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+%% ``The contents of this file are subject to the Erlang Public License,
+%% Version 1.1, (the "License"); you may not use this file except in
+%% compliance with the License. You should have received a copy of the
+%% Erlang Public License along with this software. If not, it can be
+%% retrieved via the world wide web at http://www.erlang.org/.
+%%
+%% Software distributed under the License is distributed on an "AS IS"
+%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
+%% the License for the specific language governing rights and
+%% limitations under the License.
+%%
+%% The Initial Developer of the Original Code is Ericsson Utvecklings
+%% AB. Portions created by Ericsson are Copyright 1999, Ericsson
+%% Utvecklings AB. All Rights Reserved.''
+%%
+%% $Id$
+%%
+%% @private
+%% @copyright Richard Carlsson 2001-2003. Portions created by Ericsson
+%% are Copyright 1999, Ericsson Utvecklings AB. All Rights Reserved.
+%% @author Richard Carlsson <[email protected]>
+%% @see edoc
+%% @end
+
+%% @doc Tokeniser for EDoc. Based on the Erlang standard library module
+%% {@link //stdlib/erl_scan}.
+
+-module(edoc_scanner).
+
+%% NOTE: the interface to this module is ancient and should be updated.
+%% Please do not regard these exported functions as stable. Their
+%% behaviour is described in the documentation of the module `erl_scan'.
+%%
+%% Since there are no `full stop' tokens in EDoc specifications, the
+%% `tokens' function *always* returns `{more, Continuation}' unless an
+%% error occurs.
+
+-export([string/1,string/2,format_error/1]).
+
+-import(lists, [reverse/1]).
+
+string(Cs) -> string(Cs, 1).
+
+string(Cs, StartPos) ->
+ case scan(Cs, StartPos) of
+ {ok,Toks} -> {ok,Toks,StartPos};
+ {error,E} -> {error,E,StartPos}
+ end.
+
+%% format_error(Error)
+%% Return a string describing the error.
+
+format_error({string,Quote,Head}) ->
+ ["unterminated string starting with " ++ io_lib:write_string(Head,Quote)];
+format_error({illegal,Type}) -> io_lib:fwrite("illegal ~w", [Type]);
+format_error(char) -> "unterminated character";
+format_error(scan) -> "premature end";
+format_error({base,Base}) -> io_lib:fwrite("illegal base '~w'", [Base]);
+format_error(float) -> "bad float";
+
+format_error(Other) -> io_lib:write(Other).
+
+%% Reserved words, not atoms:
+reserved('where') -> true;
+reserved(_) -> false.
+
+%% scan(CharList, StartPos)
+%% This takes a list of characters and tries to tokenise them.
+%%
+%% The token list is built in reverse order (in a stack) to save appending
+%% and then reversed when all the tokens have been collected. Most tokens
+%% are built in the same way.
+%%
+%% Returns:
+%% {ok,[Tok]}
+%% {error,{ErrorPos,edoc_scanner,What}}
+
+scan(Cs, Pos) ->
+ scan1(Cs, [], Pos).
+
+%% scan1(Characters, TokenStack, Position)
+%% Scan a list of characters into tokens.
