%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2003-2009. All Rights Reserved.
%%
%% 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 online 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.
%%
%% %CopyrightEnd%
%%
%% Description : Helper module to xmerl_xpath: XPATH predicates.
-module(xmerl_xpath_pred).
%% API
-export([eval/2]).
%% internal functions (called via apply/3)
-export([boolean/1, boolean/2,
ceiling/2,
concat/2,
contains/2,
count/2,
floor/2,
fn_false/2,
fn_not/2,
fn_true/2,
id/2,
lang/2,
last/2,
'local-name'/2,
'namespace-uri'/2,
name/2,
string/2,
nodeset/1,
'normalize-space'/2,
number/1, number/2,
position/2,
round/2,
'starts-with'/2,
string/1,
'string-length'/2,
substring/2,
'substring-after'/2,
'substring-before'/2,
sum/2,
translate/2]).
-export([core_function/1]).
-include("xmerl.hrl").
-include("xmerl_xpath.hrl").
%% -record(obj, {type,
%% value}).
-define(string(X), #xmlObj{type = string,
value = X}).
-define(nodeset(X), #xmlObj{type = nodeset,
value = X}).
-define(number(X), #xmlObj{type = number,
value = X}).
-define(boolean(X), #xmlObj{type = boolean,
value = X}).
eval(Expr, C = #xmlContext{context_node = #xmlNode{pos = Pos}}) ->
Obj = expr(Expr, C),
Res = case Obj#xmlObj.type of
number when Obj#xmlObj.value == Pos ->
true;
number ->
false;
boolean ->
Obj#xmlObj.value;
_ ->
mk_boolean(C, Obj)
end,
% io:format("eval(~p, ~p) -> ~p~n", [Expr, Pos, Res]),
Res.
string(X) ->
?string(X).
nodeset(X) ->
?nodeset(X).
number(X) ->
?number(X).
boolean(X) ->
?boolean(X).
expr({arith, Op, E1, E2}, C) ->
arith_expr(Op, E1, E2, C);
expr({comp, Op, E1, E2}, C) ->
comp_expr(Op, E1, E2, C);
expr({bool, Op, E1, E2}, C) ->
bool_expr(Op, E1, E2, C);
expr({'negative', E}, C) ->
N = mk_number(C, E),
- N;
expr({number, N}, _C) ->
?number(N);
expr({literal, S}, _C) ->
?string(S);
expr({function_call, F, Args}, C) ->
case core_function(F) of
{true, F1} ->
?MODULE:F1(C, Args);
true ->
?MODULE:F(C, Args);
false ->
%% here, we should look up the function in the context provided
%% by the caller, but we haven't figured this out yet.
exit({not_a_core_function, F})
end;
expr({path, Type, PathExpr}, C) ->
#state{context=#xmlContext{nodeset = NS}} =
xmerl_xpath:eval_path(Type, PathExpr, C),
?nodeset(NS);
expr(Expr, _C) ->
exit({unknown_expr, Expr}).
arith_expr('+', E1, E2, C) ->
?number(mk_number(C, E1) + mk_number(C, E2));
arith_expr('-', E1, E2, C) ->
?number(mk_number(C, E1) - mk_number(C, E2));
arith_expr('*', E1, E2, C) ->
?number(mk_number(C, E1) * mk_number(C, E2));
arith_expr('div', E1, E2, C) ->
?number(mk_number(C, E1) / mk_number(C, E2));
arith_expr('mod', E1, E2, C) ->
?number(mk_number(C, E1) rem mk_number(C, E2)).
comp_expr('>', E1, E2, C) ->
N1 = expr(E1,C),
N2 = expr(E2,C),
?boolean(compare_ineq_format(N1,N2,C) > compare_ineq_format(N2,N1,C));
comp_expr('<', E1, E2, C) ->
N1 = expr(E1,C),
N2 = expr(E2,C),
?boolean(compare_ineq_format(N1,N2,C) > compare_ineq_format(N2,N1,C));
comp_expr('>=', E1, E2, C) ->
N1 = expr(E1,C),
N2 = expr(E2,C),
?boolean(compare_ineq_format(N1,N2,C) > compare_ineq_format(N2,N1,C));
comp_expr('<=', E1, E2, C) ->
N1 = expr(E1,C),
N2 = expr(E2,C),
?boolean(compare_ineq_format(N1,N2,C) > compare_ineq_format(N2,N1,C));
comp_expr('=', E1, E2, C) ->
N1 = expr(E1,C),
N2 = expr(E2,C),
?boolean(compare_eq_format(N1,N2,C) == compare_eq_format(N2,N1,C));
comp_expr('!=', E1, E2, C) ->
N1 = expr(E1,C),
N2 = expr(E2,C),
?boolean(compare_eq_format(N1,N2,C) /= compare_eq_format(N2,N1,C)).
