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%% Copyright (c) 2017-2018, Loïc Hoguin <[email protected]>
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
%% Asciidoc User Guide 29
-module(asciideck_attributes_parser).
-export([parse/1]).
-type attributes() :: #{
%% The raw attribute list.
0 := binary(),
%% Positional attributes.
pos_integer() => binary(),
%% Named attributes.
binary() => binary()
}.
-export_type([attributes/0]).
-define(IS_WS(C), (C =:= $\s) or (C =:= $\t)).
-spec parse(binary()) -> attributes().
parse(Data) ->
parse(Data, #{0 => Data}, 1).
parse(<<>>, Attrs, _) ->
Attrs;
parse(Data, Attrs, Nth) ->
case parse_attr(Data, <<>>) of
{Value, Rest} when Nth =/= undefined ->
parse(Rest, Attrs#{Nth => Value}, Nth + 1);
{Name, Value, Rest} ->
parse(Rest, Attrs#{Name => Value}, undefined)
end.
parse_attr(<<>>, Acc) ->
{Acc, <<>>};
%% Skip preceding whitespace.
parse_attr(<<C, R/bits>>, <<>>) when ?IS_WS(C) ->
parse_attr(R, <<>>);
%% Parse quoted positional attributes in their own function.
parse_attr(<<$", R/bits>>, <<>>) ->
parse_quoted_attr(R, <<>>);
%% We have a named attribute, parse the value.
parse_attr(<<$=, R/bits>>, Name) when Name =/= <<>> ->
parse_attr_value(R, asciideck_block_parser:trim(Name, trailing), <<>>);
%% We have a positional attribute.
parse_attr(<<$,, R/bits>>, Value) ->
{asciideck_block_parser:trim(Value, trailing), R};
%% Continue.
parse_attr(<<C, R/bits>>, Acc) when C =/= $= ->
parse_attr(R, <<Acc/binary, C>>).
%% Get everything until the next double quote.
parse_quoted_attr(<<$", R/bits>>, Acc) ->
parse_quoted_attr_end(R, Acc);
parse_quoted_attr(<<$\\, $", R/bits>>, Acc) ->
parse_quoted_attr(R, <<Acc/binary, $">>);
parse_quoted_attr(<<C, R/bits>>, Acc) ->
parse_quoted_attr(R, <<Acc/binary, C>>).
%% Skip the whitespace until the next comma or eof.
parse_quoted_attr_end(<<>>, Value) ->
{Value, <<>>};
parse_quoted_attr_end(<<$,, R/bits>>, Value) ->
{Value, R};
parse_quoted_attr_end(<<C, R/bits>>, Value) when ?IS_WS(C) ->
parse_quoted_attr_end(R, Value).
parse_attr_value(<<>>, Name, Acc) ->
{Name, Acc, <<>>};
%% Skip preceding whitespace.
parse_attr_value(<<C, R/bits>>, Name, <<>>) when ?IS_WS(C) ->
parse_attr_value(R, Name, <<>>);
%% Parse quoted positional attributes in their own function.
parse_attr_value(<<$", R/bits>>, Name, <<>>) ->
{Value, Rest} = parse_quoted_attr(R, <<>>),
{Name, Value, Rest};
%% Done.
parse_attr_value(<<$,, R/bits>>, Name, Value) ->
{Name, asciideck_block_parser:trim(Value, trailing), R};
%% Continue.
parse_attr_value(<<C, R/bits>>, Name, Acc) ->
parse_attr_value(R, Name, <<Acc/binary, C>>).
-ifdef(TEST).
attribute_0_test() ->
#{0 := <<"Hello,world,width=\"50\"">>} = parse(<<"Hello,world,width=\"50\"">>),
ok.
parse_test() ->
#{} = parse(<<>>),
#{
1 := <<"Hello">>
} = parse(<<"Hello">>),
#{
1 := <<"quote">>,
2 := <<"Bertrand Russell">>,
3 := <<"The World of Mathematics (1956)">>
} = parse(<<"quote, Bertrand Russell, The World of Mathematics (1956)">>),
#{
1 := <<"22 times">>,
<<"backcolor">> := <<"#0e0e0e">>,
<<"options">> := <<"noborders,wide">>
} = parse(<<"\"22 times\", backcolor=\"#0e0e0e\", options=\"noborders,wide\"">>),
#{
1 := <<"A footnote, "with an image" image:smallnew.png[]">>
} = parse(<<"A footnote, "with an image" image:smallnew.png[]">>),
ok.
-endif.
|
