Welcome to the introduction to PHP. I always like to put what we're talking about in a historical context, and PHP is a language that owes its inspiration to many different languages. If we go all the way back to the beginning of programming, we had machine code where we built hardware and we programmed it very directly. We had very little memory, so we had to be very careful with our programming. The early days of computing were science calculations, where you're doing weather and you're doing, you know, ballistics calculations and very mathematical things. And languages evolved that were just slightly above the assembly language that made us more productive and languages like Fortran 1955, and really some of the earliest things that we did. But what happened as we moved from the 50s through the 60s to the 70s is, it became increasingly clear that numeric data was not just what we were going to do with computers. Strings, letters like hello, like the word hello. So writing programs like text editors and Twitter and stuff like that in a language like Fortran would have just not worked very well. We began to see in the early 70s, as human interaction mediated by a computer became an important part of what we were going to do. String oriented languages started to evolve. There were lots of string oriented languages. There are just thousands of different languages. I remember working through that and like, here's Pascal that's really cool. Here's Snowball, that's really cool and Fortran 77 had strings in it. But then what happened was, this language C came out, and C was this amazing language. It's crude. Someday I'd love to teach a MOOC on C. It's very crude but very powerful. It turns out that C is the language that's used to write things like PHP and Python and Perl. The C language gave us the speed of assembly language with portability between different computer systems. But it also did strings pretty well. It doesn't do strings as well as modern languages, but it strings really well. So this moment where we transitioned from Fortran to C as the most important language of computing, is when humans start to send messages through computers and talk. So C has created lots of offshoots. Anytime you see a language that has curly braces, then you know some of it's inspiration to C. So we see languages like C++ which is an object oriented version of C, Objective-C, which is another object oriented version of C, Java which was this web language. It was a web version of C. Microsoft C-Sharp was really inspired by a combination of C++, and the JavaScript language which came out in 1995 really took a lot of its inspiration from C, and other weird languages at the time because it has a different object oriented pattern than all these other ones. So Java, C++ and Objective-C have one object oriented pattern and JavaScript actually has a very different one. We'll talk about that later. So there's all these system, the nerdy languages. At the same time that we are building and innovating in nerdy languages, we were building languages not so much for end users, but for system administrators, people who didn't see themselves as professional programmers. These languages were very much inspired by C and written in C. So Perl which is a report generator that was started in '87, Python which started in 1991, which now has become a super popular one. I teach a popular MOOC on Python as well. They were written in C and so they took their inspiration from C. While Python doesn't have curly braces, and Perl doesn't have curly braces, they have things like str functions etc,. that inspire themselves from C, but they were written in C. So Python and Perl inherited a lot of what they basically do at low levels in terms of functions that they do from C. So PHP, the language we're talking about today, is also a derivative of C. Actually it has a lot of inspiration from C, because it has curly braces. It has some of the same str functions, str blah blah blah. Those came from C and were adapted to work in PHP. So below this line, one of the focuses was simplicity, ease of use. Because this was the Pro computer scientist, if you're a computer scientist then this is like building this and building games and doing data analysis, in a non computer science stuff. That's why, if you look at computer science curriculums, they're all up here. Eventually, like I said, someday I want to teach a C class, because I think that even if you're not a computer scientist, I think there's a lot to learn, to go back to the origins. I even [inaudible]. What I'd like to do is teach this class, this class. I don't think I'm ever going to teach a Perl class. I will teach both of these classes because I want to see a real scene of even if you're not a computer scientist, I want to see the whole history of how your language came to be. With that, up next we're going to talk about PHP.
