc, ArgPos, Args);
false ->
[Arg | Tail] = Args,
try
parse(OptSpecList, [{Name, to_type(ArgSpec, Arg)} | OptAcc], ArgAcc, ArgPos, Tail)
catch
error:_ ->
throw({error, {invalid_option_arg, {Name, Arg}}})
end
end.
%% @doc Find the option for the discrete argument in position specified in the
%% Pos argument.
-spec find_non_option_arg([option_spec()], integer()) -> {value, option_spec()} | false.
find_non_option_arg([{_Name, undefined, undefined, _ArgSpec, _Help} = OptSpec | _Tail], 0) ->
{value, OptSpec};
find_non_option_arg([{_Name, undefined, undefined, _ArgSpec, _Help} | Tail], Pos) ->
find_non_option_arg(Tail, Pos - 1);
find_non_option_arg([_Head | Tail], Pos) ->
find_non_option_arg(Tail, Pos);
find_non_option_arg([], _Pos) ->
false.
%% @doc Append options that were not present in the command line arguments with
%% their default arguments.
-spec append_default_options([option_spec()], [option()]) -> [option()].
append_default_options([{Name, _Short, _Long, {_Type, DefaultArg}, _Help} | Tail], OptAcc) ->
append_default_options(Tail,
case lists:keymember(Name, 1, OptAcc) of
false ->
[{Name, DefaultArg} | OptAcc];
_ ->
OptAcc
end);
%% For options with no default argument.
append_default_options([_Head | Tail], OptAcc) ->
append_default_options(Tail, OptAcc);
append_default_options([], OptAcc) ->
OptAcc.
%% @doc Add an option with argument converting it to the data type indicated by the
%% argument specification.
-spec add_option_with_arg(option_spec(), string(), [option()]) -> [option()].
add_option_with_arg({Name, _Short, _Long, ArgSpec, _Help} = OptSpec, Arg, OptAcc) ->
case is_valid_arg(ArgSpec, Arg) of
true ->
try
[{Name, to_type(ArgSpec, Arg)} | OptAcc]
catch
error:_ ->
throw({error, {invalid_option_arg, {Name, Arg}}})
end;
false ->
add_option_with_implicit_arg(OptSpec, OptAcc)
end.
%% @doc Add an option with argument that was part of an assignment expression
%% (e.g. "--verbose=3") converting it to the data type indicated by the
%% argument specification.
-spec add_option_with_assigned_arg(option_spec(), string(), [option()]) -> [option()].
add_option_with_assigned_arg({Name, _Short, _Long, ArgSpec, _Help}, Arg, OptAcc) ->
try
[{Name, to_type(ArgSpec, Arg)} | OptAcc]
catch
error:_ ->
throw({error, {invalid_option_arg, {Name, Arg}}})
end.
%% @doc Add an option that required an argument but did not have one. Some data
%% types (boolean, integer) allow implicit or assumed arguments.
-spec add_option_with_implicit_arg(option_spec(), [option()]) -> [option()].
add_option_with_implicit_arg({Name, _Short, _Long, ArgSpec, _Help}, OptAcc) ->
case arg_spec_type(ArgSpec) of
boolean ->
%% Special case for boolean arguments: if there is no argument we
%% set the value to 'true'.
[{Name, true} | OptAcc];
integer ->
%% Special case for integer arguments: if the option had not been set
%% before we set the value to 1. This is needed to support options like
%% "-v" to return something like {verbose, 1}.
[{Name, 1} | OptAcc];
_ ->
throw({error, {missing_option_arg, Name}})
end.
%% @doc Add an option with an implicit or assumed argument.
-spec add_option_with_implicit_incrementable_arg(option_spec() | arg_spec(), [option()]) -> [option()].
add_option_with_implicit_incrementable_arg({Name, _Short, _Long, ArgSpec, _Help}, OptAcc) ->
case arg_spec_type(ArgSpec) of
boolean ->
%% Special case for boolean arguments: if there is no argument we
%% set the value to 'true'.
[{Name, true} | OptAcc];
integer ->
%% Special case for integer arguments: if the option had not been set
%% before we set the value to 1; if not we increment the previous value
%% the option had. This is needed to support options like "-vvv" to
%% return something like {verbose, 3}.
case OptAcc of
[{Name, Count} | Tail] ->
[{Name, Count + 1} | Tail];
_ ->
[{Name, 1} | OptAcc]
end;
_ ->
throw({error, {missing_option_arg, Name}})
end.
