From 121fe344744dbf2fe2b91c51b8b3807a7a2fbd7c Mon Sep 17 00:00:00 2001
From: alisdair sullivan <alisdairsullivan@yahoo.ca>
Date: Tue, 18 May 2010 12:16:25 -0700
Subject: [PATCH] first working version

---
 src/jsx_common.hrl |  57 ++++++
 src/jsx_utf8.erl   | 460 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 517 insertions(+)
 create mode 100644 src/jsx_common.hrl
 create mode 100644 src/jsx_utf8.erl

diff --git a/src/jsx_common.hrl b/src/jsx_common.hrl
new file mode 100644
index 0000000..65decf6
--- /dev/null
+++ b/src/jsx_common.hrl
@@ -0,0 +1,57 @@
+-record(opts, {
+    comments = false,
+    escaped_unicode = ascii
+}).
+
+%% whitespace
+-define(space, 16#20).
+-define(tab, 16#09).
+-define(cr, 16#0D).
+-define(newline, 16#0A).
+
+%% object delimiters
+-define(start_object, 16#7B).
+-define(end_object, 16#7D).
+
+%% array delimiters
+-define(start_array, 16#5B).
+-define(end_array, 16#5D).
+
+%% kv seperator
+-define(comma, 16#2C).
+-define(quote, 16#22).
+-define(colon, 16#3A).
+
+%% string escape sequences
+-define(escape, 16#5C).
+-define(rsolidus, 16#5C).
+-define(solidus, 16#2F).
+-define(formfeed, 16#0C).
+-define(backspace, 16#08).
+-define(unicode, 16#75).
+
+%% math
+-define(zero, 16#30).
+-define(decimalpoint, 16#2E).
+-define(negative, 16#2D).
+-define(positive, 16#2B).
+
+%% comments
+-define(star, 16#2a).
+
+-define(is_hex(Symbol),
+    (Symbol >= $a andalso Symbol =< $z); (Symbol >= $A andalso Symbol =< $Z); 
+        (Symbol >= $0 andalso Symbol =< $9)
+).
+
+-define(is_nonzero(Symbol),
+    Symbol >= $1 andalso Symbol =< $9
+).
+
+-define(is_noncontrol(Symbol),
+    Symbol >= ?space
+).
+
+-define(is_whitespace(Symbol),
+    Symbol =:= ?space; Symbol =:= ?tab; Symbol =:= ?cr; Symbol =:= ?newline
+).
\ No newline at end of file
diff --git a/src/jsx_utf8.erl b/src/jsx_utf8.erl
new file mode 100644
index 0000000..6580807
--- /dev/null
+++ b/src/jsx_utf8.erl
@@ -0,0 +1,460 @@
+-module(jsx_utf8).
+
+-export([start/4]).
+
+-include("jsx_common.hrl").
+
+callback(eof, Callbacks) ->
+    lists:reverse(Callbacks);
+callback(Event, Callbacks) ->
+    [Event] ++ Callbacks.
+    
+
+%% this code is mostly autogenerated and mostly ugly. apologies. for more insight on
+%%   Callbacks or Opts, see the comments accompanying callback/2 (in this file) and
+%%   parse_opts/1 (in jsx.erl). Stack is a stack of flags used to track depth. all
+%%   pops, peeks and pushes are inlined. comments are handled in function to get around
+%%   a limitation of erlang's binary matching optimizations, and a function_clause
+%%   error is raised if comments are disallowed to maintain consistency with behaviour
+%%   of other invalid input
+
+start(<<?start_object/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    object(Rest, [key|Stack], callback(start_object, Callbacks), Opts);
+start(<<?start_array/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    array(Rest, [array|Stack], callback(start_array, Callbacks), Opts);
+start(<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> start(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+start(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) -> 
+    start(Rest, Stack, Callbacks, Opts);
+start(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> start(Stream, Stack, Callbacks, Opts) end.
