/* Part of SWI-Prolog Author: Jan Wielemaker, Michiel Hildebrand E-mail: J.Wielemaker@uva.nl WWW: http://www.swi-prolog.org Copyright (C): 2007-2010, University of Amsterdam VU University Amsterdam This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this library; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA As a special exception, if you link this library with other files, compiled with a Free Software compiler, to produce an executable, this library does not by itself cause the resulting executable to be covered by the GNU General Public License. This exception does not however invalidate any other reasons why the executable file might be covered by the GNU General Public License. */ :- module(javascript, [ js_call//1, % +Function(Arg..) js_new//2, % +Id, +Function(+Args) js_args//1 % +Args ]). :- use_module(library(http/html_write)). :- use_module(library(http/json_convert)). :- use_module(library(http/json)). :- use_module(library(error)). :- use_module(library(debug)). /** Utilities for including javascript This library is a supplement to library(http/html_write) for producing JavaScript fragments. Its main role is to be able to call JavaScript functions with valid arguments constructed from Prolog data. E.g. suppose you want to call a JavaScript functions to process a list of names represented as Prolog atoms. This can be done using the call below, while without this library you would have to be careful to properly escape special characters. == numbers_script(Names) --> html(script(type('text/javascript'), [ \js_call('ProcessNumbers'(Names) ]), == The accepted arguments are described with js_args//1. */ %% js_call(+Term)// is det. % % Emit a call to a Javascript function. The Prolog functor is the % name of the function. The arguments are converted from Prolog to % JavaScript using js_args//1. Please not that Prolog functors can % be quoted atom and thus the following is legal: % % == % ... % html(script(type('text/javascript'), % [ \js_call('x.y.z'(hello, 42) % ]), % == js_call(Term) --> { Term =.. [Function|Args] }, html([Function, '(']), js_args(Args), html(');\n'). %% js_new(+Id, +Term)// is det. % % Emit a call to a Javascript object declaration. This is the same % as: % % == % ['var ', Id, ' = new ', \js_call(Term)] % == js_new(Id, Term) --> { Term =.. [Function|Args] }, html(['var ', Id, ' = new ', Function, '(']), js_args(Args), html(');\n'). %% js_args(+Args:list)// is det. % % Write javascript function arguments. Each argument is separated % by a comma. Elements of the list may contain the following % terms: % % $ Variable : % Emitted as Javascript =null= % $ List : % Produces a Javascript list, where each element is processed % by this library. % $ object(Attributes) : % Where Attributes is a Key-Value list where each pair can be % written as Key-Value, Key=Value or Key(Value), accomodating % all common constructs for this used in Prolog. % $ json(Term) : % Emits a term using json_write/3. % $ @(true), @(false), @(null) : % Emits these constants without quotes. % $ Number : % Emited literally % $ symbol(Atom) : % Emitted without quotes. Can be used for JavaScript symbols % (e.i., function and variable-names) % $ Atom or String : % Emitted as quoted JavaScript string. js_args([]) --> []. js_args([H|T]) --> ( js_arg(H) -> ( { T == [] } -> [] ; html(', '), js_args(T) ) ; { type_error(javascript_argument, H) } ). js_arg(H) --> { var(H) }, !, [null]. js_arg(object(H)) --> { is_list(H) }, !, html([ '{', \js_kv_list(H), '}' ]). js_arg(@(true)) --> [true]. js_arg(@(false)) --> [false]. js_arg(@(null)) --> [null]. js_arg(symbol(H)) --> [H]. js_arg(json(Term)) --> { json_to_string(json(Term), String), debug(json_arg, '~w~n', String) }, [ String ]. js_arg(H) --> { is_list(H) }, !, html([ '[', \js_args(H), ']' ]). js_arg(H) --> { number(H) }, !, [H]. js_arg(H) --> { atomic(H), !, js_quoted_string(H, Q) }, [ '\'', Q, '\'' ]. js_kv_list([]) --> []. js_kv_list([H|T]) --> ( js_kv(H) -> ( { T == [] } -> [] ; html(', '), js_kv_list(T) ) ; { type_error(javascript_key_value, H) } ). js_kv(Key-Value) --> html(['\'',Key,'\':',\js_arg(Value)]). js_kv(Key=Value) --> html(['\'',Key,'\':',\js_arg(Value)]). js_kv(Term) --> { compound(Term), Term =.. [Key,Value] }, !, html(['\'',Key,'\':',\js_arg(Value)]). %% js_quoted_string(+Raw, -Quoted) % % Quote text for use in JavaScript. Quoted does _not_ include the % leading and trailing quotes. % % @tbd Join with json stuff. js_quoted_string(Raw, Quoted) :- atom_codes(Raw, Codes), phrase(js_quote_codes(Codes), QuotedCodes), atom_codes(Quoted, QuotedCodes). js_quote_codes([]) --> []. js_quote_codes([0'\r,0'\n|T]) --> !, "\\n", js_quote_codes(T). js_quote_codes([H|T]) --> js_quote_code(H), js_quote_codes(T). js_quote_code(0'') --> !, "\\'". js_quote_code(34) --> !, [92,34]. js_quote_code(0'\\) --> !, "\\\\". js_quote_code(0'\n) --> !, "\\n". js_quote_code(0'\r) --> !, "\\r". js_quote_code(0'\t) --> !, "\\t". js_quote_code(C) --> [C]. %% json_to_string(+JSONTerm, -String) % % Write JSONTerm to String. json_to_string(JSON, String) :- with_output_to(string(String), json_write(current_output,JSON,[width(0)])).