Grooming in primates increases group cohesion.

So this is a demonstration of a lexical analyzer.

lexical analysis, parsing, semantic analysis, optimization, and code generation.

This process is called dun, dun, dun, dun lexical analysis.

We're going to see how to implement this in our lexical analyzer, but recall that our lexical analyzer was just based on regular expressions.

However, quite a few other things make use of lexical analysis.

It's the smallest unit of the output of a lexical analysis.

Lexical here has the same roots and lexicon like a dictionary.

This function call tells our lexical analysis library that we want to use all of the token definitions above to make a lexical analyzer, and break up strings.

So we just learned how to do that JavaScript token in lexical analysis.

Now, recall that the output of a lexical analyzer is a list of tokens.

Water's ability to stick to itself is called cohesion, while water's ability to stick to other substances is called adhesion.

You're already familiar with all of the key concepts in making a lexical analysis library.

And we did Lexing or Lexical Analysis to break it up into a list of tokens.

For example, once I put these 3 rules together, they become a lexer, or lexical analyzer.

And then we'll have the terminal categories or lexical categories, categories that define classes of words.

By looking at this output, we can notice mistakes in our lexical analyzer and help fix them.

If you're making a lexical analyzer for HTML or JavaScript, ordering your token definitions is of prime importance.

And that task uses exactly the same sort of lexical analysis string matching that we've talked about here.

A lexical analyzer or lexer this is a term of art is just a collection of such tokens.

And in fact, suppose we passed to this lexical analyzer the input string 33 is less than 55.

And it turns out that there's effectively a standard, this notion of making lexical analyzers or making parsers.

It's telling Python where to find our lexical analyzer software or libraries that we're going to build upon.

These other numbers, after lexical analyzer token STRlNG, with token value, ' This ' are the line and character number information.

In JavaScript, we use curly braces and closing curly braces to denote this sort of lexical or syntactic scope.

The original tool for this was called Lex, a lexical analyzer generator, and the name in there, generator, is important.

Just like regular expressions were called RE to save space, a lexical analyzer is just called lex to save space.

It was called a lexical analyzer generator, but it was proprietary software at the time and it only worked for C.

But those two things commitment to religion and strong social cohesion also made it difficult for them to change at the end and to learn from the Inuit.

That's exactly the same format that are used in the lexical analyzer and parser generator tools for all of the other languages.

There are a large number of great uses of regular expressions and lexical analysis beyond just building web browsers or writing language interpreters.

For example, the Greenland Norse, in this difficult environment, were held together for four and a half centuries by their shared commitment to religion, and by their strong social cohesion.

The goal of lexical analysis, then, is to divide the program text into its words, or what we call in compiler speak, the tokens.

So now I'm going to show you how to make a lexical analyzer which, recall is just a bunch of token definitions put together.

But if you're a repressive government searching for political enemies, you might instead remove them, eliminate them, disrupt their social group, and those who remain behind lose social cohesion and organization.

Seen from those stairs, all politicians today seem the same, and politics has come to resemble a sport that inspires more aggressiveness and pessimism than social cohesion and the desire for civic protaganism.

With the lexing and parsing, the lexical analysis and syntactical analysis that we'll cover in this class, do they carry over to parsing real world languages

I would like you to define a variable called (webpage) that holds a string that causes our lexical analyzer to produce exactly these 6 bits of output

That sort of readability metric can be easily computed using exactly the sort of break a string up into words kind of lexical analysis that we've been focusing on.

I hinted at this in the beginning of Unit 1, but things like phone numbers and credit card numbers are recognized and processed using regular expressions essentially using lexical analysis.

We're going to be focusing on lexical analysis, a process whereby we break down a string, like a sentence or an utterance or a webpage, into a list of tokens.

collocation a recurrent word combination characterized by cohesion in that the components of the collocation must co occur within an utterance or series of utterances, even though they do not necessarily have to maintain immediate proximity to one another

There was a very interesting and wide reaching question on the forums about the uses of lexical analysis and regular expressions and this general sort of string processing outside of what we're doing in this class.

We are going to start with your average web page, a string of HTML with some embedded Java script, and we wanted to break it down into tokens or words, and that process is called lexical analysis.

Well it consists five phases lexical analysis and parsing, which together take care of the syntactic aspects of the language, semantic analysis, which, of course, takes care of more semantic aspects, things like types and scope rules.