+
+    
+maybe_done(<<?end_object/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback(end_object, Callbacks), Opts);
+maybe_done(<<?end_array/utf8, Rest/binary>>, [array|Stack], Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback(end_array, Callbacks), Opts);
+maybe_done(<<?comma/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts) ->
+    key(Rest, [key|Stack], Callbacks, Opts);
+maybe_done(<<?comma/utf8, Rest/binary>>, [array|_] = Stack, Callbacks, Opts) ->
+    value(Rest, Stack, Callbacks, Opts);
+maybe_done(<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> maybe_done(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+maybe_done(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) ->
+    maybe_done(Rest, Stack, Callbacks, Opts);
+maybe_done(<<>>, [], Callbacks, _Opts) ->
+    callback(eof, Callbacks);  
+maybe_done(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> maybe_done(Stream, Stack, Callbacks, Opts) end.
+
+
+object(<<?end_object/utf8, Rest/binary>>, [key|Stack], Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback(end_object, Callbacks), Opts);
+object(<<?quote/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    string(Rest, Stack, Callbacks, Opts, []);
+object(<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> object(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+object(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) ->
+    object(Rest, Stack, Callbacks, Opts);
+object(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> object(Stream, Stack, Callbacks, Opts) end.
+        
+        
+array(<<?quote/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    string(Rest, Stack, Callbacks, Opts, []);
+array(<<?start_object/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    object(Rest, [key|Stack], callback(start_object, Callbacks), Opts);
+array(<<?start_array/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    array(Rest, [array|Stack], callback(start_array, Callbacks), Opts);
+array(<<?end_array/utf8, Rest/binary>>, [array|Stack], Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback(end_array, Callbacks), Opts);
+array(<<$t/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    tr(Rest, Stack, Callbacks, Opts);
+array(<<$f/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    fa(Rest, Stack, Callbacks, Opts);
+array(<<$n/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    nu(Rest, Stack, Callbacks, Opts);
+array(<<?negative/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    negative(Rest, Stack, Callbacks, Opts, "-");
+array(<<?zero/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    zero(Rest, Stack, Callbacks, Opts, "0");
+array(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_nonzero(S) ->
+    integer(Rest, Stack, Callbacks, Opts, [S]);
+array(<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> array(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+array(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) -> 
+    array(Rest, Stack, Callbacks, Opts);
+array(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> array(Stream, Stack, Callbacks, Opts) end.  
+
+        
+value(<<?quote/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    string(Rest, Stack, Callbacks, Opts, []);
+value(<<?start_object/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    object(Rest, [key|Stack], callback(start_object, Callbacks), Opts);
+value(<<?start_array/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    array(Rest, [array|Stack], callback(start_array, Callbacks), Opts);
+value(<<$t/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    tr(Rest, Stack, Callbacks, Opts);
+value(<<$f/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    fa(Rest, Stack, Callbacks, Opts);
+value(<<$n/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    nu(Rest, Stack, Callbacks, Opts);
+value(<<?negative/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    negative(Rest, Stack, Callbacks, Opts, "-");
+value(<<?zero/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    zero(Rest, Stack, Callbacks, Opts, "0");
+value(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_nonzero(S) ->
+    integer(Rest, Stack, Callbacks, Opts, [S]);
+value(<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> value(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+value(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) -> 
+    value(Rest, Stack, Callbacks, Opts);
+value(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> value(Stream, Stack, Callbacks, Opts) end.
+      
+
+colon(<<?colon/utf8, Rest/binary>>, [key|Stack], Callbacks, Opts) ->
+    value(Rest, [object|Stack], Callbacks, Opts);
+colon(<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> colon(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+colon(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) ->
+    colon(Rest, Stack, Callbacks, Opts);
+colon(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> colon(Stream, Stack, Callbacks, Opts) end.