bool_expr('or', E1, E2, C) ->
?boolean(mk_boolean(C, E1) or mk_boolean(C, E2));
bool_expr('and', E1, E2, C) ->
?boolean(mk_boolean(C, E1) and mk_boolean(C, E2)).
%% According to chapter 3.4 in XML Path Language ver 1.0 the format of
%% the compared objects are depending on the type of the other
%% object.
%% 1. Comparisons involving node-sets is treated equally despite
%% of which comparancy operand is used. In this case:
%% - node-set comp node-set: string values are used
%% - node-set comp number : ((node-set string value) -> number)
%% - node-set comp boolean : (node-set string value) -> boolean
%% 2. Comparisons when neither object is a node-set and the operand
%% is = or != the following transformation is done before comparison:
%% - if one object is a boolean the other is converted to a boolean.
%% - if one object is a number the other is converted to a number.
%% - otherwise convert both to the string value.
%% 3. Comparisons when neither object is a node-set and the operand is
%% <=, <, >= or > both objects are converted to a number.
compare_eq_format(N1=#xmlObj{type=T1},N2=#xmlObj{type=T2},C) when T1==nodeset;
T2==nodeset ->
compare_nseq_format(N1,N2,C);
compare_eq_format(N1=#xmlObj{type=T1},#xmlObj{type=T2},C) when T1==boolean;
T2==boolean ->
mk_boolean(C,N1);
compare_eq_format(N1=#xmlObj{type=T1},#xmlObj{type=T2},C) when T1==number;
T2==number ->
mk_number(C,N1);
compare_eq_format(N1,_,C) ->
mk_string(C,string_value(N1)).
compare_ineq_format(N1=#xmlObj{type=T1},
N2=#xmlObj{type=T2},C) when T1==nodeset;
T2==nodeset ->
compare_nseq_format(N1,N2,C);
compare_ineq_format(N1,_N2,C) ->
mk_number(C,N1).
compare_nseq_format(N1=#xmlObj{type = number},_N2,C) ->
mk_number(C,N1);
compare_nseq_format(N1=#xmlObj{type = boolean},_N2,C) ->
mk_boolean(C,N1);
compare_nseq_format(N1=#xmlObj{type = string},_N2,C) ->
mk_string(C,N1);
compare_nseq_format(N1=#xmlObj{type = nodeset},_N2=#xmlObj{type=number},C) ->
%% transform nodeset value to its string-value
mk_number(C,string_value(N1));
compare_nseq_format(N1=#xmlObj{type = nodeset},_N2=#xmlObj{type=boolean},C) ->
mk_boolean(C,N1);
compare_nseq_format(N1=#xmlObj{type = nodeset},_N2,C) ->
mk_string(C,string_value(N1)).
core_function('last') -> true;
core_function('position') -> true;
core_function('count') -> true;
core_function('id') -> true;
core_function('local-name') -> true;
core_function('namespace-uri') -> true;
core_function('name') -> true;
core_function('string') -> true;
core_function('concat') -> true;
core_function('starts-with') -> true;
core_function('contains') -> true;
core_function('substring-before') -> true;
core_function('substring-after') -> true;
core_function('string-length') -> true;
core_function('normalize-space') -> true;
core_function('translate') -> true;
core_function('boolean') -> true;
core_function('not') -> {true, fn_not};
core_function('true') -> {true, fn_true};
core_function('false') -> {true, fn_false};
core_function('lang') -> true;
core_function('number') -> true;
core_function('sum') -> true;
core_function('floor') -> true;
core_function('ceiling') -> true;
core_function('round') -> true;
core_function(_) ->
false.
%%% node set functions
%% number: last()
last(#xmlContext{nodeset = Set}, []) ->
?number(length(Set)).
