Comment by colin_mccabe | Hacker News Reader

Comment by colin_mccabe | Hacker News Reader

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I agree that the Java compiler itself runs fast, but many of the surrounding tools in the Java ecosystem are not fast. For example, Maven takes several minutes to rebuild Hadoop. Based on my experiences, neither Gradle nor ant are that much fast than Maven (although they are a bit faster.)

I disagree that "most compiled languages... are fast to compile." Scala is relatively slow to compile (I've seen Spark take over an hour to build). OCaml and SML are none too speedy to compile. Rust's compiler is rather slow (they're going to focus on speeding it up, I have heard.) It seems like most compiled languages that people actually use are slow to compile.

Go is a big exception due to its conscious decision to focus on fast compile times. This choice wasn't free-- it involved carefully considering tradeoffs. For example, Go compiles source code files unit-by-unit, forgoing global optimizations in the name of time. The grammar of the language is simpler, in order to enable more efficient parsing. Features like operator overloading are not present. It is trivial to tell what is a function call what is not-- there is no "syntactic sugar" like Ruby's function calls without parens.

Hadoop is 2 million lines of code. Yes, that's going to take a few minutes to compile no matter what language it's written in (if it has a compile stage at all).

By "most compiled languages" I guess I was thinking of the most popular ones, not literally all compiled languages. Sloppy phrasing, sorry. The top compiled languages according to TIOBE are Java, C, C++, C# (actually these are the top languages in general). Then they're all scripting languages until position 11 which is Delphi. So those are the top 5 and except for C/C++ they compile fast.

OCaml, SML, Haskell, Rust etc are all rather rare languages.

I don't agree that 2 million lines of code is "going to take a few minutes to compile no matter what [compiled] language it's written in." Based on my experiences with Go so far, I believe Go could get that significantly faster, probably under a minute. Also, the "several minutes" number I quoted is also for incremental compiles where only one very small thing has changed, not just for full compiles, which take even longer.

TIOBE is a poor measure of programming language popularity for a lot of reasons. But even if we accept that Java, C, C++, and C# are the top languages, I already commented that Java's build is not that fast in the real world (except for very small projects). I don't have any first-hand experience with C#, but I've never heard anyone claim fast compilation is an advantage of that language. C and C++ are slow builders, as we already know. So the top compiled languages are rather slow compilers, which is one reason why scripting languages (I assume you mean non-ahead-of-time-compiled-languages) became popular in the 2000s. This is one part of what Rob Pike was talking about when he said "poorly designed static type systems drive people to dynamic typing."

I would be skeptical of that, but I wasn't able to find LOC/sec stats for the Go compiler(s) anywhere. If you can point me to LOC/sec performance figures, that'd be interesting.

Gradle/Maven don't do incremental compilation at the level of the file, so yes, they're gonna redo the whole thing each time. Use an IDE for that. IntelliJ will happily do incremental compilation in Java projects at the level of the individual file (and there's no relinking overhead).

I understand that you're saying the top languages are slow builders, but it's just not the case. It sounds like you've used tools which simply aren't optimised for build times and judging the language based on that. But I usually have roundtrip times between editing my code and running the recompiled program of about a second when working with Java.

I have used both Eclipse and Intellij for building Hadoop, and neither could get incremental compilation under 30 seconds. In fact, it was often much more than that. Eclipse was a huge pain to use with Hadoop because it was always getting something wrong-- many times when you updated the project dependencies, Eclipse would essentially break and need manual fixing. Even loading up the project in either IDE takes at least a solid minute, with an SSD, Intel i7, and 16 GB of RAM.

Prior to using Java, I used C++ for 10 years. Every project I worked on had compile time problems. It was an open secret that we spent most of our time waiting for compiles.

It's very common for people working on small projects to feel good about their compile times. But sometimes projects grow up, and they outgrow the language and the tools they were designed in.

> TIOBE is a poor measure of programming language popularity for a lot of reasons.

And yet, it is completely consistent with pretty much all other measurements of programming language popularity (github, job postings, StackOverflow answers, etc...).

So maybe it's not that poor a measure after all.

According to TIOBE, Groovy rose from 0.33% to 1.8% in the last two months, and from 0.11% to 1.8% in the last 12 months. Click on "Groovy" from the main page and you'll get the graph at http://www.tiobe.com/tiobe_index?page=Groovy . Now say "maybe TIOBE's not that poor a measure of programming language popularity" with a straight face. These stats are gamed by language backers to make their language look good when selling consulting services and tickets to conferences, convincing programmers to contribute free work to their product, etc.

TIL that there are still people who believe that parsing has any impact on compilation speed.

Do you know Walter Bright?

The guy that created the first C++ native compiler and one of the D authors?

http://www.drdobbs.com/cpp/c-compilation-speed/228701711

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