alasql/src/57case.js

AlaSQL.js - JavaScript SQL database library for relational and graph data manipulation with support of localStorage, IndexedDB, and Excel

/*
//
// CASE for Alasql.js
// Date: 03.11.2014
// (c) 2014, Andrey Gershun
//
*/

yy.CaseValue = function(params) { return yy.extend(this, params); };
yy.CaseValue.prototype.toString = function() {
	var s = 'CASE ';
	if(this.expression) s += this.expression.toString();
	if(this.whens) {
		s += this.whens.map(function(w) { return ' WHEN '+
			w.when.toString() + ' THEN '+w.then.toString()}).join();
	}
	s += ' END';
	return s;
};

yy.CaseValue.prototype.findAggregator = function (query){
//	console.log(this.toString());
	if(this.expression && this.expression.findAggregator) this.expression.findAggregator(query);
	if(this.whens && this.whens.length > 0) {
		this.whens.forEach(function(w) { 
			if(w.when.findAggregator) w.when.findAggregator(query);
			if(w.then.findAggregator) w.then.findAggregator(query);
		});
	};
	if(this.elses && this.elses.findAggregator) this.elses.findAggregator(query);
};

yy.CaseValue.prototype.toJavaScript = function(context, tableid, defcols) {

	var s = '((function('+context+',params,alasql){var r;';
	if(this.expression) {
//			this.expression.toJavaScript(context, tableid)
		s += 'v='+this.expression.toJavaScript(context, tableid, defcols)+';';
		s += (this.whens||[]).map(function(w) { return ' if(v=='+w.when.toJavaScript(context,tableid, defcols)
			+') {r='+w.then.toJavaScript(context,tableid, defcols)+'}'; }).join(' else ');
		if(this.elses) s += ' else {r='+this.elses.toJavaScript(context,tableid, defcols)+'}';
	} else {
		s += (this.whens||[]).map(function(w) { return ' if('+w.when.toJavaScript(context,tableid, defcols)
			+') {r='+w.then.toJavaScript(context,tableid, defcols)+'}'; }).join(' else ');
		if(this.elses) s += ' else {r='+this.elses.toJavaScript(context,tableid,defcols)+'}';
	}
	// TODO remove bind from CASE
	s += ';return r;}).bind(this))('+context+',params,alasql)';

	return s;
};