%% @doc Retrieve the data type form an argument specification.
-spec arg_spec_type(arg_spec()) -> arg_type() | undefined.
arg_spec_type({Type, _DefaultArg}) ->
Type;
arg_spec_type(Type) when is_atom(Type) ->
Type.
%% @doc Convert an argument string to its corresponding data type.
-spec to_type(arg_spec() | arg_type(), string()) -> arg_value().
to_type({Type, _DefaultArg}, Arg) ->
to_type(Type, Arg);
to_type(binary, Arg) ->
list_to_binary(Arg);
to_type(atom, Arg) ->
list_to_atom(Arg);
to_type(integer, Arg) ->
list_to_integer(Arg);
to_type(float, Arg) ->
list_to_float(Arg);
to_type(boolean, Arg) ->
LowerArg = string:to_lower(Arg),
case is_arg_true(LowerArg) of
true ->
true;
_ ->
case is_arg_false(LowerArg) of
true ->
false;
false ->
erlang:error(badarg)
end
end;
to_type(_Type, Arg) ->
Arg.
-spec is_arg_true(string()) -> boolean().
is_arg_true(Arg) ->
(Arg =:= "true") orelse (Arg =:= "t") orelse
(Arg =:= "yes") orelse (Arg =:= "y") orelse
(Arg =:= "on") orelse (Arg =:= "enabled") orelse
(Arg =:= "1").
-spec is_arg_false(string()) -> boolean().
is_arg_false(Arg) ->
(Arg =:= "false") orelse (Arg =:= "f") orelse
(Arg =:= "no") orelse (Arg =:= "n") orelse
(Arg =:= "off") orelse (Arg =:= "disabled") orelse
(Arg =:= "0").
-spec is_valid_arg(arg_spec(), nonempty_string()) -> boolean().
is_valid_arg({Type, _DefaultArg}, Arg) ->
is_valid_arg(Type, Arg);
is_valid_arg(boolean, Arg) ->
is_boolean_arg(Arg);
is_valid_arg(integer, Arg) ->
is_non_neg_integer_arg(Arg);
is_valid_arg(float, Arg) ->
is_non_neg_float_arg(Arg);
is_valid_arg(_Type, _Arg) ->
true.
-spec is_implicit_arg(arg_spec(), nonempty_string()) -> boolean().
is_implicit_arg({Type, _DefaultArg}, Arg) ->
is_implicit_arg(Type, Arg);
is_implicit_arg(boolean, Arg) ->
not is_boolean_arg(Arg);
is_implicit_arg(integer, Arg) ->
not is_integer_arg(Arg);
is_implicit_arg(_Type, _Arg) ->
false.
-spec is_boolean_arg(string()) -> boolean().
is_boolean_arg(Arg) ->
LowerArg = string:to_lower(Arg),
is_arg_true(LowerArg) orelse is_arg_false(LowerArg).
-spec is_integer_arg(string()) -> boolean().
is_integer_arg("-" ++ Tail) ->
is_non_neg_integer_arg(Tail);
is_integer_arg(Arg) ->
is_non_neg_integer_arg(Arg).
-spec is_non_neg_integer_arg(string()) -> boolean().
is_non_neg_integer_arg([Head | Tail]) when Head >= $0, Head =< $9 ->
is_non_neg_integer_arg(Tail);
is_non_neg_integer_arg([_Head | _Tail]) ->
false;
is_non_neg_integer_arg([]) ->
true.
-spec is_non_neg_float_arg(string()) -> boolean().
is_non_neg_float_arg([Head | Tail]) when (Head >= $0 andalso Head =< $9) orelse Head =:= $. ->
is_non_neg_float_arg(Tail);
is_non_neg_float_arg([_Head | _Tail]) ->
false;
is_non_neg_float_arg([]) ->
true.
%% @doc Show a message on standard_error indicating the command line options and
%% arguments that are supported by the program.
-spec usage([option_spec()], string()) -> ok.
usage(OptSpecList, ProgramName) ->
usage(OptSpecList, ProgramName, standard_error).