%% number: position()
position(#xmlContext{context_node = #xmlNode{pos = Pos}}, []) ->
?number(Pos).
%% number: count(node-set)
count(C, [Arg]) ->
?number(length(mk_nodeset(C, Arg))).
%% node-set: id(object)
id(C, [Arg]) ->
WD = C#xmlContext.whole_document,
NS0 = [WD],
Obj = mk_object(C,Arg),
case Obj#xmlObj.type of
nodeset ->
NodeSet = Obj#xmlObj.value,
IdTokens =
lists:foldl(
fun(N, AccX) ->
StrVal = string_value(N),
TokensX = id_tokens(StrVal),
TokensX ++ AccX
end, [], NodeSet),
NewNodeSet =
xmerl_xpath:axis(descendant_or_self,
fun(Node) ->
attribute_test(Node, id, IdTokens)
end, C#xmlContext{nodeset = NS0}),
?nodeset(NewNodeSet);
_ ->
StrVal = string_value(Obj#xmlObj.value),
IdTokens = id_tokens(StrVal),
NodeSet = [(WD#xmlNode.node)#xmlDocument.content],
NewNodeSet = lists:foldl(
fun(Tok, AccX) ->
select_on_attribute(NodeSet, id, Tok, AccX)
end, [], IdTokens),
?nodeset(NewNodeSet)
end.
id_tokens(Str=#xmlObj{type=string}) ->
string:tokens(Str#xmlObj.value, " \t\n\r").
%%id_tokens(Str) when list(Str) ->
%% string:tokens(Str, " \t\n\r").
attribute_test(#xmlNode{node = #xmlElement{attributes = Attrs}},
Key, Vals) ->
case lists:keysearch(Key, #xmlAttribute.name, Attrs) of
{value, #xmlAttribute{value = V}} ->
lists:member(V, Vals);
_ ->
false
end;
attribute_test(_Node, _Key, _Vals) ->
false.
%%% CONTINUE HERE!!!!
%% string: local-name(node-set?)
'local-name'(C, []) ->
local_name1(default_nodeset(C));
'local-name'(C, [Arg]) ->
local_name1(mk_nodeset(C, Arg)).
local_name1([]) ->
?string([]);
local_name1([#xmlNode{type=element,node=El}|_]) ->
#xmlElement{name=Name,nsinfo=NSI} = El,
local_name2(Name,NSI);
local_name1([#xmlNode{type=attribute,node=Att}|_]) ->
#xmlAttribute{name=Name,nsinfo=NSI} = Att,
local_name2(Name,NSI);
local_name1([#xmlElement{name = Name, nsinfo = NSI}|_]) ->
local_name2(Name,NSI).
local_name2(Name, NSI) ->
case NSI of
{_Prefix, Local} ->
?string(Local);
[] ->
?string(atom_to_list(Name))
end.
%% string: namespace-uri(node-set?)
'namespace-uri'(C, []) ->
ns_uri(default_nodeset(C));
'namespace-uri'(C, [Arg]) ->
ns_uri(mk_nodeset(C, Arg)).
ns_uri([]) ->
?string([]);
ns_uri([#xmlElement{nsinfo = NSI, namespace = NS}|_]) ->
ns_uri2(NSI,NS);
ns_uri([#xmlNode{type=element,node=El}|_]) ->
#xmlElement{nsinfo=NSI, namespace = NS} = El,
ns_uri2(NSI,NS);
ns_uri([#xmlNode{type=attribute,node=Att}|_]) ->
#xmlAttribute{nsinfo=NSI, namespace = NS} = Att,
ns_uri2(NSI,NS);
ns_uri(_) ->
?string([]).
ns_uri2(NSI,NS) ->
case NSI of
{Prefix, _} ->
case lists:keysearch(Prefix, 1, NS#xmlNamespace.nodes) of
false ->
?string([]);
{value, {_K, V}} ->
string_value(V)
end;
[] ->
?string([])
end.
