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Diffstat (limited to 'book/src/main/scalatex/book/Intro.scalatex')
| -rw-r--r-- | book/src/main/scalatex/book/Intro.scalatex | 44 |
1 files changed, 22 insertions, 22 deletions
diff --git a/book/src/main/scalatex/book/Intro.scalatex b/book/src/main/scalatex/book/Intro.scalatex index dbe1960..f9e0761 100644 --- a/book/src/main/scalatex/book/Intro.scalatex +++ b/book/src/main/scalatex/book/Intro.scalatex @@ -23,19 +23,19 @@ }); @p - As you can see, both of the above programs do identical things: it's just that the one on the left is written in Scala and the one on the right is in Javascript. + As you can see, both of the above programs do identical things: it's just that the one on the left is written in Scala and the one on the right is in Javascript. @p Traditionally, Scala has been a language which runs on the JVM. This eliminates it from consideration in many cases, e.g. when you need to build interactive web apps, you need to fall back to Javascript to run your client-side code, at a great loss in terms of toolability and maintainability. Scala.js lets you to develop web applications with the safety and toolability that comes with a statically typed language: @ul - @li + @li Typo-safety due to its compiler which catches many silly errors before the code is run - @li + @li In-editor support for autocomplete, error-highlghting, refactors, and intelligent navigation - @li + @li Very small compiled executables, in the 100-400kb range - @li + @li Source-maps for ease of debugging @p @@ -43,7 +43,7 @@ @sect{About Javascript} @p - Javascript is the language supported by web browsers, and is the only language available if you wish to write interactive web applications. As more and more activity moves online, the importance of web apps will only increase over time. + Javascript is the language supported by web browsers, and is the only language available if you wish to write interactive web applications. As more and more activity moves online, the importance of web apps will only increase over time. @sect{Javascript-the-language} @p @@ -58,11 +58,11 @@ However, even as Javascript-the-language sucks, Javascript-the-platform has some very nice properties that make it a good target for application developers: @ul - @li + @li Zero-install distribution: just go to a URL and have the application downloaded and ready to use. - @li + @li Hyperlinks: being able to link to a particular page or item within a web app is a feature other platforms lack, and makes it much easier to cross-reference between different systems - @li + @li Sandboxed security: before the advent of mobile apps, web apps were the most secure runtime available, offering none of the risk or worry that comes with installing desktop software @p @@ -71,7 +71,7 @@ @hr @p - This is where Scala.js comes in. As developers we want Javascript-the-platform, with its ease-of-distribution, hyperlinks and security characteristics. We do not want Javascript-the-language, with its propensity for bugs, verbosity, and fragility. + This is where Scala.js comes in. As developers we want Javascript-the-platform, with its ease-of-distribution, hyperlinks and security characteristics. We do not want Javascript-the-language, with its propensity for bugs, verbosity, and fragility. @sect{The Promise} @@ -91,7 +91,7 @@ At a first approximation, Scala.js provides you a sane language to do development in the web browser. Not only do you have an expressive language with static types, you also have great tooling with IDEs like IntelliJ and Eclipse, a rich library of standard collections, and many other modern conveniences that we take for granted but are curiously missing when working in the wild west of web development: the browser! @p - While not useful for small applications, where most of the logic is gluing together external APIs, this comes in very useful in large applications where a lot of the complexity and room-for-error is entirely internal. With larger apps, you can no longer blame browser vendors for confusing APIs that make your code terrible: these confusing APIs only lurk in the peripherals around a larger, complex application. One thing you learn working in large-ish web client-side code-bases is that the bulk of the confusion and complexity is no-one's fault but your own, as a team. + While not useful for small applications, where most of the logic is gluing together external APIs, this comes in very useful in large applications where a lot of the complexity and room-for-error is entirely internal. With larger apps, you can no longer blame browser vendors for confusing APIs that make your code terrible: these confusing APIs only lurk in the peripherals around a larger, complex application. One thing you