The Post JavaScript Apocalypse - Douglas Crockford

welcome to bakka lips so what are some ideas about what should be in the next language the language that replaces JavaScript being an optimist I believe there's got to be a next language it doesn't stop here so just be sad for our children right we need to figure out of so the title of this talk is actually quite controversial there is some experts who who say that it should be we put JavaScript apocalypse and others who say now now it's the patched JavaScript apocalypse in this confusion post put in patch is due to HTTP the hypertext transport protocol it contains three commands for moving some information from one machine to another and they are almost identical but there are concerns that in some cases it makes a tremendous difference which one you use that disaster could occur if you're using the wrong one but it's not clear from looking at the names which one that should be and in what situations so I see this as a problem I think in a well-designed system it should be obvious what the correct thing to do is and you shouldn't have to struggle with these sorts of confusing things so I look on this as a source of clutter and clutter messes things up and actually makes things worse for us we spend our lives accumulating stuff it's been said that the the one who dies with the most tool most toys wins and silly-- accumulate all this stuff and we think the stuff that we have has value we think of it in terms of its cost of acquisition or maybe its cost of replacement but actually the more stuff you have the more likely that the stuff is going to have negative value to you that it's getting in the way it's actually degrading the quality of your life in some cases you're looking for something that you know lives in your stuff and you cannot find it because there's all this other stuff in the way so that that extra stuff is reducing the value of the valuable stuff to zero while adding no value of its own in some cases some of your stuff literally destroying other stuff you might have a pile of stuff and it's the weight is destroying the stuff that's on the bottom or maybe the stuff on the top is leaking down into the bottom and it's making stuff worse so there's this idea that you can improve the quality of your life by getting rid of some of your stuff you identify the stuff that you don't need and then you put it on eBay or you sell it recycle it or if it's worthless you can get rid of it if it's worthless plighted nevermind anyway thinking about clutter it's a difficult thing to deal with so I look to an authority this is Kumari or Marie Kondo brilliant Japanese woman maybe the world's biggest authority on organization she teaches people how to organize their homes and places so that they can enjoy them better and she teaches how to store and organize and fold and get rid of stuff so one of the things she teaches is you go into a room and you take everything in the room have the drawers off the shelves and put it in the middle of the floor and then you pick up each item and you ask a question of each item you say to chemical deskah which means you throb do you vibrate and if the thing speaks to you then you keep it there's some emotional connection with that thing that this is something you keep and if it doesn't then you think about getting rid of it now when she teaches in English she doesn't say throb or vibrate because it makes some people giggle like that guy oh so instead she says does it spark joy which is just delightful so you pick up the thing you ask it does this spark joy and if it does then you definitely keep it if not you should consider getting rid of it so I would like to apply her methodology to our programming systems to our you know particularly to our programming languages but spark joy doesn't work for us because everything sparks joy we love all the clutter in our languages and we we can't get rid of it and so sparking joy is not a sufficient criteria to get rid of the clutter in programming much as we need to so I want to show you some examples of clutter things that we've lived with for a long time perhaps so long that we can't even recognize that they're cluttered and look at what we might do to clean them up I'm going to start with ASCII the American Standard Code for information interchange ASCII is a really important code it was for a long time the standard character set the United States it is still the first hundred twenty-eight characters of the Unicode set so ASCII is still in use everywhere in the world it contains two characters which are problematic and they were both borrowed from typewriters space is from the space bar it's a thing that allows the carriage on the typewriter to move forward one character space and the other is cab tab was short for tabulator or cab ulation it was a key that when you pressed it would release the carriage allowing it to move freely until it hit a mechanical obstruction called a tab stop and the purpose of tab was to make it easier to type in columns of numbers so we have both of these characters and they can both be used in the preparation of computer programs and it's not obvious which is better than the other and so we use from both which is itself a problem because there's some coding standards which are hostile to one another it makes interoperability more difficult sometimes makes formatting more difficult but more than that it's just a colossal waste of time that this argument about tabs versus spaces just goes on and there's no end because it doesn't appear that anybody is right so there's a brilliant