%% @doc Show a message on standard_error or standard_io indicating the command line options and
%% arguments that are supported by the program.
-spec usage([option_spec()], string(), output_stream() | string()) -> ok.
usage(OptSpecList, ProgramName, OutputStream) when is_atom(OutputStream) ->
io:format(OutputStream, "~s~n~n~s~n",
[usage_cmd_line(ProgramName, OptSpecList), usage_options(OptSpecList)]);
%% @doc Show a message on standard_error indicating the command line options and
%% arguments that are supported by the program. The CmdLineTail argument
%% is a string that is added to the end of the usage command line.
usage(OptSpecList, ProgramName, CmdLineTail) ->
usage(OptSpecList, ProgramName, CmdLineTail, standard_error).
%% @doc Show a message on standard_error or standard_io indicating the command line options and
%% arguments that are supported by the program. The CmdLineTail argument
%% is a string that is added to the end of the usage command line.
-spec usage([option_spec()], ProgramName :: string(), CmdLineTail :: string(), output_stream() | [{string(), string()}]) -> ok.
usage(OptSpecList, ProgramName, CmdLineTail, OutputStream) when is_atom(OutputStream) ->
io:format(OutputStream, "~s~n~n~s~n",
[usage_cmd_line(ProgramName, OptSpecList, CmdLineTail), usage_options(OptSpecList)]);
%% @doc Show a message on standard_error indicating the command line options and
%% arguments that are supported by the program. The CmdLineTail and OptionsTail
%% arguments are a string that is added to the end of the usage command line
%% and a list of tuples that are added to the end of the options' help lines.
usage(OptSpecList, ProgramName, CmdLineTail, OptionsTail) ->
usage(OptSpecList, ProgramName, CmdLineTail, OptionsTail, standard_error).
%% @doc Show a message on standard_error or standard_io indicating the command line options and
%% arguments that are supported by the program. The CmdLineTail and OptionsTail
%% arguments are a string that is added to the end of the usage command line
%% and a list of tuples that are added to the end of the options' help lines.
-spec usage([option_spec()], ProgramName :: string(), CmdLineTail :: string(),
[{OptionName :: string(), Help :: string()}], output_stream()) -> ok.
usage(OptSpecList, ProgramName, CmdLineTail, OptionsTail, OutputStream) ->
io:format(OutputStream, "~s~n~n~s~n",
[usage_cmd_line(ProgramName, OptSpecList, CmdLineTail), usage_options(OptSpecList, OptionsTail)]).
-spec usage_cmd_line(ProgramName :: string(), [option_spec()]) -> iolist().
usage_cmd_line(ProgramName, OptSpecList) ->
usage_cmd_line(ProgramName, OptSpecList, "").
-spec usage_cmd_line(ProgramName :: string(), [option_spec()], CmdLineTail :: string()) -> iolist().
usage_cmd_line(ProgramName, OptSpecList, CmdLineTail) ->
Prefix = "Usage: " ++ ProgramName,
PrefixLength = length(Prefix),
LineLength = line_length(),
%% Only align the command line options after the program name when there is
%% enough room to do so (i.e. at least 25 characters). If not, show the
%% command line options below the program name with a 2-character indentation.
if
(LineLength - PrefixLength) > ?MIN_USAGE_COMMAND_LINE_OPTION_LENGTH ->
Indentation = lists:duplicate(PrefixLength, $\s),
[FirstOptLine | OptLines] = usage_cmd_line_options(LineLength - PrefixLength, OptSpecList, CmdLineTail),
IndentedOptLines = [[Indentation | OptLine] || OptLine <- OptLines],
[Prefix, FirstOptLine | IndentedOptLines];
true ->
IndentedOptLines = [[" " | OptLine] || OptLine <- usage_cmd_line_options(LineLength, OptSpecList, CmdLineTail)],
[Prefix, $\n, IndentedOptLines]
end.
%% @doc Return a list of the lines corresponding to the usage command line
%% already wrapped according to the maximum MaxLineLength.
