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Hello World in V
What is V Language?
V is a recently emerged programming language.
The official website states:
The V Programming Language
Simple, fast, safe, compiled. For developing maintainable software.
It seems to be simple, fast, and safe.
My Environment
OS: macOS 12.3 21E230 x86_64
Device: MacBook Pro 2019 13-inch
CPU: Intel i7-8569U (8) @ 2.80GHz
Memory: 16GB
Installation
Documentation
As of now (2022/04/05), it seems building from source is the only method available.
I will proceed with building it.
git, a C compiler (any of tcc, gcc, or clang), and make are required.
For Linux or macOS:
git clone https://github.com/vlang/v
cd v
make
For Windows:
git clone https://github.com/vlang/v
cd v
make.bat -tcc
If you want to use v globally:
sudo ./v symlink
This will allow you to use v from anywhere.
v
You can see descriptions of commands with v help.
$ v help
V is a tool for managing V source code.
Usage:
v [options] [command] [arguments]
Examples:
v hello.v Compile the file `hello.v` and output it as `hello` or `hello.exe`.
v run hello.v Same as above but also run the produced executable immediately after compilation.
v -cg run hello.v Same as above, but make debugging easier (in case your program crashes).
v -o h.c hello.v Translate `hello.v` to `h.c`. Do not compile further.
v -o - hello.v Translate `hello.v` and output the C source code to stdout. Do not compile further.
v watch hello.v Re-does the same compilation, when a source code change is detected.
The program is only compiled, not run.
v watch run hello.v Re-runs the same `hello.v` file, when a source code change is detected.
V supports the following commands:
* New project scaffolding:
new Setup the file structure for a V project (in a sub folder).
init Setup the file structure for an already existing V project.
* Ordinary development:
run Compile and run a V program.
test Run all test files in the provided directory.
fmt Format the V code provided.
vet Report suspicious code constructs.
doc Generate the documentation for a V module.
vlib-docs Generate and open the documentation of all the vlib modules.
repl Run the REPL.
watch Re-compile/re-run a source file, each time it is changed.
* Installation/self updating:
symlink Create a symbolic link for V.
up Run the V self-updater.
self [-prod] Run the V self-compiler, use -prod to optimize compilation.
version Print the version text and exits.
* Module/package management:
install Install a module from VPM.
remove Remove a module that was installed from VPM.
search Search for a module from VPM.
update Update an installed module from VPM.
upgrade Upgrade all the outdated modules.
list List all installed modules.
outdated List installed modules that need updates.
show Display information about a module on vpm
* Others:
doctor Display some useful info about your system to help reporting bugs.
translate Translate C code to V (coming soon in 0.3).
tracev Produce a tracing version of the v compiler.
Use `tracev yourfile.v` when the compiler panics.
NB: `tracev` is much slower and more verbose than ordinary `v`
Use "v help <command>" for more information about a command, example: `v help build`, `v help build-c`, `v help build-native`
Use "v help other" to see less frequently used commands.
Use "v help topics" to see a list of all known help topics.
Note: Help is required to write more help topics.
Only build, new, init, doc, fmt, vet, run, test, watch, search, install, remove, update, bin2v, check-md are properly documented currently.
v
You can enter an interactive mode like Python by running the command above.
$ v
____ ____
\ \ / / | Welcome to the V REPL (for help with V itself, type exit , then run v help ).
\ \/ / | Note: the REPL is highly experimental. For best V experience, use a text editor,
\ / | save your code in a main.v file and execute: v run main.v
\ / | V 0.2.4 0bd8fbc . Use list to see the accumulated program so far.
\__/ | Use Ctrl-C or exit to exit, or help to see other available commands.
Basic arithmetic looks like this:
>>> 1 + 1
2
>>> 3 * 4
12
>>> 0.004 - 0.001
0.003
>>> 1 / 3
0
>>> 1.0 / 3.0
0.3333333
Calculations work normally, but it feels incredibly slow. It feels like an addition takes about 2 seconds. Since the V language is apparently transpiled to C once, I assume a build process is being performed every time.
Hello, World
Extensions
I use VS Code, so I will install the extension.
It comes with syntax highlighting and snippets.
Unfortunately, as of now (2022/04/05), it doesn't seem to have a formatting feature.
It doesn't point out syntax errors and the suggestions are weak, so it's not very reliable...
Creating a Project
You can easily create a project using the v command installed earlier.
$ v new
Input your project name: hello_world
Input your project description:
Input your project version: (0.0.0)
Input your project license: (MIT)
Initialising ...
Complete!
It's similar to npm init.
When executed, a new directory named hello_world is created.
Open this in VS Code.
It should look something like this.
(The nested .gitignore is due to another extension.)
Execution
The program to output "Hello, World" is already created, so all that's left is to run it.
$ v run ./hello_world.v
Hello World!
Done.
The code should look something like this.
module main
fn main() {
println('Hello World!')
}
It feels like a mix of Rust and Go.
Conclusion
We've successfully done "Hello, World" in V.
If you want to know more detailed specifications, please refer to the official documentation.
Strings, arrays, and for-loops have unique specifications and are interesting.
Discussion