show on HBO called Silicon Valley anybody seen Silicon Valley it's the best show ever made about programming you should all go out and buy HBO because HBO deserves to be compensated for making such a good show about what we do no one else has done that so you know you also get if you buy Silicon Valley you also get Game of Thrones and Westworld and stuff like that but this is the show you want this is the good stuff so it's about Richard Hendricks who is a brilliant programmer and his adventure is in trying to start a software company in California he's a brilliant guy he works really hard he's spending so much time trying to start his companies that he doesn't have time to find a girlfriend you might know the type or he might be the type anyway in season 3 he finally finds someone and she's perfect for him she's nice she's smart she's a programmer she seems to like him for some reason but she uses spaces instead of cans and it makes him crazy and it turns out his affection for an invisible control character is greater than anything he could feel for another human being and so he ends up destroying their relationship because he uses cows he just so you know all the human misery that's caused by this conflict tab spaces what to do so this is clutter right with two ways of doing things I want to get uncluttered I want to do it one way so I'm going to get rid of one just so that we stop all the waste and all the confusion all the craziness which one do you get rid of there's only one that I can get rid of I need the space space is an essential thing it does things besides put things into columns so I've got to get rid of tab I don't need tab and I know that's going to make some of you cry but that's just how it is turns out tab does not spark joy so now we know [Laughter] so ASCII also provided two characters for quoting things the single quote and the double quote and JavaScript employs both so in JavaScript you can make a string with double quotes or a single quotes when they work exactly the same way they just look different and for a long time I tried to figure out how to make sense out of that that you know for some purposes I want to use a single quote for other purposes I want to use the double quote and I thought it made sense but I saw other people who had different conventions which also made equally as much sense than they were incompatible and like there's no way to resolve this so ultimately I think we have to get rid of one and the one that makes sense to get rid of is the single quote and that's because it's also hope well no it's because it's overloaded as the apostrophe and so there are you're more likely to make mistakes using single quote than double quote and I really down on the stakes I'm trying to figure out how to be error-free as much as possible so single quote does not spark joy one of the the most important things that ASCII did was come up with the way that we encode uppercase and lowercase the original plan for ASCII was it was going to be a six bit character set that would give you 64 codes which isn't very much and in order to support lowercase they're going to add two control characters for doing shifting so you could shift one way and you get lowercase characters and shift the other way and get uppercase characters if they'd followed through on this then everything would be just a you know we teach our kids that's an A and there are two ways a can look but they're both a and that's how it works so we would distinguish uppercase and lowercase the same way we distinguish bold and weight or italics or underlining or color or thing else but we didn't do that and the reason we didn't was at that time they were shipping these character codes over teletype lines and those lines were very noisy and so it was not uncommon for a character to get a bit or more damaged and it would arrive garbled and their concern was that if a shift character gets garbled then the rest of the message is going to look stupid you know it turns into shouting and stuff and we didn't want to do that so to avoid that particular error they decided to increase the size of ASCII to seven bits I gave mine to 28 characters and then it became possible to give each of the lowercase characters a unique code and in doing so they invented case sensitivity which had never existed prior to that and the concept and that is a source of bugs for us today you know some things want to be case sensitive because it's faster and some things want to be case insensitive because it's correct and boom you know so that happened I can't fix that's too late for that one JavaScript gives us let and far at least sense key at six they both do the same thing they both declare a variable in a function which you definitely want to be doing but it's confusing having two of them and I've seen people argue well you should use var in this case and let in that case you don't want to be doing that it's just confusing so we want to be using just one of them and I think the one we want to be using is let and the reason I prefer let is the Java guys don't get as confused if you're using let because let respects block scope we don't need block scope but the Java guys don't understand function scope and so we should do that now the problem with this recommendation is it does not work for ie because an IE let doesn't exist so it's a syntax error so my advice is stop ie write no more ie even Microsoft doesn't let any more they want us to move the edge I think they're exactly right let's stop doing that yet six also introduced Const which is like Colette except you cannot