How to Deploy a Perl/Python/Ruby Script Without Installing an Interpreter

How can I deploy a Perl/Python/Ruby script without installing an interpreter?

You can use Perl Archive Toolkit to bring a minimal perl core + needed modules + your Perl program with you.

And you can even convert it using PAR Packer to a windows exe file that will run just like any other program, from an end user's perspective.

How can you interact with Perl programs from Ruby?

What you want doesn't really exist, to my knowledge.

The closest thing to what you want, on a generic level, is XDebug. It turns a process into a little server that will accept debugging commands. This is generally used for debugging and profiling and not as interprocess communication, but its a possibility. I believe ActiveState's Perl can be run as an XDebug server.

Otherwise, you need explicitly program in some sort of side-channel that your Perl program listens to for commands (which is what XDebug does). It can be as simple as opening a socket that reads a string, evals it, encodes the result as YAML (or whatever) and writes it back. A REPL, but on a socket rather than on a terminal.

There are, obviously, security implications which will be left as an exercise for the reader. You also don't want listening to the socket to interrupt the program so you will now need something event-driven or threaded.

Sorry I don't have anything more specific. It would make a great CPAN module.

How to compile a Perl script to a Windows executable with Strawberry Perl?

Install PAR::Packer from CPAN (it is free) and use pp utility.

Can Ruby, PHP, or Perl create a pre-compiled file for the code like Python?

There is no portable bytecode specification for Ruby, and thus also no standard way to load precompiled bytecode archives. However, almost all Ruby implementations use some kind of bytecode or intcode format, and several of them can dump and reload bytecode archives.

YARV always compiles to bytecode before executing the code, however that is usually only done in memory. There are ways to dump out the bytecode to disk. At the moment, there is no way to read it back in, however. This will change in the future: work is underway on a bytecode verifier for YARV, and once that is done, bytecode can safely be loaded into the VM, without fear of corruption. Also, the JRuby developers have indicated that they are willing to implement a YARV VM emulator inside JRuby, once the YARV bytecode format and verifier are stabilized, so that you could load YARV bytecode into JRuby. (Note that this version is obsolete.)

Rubinius also always compiles to bytecode, and it has a format for compiled files (.rbc files, analogous to JVM .class files) and there is talk about a bytecode archive format (.rba files, analogous to JVM .jar files). There is a chance that Rubinius might implement a YARV emulator, if deploying apps as YARV bytecode ever becomes popular. Also, the JRuby developers have indicated that they are willing to implement a Rubinius bytecode emulator inside JRuby, if Rubinius bytecode becomes a popular way of deploying Ruby apps. (Note that this version is obsolete.)

XRuby is a pure compiler, it compiles Ruby sourcecode straight to JVM bytecode (.class files). You can deploy these .class files just like any other Java application.

JRuby started out as an interpreter, but it has both a JIT compiler and an AOT compiler (jrubyc) that can compile Ruby sourcecode to JVM bytecode (.class files). Also, work is underway to create a new compiler that can compile (type-annotated) Ruby code to JVM bytecode that actually looks like a Java class and can be used from Java code without barriers.

Ruby.NET is a pure compiler that compiles Ruby sourcecode to CIL bytecode (PE .dll or .exe files). You can deploy these just like any other CLI application.

IronRuby also compiles to CIL bytecode, but typically does this in-memory. However, you can pass commandline switches to it, so it dumps the .dll and .exe files out to disk. Once you have those, they can be deployed normally.

BlueRuby automatically pre-parses Ruby sourcecode into BRIL (BlueRuby Intermediate Language), which is basically a serialized parsetree. (See Blue Ruby - A Ruby VM in SAP ABAP(PDF) for details.)

I think (but I am definitely not sure) that there is a way to get Cardinal to dump out Parrot bytecode archives. (Actually, Cardinal only compiles to PAST, and then Parrot takes over, so it would be Parrot's job to dump and load bytecode archives.)