%% name(node-set) -> xmlObj{type=string}
%% The name function returns a string containing the QName of the node
%% first in document order. The representation of the QName is not
%% standardized and applications have their own format. At
%% http://xml.coverpages.org/clarkNS-980804.html (the author of XPath)
%% adopts the format "namespace URI"+"local-name" but according to
%% other sources it is more common to use the format:
%% '{'"namespace URI"'}'"local-name". This function also uses this
%% latter form.
name(C,[]) ->
name1(default_nodeset(C));
name(C, [Arg]) ->
name1(mk_nodeset(C, Arg)).
name1([]) ->
?string([]);
name1(NodeSet) ->
NSVal =
case ns_uri(NodeSet) of
#xmlObj{value=NSStr} when NSStr =/= [] ->
"{"++NSStr++"}";
_ ->
""
end,
#xmlObj{value=LocalName} = local_name1(NodeSet),
?string(NSVal++LocalName).
%%% String functions
%% string: string(object?)
string(C, []) ->
ns_string(default_nodeset(C));
string(C, [Arg]) ->
string_value(mk_object(C, Arg)).
ns_string([Obj|_]) ->
string_value(Obj).
string_value(#xmlObj{type=nodeset,value=[]}) ->
?string("");
string_value(N=#xmlObj{type=nodeset}) ->
string_value(hd(N#xmlObj.value));
string_value(N=#xmlObj{}) ->
string_value(N#xmlObj.value);
%% Needed also string_value for root_nodes, elements (concatenation of
%% al decsendant text nodes) and attribute nodes (normalized value).
string_value(A=#xmlNode{type=attribute}) ->
#xmlAttribute{value=AttVal}=A#xmlNode.node,
?string(AttVal);
string_value(El=#xmlNode{type=element}) ->
#xmlElement{content=C} = El#xmlNode.node,
TextValue = fun(#xmlText{value=T},_Fun) -> T;
(#xmlElement{content=Cont},Fun) -> Fun(Cont,Fun);
(_,_) -> []
end,
TextDecendants=fun(X) -> TextValue(X,TextValue) end,
?string(lists:flatten(lists:map(TextDecendants,C)));
string_value(T=#xmlNode{type=text}) ->
#xmlText{value=Txt} = T#xmlNode.node,
?string(Txt);
string_value(T=#xmlNode{type=comment}) ->
#xmlComment{value=Txt} = T#xmlNode.node,
?string(Txt);
string_value(infinity) -> ?string("Infinity");
string_value(neg_infinity) -> ?string("-Infinity");
string_value(A) when is_atom(A) ->
?string(atom_to_list(A));
string_value(N) when is_integer(N) ->
?string(integer_to_list(N));
string_value(N) when is_float(N) ->
N1 = round(N * 10000000000000000),
?string(strip_zeroes(integer_to_list(N1)));
string_value(Str) when is_list(Str) ->
?string(Str).
strip_zeroes(Str) ->
strip_zs(lists:reverse(Str), 15).
strip_zs([H|T], 0) ->
lists:reverse(T) ++ [$., H];
strip_zs("0" ++ T, N) ->
strip_zs(T, N-1);
strip_zs([H|T], N) ->
strip_zs(T, N-1, [H]).
strip_zs([H|T], 0, Acc) ->
lists:reverse(T) ++ [$.,H|Acc];
strip_zs([H|T], N, Acc) ->
strip_zs(T, N-1, [H|Acc]).
%% string: concat(string, string, string*)
concat(C, Args = [_, _|_]) ->
Strings = [mk_string(C, A) || A <- Args],
?string(lists:concat(Strings)).
%% boolean: starts-with(string, string)
'starts-with'(C, [A1, A2]) ->
?boolean(lists:prefix(mk_string(C, A2), mk_string(C, A1))).
%% boolean: contains(string, string)
contains(C, [A1, A2]) ->
Pos = string:str(mk_string(C, A1), mk_string(C, A2)),
?boolean(Pos > 0).
%% string: substring-before(string, string)
'substring-before'(C, [A1, A2]) ->
S1 = mk_string(C, A1),
S2 = mk_string(C, A2),
Pos = string:str(S1, S2),
?string(string:substr(S1, 1, Pos)).
%% string: substring-after(string, string)
'substring-after'(C, [A1, A2]) ->
S1 = mk_string(C, A1),
S2 = mk_string(C, A2),
case string:str(S1, S2) of
0 ->
?string([]);
Pos ->
?string(string:substr(S1, Pos))
end.
