public FunctionEvaluator bind(String name, String value) {
        if (evaluated)
            throw new IllegalStateException("Cannot bind a new value in a used evaluator");
        context.put(name, new StringValue(value));
        return this;
    }
Binds the given variable referred in this expression to the given value.
String values are not yet supported in tensors.

@param name the variable to bind
@param value the value this becomes bound to
@return this for chaining
model-evaluation/src/main/java/ai/vespa/models/evaluation/FunctionEvaluator.java