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Running a Program

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Gianmarco edited this page May 28, 2023 · 3 revisions

You can use the harlock language in three separate ways:

Start the REPL

You can start the REPL for harlock by just typing harlock into a shell;

Harlock v0.4.1 - amd64 on linux
>>> var hello = "Hello, world! 🐱" 
>>> print(hello)
Hello, world! 🐱
>>>

Run a script

To run a script, simply save an application into a text file and pass its name as the first argument into the harlock interpreter, like so:

harlock script.hlk

I generally use the .hlk extension to define a harlock script.

Note that harlock fully supports UTF-8.

Embed a script

One cool thing (or at least I think it is!) that you can do with the harlock tool is that you can actually embed the whole harlock runtime together with the scripts, and produce one single statically linked go binary that contains every dependency you need to run your script.

This solves the problem of having to install an interpreter, having dependencies or access to the machine where you have to build everything. Instead of having all of those issues, you just ship a single binary.

Running harlock -help reveals how to do it:

[~]$ harlock -help
usage: harlock [flags] [filename] [args]

Execute an harlock script or start a REPL session. 
If the optional filename argument is passed, it must 
be a valid name for an existing file, the contents of 
which will be executed. 

If a filename is passed, a number of additional args can 
be passed, that will be available within the running 
application through the args global variable. If no file 
is passed, the interpreter starts in interactive-mode.

Flags:
  -embed string
        embed the input script into an executable
        containing the interpreter runtime, instead 
        of running the script; this requires a local 
        go installation
  -help
        show the help message
  -version
        print the version for this build

So you can embed a harlock script into an executable together with the harlock runtime by using the embed flag:

harlock -embed script.hlk

This is only possible if you have a local go installation (version >= 1.18).

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