learn working in large-ish web client-side code-bases is that the bulk of the confusion and complexity is no-one's fault but your own, as a team. @p At this point, all of Google, Facebook, and Microsoft have all announced work on a typed variant of Javascript. These are not academic exercises: Dart/AtScript/Flow/Typescript are all problems that solve a real need, that these large companies have all faced once they've grown beyond a certain size. Clearly, Javascript isn't cutting it anymore, and the convenience and "native-ness" of the language is more than made up for in the constant barrage of self-inflicted problems. Scala.js takes this idea and runs with it! @@ -128,12 +128,12 @@ @sect{Client-Server Integration} @p - There is an endless supply of new platforms which have promised to change-the-way-we-do-web-development-forever. From old-timers like @a("Ur-Web", href:="http://www.impredicative.com/ur/"), to @a("GWT", href:="http://www.gwtproject.org/"), to Asana's @a("LunaScript", href:="https://asana.com/luna"), to more recently things like @a("Meteor.js", href:="https://www.meteor.com/"). + There is an endless supply of new platforms which have promised to change-the-way-we-do-web-development-forever. From old-timers like @a("Ur-Web", href:="http://www.impredicative.com/ur/"), to @a("GWT", href:="http://www.gwtproject.org/"), to Asana's @a("LunaScript", href:="https://asana.com/luna"), to more recently things like @a("Meteor.js", href:="https://www.meteor.com/"). @p - One common theme in all these platforms is that their main selling point is their tight, seamless client-server integration, to the point where you can just make method calls across the client-server boundary and the platform/language/compiler figures out what to do. + One common theme in all these platforms is that their main selling point is their tight, seamless client-server integration, to the point where you can just make method calls across the client-server boundary and the platform/language/compiler figures out what to do. @p With Scala.js and Scala-JVM, such conveniences like making method calls across the client-server boundary is the boring reality. Not only are the calls transparent, they are also statically checked, so any mistake in the route name or the parameters it expects, or the result type it returns to you, will be caught by the compiler long before even manual testing. - + @hr @p @@ -152,27 +152,27 @@ A whirlwind tour of the various things that Scala.js can be used for. We will cover: @ul - @li + @li Your first Scala.js application: setting up your development environment, cloning the example repository, debugging and finally publishing your first toy application - @li + @li An interactive web app using Scala.js: how you interact with the HTML DOM, how you utilize Ajax calls and other browser APIs that are common in Javascript-heavy applications - @li + @li A Scala.js library: how to write a module that can be depended on by applications both your own and by others, and be used both with Scala.js and Scala-on-the-JVM - @li + @li Client-Server integration: We will build a simple web application with a Scala server and Scala.js client. In the process, we'll explore how to share code between client and server, how to get compiler-checked/boilerplate-free Ajax calls between client and server, and many other long-standing holy-grails of web development - - @p + + @p After going through this chapter and following along with the exercises, you should have a good sense of how Scala.js works and how it feels building things in Scala.js. You would not be an expert, but you'll know where to get started if you decide to try out Scala.js for your next project. @sect{Part 2: In Depth} @p This section of the book will cover lots of content that does not fit in the earlier Hands-On portion of the book. Things that aren't immediately necessary to get something up and running, things that only advanced users would care about, things that you probably don't need to know but you'd like to know out of intellectual curiosity. - @p + @p In general, this section of the book will go much deeper into Scala.js, much more than is necessary to get your first applications built. We will talk about the small number of semantic differences between Scala.js and Scala, details of the foreign-function-interface with Javascript, the various optimization levels and what they do. Nothing pressing or urgently needed, but all very interesting, and worth reading if you want to really understand Scala.js in depth. @hr - + @p As mentioned earlier, these chapters can be read in any order. In keeping with the spirit of the book, we'll jump right into the Hands On to give you the experience, and save the talking and philosophizing for later. Let's go! |