+
+scan1([$\n|Cs], Toks, Pos) -> % Newline
+ scan1(Cs, Toks, Pos+1);
+scan1([C|Cs], Toks, Pos) when C >= 0, C =< $ -> % Skip blanks
+ scan1(Cs, Toks, Pos);
+scan1([C|Cs], Toks, Pos) when C >= $a, C =< $z -> % Unquoted atom
+ scan_atom(C, Cs, Toks, Pos);
+scan1([C|Cs], Toks, Pos) when C >= $0, C =< $9 -> % Numbers
+ scan_number(C, Cs, Toks, Pos);
+scan1([$-,C| Cs], Toks, Pos) when C >= $0, C =< $9 -> % Signed numbers
+ scan_signed_number($-, C, Cs, Toks, Pos);
+scan1([$+,C| Cs], Toks, Pos) when C >= $0, C =< $9 -> % Signed numbers
+ scan_signed_number($+, C, Cs, Toks, Pos);
+scan1([C|Cs], Toks, Pos) when C >= $A, C =< $Z -> % Variables
+ scan_variable(C, Cs, Toks, Pos);
+scan1([$_|Cs], Toks, Pos) -> % Variables
+ scan_variable($_, Cs, Toks, Pos);
+scan1([$$|Cs], Toks, Pos) -> % Character constant
+ case scan_char_const(Cs, Toks, Pos) of
+ {ok, Result} ->
+ {ok, Result};
+ {error, truncated_char} ->
+ scan_error(char, Pos);
+ {error, illegal_character} ->
+ scan_error({illegal, char}, Pos)
+ end;
+scan1([$'|Cs0], Toks, Pos) -> % Quoted atom
+ case scan_string(Cs0, $', Pos) of
+ {S,Cs1,Pos1} ->
+ case catch list_to_atom(S) of
+ A when is_atom(A) ->
+ scan1(Cs1, [{atom,Pos,A}|Toks], Pos1);
+ _Error -> scan_error({illegal,atom}, Pos)
+ end;
+ {error, premature_end} ->
+ scan_error({string,$',Cs0}, Pos);
+ {error, truncated_char} ->
+ scan_error(char, Pos);
+ {error, illegal_character} ->
+ scan_error({illegal, atom}, Pos)
+ end;
+scan1([$"|Cs0], Toks, Pos) -> % String
+ case scan_string(Cs0, $", Pos) of
+ {S,Cs1,Pos1} ->
+ case Toks of
+ [{string, Pos0, S0} | Toks1] ->
+ scan1(Cs1, [{string, Pos0, S0 ++ S} | Toks1],
+ Pos1);
+ _ ->
+ scan1(Cs1, [{string,Pos,S}|Toks], Pos1)
+ end;
+ {error, premature_end} ->
+ scan_error({string,$",Cs0}, Pos);
+ {error, truncated_char} ->
+ scan_error(char, Pos);
+ {error, illegal_character} ->
+ scan_error({illegal, string}, Pos)
+ end;
+%% Punctuation characters and operators, first recognise multiples.
+scan1([$-,$>|Cs], Toks, Pos) ->
+ scan1(Cs, [{'->',Pos}|Toks], Pos);
+scan1([$:,$:|Cs], Toks, Pos) ->
+ scan1(Cs, [{'::',Pos}|Toks], Pos);
+scan1([$/,$/|Cs], Toks, Pos) ->
+ scan1(Cs, [{'//',Pos}|Toks], Pos);
+scan1([C|Cs], Toks, Pos) -> % Punctuation character
+ P = list_to_atom([C]),
+ scan1(Cs, [{P,Pos}|Toks], Pos);
+scan1([], Toks0, _Pos) ->
+ Toks = reverse(Toks0),
+ {ok,Toks}.
+
+%% Note that `_' is not accepted as a variable token.
+scan_variable(C, Cs, Toks, Pos) ->
+ {Wcs,Cs1} = scan_name(Cs, []),
+ W = [C|reverse(Wcs)],
+ case W of
+ "_" ->
+ scan_error({illegal,token}, Pos);
+ _ ->
+ case catch list_to_atom(W) of
+ A when is_atom(A) ->
+ scan1(Cs1, [{var,Pos,A}|Toks], Pos);
+ _ ->
+ scan_error({illegal,variable}, Pos)
+ end
+ end.
+
+scan_atom(C, Cs, Toks, Pos) ->
+ {Wcs,Cs1} = scan_name(Cs, []),
+ W = [C|reverse(Wcs)],
+ case catch list_to_atom(W) of
+ A when is_atom(A) ->
+ case reserved(A) of
+ true ->
+ scan1(Cs1, [{A,Pos}|Toks], Pos);
+ false ->
+ scan1(Cs1, [{atom,Pos,A}|Toks], Pos)
+ end;
+ _ ->
+ scan_error({illegal,token}, Pos)
+ end.
+
+%% scan_name(Cs) -> lists:splitwith(fun (C) -> name_char(C) end, Cs).
+
+scan_name([C|Cs], Ncs) ->
+ case name_char(C) of
+ true ->
+ scan_name(Cs, [C|Ncs]);
+ false ->
+ {Ncs,[C|Cs]} % Must rebuild here, sigh!