-spec usage_cmd_line_options(MaxLineLength :: non_neg_integer(), [option_spec()], CmdLineTail :: string()) -> iolist().
usage_cmd_line_options(MaxLineLength, OptSpecList, CmdLineTail) ->
usage_cmd_line_options(MaxLineLength, OptSpecList ++ string:tokens(CmdLineTail, " "), [], 0, []).
usage_cmd_line_options(MaxLineLength, [OptSpec | Tail], LineAcc, LineAccLength, Acc) ->
Option = [$\s | lists:flatten(usage_cmd_line_option(OptSpec))],
OptionLength = length(Option),
%% We accumulate the options in LineAcc until its length is over the
%% maximum allowed line length. When that happens, we append the line in
%% LineAcc to the list with all the lines in the command line (Acc).
NewLineAccLength = LineAccLength + OptionLength,
if
NewLineAccLength < MaxLineLength ->
usage_cmd_line_options(MaxLineLength, Tail, [Option | LineAcc], NewLineAccLength, Acc);
true ->
usage_cmd_line_options(MaxLineLength, Tail, [Option], OptionLength + 1,
[lists:reverse([$\n | LineAcc]) | Acc])
end;
usage_cmd_line_options(MaxLineLength, [], [_ | _] = LineAcc, _LineAccLength, Acc) ->
%% If there was a non-empty line in LineAcc when there are no more options
%% to process, we add it to the list of lines to return.
usage_cmd_line_options(MaxLineLength, [], [], 0, [lists:reverse(LineAcc) | Acc]);
usage_cmd_line_options(_MaxLineLength, [], [], _LineAccLength, Acc) ->
lists:reverse(Acc).
-spec usage_cmd_line_option(option_spec()) -> string().
usage_cmd_line_option({_Name, Short, _Long, undefined, _Help}) when Short =/= undefined ->
%% For options with short form and no argument.
[$[, $-, Short, $]];
usage_cmd_line_option({_Name, _Short, Long, undefined, _Help}) when Long =/= undefined ->
%% For options with only long form and no argument.
[$[, $-, $-, Long, $]];
usage_cmd_line_option({_Name, _Short, _Long, undefined, _Help}) ->
[];
usage_cmd_line_option({Name, Short, Long, ArgSpec, _Help}) when is_atom(ArgSpec) ->
%% For options with no default argument.
if
%% For options with short form and argument.
Short =/= undefined -> [$[, $-, Short, $\s, $<, atom_to_list(Name), $>, $]];
%% For options with only long form and argument.
Long =/= undefined -> [$[, $-, $-, Long, $\s, $<, atom_to_list(Name), $>, $]];
%% For options with neither short nor long form and argument.
true -> [$[, $<, atom_to_list(Name), $>, $]]
end;
usage_cmd_line_option({Name, Short, Long, ArgSpec, _Help}) when is_tuple(ArgSpec) ->
%% For options with default argument.
if
%% For options with short form and default argument.
Short =/= undefined -> [$[, $-, Short, $\s, $[, $<, atom_to_list(Name), $>, $], $]];
%% For options with only long form and default argument.
Long =/= undefined -> [$[, $-, $-, Long, $\s, $[, $<, atom_to_list(Name), $>, $], $]];
%% For options with neither short nor long form and default argument.
true -> [$[, $<, atom_to_list(Name), $>, $]]
end;
usage_cmd_line_option(Option) when is_list(Option) ->
%% For custom options that are added to the command line.
Option.
%% @doc Return a list of help messages to print for each of the options and arguments.
-spec usage_options([option_spec()]) -> [string()].
usage_options(OptSpecList) ->
usage_options(OptSpecList, []).
%% @doc Return a list of usage lines to print for each of the options and arguments.
-spec usage_options([option_spec()], [{OptionName :: string(), Help :: string()}]) -> [string()].
usage_options(OptSpecList, CustomHelp) ->
%% Add the usage lines corresponding to the option specifications.
{MaxOptionLength0, UsageLines0} = add_option_spec_help_lines(OptSpecList, 0, []),
%% Add the custom usage lines.
{MaxOptionLength, UsageLines} = add_custom_help_lines(CustomHelp, MaxOptionLength0, UsageLines0),
MaxLineLength = line_length(),
lists:reverse([format_usage_line(MaxOptionLength + 1, MaxLineLength, UsageLine) || UsageLine <- UsageLines]).
