docs.daveops.net

Snippets for yer computer needs

Programming Languages

C

resources

overview

Memory

Casting

keywords

Standards

C23

Install tooling in Fedora

sudo yum groupinstall "C Development Tools and Libraries"

Open and read file

const char *filename = "file.txt";
unsigned char byte;
FILE *fp;

fp = fopen(filename, "rb");

if (!fp) {
        printf("Couldn't open file\n");
        return 1;
}

while(!feof(fp)) {
        fread(&byte, sizeof(int), 1, fp);
        printf("%i\n",byte);
}

fclose(fp);

libraries

glibc

Get version

/lib/libc.so.6

or

#include <stdio.h>
#include <gnu/libc-version.h>
int main (void) { puts (gnu_get_libc_version ()); return 0; }

C++

resources

https://en.cppreference.com/

Go

resources

official website

docs

godoc -http=:8080

Language Specification

Go Koans

overview

syntax cheatsheet

package main

import (
    "fmt"
    "os"
    "bufio"
)

func read_file(path string) string {
        f, err := os.Open(filearg)
        if err != nil {
                panic(err)
        }
    scanner := bufio.NewScanner(f)
    for scanner.Scan() {
        fmt.Println(scanner.Text())
    }
}

func main() {
        fmt.Println("hello world")
}

Modules

go mod init $MODULE_NAME
go mod vendor
go get -u

FastCGI

package main

import (
    "fmt"
    "net/http"
    "net/http/fcgi"
)

func hello(w http.ResponseWriter, r *http.Request) {
    fmt.Fprintln(w, "Hello")
}

func main() {
    http.HandleFunc("/", hello)

    err := fcgi.Serve(nil, nil)
    if err != nil {
        panic(err)
    }
}

Templating

{{/* comment */}}  Defines a comment
{{.}}              Renders root element
{{.Foo}}           Renders the "Foo"-field in a nested element

{{if .Done}} {{else}} {{end}}   Defines an if-statement
{{range .Items}} {{.}} {{end}}  Loops over all “Items” and renders each using {{.}}
{{block "bar" .}} {{end}}       Defines a block with the name "bar"

Static linking

If you’re not using CGo, you can statically link with CGO_ENABLED.

In Fedora this appears to be on by default

CGO_ENABLED=0 go build

Cross-compilation

# Compile for AMD64 Linux
GOOS=linux GOARCH=amd64 go build

https://golang.org/doc/install/source#environment

libraries

Mage

https://magefile.org/

Java

overview

Types

type note
byte 8-bit signed two’s complement integer
short 16-bit signed two’s complement integer
int 32-bit signed two’s complement integer
long 64-bit two’s complement integer
float single-precision 32-bit IEEE 754 floating point
double double-precision 64-bit IEEE 754 floating point
boolean the size isn’t precisely defined

SSL

Debugging

# print each handshake message
java -Djavax.net.debug=ssl:handshake MyApp

Numeric literals

You can use underscore characters in SE7+ example: long hexBytes = 0xFF_CC_DA_B5;

Zero copy

Avoid copying the file data across user/kernel boundary, instead have the kernel put the file in a buffer and use DMA to pass the data directly.

https://www.ibm.com/developerworks/linux/library/j-zerocopy/

AES intrinsics

Requires Java 8 and Intel 2010+ Westmere

-XX:+UseAES -XX:+UseAESIntrinsics

libraries

Maven

https://maven.apache.org/

Zig

resources

Official website

overview

CLI

# Get Clang version
zig cc --version
# Get compilable targets
zig targets

releases

0.5.0 - async

Julia

resources

official website

Forth

overview

syntax

words action
. pop an element off the stack
.s display the contents of stack
drop drop top of stack
\ comment
see decompile
words action
include includes a forth source file

colon definitions

: funcname ( stack effect comment )
  do stuff ;

\ local variables
: funcname { a b -- b a }
  b a ;

Kotlin

resources

official website

Prolog

resources

https://bernardopires.com/2013/10/try-logic-programming-a-gentle-introduction-to-prolog/