Would it be possible to integrate Python or Perl with Ruby?

Integrating dynamic languages is one of the goals of the Parrot project. It's a virtual machine that dynamic language compilers target. Once compiled to the same virtual machine, you should be able to used the "object" form in any of the languages no matter the object's source.

The issue at the moment, however, is stabilizing the virtual machine and finishing off the mostly done compilers. However, that's been the state for a long time. :)

Which dynamic language can easily use libraries from other languages?

Perl has very good support for other languages via the Inline set of modules.

Inline::Python allows you to import Python modules, classes and functions into your Perl code and call them from Perl as if they were native - see Importing Functions.

Inline::Ruby works virtually the same way.

Why are scripting languages (e.g. Perl, Python, and Ruby) not suitable as shell languages?

There are a couple of differences that I can think of; just thoughtstreaming here, in no particular order:

Python & Co. are designed to be good at scripting. Bash & Co. are designed to be only good at scripting, with absolutely no compromise. IOW: Python is designed to be good both at scripting and non-scripting, Bash cares only about scripting.

Bash & Co. are untyped, Python & Co. are strongly typed, which means that the number 123, the string 123 and the file 123 are quite different. They are, however, not statically typed, which means they need to have different literals for those, in order to keep them apart.

Example:

                | Ruby             | Bash    
-----------------------------------------
number          | 123              | 123
string          | '123'            | 123
regexp          | /123/            | 123
file            | File.open('123') | 123
file descriptor | IO.open('123')   | 123
URI             | URI.parse('123') | 123
command         | `123`            | 123

Python & Co. are designed to scale up to 10000, 100000, maybe even 1000000 line programs, Bash & Co. are designed to scale down to 10 character programs.
In Bash & Co., files, directories, file descriptors, processes are all first-class objects, in Python, only Python objects are first-class, if you want to manipulate files, directories etc., you have to wrap them in a Python object first.
Shell programming is basically dataflow programming. Nobody realizes that, not even the people who write shells, but it turns out that shells are quite good at that, and general-purpose languages not so much. In the general-purpose programming world, dataflow seems to be mostly viewed as a concurrency model, not so much as a programming paradigm.

I have the feeling that trying to address these points by bolting features or DSLs onto a general-purpose programming language doesn't work. At least, I have yet to see a convincing implementation of it. There is RuSH (Ruby shell), which tries to implement a shell in Ruby, there is rush, which is an internal DSL for shell programming in Ruby, there is Hotwire, which is a Python shell, but IMO none of those come even close to competing with Bash, Zsh, fish and friends.

Actually, IMHO, the best current shell is Microsoft PowerShell, which is very surprising considering that for several decades now, Microsoft has continually had the worst shells evar. I mean, COMMAND.COM? Really? (Unfortunately, they still have a crappy terminal. It's still the "command prompt" that has been around since, what? Windows 3.0?)

PowerShell was basically created by ignoring everything Microsoft has ever done (COMMAND.COM, CMD.EXE, VBScript, JScript) and instead starting from the Unix shell, then removing all backwards-compatibility cruft (like backticks for command substitution) and massaging it a bit to make it more Windows-friendly (like using the now unused backtick as an escape character instead of the backslash which is the path component separator character in Windows). After that, is when the magic happens.

They address problem 1 and 3 from above, by basically making the opposite choice compared to Python. Python cares about large programs first, scripting second. Bash cares only about scripting. PowerShell cares about scripting first, large programs second. A defining moment for me was watching a video of an interview with Jeffrey Snover (PowerShell's lead designer), when the interviewer asked him how big of a program one could write with PowerShell and Snover answered without missing a beat: "80 characters." At that moment I realized that this is finally a guy at Microsoft who "gets" shell programming (probably related to the fact that PowerShell was neither developed by Microsoft's programming language group (i.e. lambda-calculus math nerds) nor the OS group (kernel nerds) but rather the server group (i.e. sysadmins who actually use shells)), and that I should probably take a serious look at PowerShell.