-spec add_option_spec_help_lines([option_spec()], PrevMaxOptionLength :: non_neg_integer(), [usage_line_with_length()]) ->
{MaxOptionLength :: non_neg_integer(), [usage_line_with_length()]}.
add_option_spec_help_lines([OptSpec | Tail], PrevMaxOptionLength, Acc) ->
OptionText = usage_option_text(OptSpec),
HelpText = usage_help_text(OptSpec),
{MaxOptionLength, ColsWithLength} = get_max_option_length({OptionText, HelpText}, PrevMaxOptionLength),
add_option_spec_help_lines(Tail, MaxOptionLength, [ColsWithLength | Acc]);
add_option_spec_help_lines([], MaxOptionLength, Acc) ->
{MaxOptionLength, Acc}.
-spec add_custom_help_lines([usage_line()], PrevMaxOptionLength :: non_neg_integer(), [usage_line_with_length()]) ->
{MaxOptionLength :: non_neg_integer(), [usage_line_with_length()]}.
add_custom_help_lines([CustomCols | Tail], PrevMaxOptionLength, Acc) ->
{MaxOptionLength, ColsWithLength} = get_max_option_length(CustomCols, PrevMaxOptionLength),
add_custom_help_lines(Tail, MaxOptionLength, [ColsWithLength | Acc]);
add_custom_help_lines([], MaxOptionLength, Acc) ->
{MaxOptionLength, Acc}.
-spec usage_option_text(option_spec()) -> string().
usage_option_text({Name, undefined, undefined, _ArgSpec, _Help}) ->
%% Neither short nor long form (non-option argument).
"<" ++ atom_to_list(Name) ++ ">";
usage_option_text({_Name, Short, undefined, _ArgSpec, _Help}) ->
%% Only short form.
[$-, Short];
usage_option_text({_Name, undefined, Long, _ArgSpec, _Help}) ->
%% Only long form.
[$-, $- | Long];
usage_option_text({_Name, Short, Long, _ArgSpec, _Help}) ->
%% Both short and long form.
[$-, Short, $,, $\s, $-, $- | Long].
-spec usage_help_text(option_spec()) -> string().
usage_help_text({_Name, _Short, _Long, {_ArgType, ArgValue}, [_ | _] = Help}) ->
Help ++ " [default: " ++ default_arg_value_to_string(ArgValue) ++ "]";
usage_help_text({_Name, _Short, _Long, _ArgSpec, Help}) ->
Help.
%% @doc Calculate the maximum width of the column that shows the option's short
%% and long form.
-spec get_max_option_length(usage_line(), PrevMaxOptionLength :: non_neg_integer()) ->
{MaxOptionLength :: non_neg_integer(), usage_line_with_length()}.
get_max_option_length({OptionText, HelpText}, PrevMaxOptionLength) ->
OptionLength = length(OptionText),
{erlang:max(OptionLength, PrevMaxOptionLength), {OptionLength, OptionText, HelpText}}.
%% @doc Format the usage line that is shown for the options' usage. Each usage
%% line has 2 columns. The first column shows the options in their short
%% and long form. The second column shows the wrapped (if necessary) help
%% text lines associated with each option. e.g.:
%%
%% -h, --host Database server host name or IP address; this is the
%% hostname of the server where the database is running
%% [default: localhost]
%% -p, --port Database server port [default: 1000]
%%
-spec format_usage_line(MaxOptionLength :: non_neg_integer(), MaxLineLength :: non_neg_integer(),
usage_line_with_length()) -> iolist().
format_usage_line(MaxOptionLength, MaxLineLength, {OptionLength, OptionText, [_ | _] = HelpText})
when MaxOptionLength < (MaxLineLength div 2) ->
%% If the width of the column where the options are shown is smaller than
%% half the width of a console line then we show the help text line aligned
%% next to its corresponding option, with a separation of at least 2
%% characters.
[Head | Tail] = wrap_text_line(MaxLineLength - MaxOptionLength - 3, HelpText),
FirstLineIndentation = lists:duplicate(MaxOptionLength - OptionLength + 1, $\s),
Indentation = [$\n | lists:duplicate(MaxOptionLength + 3, $\s)],
[" ", OptionText, FirstLineIndentation, Head,
[[Indentation, Line] || Line <- Tail], $\n];
format_usage_line(_MaxOptionLength, MaxLineLength, {_OptionLength, OptionText, [_ | _] = HelpText}) ->
%% If the width of the first column is bigger than the width of a console
%% line, we show the help text on the next line with an indentation of 6
%% characters.