+ end;
+scan_name([], Ncs) ->
+ {Ncs,[]}.
+
+name_char(C) when C >= $a, C =< $z -> true;
+name_char(C) when C >= $\337, C =< $\377, C /= $\367 -> true;
+name_char(C) when C >= $A, C =< $Z -> true;
+name_char(C) when C >= $\300, C =< $\336, C /= $\327 -> true;
+name_char(C) when C >= $0, C =< $9 -> true;
+name_char($_) -> true;
+name_char($@) -> true;
+name_char(_) -> false.
+
+%% scan_string(CharList, QuoteChar, Pos) ->
+%% {StringChars,RestChars, NewPos}
+
+scan_string(Cs, Quote, Pos) ->
+ scan_string(Cs, [], Quote, Pos).
+
+scan_string([Quote|Cs], Scs, Quote, Pos) ->
+ {reverse(Scs),Cs,Pos};
+scan_string([], _Scs, _Quote, _Pos) ->
+ {error, premature_end};
+scan_string(Cs0, Scs, Quote, Pos) ->
+ case scan_char(Cs0, Pos) of
+ {C,Cs,Pos1} ->
+ %% Only build the string here
+ scan_string(Cs, [C|Scs], Quote, Pos1);
+ Error ->
+ Error
+ end.
+
+%% Note that space characters are not allowed
+scan_char_const([$\040 | _Cs0], _Toks, _Pos) ->
+ {error, illegal_character};
+scan_char_const(Cs0, Toks, Pos) ->
+ case scan_char(Cs0, Pos) of
+ {C,Cs,Pos1} ->
+ scan1(Cs, [{char,Pos,C}|Toks], Pos1);
+ Error ->
+ Error
+ end.
+
+%% {Character,RestChars,NewPos} = scan_char(Chars, Pos)
+%% Read a single character from a string or character constant. The
+%% pre-scan phase has checked for errors here.
+%% Note that control characters are not allowed.
+
+scan_char([$\\|Cs], Pos) ->
+ scan_escape(Cs, Pos);
+scan_char([C | _Cs], _Pos) when C =< 16#1f ->
+ {error, illegal_character};
+scan_char([C|Cs], Pos) ->
+ {C,Cs,Pos};
+scan_char([], _Pos) ->
+ {error, truncated_char}.
+
+%% The following conforms to Standard Erlang escape sequences.
+
+scan_escape([O1, O2, O3 | Cs], Pos) when % \<1-3> octal digits
+ O1 >= $0, O1 =< $3, O2 >= $0, O2 =< $7, O3 >= $0, O3 =< $7 ->
+ Val = (O1*8 + O2)*8 + O3 - 73*$0,
+ {Val,Cs,Pos};
+scan_escape([O1, O2 | Cs], Pos) when
+ O1 >= $0, O1 =< $7, O2 >= $0, O2 =< $7 ->
+ Val = (O1*8 + O2) - 9*$0,
+ {Val,Cs,Pos};
+scan_escape([O1 | Cs], Pos) when
+ O1 >= $0, O1 =< $7 ->
+ {O1 - $0,Cs,Pos};
+scan_escape([$^, C | Cs], Pos) -> % \^X -> CTL-X
+ if C >= $\100, C =< $\137 ->
+ {C - $\100,Cs,Pos};
+ true -> {error, illegal_control_character}
+ end;
+scan_escape([C | Cs], Pos) ->
+ case escape_char(C) of
+ C1 when C1 > $\000 -> {C1,Cs,Pos};
+ _ -> {error, undefined_escape_sequence}
+ end;
+scan_escape([], _Pos) ->
+ {error, truncated_char}.
+
+%% Note that we return $\000 for undefined escapes.
+escape_char($b) -> $\010; % \b = BS
+escape_char($d) -> $\177; % \d = DEL
+escape_char($e) -> $\033; % \e = ESC
+escape_char($f) -> $\014; % \f = FF
+escape_char($n) -> $\012; % \n = LF
+escape_char($r) -> $\015; % \r = CR
+escape_char($s) -> $\040; % \s = SPC
+escape_char($t) -> $\011; % \t = HT
+escape_char($v) -> $\013; % \v = VT
+escape_char($\\) -> $\134; % \\ = \
+escape_char($') -> $\047; % \' = '
+escape_char($") -> $\042; % \" = "
+escape_char(_C) -> $\000.