Number 2 is solved by having arguments be statically typed. So, you can write just 123 and PowerShell knows whether it is a string or a number or a file, because the cmdlet (which is what shell commands are called in PowerShell) declares the types of its arguments to the shell. This has pretty deep ramifications: unlike Unix, where each command is responsible for parsing its own arguments (the shell basically passes the arguments as an array of strings), argument parsing in PowerShell is done by the shell. The cmdlets specify all their options and flags and arguments, as well as their types and names and documentation(!) to the shell, which then can perform argument parsing, tab completion, IntelliSense, inline documentation popups etc. in one centralized place. (This is not revolutionary, and the PowerShell designers acknowledge shells like the DIGITAL Command Language (DCL) and the IBM OS/400 Command Language (CL) as prior art. For anyone who has ever used an AS/400, this should sound familiar. In OS/400, you can write a shell command and if you don't know the syntax of certain arguments, you can simply leave them out and hit F4, which will bring a menu (similar to an HTML form) with labelled fields, dropdown, help texts etc. This is only possible because the OS knows about all the possible arguments and their types.) In the Unix shell, this information is often duplicated three times: in the argument parsing code in the command itself, in the bash-completion script for tab-completion and in the manpage.

Number 4 is solved by the fact that PowerShell operates on strongly typed objects, which includes stuff like files, processes, folders and so on.

Number 5 is particularly interesting, because PowerShell is the only shell I know of, where the people who wrote it were actually aware of the fact that shells are essentially dataflow engines and deliberately implemented it as a dataflow engine.

Another nice thing about PowerShell are the naming conventions: all cmdlets are named Action-Object and moreover, there are also standardized names for specific actions and specific objects. (Again, this should sound familar to OS/400 users.) For example, everything which is related to receiving some information is called Get-Foo. And everything operating on (sub-)objects is called Bar-ChildItem. So, the equivalent to ls is Get-ChildItem (although PowerShell also provides builtin aliases ls and dir – in fact, whenever it makes sense, they provide both Unix and CMD.EXE aliases as well as abbreviations (gci in this case)).

But the killer feature IMO is the strongly typed object pipelines. While PowerShell is derived from the Unix shell, there is one very important distinction: in Unix, all communication (both via pipes and redirections as well as via command arguments) is done with untyped, unstructured strings. In PowerShell, it's all strongly typed, structured objects. This is so incredibly powerful that I seriously wonder why noone else has thought of it. (Well, they have, but they never became popular.) In my shell scripts, I estimate that up to one third of the commands is only there to act as an adapter between two other commands that don't agree on a common textual format. Many of those adapters go away in PowerShell, because the cmdlets exchange structured objects instead of unstructured text. And if you look inside the commands, then they pretty much consist of three stages: parse the textual input into an internal object representation, manipulate the objects, convert them back into text. Again, the first and third stage basically go away, because the data already comes in as objects.

However, the designers have taken great care to preserve the dynamicity and flexibility of shell scripting through what they call an Adaptive Type System.

Anyway, I don't want to turn this into a PowerShell commercial. There are plenty of things that are not so great about PowerShell, although most of those have to do either with Windows or with the specific implementation, and not so much with the concepts. (E.g. the fact that it is implemented in .NET means that the very first time you start up the shell can take up to several seconds if the .NET framework is not already in the filesystem cache due to some other application that needs it. Considering that you often use the shell for well under a second, that is completely unacceptable.)

The most important point I want to make is that if you want to look at existing work in scripting languages and shells, you shouldn't stop at Unix and the Ruby/Python/Perl/PHP family. For example, Tcl was already mentioned. Rexx would be another scripting language. Emacs Lisp would be yet another. And in the shell realm there are some of the already mentioned mainframe/midrange shells such as the OS/400 command line and DCL. Also, Plan9's rc.