+  
+        
+key(<<?quote/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    string(Rest, Stack, Callbacks, Opts, []);
+key(<<?rsolidus/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> key(Resume, Stack, Callbacks, Opts) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+key(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts) when ?is_whitespace(S) ->
+    key(Rest, Stack, Callbacks, Opts);
+key(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> key(Stream, Stack, Callbacks, Opts) end.
+      
+      
+%% string has an additional parameter, an accumulator (Acc) used to hold the intermediate
+%%   representation of the string being parsed. using a list of integers representing
+%%   unicode codepoints is faster than constructing binaries, many of which will be
+%%   converted back to lists by the user anyways.
+        
+string(<<?quote/utf8, Rest/binary>>, [key|_] = Stack, Callbacks, Opts, Acc) ->
+    colon(Rest, Stack, callback({key, lists:reverse(Acc)}, Callbacks), Opts);
+string(<<?quote/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback({string, lists:reverse(Acc)}, Callbacks), Opts);
+string(<<?rsolidus/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    escape(Rest, Stack, Callbacks, Opts, Acc);
+string(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_noncontrol(S) ->
+    string(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+string(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> string(Stream, Stack, Callbacks, Opts, Acc) end.
+
+
+%% only thing to note here is the additional accumulator passed to escaped_unicode used
+%%   to hold the codepoint sequence. unescessary, but nicer than using the string 
+%%   accumulator. 
+    
+escape(<<"b"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    string(Rest, Stack, Callbacks, Opts, "\b" ++ Acc);
+escape(<<"f"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    string(Rest, Stack, Callbacks, Opts, "\f" ++ Acc);
+escape(<<"n"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    string(Rest, Stack, Callbacks, Opts, "\n" ++ Acc);
+escape(<<"r"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    string(Rest, Stack, Callbacks, Opts, "\r" ++ Acc);
+escape(<<"t"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    string(Rest, Stack, Callbacks, Opts, "\t" ++ Acc);
+escape(<<"u"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    escaped_unicode(Rest, Stack, Callbacks, Opts, Acc, []);      
+escape(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) 
+        when S =:= ?quote; S =:= ?solidus; S =:= ?rsolidus ->
+    string(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+escape(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> escape(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+
+%% this code is ugly and unfortunate, but so is json's handling of escaped unicode
+%%   codepoint sequences. if the ascii option is present, the sequence is converted
+%%   to a codepoint and inserted into the string if it represents an ascii value. if 
+%%   the codepoint option is present the sequence is converted and inserted as long
+%%   as it represents a valid 16 bit integer value (this is where json's spec gets
+%%   insane). any other option and the sequence is converted back to an erlang string
+%%   and appended to the string in place.
+    
+escaped_unicode(<<D/utf8, Rest/binary>>, Stack, Callbacks, Opts, String, [C, B, A]) ->
+    X = erlang:list_to_integer([A, B, C, D], 16),
+    case Opts#opts.escaped_unicode of
+        ascii when X < 16#0080 ->
+            string(Rest, Stack, Callbacks, Opts, [X] ++ String)
+        ; codepoint ->
+            string(Rest, Stack, Callbacks, Opts, [X] ++ String)
+        ; _ ->
+            string(Rest, Stack, Callbacks, Opts, [?rsolidus, $u, A, B, C, D] ++ String)
+    end;
+escaped_unicode(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, String, Acc) when ?is_hex(S) ->
+    escaped_unicode(Rest, Stack, Callbacks, Opts, String, [S] ++ Acc);
+escaped_unicode(<<>>, Stack, Callbacks, Opts, String, Acc) ->
+    fun(Stream) -> escaped_unicode(Stream, Stack, Callbacks, Opts, String, Acc) end.
+    
+    
+%% like strings, numbers are collected in an intermediate accumulator before
+%%   being emitted to the callback handler. no processing of numbers is done in
+%%   process, it's left for the user, though there are convenience functions to
+%%   convert them into erlang floats/integers in jsx_utils.erl.