modify that variable anymore or you can't replace that variable with another value which is a good thing so generally when given a choice I would prefer to use Const than let JavaScript gives us to bottom values null and undefined there's an argument in the language design community share the language even have bottom values but there's nobody who thinks you should have two of them and you know due to some accident javascript has two of them and they are not interchangeable for many purposes they work the same but there are some specific cases where they're not and when you have things which look to be the same but aren't actually the same for no good reason that creates confusion and bugs and that's bad so I want to get rid of one of them and usually when I have a choice between two words I want to go with the shorter one but not this time this time I'm going with undefined and getting read null for one thing null has the the type of problem type of null is not null it's object which is horribly wrong and if you never use null then you don't care so that I can stay broken and nothing breaks undefined as a is not a good word it's really confusing but you know we're kind of stuck with that now the idea of null as a special kind of pointer as a standard feature of programming languages is due to Tony Hoare there's a brilliant British programmer everybody know yeah and they should teach history here the important stuff anyway he came up with that idea and he now regrets it he calls it a billion dollar mistake I don't know why he didn't call it a billion pound mistake but the color billion dollar mistake and he came up with that figure by estimating the accumulated cost of all of the nullpointerexception said he cause so you know it shouldn't be a special kind of pointer that fails it should have been something else what I think it should have done is in a mutable empty object in the sense of a JavaScript object where it's a thing and you can't store anything into it if you try to store anything into it that'll throw an exception and if you try to extract anything from it you'll just get it all again which would be fine and it could be implemented in a JavaScript like language very simply we just create a constant which contains a frozen the empty object that doesn't inherit anything so in fact for some purposes instead of using undefined you might actually want to create your own thing give it another similar confusing name like maybe nil and non or something like that or even empty and do that with it now functional programming is becoming really really important now finally after well we started doing functional programming in the very late 40s early 50s and it's just kind of now getting to the mainstream javascript is a to senses of a functional language a functional language is a language that uses functions there are two senses of what functions mean there's functions as what we do in programming you know like a JavaScript function there's also the idea of a mathematical function and that sometimes called pure functional programming a mathematical function isn't really about computation it's about mapping a pure function will map values from one thing to another and the process of mapping doesn't allow for side-effects or any other stuff going on it's just one thing so in a mathematical function in a pure function a given input will always yield exactly the same output and they allow for no mutation no side-effects nothing else is going on just them happening every one value to another and that turns out to be a really cool thing and you get some nice benefits from that one of them is testability programs written this way become much easier to test because once you've shown that a function returns the correct value you're done nothing else can ever cause that function to now misfire or behave incorrectly so that significantly simplifies the process of testing an even better benefit is in composability that when functions are pure you can string them together and compose them in really interesting ways and that becomes a very very effective way of programming much more efficient maybe the best benefit is parallelism the problem we have with threads and in a crappy language like Java is that we're trying to do read-modify-write of shared memory and that is an inherently dangerous thing if you do it incorrectly it means you get races which are horrendously difficult bugs to find and correct the way you mitigate that is by locking which slows programs down profoundly and if you're just doing stuff with pure functions you can run full-speed that the functions never read-modify-write because we're not allowed to mutate they can't have side-effects so they just run and run and run and there's nothing to slow them down so the fastest programs that we can write are probably going to be functions that are pure which is again a really good reason for doing it so we can convert JavaScript into a pure functional programming language and the way we do that is by removing the impurities so we'll start by removing the date function because every time you get you'd call the date function you get a different value and that's not a mathematically pure function so we can get rid of that we have to get rid of the random function same reason every time you call random you get a different number that's not pure so that's got to go we have to take out the delete operator because it can modify an object we have to take out object type to assign and similar functions because they will attempt to modify an object we can't allow for modification