Programming
C++17 introduces a new type-safe union in the form of std::variant. At any time, it can store a single value from one of many types. We need to include <variant> to use this feature. Let us look at a simple example to get started: First, we define a variant object v1 to hold either an int […]
C++17 enhances if and switch statements with the ability to define variables whose life-time is limited to the corresponding scope. This is in keeping with the general guideline that variables should have a tight scope, i.e., should be defined as close to the point of use as possible and should not live beyond where they […]
One of the advanced features of iLangGen is the ability to embed arbitrary function calls on the RHS of grammar rules. Such functions impart interesting dynamic behaviour to the generated data. For convenience and flexibility, iLangGen supports two types of function calls – Direct and Indirect. In the case of the Direct function call, the […]
We are familiar with the advantages of class inheritance in object-oriented languages such as C++, C#, Java, and Python. The ability to reuse functionality via inheritance allows us to express our software design optimally, without having to write redundant code. iLangGen encourages the reuse of grammars by supporting Grammar Inheritance, where a grammar can explicitly […]
Many times, we need to repeatedly generate an element, or in general, have a way to control the number times one or more elements get generated. iLangGen supports all the standard cases: – Zero or once – Zero or more times (unbounded) – Zero or more times (bounded) – One or more times (unbounded) – […]
The two primary areas in Natural Language processing are Natural Language Understanding and Natural Language Generation. The former is concerned with processing and making sense of natural language text, whereas the latter is concerned with synthesizing text, possibly from some deep representation. Both are fascinating and at the same time, challenging, areas of research. The […]
In today’s post, let us see how we can enhance the grammar representation discussed so far to include both Number constraint and Parse Tree. Fortunately, this turns out to be quite straightforward. Just as we do in Prolog, we need to include additional parameters, as needed, to each grammar rule. In the earlier two posts, […]
In the last post, I showed how we can implement DCGs in LispWorks using the KnowledgeWorks package. The grammar discussed in that post did not take into account subject/predicate number agreement. This is one of the basic constraints in English grammar. Today I will show how easy it is to encode this constraint. Here is […]
Definite Clause Grammars (DCG) are an elegant formalism for specifying context free grammars, and part of their popularity is due to their support in the Prolog language. Most books on Natural Language processing usually include a brief coverage of DCGs, even though Natural languages are not context-free. Because of the ability to attach arbitrary actions […]
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