%% string: substring(string, number, number?)
substring(C, [A1, A2]) ->
S = mk_string(C, A1),
Pos = mk_integer(C, A2),
?string(string:substr(S, Pos));
substring(C, [A1, A2, A3]) ->
S = mk_string(C, A1),
Pos = mk_integer(C, A2),
Length = mk_integer(C, A3),
?string(string:substr(S, Pos, Length)).
%% number: string-length(string?)
'string-length'(C = #xmlContext{context_node = N}, []) ->
length(mk_string(C, string_value(N)));
'string-length'(C, [A]) ->
length(mk_string(C, A)).
%% string: normalize-space(string?)
'normalize-space'(C = #xmlContext{context_node = N}, []) ->
normalize(mk_string(C, string_value(N)));
'normalize-space'(C, [A]) ->
normalize(mk_string(C, A)).
%% string: translate(string, string, string)
translate(C, [A1, A2, A3]) ->
S1 = mk_string(C, A1),
S2 = mk_string(C, A2),
S3 = mk_string(C, A3),
?string(translate1(S1, translations(S2, S3))).
translate1([H|T], Xls) ->
case lists:keysearch(H, 1, Xls) of
{value, {_, remove}} ->
translate1(T, Xls);
{value, {_, replace, H1}} ->
[H1|translate1(T, Xls)];
false ->
[H|translate1(T, Xls)]
end;
translate1([], _) ->
[].
translations([H|T], [H1|T1]) ->
[{H, replace, H1}|translations(T, T1)];
translations(Rest, []) ->
[{X, remove} || X <- Rest];
translations([], _Rest) ->
[].
%% boolean: boolean(object)
boolean(C, [Arg]) ->
?boolean(mk_boolean(C, Arg)).
%% boolean: not(boolean) ->
fn_not(C, [Arg]) ->
?boolean(not(mk_boolean(C, Arg))).
%% boolean: true() ->
fn_true(_C, []) ->
?boolean(true).
%% boolean: false() ->
fn_false(_C, []) ->
?boolean(false).
%% boolean: lang(string) ->
lang(C = #xmlContext{context_node = N}, [Arg]) ->
S = mk_string(C, Arg),
Lang =
case N of
#xmlElement{language = L} -> L;
#xmlAttribute{language = L} -> L;
#xmlText{language = L} -> L;
#xmlComment{language = L} -> L;
_ -> []
end,
case Lang of
[] ->
?boolean(false);
_ ->
?boolean(match_lang(upcase(S), upcase(Lang)))
end.
upcase([H|T]) when H >= $a, H =< $z ->
[H+($A-$a)|upcase(T)];
upcase([H|T]) ->
[H|upcase(T)];
upcase([]) ->
[].
match_lang([H|T], [H|T1]) ->
match_lang(T, T1);
match_lang([], "-" ++ _) ->
true;
match_lang([], []) ->
true;
match_lang(_, _) ->
false.
%% number: number(object)
number(C = #xmlContext{context_node = N}, []) ->
?number(mk_number(C, string(C, N)));
number(C, [Arg]) ->
?number(mk_number(C, Arg)).
sum(C, [Arg]) ->
NS = mk_nodeset(C, Arg),
lists:foldl(
fun(N, Sum) ->
Sum + mk_number(C, string(C, N))
end, 0, NS).
floor(C, [Arg]) ->
Num = mk_number(C, Arg),
case trunc(Num) of
Num1 when Num1 > Num ->
?number(Num1-1);
Num1 ->
?number(Num1)
end.
ceiling(C, [Arg]) ->
Num = mk_number(C, Arg),
case trunc(Num) of
Num1 when Num1 < Num ->
?number(Num1+1);
Num1 ->
?number(Num1)
end.
round(C, [Arg]) ->
case mk_number(C, Arg) of
A when is_atom(A) ->
A;
N when is_integer(N) ->
N;
F when is_float(F) ->
round(F)
end.
select_on_attribute([E = #xmlElement{attributes = Attrs}|T], K, V, Acc) ->
case lists:keysearch(K, #xmlAttribute.name, Attrs) of
{value, #xmlAttribute{value = V}} ->
Acc2 = select_on_attribute(E#xmlElement.content,K,V,[E|Acc]),
select_on_attribute(T, K, V, Acc2);
_ ->
Acc2 = select_on_attribute(E#xmlElement.content,K,V,Acc),
select_on_attribute(T, K, V, Acc2)
end;
select_on_attribute([H|T], K, V, Acc) when is_record(H,xmlText) ->
select_on_attribute(T, K, V, Acc);
select_on_attribute([], _K, _V, Acc) ->
Acc.
