A conditional is an if-then-else construct. We take these for granted now, but Fortran I didn't have them. It had only a conditional goto closely based on the underlying machine instruction. In Lisp, functions are a data type just like integers or strings. They have a literal representation, can be stored in variables, can be passed as arguments, and. Lisp was the first programming language to support. In Lisp, all variables are effectively pointers.
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In some ways it was less powerful than more recent assembly languages; there were no subroutines, for example, only branches. Present-day fortran is now arguably closer to lisp than to fortran. Lisp and Fortran were the trunks of two separate evolutionary trees, one rooted in math and one rooted in machine architecture. These two trees have been converging ever since. Lisp started out powerful, and over the next twenty years got fast. So-called mainstream languages started out fast, and over the next forty years gradually got more powerful, until now the most advanced of them are fairly online close to lisp. Close, but they are still missing a few things. What Made lisp Different When it was first developed, lisp embodied nine new ideas. Some of these appeal we now take for granted, others are only seen in more advanced languages, and two are still unique to lisp. The nine ideas are, in order of their adoption by the mainstream, conditionals.
So the short explanation of why this 1950s language is not obsolete is that it was not technology but math, and math doesn't get stale. The right thing to compare lisp to is not 1950s hardware, but, say, the quicksort algorithm, which was discovered in 1960 and is still the fastest general-purpose sort. There is one other language still surviving from the 1950s, fortran, and it represents the opposite approach to language design. Lisp was a piece of theory that unexpectedly got turned into a programming language. Fortran fuller was developed intentionally as a programming language, but what we would now consider a very low-level one. Fortran i, the language that was developed in 1956, was a very different animal from present-day fortran. Fortran I was pretty much assembly language with math.
This was the lisp function eval., which computes the value of a lisp expression. Writing eval required inventing a notation representing Lisp functions as Lisp data, and such a notation was devised for the purposes of the paper with no thought that it would be used to express Lisp programs in practice. What happened next barbing was that, some time in late 1958, Steve russell, one of McCarthy's grad students, looked at this definition of eval and realized that if he translated it into machine language, the result would be a lisp interpreter. This was a big surprise at the time. Here is what McCarthy said about it later in an interview: Steve russell said, look, why don't I program this eval., and I said to him, ho, ho, you're confusing theory with practice, this eval is intended for reading, not for computing. But he went ahead and did. That is, he compiled the eval in my paper into ibm 704 machine code, fixing bugs, and then advertised this as a lisp interpreter, which it certainly was. So at that point Lisp had essentially long the form that it has today. Suddenly, in a matter of weeks I think, mcCarthy found his theoretical exercise transformed into an actual programming language- and a more powerful one than he had intended.
I mean, in 1958, computers were refrigerator-sized behemoths with the processing power of a wristwatch. How could any technology that old even be relevant, let alone superior to the latest developments? I'll tell you how. It's because lisp was not really designed to be a programming language, at least not in the sense we mean today. What we mean by a programming language is something we use to tell a computer what. McCarthy did eventually intend to develop a programming language in this sense, but the lisp that we actually ended up with was based on something separate that he did as a theoretical exercise - an effort to define a more convenient alternative to the turing. As McCarthy said later, Another way to show that Lisp was neater than Turing machines was to write a universal Lisp function and show that it is briefer and more comprehensible than the description of a universal Turing machine.
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Within the hacker subculture, there is another language called Perl that is considered a lot cooler than java. Slashdot, for example, is generated by perl. I don't think you would find those guys using java server Pages. But there is another, newer language, called Python, whose users tend sports to look down on Perl, and more waiting in the wings. If you look at these languages in order, java, perl, python, you notice an interesting pattern. At least, you notice this pattern if you are a lisp put hacker.
Each one is progressively more like lisp. Python copies even features that many lisp hackers consider to be mistakes. You could translate simple lisp programs into python line for line. It's 2002, and programming languages have almost caught up with 1958. Catching Up with Math What I mean is that Lisp was first discovered by john McCarthy in 1958, and popular programming languages are only now catching up with the ideas he developed then. Now, how could that be true? Isn't computer technology something that changes very rapidly?
If the pointy-haired boss had to think about the problem in its full complexity, it would make his brain explode. As long as he considers all languages equivalent, all he has to do is choose the one that seems to have the most momentum, and since that is more a question of fashion than technology, even he can probably get the right answer. But if languages vary, he suddenly has to solve two simultaneous equations, trying to find an optimal balance between two things he knows nothing about: the relative suitability of the twenty or so leading languages for the problem he needs to solve, and the odds. If that's what's on the other side of the door, it is no surprise that the pointy-haired boss doesn't want to open. The disadvantage of believing that all programming languages are equivalent is that it's not true.
But the advantage is that it makes your life a lot simpler. And I think that's the main reason the idea is so widespread. It is a comfortable idea. We know that java must be pretty good, because it is the cool, new programming language. If you look at the world of programming languages from a distance, it looks like java is the latest thing. (From far enough away, all you can see is the large, flashing billboard paid for by sun.) But if you look at this world up close, you find that there are degrees of coolness.
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James Gosling, or the pointy-haired boss? Not surprisingly, gosling is right. Some languages margaret are better, for certain problems, than others. And you know, that raises some interesting questions. Java was designed to be better, for certain problems, than. When is java better and when is C? Are there situations where other languages are better than either of them? Once you start considering this question, you have opened a real can of worms.business
But all languages are not equivalent, and I think i can prove this to you without even getting into the differences between them. If you asked the pointy-haired boss in 1992 what language software should be written in, he would have answered with as little hesitation as he does today. Software should be written. But if languages are all equivalent, why should the pointy-haired boss's opinion ever change? In fact, why should the developers of java have even bothered to create a new language? Presumably, biography if you create a new language, it's because you think it's better in some way than what people already had. And in fact, gosling makes it clear in the first java white paper that java was designed to fix some problems with. So there you have it: languages are not all equivalent. If you follow the trail through the pointy-haired boss's brain to java and then back through java's history to its origins, you end up holding an idea that contradicts the assumption you started with.
that also means there will always be lots of java programmers, so if the programmers working for me now quit, as programmers working for me mysteriously always do, i can easily replace them. Well, this doesn't sound that unreasonable. But it's all based on one unspoken assumption, and that assumption turns out to be false. The pointy-haired boss believes that all programming languages are pretty much equivalent. If that were true, he would be right on target. If languages are all equivalent, sure, use whatever language everyone else is using.
In the software business daddy there is an ongoing struggle between the pointy-headed academics, and another equally formidable force, the pointy-haired bosses. Everyone knows who the pointy-haired boss is, right? I think most people in the technology world not only recognize this cartoon character, but know the actual person in their company that he is modelled upon. The pointy-haired boss miraculously combines two qualities that are common by themselves, but rarely seen together: (a) he knows nothing whatsoever about technology, and (b) he has very strong opinions about. Suppose, for example, you need to write a piece of software. The pointy-haired boss has no idea how this software has to work, and can't tell one programming language from another, and yet he knows what language you should write. He thinks you should write it in java. Why does he think this? Let's take a look inside the brain of the pointy-haired boss.
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Unfortunately, our website is currently unavailable in most European countries. We are engaged on the issue and committed to shredder looking at options that support our full range of digital offerings to the eu market. We continue to identify technical compliance solutions that will provide all readers with our award-winning journalism. Want to start a startup? Get funded by, y combinator. May 2002 "We were after the c programmers. We managed to drag a lot of them about halfway to lisp." - guy steele, co-author of the java spec.