+
+%% scan_number(Char, CharList, TokenStack, Pos)
+%% We handle sign and radix notation:
+%% [+-]<digits> - the digits in base [+-]10
+%% [+-]<digits>.<digits>
+%% [+-]<digits>.<digits>E+-<digits>
+%% [+-]<digits>#<digits> - the digits read in base [+-]B
+%%
+%% Except for explicitly based integers we build a list of all the
+%% characters and then use list_to_integer/1 or list_to_float/1 to
+%% generate the value.
+
+%% SPos == Start position
+%% CPos == Current position
+
+scan_number(C, Cs0, Toks, Pos) ->
+ {Ncs,Cs,Pos1} = scan_integer(Cs0, [C], Pos),
+ scan_after_int(Cs, Ncs, Toks, Pos, Pos1).
+
+scan_signed_number(S, C, Cs0, Toks, Pos) ->
+ {Ncs,Cs,Pos1} = scan_integer(Cs0, [C, S], Pos),
+ scan_after_int(Cs, Ncs, Toks, Pos, Pos1).
+
+scan_integer([C|Cs], Stack, Pos) when C >= $0, C =< $9 ->
+ scan_integer(Cs, [C|Stack], Pos);
+scan_integer(Cs, Stack, Pos) ->
+ {Stack,Cs,Pos}.
+
+scan_after_int([$.,C|Cs0], Ncs0, Toks, SPos, CPos) when C >= $0, C =< $9 ->
+ {Ncs,Cs,CPos1} = scan_integer(Cs0, [C,$.|Ncs0], CPos),
+ scan_after_fraction(Cs, Ncs, Toks, SPos, CPos1);
+scan_after_int(Cs, Ncs, Toks, SPos, CPos) ->
+ N = list_to_integer(reverse(Ncs)),
+ scan1(Cs, [{integer,SPos,N}|Toks], CPos).
+
+scan_after_fraction([$E|Cs], Ncs, Toks, SPos, CPos) ->
+ scan_exponent(Cs, [$E|Ncs], Toks, SPos, CPos);
+scan_after_fraction([$e|Cs], Ncs, Toks, SPos, CPos) ->
+ scan_exponent(Cs, [$e|Ncs], Toks, SPos, CPos);
+scan_after_fraction(Cs, Ncs, Toks, SPos, CPos) ->
+ case catch list_to_float(reverse(Ncs)) of
+ N when is_float(N) ->
+ scan1(Cs, [{float,SPos,N}|Toks], CPos);
+ _Error -> scan_error({illegal,float}, SPos)
+ end.
+
+%% scan_exponent(CharList, NumberCharStack, TokenStack, StartPos, CurPos)
+%% Generate an error here if E{+|-} not followed by any digits.
+
+scan_exponent([$+|Cs], Ncs, Toks, SPos, CPos) ->
+ scan_exponent1(Cs, [$+|Ncs], Toks, SPos, CPos);
+scan_exponent([$-|Cs], Ncs, Toks, SPos, CPos) ->
+ scan_exponent1(Cs, [$-|Ncs], Toks, SPos, CPos);
+scan_exponent(Cs, Ncs, Toks, SPos, CPos) ->
+ scan_exponent1(Cs, Ncs, Toks, SPos, CPos).
+
+scan_exponent1([C|Cs0], Ncs0, Toks, SPos, CPos) when C >= $0, C =< $9 ->
+ {Ncs,Cs,CPos1} = scan_integer(Cs0, [C|Ncs0], CPos),
+ case catch list_to_float(reverse(Ncs)) of
+ N when is_float(N) ->
+ scan1(Cs, [{float,SPos,N}|Toks], CPos1);
+ _Error -> scan_error({illegal,float}, SPos)
+ end;
+scan_exponent1(_, _, _, _, CPos) ->
+ scan_error(float, CPos).
+
+scan_error(In, Pos) ->
+ {error,{Pos,edoc_scanner,In}}.
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