%%%%
mk_nodeset(_C0, #xmlContext{nodeset = NS}) ->
NS;
mk_nodeset(_C0, #xmlObj{type = nodeset, value = NS}) ->
NS;
mk_nodeset(C0, Expr) ->
case expr(Expr, C0) of
#xmlObj{type = nodeset, value = NS} ->
NS;
Other ->
exit({expected_nodeset, Other})
end.
default_nodeset(#xmlContext{context_node = N}) ->
[N].
mk_object(_C0, Obj = #xmlObj{}) ->
Obj;
mk_object(C0, Expr) ->
expr(Expr, C0).
mk_string(_C0, #xmlObj{type = string, value = V}) ->
V;
mk_string(C0, Obj = #xmlObj{}) ->
mk_string(C0,string_value(Obj));
mk_string(C0, Expr) ->
mk_string(C0, expr(Expr, C0)).
mk_integer(_C0, #xmlObj{type = number, value = V}) when is_float(V) ->
round(V);
mk_integer(_C0, #xmlObj{type = number, value = V}) when is_integer(V) ->
V;
mk_integer(C, Expr) ->
mk_integer(C, expr(Expr, C)).
mk_number(_C, #xmlObj{type = string, value = V}) ->
scan_number(V);
mk_number(_C, #xmlObj{type = number, value = V}) ->
V;
mk_number(C, N=#xmlObj{type = nodeset}) ->
mk_number(C,string_value(N));
mk_number(_C, #xmlObj{type = boolean, value = false}) ->
0;
mk_number(_C, #xmlObj{type = boolean, value = true}) ->
1;
mk_number(C, Expr) ->
mk_number(C, expr(Expr, C)).
mk_boolean(_C, #xmlObj{type = boolean, value = V}) ->
V;
mk_boolean(_C, #xmlObj{type = number, value = 0}) ->
false;
mk_boolean(_C, #xmlObj{type = number, value = V}) when is_float(V) ; is_integer(V) ->
true;
mk_boolean(_C, #xmlObj{type = nodeset, value = []}) ->
false;
mk_boolean(_C, #xmlObj{type = nodeset, value = _V}) ->
true;
mk_boolean(_C, #xmlObj{type = string, value = []}) ->
false;
mk_boolean(_C, #xmlObj{type = string, value = _V}) ->
true;
mk_boolean(C, Expr) ->
mk_boolean(C, expr(Expr, C)).
normalize([H|T]) when ?whitespace(H) ->
normalize(T);
normalize(Str) ->
ContF = fun(_ContF, RetF, _S) ->
RetF()
end,
normalize(Str,
#xmerl_scanner{acc_fun = fun() -> exit(acc_fun) end,
event_fun = fun() -> exit(event_fun) end,
hook_fun = fun() -> exit(hook_fun) end,
continuation_fun = ContF},
[]).
normalize(Str = [H|_], S, Acc) when ?whitespace(H) ->
case xmerl_scan:accumulate_whitespace(Str, S, preserve, Acc) of
{" " ++ Acc1, [], _S1} ->
lists:reverse(Acc1);
{Acc1, [], _S1} ->
lists:reverse(Acc1);
{Acc1, T1, S1} ->
normalize(T1, S1, Acc1)
end;
normalize([H|T], S, Acc) ->
normalize(T, S, [H|Acc]);
normalize([], _S, Acc) ->
lists:reverse(Acc).
scan_number([H|T]) when ?whitespace(H) ->
scan_number(T);
scan_number("-" ++ T) ->
case catch xmerl_xpath_scan:scan_number(T) of
{{number, N}, Tail} ->
case is_all_white(Tail) of
true ->
N;
false ->
'NaN'
end;
_Other ->
'NaN'
end;
scan_number(T) ->
case catch xmerl_xpath_scan:scan_number(T) of
{{number, N}, Tail} ->
case is_all_white(Tail) of
true ->
N;
false ->
'NaN'
end;
_Other ->
'NaN'
end.
is_all_white([H|T]) when ?whitespace(H) ->
is_all_white(T);
is_all_white([_H|_T]) ->
false;
is_all_white([]) ->
true.
