lib/sparql/SparqlString.js
var Class = require('../ext/Class');
var NodeFactory = require('../rdf/NodeFactory');
var VarUtils = require('./VarUtils');
/**
* An string object that supports variable substitution and extraction
* to be used for ElementString and ExprString
*
*/
var SparqlString = Class.create({
classLabel: 'jassa.sparql.SparqlString',
initialize: function(value, varsMentioned) {
this.value = value;
this.varsMentioned = varsMentioned ? varsMentioned : [];
},
toString: function() {
return this.value;
},
getString: function() {
return this.value;
},
copySubstitute: function(fnNodeMap) {
var str = this.value;
var newVarsMentioned = [];
// Avoid double substitution of variables by using some unlikely prefix
// instead of the question mark
var placeholder = '@@@@';
var reAllPlaceholders = new RegExp(placeholder, 'g');
this.varsMentioned.forEach(function(v) {
// A variable must not end in \w (this equals: _, [0-9], [a-z] or [a-Z])
var reStr = '\\?' + v.getName() + '([^\\w])?';
var re = new RegExp(reStr, 'g');
var node = fnNodeMap(v);
if (node) {
// console.log('Node is ', node);
var replacement;
if (node.isVariable()) {
// console.log('Var is ' + node + ' ', node);
replacement = placeholder + node.getName();
newVarsMentioned.push(node);
} else {
replacement = node.toString();
}
str = str.replace(re, replacement + '$1');
} else {
newVarsMentioned.push(v);
}
});
str = str.replace(reAllPlaceholders, '?');
return new SparqlString(str, newVarsMentioned);
},
getVarsMentioned: function() {
return this.varsMentioned;
}
});
SparqlString.create = function(str, varNames) {
var vars;
if (varNames != null) {
vars = varNames.map(function(varName) {
return NodeFactory.createVar(varName);
});
} else {
vars = VarUtils.extractSparqlVars(str);
}
// vars = vars ? vars :
var result = new SparqlString(str, vars);
return result;
};
module.exports = SparqlString;