array dot splice and and all the other array methods we have to take those out as well we can keep slice because it makes a copy of an array so that one's good but the ones that modify an array we have to get rid of array dot sorts could have been a pure function but it was implemented incorrectly and it is not so sadly we have to get rid of that one the regular expression exec function wants to modify the regular expression object so sadly that's got to go assignment right equals something that goes the VAR statement if you don't if you don't have a sign materials we have to get rid of that as well but we can keep Const console has a role so we could call a function and put its return value in a Const and then we could use about value in multiple places in the remainder of the function that's that's cool that's pure we can do that for statement that wants to modify an induction variable we can't be modifying so for us got to go it's not probably loops in general probably going to go users turns out every time the user does something it could be different users are surprisingly non-mathematical so you're going to have to go and the network yeah and every time you get something from the network you could get something else so that's not pure so networks got to go so a pure functional programming model doesn't make any sense because the universe is mutating and unless no programs can deal with the mutation of the universe they're limited in how useful they can be but purity is still really valuable and so we need to figure out the models which allow us to be as pure as we can while still permitting enough impurity to actually allow us to get work done one of the new features in es6 is generators something that I think shouldn't have happened just because it's unnecessary a generator is a function which every time you call it will return a new value so generators are not pure but they're still very useful and it turns out using higher-order functions you can get generators without the weird special syntax with the yield and the asterisk so this if you need generators this is how I think you should make them so we've got a factory function which is the thing that makes generators and it can take arguments and the variables of the factory function become the state variables of the generator and the factory returns a function which is the generator function and each time it's called it will compute a new value and update the state variables that are in the closure of the outer function and return the value this is a really straightforward pattern it's really easy to write so here's a an example this is the element generator which will receive an array and return a generator which will return each individual element of that array really straightforward I like this better than the equivalent thing you would get by using the function star syntax callbacks are really important mechanism for dealing with a synchronicity and and other patterns and there's a question or callbacks are also used in continuation passing style it's a really powerful way of expressing programs and so it means that a function not only gets its normal arguments it also gets a special argument which is the function to call with result and there are two places where you could put it you could make it the first parameter or you could make it the last parameter and up until now it's been up to you you want to put it in the first position you want to put in the last position and since you have a choice we will apparently at random choose one and then we will argue about it and that makes it a Ralph's ability much harder because if I'm putting them first and you're putting them last my code has to work together it's just annoying so it'd be good if we could figure out what the right answer is and it turns out es6 tells us what the right answer is that they want to be first the reason they want to be first is we now have the ellipsis operator which is my second most favorite feature in es6 which says take all the rest of the arguments and make an array and stick them in there and pass that as the last argument and that only works in the last position which means if we want to call back the call back really needs to be in the first position so those of you are putting in the last yeah it got some work to do promises were added in es6 because yes because w3c was was threatening to standardize them and echo said you can't do that you can screw it all up so basically Ekman took w3w three C's spec and published it like which didn't really prevent anything from getting screwed up so we got that the original purpose of promises was not to provide for a synchronicity but that's the major function for it now and I don't think they do all that good a job they've actually do work and they're much better than doing nested callbacks but I think we could do better for example I developed a library called our queue which is sort of a cryptic name I kind of regret that now but I was feeling very terse the day I named it which provides for a much nicer composable way of dealing with a synchronicity particularly for the kinds of things you would do in a server where I want to do these things as a sequence or I want to do these things in parallel and I want them to all compose together and be good in an asynchronous way our queue does that so we get really emotional about our syntax we love the syntax and it turns out syntax really doesn't matter but we don't know that we love it and it syntax has more to do with fashion than with functionality and so I want to look at a few examples