HelpLines = wrap_text_line(MaxLineLength - 6, HelpText),
[" ", OptionText, [["\n ", Line] || Line <- HelpLines], $\n];
format_usage_line(_MaxOptionLength, _MaxLineLength, {_OptionLength, OptionText, _HelpText}) ->
[" ", OptionText, $\n].
%% @doc Wrap a text line converting it into several text lines so that the
%% length of each one of them is never over HelpLength characters.
-spec wrap_text_line(Length :: non_neg_integer(), Text :: string()) -> [string()].
wrap_text_line(Length, Text) ->
wrap_text_line(Length, Text, [], 0, []).
wrap_text_line(Length, [Char | Tail], Acc, Count, CurrentLineAcc) when Count < Length ->
wrap_text_line(Length, Tail, Acc, Count + 1, [Char | CurrentLineAcc]);
wrap_text_line(Length, [_ | _] = Help, Acc, Count, CurrentLineAcc) ->
%% Look for the first whitespace character in the current (reversed) line
%% buffer to get a wrapped line. If there is no whitespace just cut the
%% line at the position corresponding to the maximum length.
{NextLineAcc, WrappedLine} = case string:cspan(CurrentLineAcc, " \t") of
WhitespacePos when WhitespacePos < Count ->
lists:split(WhitespacePos, CurrentLineAcc);
_ ->
{[], CurrentLineAcc}
end,
wrap_text_line(Length, Help, [lists:reverse(WrappedLine) | Acc], length(NextLineAcc), NextLineAcc);
wrap_text_line(_Length, [], Acc, _Count, [_ | _] = CurrentLineAcc) ->
%% If there was a non-empty line when we reached the buffer, add it to the accumulator
lists:reverse([lists:reverse(CurrentLineAcc) | Acc]);
wrap_text_line(_Length, [], Acc, _Count, _CurrentLineAcc) ->
lists:reverse(Acc).
default_arg_value_to_string(Value) when is_atom(Value) ->
atom_to_list(Value);
default_arg_value_to_string(Value) when is_binary(Value) ->
binary_to_list(Value);
default_arg_value_to_string(Value) when is_integer(Value) ->
integer_to_list(Value);
default_arg_value_to_string(Value) when is_float(Value) ->
float_to_list(Value);
default_arg_value_to_string(Value) ->
Value.
%% @doc Tokenize a command line string with support for single and double
%% quoted arguments (needed for arguments that have embedded whitespace).
%% The function also supports the expansion of environment variables in
%% both the Unix (${VAR}; $VAR) and Windows (%VAR%) formats. It does NOT
%% support wildcard expansion of paths.
-spec tokenize(CmdLine :: string()) -> [nonempty_string()].
tokenize(CmdLine) ->
tokenize(CmdLine, [], []).
-spec tokenize(CmdLine :: string(), Acc :: [string()], ArgAcc :: string()) -> [string()].
tokenize([Sep | Tail], Acc, ArgAcc) when ?IS_WHITESPACE(Sep) ->
NewAcc = case ArgAcc of
[_ | _] ->
%% Found separator: add to the list of arguments.
[lists:reverse(ArgAcc) | Acc];
[] ->
%% Found separator with no accumulated argument; discard it.
Acc
end,
tokenize(Tail, NewAcc, []);
tokenize([QuotationMark | Tail], Acc, ArgAcc) when QuotationMark =:= $"; QuotationMark =:= $' ->
%% Quoted argument (might contain spaces, tabs, etc.)
tokenize_quoted_arg(QuotationMark, Tail, Acc, ArgAcc);
tokenize([Char | _Tail] = CmdLine, Acc, ArgAcc) when Char =:= $$; Char =:= $% ->
%% Unix and Windows environment variable expansion: ${VAR}; $VAR; %VAR%
{NewCmdLine, Var} = expand_env_var(CmdLine),
tokenize(NewCmdLine, Acc, lists:reverse(Var, ArgAcc));
tokenize([$\\, Char | Tail], Acc, ArgAcc) ->
%% Escaped char.
tokenize(Tail, Acc, [Char | ArgAcc]);
tokenize([Char | Tail], Acc, ArgAcc) ->
tokenize(Tail, Acc, [Char | ArgAcc]);
tokenize([], Acc, []) ->
lists:reverse(Acc);
tokenize([], Acc, ArgAcc) ->
lists:reverse([lists:reverse(ArgAcc) | Acc]).