Tcl

overview

syntax cheatsheet


 if {blah == 0} {
 # blah
 } elseif {blah == 1} {
 # blah!
 } else {
 # blah?
 }

 switch xyz {
 a
-  #drop into next block
 b {
 format 1
 }
 default {
 format 3
 }
 }   # returns 3

 set false 0
 set true 1

profiling statements

puts "unbraced: [time { expr 15 * 20 } 1000]"
puts "braced:   [time { expr {15 * 20} } 1000]"

testing

package require tcltest
namespace import ::tcltest::*

# Software under test
source sum.tcl

test sum_addTwoZerosExpectZero {
Test: [sum 0 0] == 0
} -body {
sum 0 0
} -result 0

test sum_addTwoPositiveNumbers {} -body {
sum 4 9
} -result 13

test sum_addPositiveToNegative {} -body {
sum -95 72
} -result -23

cleanupTests

disassemble statement

This is fun, because it shows just how much of a difference there is in optimizing statements

::tcl::unsupported::disassemble script {expr $a eq $b}
::tcl::unsupported::disassemble script {expr {$a eq $b}}

namespaces

namespace eval blah {}

libraries

OpenACS

ad_proc documentation metadata

Return a file

set file [open $file_path "r"]
ns_set update [ns_conn outputheaders] content-disposition "attachment; filename=$filename"
ns_returnfile 200 [ns_guesstype $file] $file_path

Make your OpenACS form’s checkbox be selected by default

In ad_page_contract:

{fries "t"}

In ad_form:

{fries:text(checkbox),optional
        {label {"Would you like fries with that?"}}
        {html {[if {$fries=="t"} {return "checked checked"}]}}
        {options {{"" t}}}
}

ADP tags

<if @datasource.variable@ eq "blue">
      <td bgcolor=#0000ff>
</if>
<elseif @datasource.variable@ eq "red">
      <td bgcolor=red>
</elseif>
<else>
      <td bgcolor=#ffffff>
</else>

Objective C

overview

i18n

NSLocalizedString strings
NSNumberFormatter numerical values
NSDateFormatter format dates
NSLocale  

Classes

Categories extend classes

Interface

/* #import is like #include, but only included once during compilation */
#import "thing.h"

@interface MyClass : SuperClass <XYZProto, AnotherProtocol> {
  int integerInstanceVariable;
}
+ (void)aClassMethod;
- (void)anInstanceMethod;

@property NSString *name;
@property NSNumber *year_a;
@property int year_b;
@property (readonly) int readonly_year;
// you can change the getter method name by changing the attribute
@property (getter=isFinished) BOOL finished;

@end

Implementation

// If you enable modules for iOS >= 7.0 or OS X >= 10.9 projects in
// Xcode 5 you can import frameworks with @import
@import Foundation;

#import "myclass.h"

@implementation MyClass {
  int integerInstanceVariable;
}

// If you want to change the instance variable name, use @synthesize
@synthesize year_a = ivar_yeara;

+ (void)aClassMethod {
  NSLog(@"This is an Objective-C string literal");
}
- (void)anInstanceMethod {
  // Set an instance variable
  _name = @"Doug E Fresh";
  // Though it's better to use accessor methods / dot syntax
  self.name = @"Fresh Prince";
}
@end

MyClass *thing = [[MyClass alloc] init]
// or, if you're not providing arguments to initialize
MyClass *thing = [MyClass new]

Objects

// setter methods are set + property name
[person setFirstName:@"Bob"];
// or use dot syntax
person.firstName = @"Bob";

Protocols

@protocol XYZProto
// by default methods are required
- (NSUInteger) numOfThings;
@optional
// Everything after @optional is optional, unless there's a @required after that
- (NSString *) stringThing;
@end

NSString *someString;
if ([self.dataSource respondsToSelector:@selector(stringThing)]) {
    someString = [self.dataSource stringThing];
}

// to inherit a protocol
@protocol XYZProto <NSObject>

@end

Collections

Arrays

// Trailing nil needed
NSArray *someArray = [NSArray arrayWithObjects:firstObject, secondObject, thirdObject, nil];
// Easier to read literal syntax (no trailing nil needed)
NSArray *someArray = @[firstObject, secondObject, thirdObject];

if ([someArray count] > 0) {
    NSLog(@"First item is: %@", [someArray objectAtIndex:0]);
    // or
    NSLog(@"First item is: %@", someArray[0]);
}

Dictionaries

NSDictionary *dictionary = @{
              @"anObject" : someObject,
           @"helloString" : @"Hello, World!",
           @"magicNumber" : @42,
                @"aValue" : someValue
};