of syntax through the ages so we'll start with Fortran Fortran 4 was my first language and this is how we wrote in its statement in Fortran in Fortran well lowercase hadn't been discovered yet when when Fortran was made so everything was all in uppercase in Fortran spaces were not significant so that if you said if space a that looks exactly the same to the compiler as Aoife and so when they design the if statement they came up with the idea of using the parentheses to separate the keyword from the condition because spaces couldn't do that in Fortran and similarly they used the closing parent to separate the end of the condition from the consequence BCPL was one of the first good parts languages it was modeled after an earlier language called Cpl which I think was designed not too far from here and it's the first curly-brace language really nice-looking language and I think they got it basically right so in BCPL the parentheses around the condition were optional and the curly braces around the consequence were required which is really really smart unfortunately when the B language and then C and then Java and JavaScript in all of those languages they got it wrong again they went back to the fortunate convention so they required the parentheses around the condition which really doesn't accomplish anything and they allowed for leaving the curly braces off of the consequence which turns out to be a problem that it's really easy to write an if statement which appears to control several statements but it only controls the first very common source of errors and because of that I recommend always put the curly braces in every time on every if and every else always put the curly braces in because it increases the likelihood that somebody including future you can improve that program without breaking it l golf 60 was a brilliant language designed by committee it's very rare for a good language to be designed by a committee and that was the one example and they did such a brilliant job they decided let's do it again so they convened a second committee and they developed Algol 68 which unfortunately was a mess and very cluttered and didn't get well adopted but I really liked their if statement I think Dijkstra suggested the syntax and I think it's just lovely so instead of having the curly braces or blocks or anything like that be just have a five statement which balances the if and the nice thing about this is that when you look at a program you've got lots of curly braces and the curly braces represent the end of blocks the end of functions the end of object literals and sometimes it's hard to know when you look at a curly brace who are you closing and a lot of what we're closing is ifs and if the if is using a different convention that it's much easier to read the program it's much clearer what's being delimited and it's easier to write programs that are correct which is really nice I think we can improve a little bit on this one so this is my suggestion for if there any language designers in the house I would like to see this in the next language so I think Python had the right idea about respecting line breaks now where a line break is significant it's probably significant to us as well as to the compiler so let's just hard code that into the language it's not being the case I don't need for them so we can take that out and there's a lovely little language called rebel which uses Coulomb as its assignment operator which i think is just so nice so I would shorten it a little bit more I don't think I'd want to go much farther than that because you know if you get too cryptic then you start to be APL and we don't want to go there but I like the idea of trying to be as minimal as we can on our syntax without losing clarity and I think this might be a way to go so talking about not Cleary so we've got the try statement exception handling is an important idea because we don't want to have after every function called to query the result and ask did you fail or not because that really slows things down so the idea was we'll have exception handling so that we don't have to do that testing so this is the the way you would write a try-catch statement in java or some other crappy language now they look like this it's big there's a lot of stuff in it so the interesting that is the code that might fail that's the stuff that we're trying to protect that we don't want to have to query everything that happens within that block and then there's everything else so the finally bit is there because Java did not have functions and basically what finally wants to do is do this stuff no matter how we exit from the try and the way that java virtual machine implements finally is with a subroutine call there's a subroutine call in return which is in the language specifically for try catch or for finally and they did it that way because they didn't have functions which would have been the correct way to do it and so since we have functions in JavaScript we don't need finally so I think I see finally it's just big noise then we've got all of these catch clauses so what's going on there the catch clauses are all there because of a failure in the type system so often a particular function or method might have multiple kinds of things that might happen there's one that is most likely to happen but there's another thing which is expected to happen sometimes you know like maybe it get to the end of something and that's going to be a different kind of response but that's not the same as failure which is what exceptions were intended to catch and so because the type