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var getStatementEvaluators = function(evaluate) {
return {
'statement-sequence': function(dataset, children, context) {
var retval = null;
children.forEach(function(child) {
retval = evaluate(child, context);
});
return retval;
},
'while': function(dataset, children, context) {
var condition = children[0];
var body = children[1];
while (evaluate(condition, context)) {
evaluate(body, context);
}
},
'compare': function(dataset, children, context) {
var operator = binaryOperators[dataset.op];
var lhs = evaluate(children[0], context);
var rhs = evaluate(children[1], context);
var result = operator(lhs, rhs);
return result;
},
'variable': function(dataset, children, context) {
return context[dataset.name];
},
'constant': function(dataset, children, context) {
return stringToType(dataset.val, dataset.type);
},
'branch': function(dataset, children, context) {
var condition = children[0];
var ifBody = children[1];
// else is optional
if (children.length > 2) {
var elseBody = children[2];
}
if (evaluate(condition, context)) {
return evaluate(ifBody, context);
} else if (elseBody) {
return evaluate(elseBody, context);
}
},
'assign': function(dataset, children, context) {
context[dataset.name] = evaluate(children[0], context);
return context[dataset.name];
},
'bin-op': function(dataset, children, context) {
var operator = binaryOperators[dataset.op];
var lhs = evaluate(children[0], context);
var rhs = evaluate(children[1], context);
return operator(lhs, rhs);
},
'return': function(dataset, children, context) {
return evaluate(children[0], context);
},
'print': function(dataset, children, context) {
var args = children.map(function(child) {
return evaluate(child, context);
});
console.log.apply(this, args);
}
};
};
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