Here I've written down four claims.

You might think, Boy, is there a context expensive grammar out there? What's the opposite of free?

These grammars that we've been introducing describe something new context free languages.

I am just gonna pause for a moment to let you think about that.

You have a regular pulse.

But if right above it I've written X 0, then we'd get a different answer.

Your pulse is normal.

It handles LL. It handles LR. It handles LALR.

like HTML or SQL, the language of database queries.

The set of languages that can be described by re write rules or grammers like this are called context free languages.

But that's an example of an application that also uses this sort of linguistic analysis perhaps a little less related to context free grammars but still in the same vein.

It relates grammars to parsing, which is one of the concepts in this class.

So in lecture, we spent a lot of time learning about context free grammars and languages.

Finite State Machines, adding a lexer that follows them automatically,

Actually, they're both just concise notations for specifying possibly infinite sets of strings.

That line above it is the context.

Sometimes this statement is true, and sometimes it's not.

Real world problems are often ambiguous and ill defined and the context is always changing.

We'll talk about it in a lot of different contexts.

It depends on the context.

This branch of the family is all about representation.

These are both infinite, infinite grammars.

In theory, you could compose it over here as well.

In most interpreters, this is a problem.

Build the system so that anybody can contribute at any amount.

This might seem a little counterintuitive but remember the glory of parsing, or the glory of context free grammars, is that a very concise grammar notation stands for an infinite number of strings.

... the misspelled word shown in context...

The brain is recording all information and driving all change in temporal context.

That's an excellent question.

In particular, it's a set of strings that can be represented by a finite state machine or a regular expression.

Well, because, sentences are more interesting.

A context free grammar can capture the language a N and b N, where N is the same.

Another common story or storyline is the claim that we have to get tough .

Y has the value of 2.

This is always true because we have our Pac Man diagram here, and also because you can take any regular language and represent it with a context free grammar.

All right. So, it's another one of these puzzle like questions.

They're the actual input that we're trying to match.

Normal Character

The input doesn't really have to be meaningful.

Perhaps a stealth thing.

This is called being lazy, and it's a phenomenal virtue when you're writing programs.

Units 3 and 4 were relatively abstract to some degree, intentionally so.

Most people write about their daily life.

All right. Now that you've gone to the hard work of defining all of those procedures,

Here's a new quiz. The Great Grammar Fix Up.