system doesn't allow a single method to return things with multiple types it will instead use the catch clause as an alternate control flow in order to sneak stuff through so it's a misuse of the exception system again motivated by problems in the type system and so basically what you get is code that looks like the Fortran assigned goto which is quite an awful thing where some other piece of code will determine what our path is going to be through this stuff which is quite awful now JavaScript because it has a superior type system basically it doesn't care I'll allow you to send whatever you need back and see you don't need to overload the exception system to handle your current result so in JavaScript it gets much easier so basically you try plan a and if that works you're great and if it doesn't then you'll go to plan B you don't even care why it failed it shouldn't matter why it failed you just know it didn't work so let's do the other thing and so that's much better so that was an example of how having a loose type system allows you to write better code another example of Java's dilemma with with types is in the index of operator or index of method so it wants to return the character position at which we find a particular substrate but there's a chance that it might not find it and so what they should have returned would have been null or something which indicates whatever we want returned we got this instead but they couldn't because ball is not compatible with int so instead they came up with minus one and the expectation is you have to remember that minus one is this weird thing the problem is that for some of the string methods - one is meaningful like on slice it means the last character of the string and so you can get into trouble if you're not aware of this weird stuff it's going to happen so let's talk about some more about types and hints so what is the type of the result of adding 2 into 32 together anybody know in truth what is the true answer of the well I didn't think I would stump everybody but the answer is int 33 33 because the result of adding two 32-bit ends together is you could get one that's one bit more Java and many other languages get this wrong they think it's in 32 which means that if that happens if you get an at 33 answer the most important of all of those bits gets thrown away without any notification and programs go wildly wrong so let's look at another one what is the type of into 32 times into 32 any guesses well well okay the answer is in 63 in 63 but Java thinks it's in 32 so it's wildly wrong it's going to throw away a whole lot of bits which again as a source of terrible errors so there's this idea that our type systems are helping us that they're preventing us from making mistakes but in fact we can show that the type system is causing mistakes here's a famous example and this is true of almost all of our modern languages today 0.1 plus 0.2 is not equal to 0.3 and I think this is shocking I think this is inexcusable but it gets worse than that it breaks the associativity you know so 0.1 plus 0.2 plus 0.3 is not equal to 0.1 plus 0.2 Putt plus 0.3 now it associativity works if in computer arithmetic if the if the two operands are represented exactly and if their result can be represented exactly and if not then then associativity will give you different amps will break and the problem is in these languages including Java Script 0.1 can not be represented exactly even though it has a very simple trivial decimal representation and it's because we're using binary floating-point and binary floating-point was something that made a lot of sense in the 50s but doesn't make sense anymore but we can't stop doing it so I recommend that we stop doing it and this is how I recommend that we do it this is a new number type called deck 64 it stored in a 64-bit word it contains two portions a 56 bit coefficient which is just an integer that's shifted over eight spots and an 8-bit exponent and the value of the number is the coefficient times 10 raised to the exponent this was inspired by a representation that was used in the EDSAC anybody know EDSAC nation they should teach it as more history EDSAC was one of the first on the scene it was built not far from here it was brilliant and wonderful and you should know this this is important stuff anyway I proposed modernizing that idea and bringing it back and when we do this then point one plus point two will be point three one of the nice things about this representation is that in a hardware implementation adding any two numbers with the same exponent for example integers will execute in one cycle and being able to do that means the advantage for having int goes away and so there's no reason to happen so any more that I propose that all future languages or all future application languages use only this number type that having a single number type in the system means that you cannot make a bug by choosing the wrong number type which is a good thing to have so if you're curious about it for example if you're an amateur language designer and you'd like to try it out there's a reference implementation in x64 assembly language it's on github you can go get that so let's talk some more about numbers what is 0/0 so it's actually a very complicated question there are a lot of answers to this question most mathematicians would say it's undefined and not in the crazy sense with Java scripts undefined meaning it's meaningless it doesn't make sense to talk about 0/0 it's just not possible it don't don't say that anymore just it's not a thing except in computation