+    
+negative(<<"0"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    zero(Rest, Stack, Callbacks, Opts, "0" ++ Acc);
+negative(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_nonzero(S) ->
+    integer(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+negative(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> negative(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+    
+zero(<<?end_object/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_object, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+zero(<<?end_array/utf8, Rest/binary>>, [array|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_array, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+zero(<<?comma/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    key(Rest, [key|Stack], callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+zero(<<?comma/utf8, Rest/binary>>, [array|_] = Stack, Callbacks, Opts, Acc) ->
+    value(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+zero(<<?decimalpoint/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    fraction(Rest, Stack, Callbacks, Opts, [?decimalpoint] ++ Acc);
+zero(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_whitespace(S) ->
+    maybe_done(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+zero(<<?rsolidus/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> zero(Resume, Stack, Callbacks, Opts, Acc) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+zero(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> zero(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+    
+integer(<<?end_object/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_object, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+integer(<<?end_array/utf8, Rest/binary>>, [array|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_array, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+integer(<<?comma/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    key(Rest, [key|Stack], callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+integer(<<?comma/utf8, Rest/binary>>, [array|_] = Stack, Callbacks, Opts, Acc) ->
+    value(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+integer(<<?decimalpoint/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    fraction(Rest, Stack, Callbacks, Opts, [?decimalpoint] ++ Acc);
+integer(<<?zero/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    integer(Rest, Stack, Callbacks, Opts, [?zero] ++ Acc);
+integer(<<"e"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    e(Rest, Stack, Callbacks, Opts, "e" ++ Acc);
+integer(<<"E"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    e(Rest, Stack, Callbacks, Opts, "e" ++ Acc);
+integer(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_nonzero(S) ->
+    integer(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+integer(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_whitespace(S) ->
+    maybe_done(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+integer(<<?rsolidus/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> integer(Resume, Stack, Callbacks, Opts, Acc) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+integer(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> integer(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+
+fraction(<<?end_object/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_object, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+fraction(<<?end_array/utf8, Rest/binary>>, [array|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_array, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+fraction(<<?comma/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    key(Rest, [key|Stack], callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+fraction(<<?comma/utf8, Rest/binary>>, [array|_] = Stack, Callbacks, Opts, Acc) ->
+    value(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+fraction(<<?zero/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    fraction(Rest, Stack, Callbacks, Opts, [?zero] ++ Acc);
+fraction(<<"e"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    e(Rest, Stack, Callbacks, Opts, "e" ++ Acc);
+fraction(<<"E"/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    e(Rest, Stack, Callbacks, Opts, "e" ++ Acc);
+fraction(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_nonzero(S) ->
+    fraction(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+fraction(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_whitespace(S) ->
+    maybe_done(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+fraction(<<?rsolidus/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> fraction(Resume, Stack, Callbacks, Opts, Acc) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+fraction(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> fraction(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+    
+e(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when S =:= ?positive; S =:= ?negative ->
+    ex(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+e(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when S =:= ?zero; ?is_nonzero(S) ->
+    exp(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+e(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> e(Stream, Stack, Callbacks, Opts, Acc) end.
+  
+    
+ex(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when S =:= ?zero; ?is_nonzero(S) ->
+    exp(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+ex(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> ex(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+
+exp(<<?end_object/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_object, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+exp(<<?end_array/utf8, Rest/binary>>, [array|Stack], Callbacks, Opts, Acc) ->
+    maybe_done(Rest, Stack, callback(end_array, callback({number, lists:reverse(Acc)}, Callbacks)), Opts);
+exp(<<?comma/utf8, Rest/binary>>, [object|Stack], Callbacks, Opts, Acc) ->
+    key(Rest, [key|Stack], callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+exp(<<?comma/utf8, Rest/binary>>, [array|_] = Stack, Callbacks, Opts, Acc) ->
+    value(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+exp(<<?zero/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    exp(Rest, Stack, Callbacks, Opts, [?zero] ++ Acc);
+exp(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_nonzero(S) ->
+    exp(Rest, Stack, Callbacks, Opts, [S] ++ Acc);
+exp(<<S/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) when ?is_whitespace(S) ->
+    maybe_done(Rest, Stack, callback({number, lists:reverse(Acc)}, Callbacks), Opts);
+exp(<<?rsolidus/utf8, Rest/binary>>, Stack, Callbacks, Opts, Acc) ->
+    case Opts#opts.comments of
+        true ->
+            maybe_comment(Rest, fun(Resume) -> exp(Resume, Stack, Callbacks, Opts, Acc) end)
+        ; false ->
+            erlang:error(function_clause, [<<?solidus/utf8, Rest/binary>>, Stack, Callbacks, Opts])
+    end;
+exp(<<>>, Stack, Callbacks, Opts, Acc) ->
+    fun(Stream) -> exp(Stream, Stack, Callbacks, Opts, Acc) end.
