In our function that does all the magic,

Then you've parsed it! That string was in the language of the grammar.

All right let's wrap this up.

You've just completed your first tough question on filling out the charts for parsing.

So the 3 of these together, E E are themselves one more E.

Recall that a compiler has five major phases,

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

And that key insight that we can stop somewhere around here is what's going to lead us to a more efficient parsing strategy.

You can never put the dot on the left. The dot is always to the right.

This way, from the bottom to the top, is generating or producing a string.

Here's the real exciting part

We had our little refresher on list comprehensions.

Students were asking about natural language processing.

I have used tools like the lexer and parser generators we're learning about in this class, Programming Languages.

Those intentionally match.

Actually, the answer is a resounding yes.

So what I'd like you to do is figure out after just 1 token of the input, what are some parse states we could be in?

Very soon, we're going to have a complete parser for HTML and JavaScript.

That's it for defining parsing functions for function calls and arguments.

Just to review a bit, this is how we did basic HTML parsing or our basic HTML grammar.

That's much more important than knowing the particular syntax for any language.

If it's not, our input is not.

If this tripped you up because it was almost too simple, don't worry about it.

We say it's a parsing rule, with p_.

You and I know that there are 2 more tokens coming, but our parser doesn't know that yet.

Plus and Minus are both left associative and they're lower precedence.

You could imagine doing another one, but this is the one we used for this class.

We wanted to cover the basics of grammars, context free grammars, how we might parse them ourselves and we taught you a particular algorithm for that in class and then how to interface with a tool that uses a similar algorithm and then given a context free grammar and a description of how to build a parse tree or an abstract syntax tree puts it all together.

Our first step is to find our Web page and lex it and parse it until we have an Abstract Syntax Tree.

All right.

Our input string is int plus int.

They were the circles.

Sure.

It's, more or less, exactly what we covered for JavaScript.

So what was the structure of FORTRAN one?

You write out a grammar and then for each rule you write out how to build up the abstract syntax tree.

This is sometimes a good software engineering practice.

So in fact, we could have seen 4 input tokens INT INT and been in this parsing state.

libipsec has found syntax error while parsing.

And the last is the word_element, luftballons.

The study of alien languages. Morphology, phonology, syntax.

Let's go through it together the Web page is broken down into words and trees.

Rates. The raises are what do the interesting and the Fed is a modifier of raises.

Parsing the folder structure...

It's as if I'm taking the rules and the grammar and changing the direction of the arrow.