/*
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* JsonSQL
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* By: Trent Richardson [http://trentrichardson.com]
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* Version 0.1
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* Last Modified: 1/1/2008
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*
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* Copyright 2008 Trent Richardson
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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window.jsonsql = {
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query: function(sql,json){
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var returnfields = sql.match(/^(select)\s+([a-z0-9_\,\.\s\*]+)\s+from\s+([a-z0-9_\.]+)(?: where\s+\((.+)\))?\s*(?:order\sby\s+([a-z0-9_\,]+))?\s*(asc|desc|ascnum|descnum)?\s*(?:limit\s+([0-9_\,]+))?/i);
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var ops = {
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fields: returnfields[2].replace(' ','').split(','),
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from: returnfields[3].replace(' ',''),
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where: (returnfields[4] == undefined)? "true":returnfields[4],
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orderby: (returnfields[5] == undefined)? []:returnfields[5].replace(' ','').split(','),
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order: (returnfields[6] == undefined)? "asc":returnfields[6],
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limit: (returnfields[7] == undefined)? []:returnfields[7].replace(' ','').split(',')
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};
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return this.parse(json, ops);
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},
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parse: function(json,ops){
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var o = { fields:["*"], from:"json", where:"", orderby:[], order: "asc", limit:[] };
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for(i in ops) o[i] = ops[i];
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var result = [];
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result = this.returnFilter(json,o);
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result = this.returnOrderBy(result,o.orderby,o.order);
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result = this.returnLimit(result,o.limit);
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return result;
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},
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returnFilter: function(json,jsonsql_o){
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var jsonsql_scope = eval(jsonsql_o.from);
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var jsonsql_result = [];
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var jsonsql_rc = 0;
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if(jsonsql_o.where == "")
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jsonsql_o.where = "true";
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for(var jsonsql_i in jsonsql_scope){
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with(jsonsql_scope[jsonsql_i]){
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if(eval(jsonsql_o.where)){
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jsonsql_result[jsonsql_rc++] = this.returnFields(jsonsql_scope[jsonsql_i],jsonsql_o.fields);
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}
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}
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}
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return jsonsql_result;
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},
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returnFields: function(scope,fields){
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if(fields.length == 0)
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fields = ["*"];
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if(fields[0] == "*")
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return scope;
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var returnobj = {};
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for(var i in fields)
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returnobj[fields[i]] = scope[fields[i]];
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return returnobj;
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},
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returnOrderBy: function(result,orderby,order){
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if(orderby.length == 0)
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return result;
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result.sort(function(a,b){
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switch(order.toLowerCase()){
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case "desc": return (eval('a.'+ orderby[0] +' < b.'+ orderby[0]))? 1:-1;
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case "asc": return (eval('a.'+ orderby[0] +' > b.'+ orderby[0]))? 1:-1;
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case "descnum": return (eval('a.'+ orderby[0] +' - b.'+ orderby[0]));
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case "ascnum": return (eval('b.'+ orderby[0] +' - a.'+ orderby[0]));
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}
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});
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return result;
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},
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returnLimit: function(result,limit){
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switch(limit.length){
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case 0: return result;
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case 1: return result.splice(0,limit[0]);
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case 2: return result.splice(limit[0]-1,limit[1]);
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}
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}
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};
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