+    
+    
+tr(<<"r"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    tru(Rest, Stack, Callbacks, Opts);
+tr(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> tr(Stream, Stack, Callbacks, Opts) end.
+    
+    
+tru(<<"u"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    true(Rest, Stack, Callbacks, Opts);
+tru(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> tru(Stream, Stack, Callbacks, Opts) end.
+
+    
+true(<<"e"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback({literal, true}, Callbacks), Opts);
+true(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> true(Stream, Stack, Callbacks, Opts) end.
+    
+    
+fa(<<"a"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    fal(Rest, Stack, Callbacks, Opts);
+fa(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> fa(Stream, Stack, Callbacks, Opts) end.
+
+
+fal(<<"l"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    fals(Rest, Stack, Callbacks, Opts);
+fal(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> fal(Stream, Stack, Callbacks, Opts) end.
+
+
+fals(<<"s"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    false(Rest, Stack, Callbacks, Opts);
+fals(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> fals(Stream, Stack, Callbacks, Opts) end.
+    
+    
+false(<<"e"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback({literal, false}, Callbacks), Opts);
+false(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> false(Stream, Stack, Callbacks, Opts) end.
+    
+
+nu(<<"u"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    nul(Rest, Stack, Callbacks, Opts);
+nu(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> nu(Stream, Stack, Callbacks, Opts) end.
+
+
+nul(<<"l"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    null(Rest, Stack, Callbacks, Opts);
+nul(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> nul(Stream, Stack, Callbacks, Opts) end.
+
+
+null(<<"l"/utf8, Rest/binary>>, Stack, Callbacks, Opts) ->
+    maybe_done(Rest, Stack, callback({literal, null}, Callbacks), Opts);
+null(<<>>, Stack, Callbacks, Opts) ->
+    fun(Stream) -> null(Stream, Stack, Callbacks, Opts) end.    
+    
+    
+%% comments are c style, /* blah blah */ and are STRONGLY discouraged. any unicode
+%%   character is valid in a comment, except, obviously the */ sequence which ends
+%%   the comment. they're implemented as a closure called when the comment ends that
+%%   returns execution to the point where the comment began. comments are not 
+%%   recorded in any way, simply parsed.    
+    
+maybe_comment(<<?star/utf8, Rest/binary>>, Resume) ->
+    comment(Rest, Resume);
+maybe_comment(<<>>, Resume) ->
+    fun(Stream) -> maybe_comment(Stream, Resume) end.
+    
+    
+comment(<<?star/utf8, Rest/binary>>, Resume) ->
+    maybe_comment_done(Rest, Resume);
+comment(<<_/utf8, Rest/binary>>, Resume) ->
+    comment(Rest, Resume);
+comment(<<>>, Resume) ->
+    fun(Stream) -> comment(Stream, Resume) end.
+    
+    
+maybe_comment_done(<<?rsolidus/utf8, Rest/binary>>, Resume) ->
+    Resume(Rest);
+maybe_comment_done(<<>>, Resume) ->
+    fun(Stream) -> maybe_comment_done(Stream, Resume) end.
+
+    
+
+        
+
+