Ruby language: compiled or jited?


#1

Is it true that ruby language will change to a compiled or jited
language, like .net or java?


#2

On Sat, 14 Feb 2009 20:41:52 -0500, Soh D. wrote:

Is it true that ruby language will change to a compiled or jited
language, like .net or java?

Ruby 1.9 introduced a bytecode-based interpreter (which converts your
program to its own bytecodes and then interprets those bytecodes a la
very old Java VMs). JRuby already has an interpreter which compiles to
the Java VM, and these days that is JITted, so I guess it’s already
changed.

–Ken


#3

Ken B. wrote:

On Sat, 14 Feb 2009 20:41:52 -0500, Soh D. wrote:

Is it true that ruby language will change to a compiled or jited
language, like .net or java?

Ruby 1.9 introduced a bytecode-based interpreter (which converts your
program to its own bytecodes and then interprets those bytecodes a la
very old Java VMs). JRuby already has an interpreter which compiles to
the Java VM, and these days that is JITted, so I guess it’s already
changed.

–Ken

Hum, does it make Ruby 1.9 a compiled language as, let’s say C#? The
reason I got interested in Ruby is because it’s an interpreted language
and I don’t have to, for every change, re-compiled it


#4

On Feb 15, 2009, at 7:04 AM, Soh D. wrote:

the Java VM, and these days that is JITted, so I guess it’s already
changed.

–Ken

Hum, does it make Ruby 1.9 a compiled language as, let’s say C#? The
reason I got interested in Ruby is because it’s an interpreted
language
and I don’t have to, for every change, re-compiled it

Ruby 1.9 would be considered a compiled language since there is a
process of converting Ruby code into bytecode (analogous to a C
compiler converting C code into Assembly). However as far as I know,
the 1.9 VM isn’t a JIT. It merely “compiles” that code each time and
runs. Like Ken said though, since JRuby runs on the JVM, it
technically JIT’d.

Every language has to be interpreted or parsed in some fashion so its
always going to take at least some time (even if miniscule) to parse
the program. If its a VM based language it’ll then either generate
bytecode and run that on the VM, otherwise it will just begin
executing code based on what the parse tree looks like (a la Ruby
1.8.x).

So in short the process between compiling and interpreting isn’t
hugely different from your point of view as far as time goes and
you’ll still have to wait, but its not going to be any great length of
time (unless its a huge script).

Hope that helps.

-Zac

Note: If I’m wrong about any of these details regarding Ruby, someone
please correct me :).


#5

On Sun, 15 Feb 2009 07:04:16 -0500, Soh D. wrote:

changed.

–Ken

Hum, does it make Ruby 1.9 a compiled language as, let’s say C#? The
reason I got interested in Ruby is because it’s an interpreted language
and I don’t have to, for every change, re-compiled it

Ruby 1.9 doesn’t have an ahead-of-time byte compilation mode as far as I
know. That means you only have to run one command to run your modified
code. Every time you run your script, the interpreter parses it and byte
compiles it, which then results in a speed increase when the interpreter
runs the script. JRuby has a mode where it parses and compiles the
script
every time (the jruby command) and an ahead-of-time compilation mode
(the
jrubyc command).

So Ruby 1.9 can run like perl/python. JRuby can run like perl/python or
like C#.

–Ken


#6

Thanx ken and Zachary,

One of the good things about a interpreted language is that if I change
a single file and saved it, the whole app is still working perfectly …
in a jited env like .net with c# (as an example) if I have to modify a
single file, then I have to build the whole app and send to the
production server this whole app again and imagine if I have a high
traffic website, I probably will have to wait to do it at 3AM … just
hope it’s not the case with new ruby 1.9 … otherwise i’ll have to look
for other programming language … maybe go back to old asp or php …


#7

thanks David … the short answer is my case scenario … i’m not really
concerned with exceptional performance since my projects are relatively
small ones…


#8

Soh D. wrote:

Hum, does it make Ruby 1.9 a compiled language as, let’s say C#? The
reason I got interested in Ruby is because it’s an interpreted language
and I don’t have to, for every change, re-compiled it

The short answer is: Yes, it’s interpreted, in roughly the same way that
Perl, Python, PHP, and JavaScript are interpreted. No, you don’t have to
recompile anything after every change – in fact, many frameworks (Rails
included) have a “development mode” which lets most changes be
incorporated immediately into your app while it’s running. And yes, it
does mean you probably have to give your source code to anyone who needs
to run your program on their local machine.

The longer answers you are getting are about the technical details,
probably pre-emptively heading off questions like “If it’s interpreted,
isn’t it slower?” And it turns out, what you’re talking about is
completely different than the question of whether a language is actually
compiled to native code.

For example, there’s no reason you couldn’t write a shell script which,
when it’s run, immediately compiles a large string (as C) into a binary
and runs that. Similarly, it’s probably possible to bundle up a JAR
containing both JRuby and your app, and whether or not any of it was
actually compiled ahead of time, such that it can simply be run as a
Java program. There are even projects which embed Ruby source code and
the Ruby interpreter to produce a single EXE (on Windows). Similarly,
gcj can compile Java bytecode down to actual binary, and LLVM takes
languages like C and makes them JIT.

So the longer answer is, unless your concern is performance, you should
only care about the shorter answer.