Building equations for multiple systems from JavaScript presentation by calling a function

test.js

"use strict";

/** Query builder */
function build_query(type, schema) {

	// Metadata for builder
	var _converters = {
		js:{
			or: function(x, y) { return '(' + x + ') || (' + y + ')'; },
			and: function(x, y) { return '(' + x + ') && (' + y + ')'; },
			eq: function(x, y) { return x + ' === ' + y; },
			gt: function(x, y) { return x + ' > ' + y; },
			lt: function(x, y) { return x + ' < ' + y; },
			plus: function(x, y) { return x + ' + ' + y; },
			minus: function(x, y) { return x + ' - ' + y; }
		},
		mysql:{
			or: function(x, y) { return '(' + x + ') OR (' + y + ')'; },
			and: function(x, y) { return '(' + x + ') AND (' + y + ')'; },
			eq: function(x, y) { return x + ' = ' + y; },
			gt: function(x, y) { return x + ' > ' + y; },
			lt: function(x, y) { return x + ' < ' + y; },
			plus: function(x, y) { return x + ' + ' + y; },
			minus: function(x, y) { return x + ' - ' + y; }
		}
	};

	var ops = _converters[type];
	return schema.apply(ops);
}

/** Our Presentation of the Match as pure JavaScript */
function our_match() {
	var id = 'x.id';
	return this.or(
		this.eq(id, 10),
		this.and(
			this.gt(id, 100),
			this.lt(id, 200)
		)
	);
}

// Let's build different queries...
console.log('mysql: ' + build_query('mysql', our_match));
console.log('js:    ' + build_query('js', our_match));

/*
 * 
 * Results:
 * 
 * $ node test.js 
 * mysql: (x.id = 10) OR ((x.id > 100) AND (x.id < 200))
 * js:    (x.id === 10) || ((x.id > 100) && (x.id < 200))
 * 
 */

/* EOF */