things will happen because someone will divide 0 by 0 anyway so the machine has to have some defined behavior so one possible answer is the machine should catch fire because it's it shouldn't happen so it shouldn't matter that the machine catches fire we know that that's actually not a good thing to do another possibility is it should be man because that's a representation of something that's meaningless although man has much more meaning than meaningless has but that's something we could say another answer is it should be zero because zero divided by anything should be zero and if that's for a lot of business applications that is the preferred answer or it could be 1 because n over N is 1 right sometimes I once programmed a mainframe where the answer was - it was exactly - it was a machine designed by Seymour Cray who's the greatest computer maker who ever lived and when you divided the 0x0 with a floating-point divide he got 2 and I'm sure somebody at control data said hey Seymour we checked this out and we get a 2 here and he said I'm not going to fix it because if I fix it it means it's going to add more circuitry to which is already a very complex circuit and I don't want to do that because it's going to make it more extensive and it's going to add one cycle to the divide time which will penalize all of the correct uses of division and I want the machine to be very fast for doing the correct things and only an idiot would try to divide 0 by 0 so I'm not going to fix it and they got away with it and as far as I know I'm the only person who ever divided 0 by 0 on that machine and I survived they didn't catch fire or anything it was good so the reason I went through that was I'm actually more concerned with this case what happens when you multiply 0 by 10 which would the answer cannot be I think the answer should be 0 regardless of the value of M and it and compiler writers used to think so too so if a compiler saw that zero is going to be one of the factors of a multiply and if the other operand is pure meaning it has no side effects we do not even need to evaluate it we don't even need to generate the code for looking at it we just return zero we're done and so the compiler goes faster and the program runs faster and everything is great that turned out to be an error when the new I Triple E floating point standard came out because it said that if n is man then the answer has to be man I think this was a mistake that it made things go slower in all cases to protect us from something that shouldn't have mattered in fact there are some programs that really want to be using zero times n in a meaningful way so who writes code like that generally not humans but code generators do and macro processors partial evaluators those sorts of programs can make very good use of zero times and also on modern CPU is one of the slowest things we can do now is a conditional jump and sometimes instead of coding a conditional jump we can encode multiply something by something that might be a 0 or a 1 and that multiplication can be significantly faster in some cases doing two multiplications in an add of either 0 or 1 or 1 and 0 that's faster than doing the conditional jump and I don't see any benefit that comes from getting an an out of that so I would propose in the next language that all of these forms return zero just because they allow us to get a little bit more performance and that we really don't benefit at all from getting them from any of these so modern languages have reserved words and the reason they have reserved words is it made it easier for compiler writers and a time when memories were very small for example a lot of the early unix work early B and C work was done on a I think as a PDP seven that had like 16 K of RAM really tiny machine and I got a compiler to run in there which is pretty amazing and one of the tricks they used in order to get that to happen was they reserved a lot of words in the language so the compiler we didn't have to figure out does this mean a variable name or does it if means something that's a statement form and we're still doing that our memories have gotten much bigger we have much better tools for writing compilers but we're still using this constraint the reason it matters is it's a hazard for programmers because it means you need to be aware of all the reserved words in the language even if you don't use those words because if you name a parameter or a variable after one of those then your program is going to fail that's a bad thing and it's bad for language maintainer z' because they want to introduce new features into the language but if there's a likelihood that anybody else has ever created a variable with that name then they're going to create failure and they're trying hard not to cause things to fail so often what they'll do is they'll come up with the with unpopular names for example when exception handling was first being proposed the way we would cause an exception to happen was through a raise command we're going to raise an exception the way might want to raise an issue or something we will raise an exception also has sort of a hardware connotation we're going to raise the exception line but they couldn't use the word raise because someone had used it to raise something to a power and that would cause breakage so they looked for a word that means something like raise that nobody was using and in desperation that came up with throw now most of you have never seen anything except throw so it probably looks natural to you now because you've never experienced anything else but it was a