-spec tokenize_quoted_arg(QuotationMark :: char(), CmdLine :: string(), Acc :: [string()], ArgAcc :: string()) -> [string()].
tokenize_quoted_arg(QuotationMark, [QuotationMark | Tail], Acc, ArgAcc) ->
%% End of quoted argument
tokenize(Tail, Acc, ArgAcc);
tokenize_quoted_arg(QuotationMark, [$\\, Char | Tail], Acc, ArgAcc) ->
%% Escaped char.
tokenize_quoted_arg(QuotationMark, Tail, Acc, [Char | ArgAcc]);
tokenize_quoted_arg($" = QuotationMark, [Char | _Tail] = CmdLine, Acc, ArgAcc) when Char =:= $$; Char =:= $% ->
%% Unix and Windows environment variable expansion (only for double-quoted arguments): ${VAR}; $VAR; %VAR%
{NewCmdLine, Var} = expand_env_var(CmdLine),
tokenize_quoted_arg(QuotationMark, NewCmdLine, Acc, lists:reverse(Var, ArgAcc));
tokenize_quoted_arg(QuotationMark, [Char | Tail], Acc, ArgAcc) ->
tokenize_quoted_arg(QuotationMark, Tail, Acc, [Char | ArgAcc]);
tokenize_quoted_arg(_QuotationMark, CmdLine, Acc, ArgAcc) ->
tokenize(CmdLine, Acc, ArgAcc).
-spec expand_env_var(CmdLine :: nonempty_string()) -> {string(), string()}.
expand_env_var(CmdLine) ->
case CmdLine of
"${" ++ Tail ->
expand_env_var("${", $}, Tail, []);
"$" ++ Tail ->
expand_env_var("$", Tail, []);
"%" ++ Tail ->
expand_env_var("%", $%, Tail, [])
end.
-spec expand_env_var(Prefix :: string(), EndMark :: char(), CmdLine :: string(), Acc :: string()) -> {string(), string()}.
expand_env_var(Prefix, EndMark, [Char | Tail], Acc)
when (Char >= $A andalso Char =< $Z) orelse (Char >= $a andalso Char =< $z) orelse
(Char >= $0 andalso Char =< $9) orelse (Char =:= $_) ->
expand_env_var(Prefix, EndMark, Tail, [Char | Acc]);
expand_env_var(Prefix, EndMark, [EndMark | Tail], Acc) ->
{Tail, get_env_var(Prefix, [EndMark], Acc)};
expand_env_var(Prefix, _EndMark, CmdLine, Acc) ->
{CmdLine, Prefix ++ lists:reverse(Acc)}.
-spec expand_env_var(Prefix :: string(), CmdLine :: string(), Acc :: string()) -> {string(), string()}.
expand_env_var(Prefix, [Char | Tail], Acc)
when (Char >= $A andalso Char =< $Z) orelse (Char >= $a andalso Char =< $z) orelse
(Char >= $0 andalso Char =< $9) orelse (Char =:= $_) ->
expand_env_var(Prefix, Tail, [Char | Acc]);
expand_env_var(Prefix, CmdLine, Acc) ->
{CmdLine, get_env_var(Prefix, "", Acc)}.
-spec get_env_var(Prefix :: string(), Suffix :: string(), Acc :: string()) -> string().
get_env_var(Prefix, Suffix, [_ | _] = Acc) ->
Name = lists:reverse(Acc),
%% Only expand valid/existing variables.
case os:getenv(Name) of
false -> Prefix ++ Name ++ Suffix;
Value -> Value
end;
get_env_var(Prefix, Suffix, []) ->
Prefix ++ Suffix.
-spec line_length() -> non_neg_integer().
line_length() ->
case io:columns() of
{ok, Columns} when Columns < ?LINE_LENGTH ->
Columns - 1;
_ ->
?LINE_LENGTH
end.
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