it was not the ideal choice so I propose that in the next language we do it better so in any function a word may be used as a language keyword or as the name of the variable or a parameter or something but not both so the programmer gets to decide so if you want a variable called if you can have a variable called if but you can't also have an if in that function so this is good for programmers because you won't trip over features you don't use if you're not aware that double for example is reserved word doesn't matter and it's good for language maintainer z' because they can introduce new features without breaking existing programs existing programs will be using the new feature already with a variable they're not going to be using the new feature nothing breaks another thing we argue about a lot is how do we represent variables or identifiers that contain more than one word and we do this a lot and we have two conventions for how you do that we've got camelcase and we've got underbar and we argue about it all the time and there is one argument that says use whichever one makes you happy which is not good because when code is written using both conventions it just looks stupid and so we don't want to do that but we can't agree on what the correct thing is and so we just argue and argue and I've heard really ridiculous arguments on both sides of it for example I've heard really smart people say camelcase is better because it weighs so much time when you have to go shift up to the underbar but which is just nuts so the reason we can't agree is because everybody is wrong the correct answer is names with spaces what's the correct way to do it and we didn't do this in the old days again because there is only a tiny amount of memory and made it harder to write the compilers but those constraints have been gone for many decades now so I think it's time to reconsider how we write our programs so I proposed this rule in the next language a name is composed of one or more text atoms which are separated by spaces and starting with an initial text atom we combine them to make the longest name that makes sense that matches something that's been defined in the scope and if a name makes sense is yeah and if it doesn't make sense then we just take the first token and then we start again on the next one really easy to implement and I think it'll give us much nicer looking programs something else I'd like to see in the next language would be programming by contract this is something that the Eiffel language did which was brilliant that you could have a function and then that function you have a little preamble or a requirements section which says these things must be true when we start this function and it could be just a series of conditions and and then at the end of the function you can also say and when we leave this function these things must also be true and you can get how these preconditions and postconditions provide very nice documentation for the thing that makes it extremely explicit what the assumptions of the function are so looking at that it's much easier to use it correctly even more important that stuff can be executed automatically so we can turn on a mode which says that stuff turns into code and so we now have diagnostic checking running in the program you know we can even leave it on in production because it's pretty fast and we get much higher reliability and it gives us much better information than types do as to what the expectations of a function are so unfortunately it fell out of fashion but it shouldn't have it's really good stuff I hope we we have that come back I hope that the next language doesn't a much better job of security because as the world is becoming more distributed and we've got programs running everywhere and more and more of the value of our lives are online it's really important that our programming languages not undermine us that they respect the importance of our relationships and help us to defend them so I don't have any specific suggestions but I think it's something we need to be concerned with and when we look at the next language we should look much harder at its security implications because in the past we have never done that and finally we should be dealing with distribution because that's how we're programming now going all the way back to Fortran we've been doing sequential programming where a program does one damn thing after another and that's not how we do stuff anymore that we now have multi cores and we expect stuff to be running concurrently in all the cores and even more than that we now have the Internet and the clouds and all of that other stuff and so a program is expected to run not just in one machine in one memory space but in n memory space with simultaneously and providing for the coordination and distribution of all that stuff that should be built into the next language because that stuff is really important mostly what we get in our language is our new syntax on the Fortran model which is nice but it's not sufficient the next language should take us much farther but there's another paradigm we need to move into and I'd like to find that in the language that replaces JavaScript so um so that's the end so just want to leave you with a warning be careful out there because the web is cluttered in full of errors thank you [Applause]

Channel: NDC Conferences

Views: 92,188

Keywords: ndc, nd london, douglas crockford, javascript, web

Id: 99Zacm7SsWQ

Length: 54min 12sec (3252 seconds)

Published: Thu Mar 16 2017

Reddit Comments

[u/tigerleapgorge]

Good talk, thank you.