NSNumber *storedNumber = [dictionary objectForKey:@"magicNumber"];
// or
NSNumber *storedNumber = dictionary[@"magicNumber"];

Blocks

Like closures/lambdas in other languages

^{ NSLog(@"It's a block!"); }

Error Handling

Error Handling Programming Guide for Cocoa

NSString *domain = @"net.daveops.MyApplication.ErrorDomain";
NSString *desc = NSLocalizedString(@"Unable to…", @"");
NSDictionary *userInfo = @{ NSLocalizedDescriptionKey : desc };

NSError *error = [NSError errorWithDomain:domain
                                     code:-101
                                 userInfo:userInfo];

Exceptions

@try {
    // do something that might throw an exception
}
@catch (NSException *exception) {
    // deal with the exception
}
@finally {
    // optional block of clean-up code
    // executed whether or not an exception occurred
}

Self

resources

official website

Perl

overview

syntax Cheatsheet

#!/usr/local/bin/perl -wT
use strict

$scalar = 0;
@array = [1,2,3];

if (expr) block elsif (expr) block else block;

sub hw {
  print "Hello World"
}

hw();

Parsing JSON

use JSON;
decode_json($json);

LWP - HTTP Get

get($url)

To save to a file

getstore($url, $file)

See if LWP is installed

perl -MLWP -le "print(LWP->VERSION)"

Smalltalk

resources

http://www.smalltalk.org

Strongtalk (Smalltalk with a strong static type system)

Pharo

“R”

resources

official website

overview

syntax cheatsheet

# create a vector
things <- c('foo', 'bar', 'baz')

import a CSV

dat <- read.csv(file="foobar.csv", header=TRUE, sep=",")

plotting

bar chart

png(file="output.png")
barplot(vector,names.arg=vector_of_names, xlab="groups", ylab="frequency")
dev.off()

COBOL

libraries

COBOL on Cogs

Fortran

libraries

Fortran.io web framework

ML

https://www.cl.cam.ac.uk/~lp15/MLbook/pub-details.html

Erlang

overview

syntax cheatsheet

% division
5 / 2.
5 div 2.
5 rem 2.

% base conversion
2#1010. % is base 2 for 10

% equality
1 =:= 1. % returns true
1 =/= 0. % returns true

Shell

help().
q().

f(Variable). % drop a variable
f(). % drop all variables

Swift

resources

official website

overview

syntax cheatsheet

No semicolons needed

No main() needed, global scope is entry point

Values are never implicitly converted to another type

String interpolation: “The building is (feet) feet tall”

let multi_line_string = """
multi
line
string
"""

let dictionary = [
  "hotpotato": 1,
  "coldpotato" 2
]

let empty_dict = [:]

if boolean_var {
  print("this is true")
}

var optionalString: String? = "Maybe hello?"

CLI

swift - start up a Swift REPL (backed by LLDB)

swiftc - compile swift code

Benefits

Variables initialized before use

PHP

resources

official website

manual

source code

git clone git@github.com:php/php-src.git

overview

syntax cheatsheet

<?php
if ($blah == 0) {
  // code
} elseif ($blah == 1) {
  // code
} else {
  // code
}

// null coalescing - ??
// $var = isset($_GET['var']) ? $_GET['var'] : 'default';
$var = $_GET['var'] ?? 'default';

$arr = array(1, 2, 3, 4);
foreach ($arr as $value) {
        print $value;
}

switch ($blah) {
  case 0:
        // code
        break;
  case 1:
        // code
        break;
  default:
        // code
        break;
}

function foo () {
  return 0;
}
?>

CLI

Get PHP config info

# Get configuration (like phpinfo())
php -i
# Get location of php.ini
php --ini

Run a server instance with a script

Requires PHP >= 5.4

http://php.net/manual/en/features.commandline.webserver.php

php -S localhost:8000 router.php

releases

8.1

Datestamps

<?php
//mktime(hour,minute,second,month,day,year)

echo date("Y/m/d", mktime(0,0,0,11,11,2011));
//2011/11/11
?>

Autogenerate a file download

<?php
header("Content-Type: text/calendar; charset=utf-8");
header("Content-Disposition: attachment; filename=test.ics");
// render file...

Turn off error reporting

<?php
error_reporting(0)
?>

Check if domain resolves

<?php
checkdnsrr($host)
?>

Authenticating users

<?php
session_start();
// Check for session injection
if (isset($_REQUEST['_SESSION'])) {
    session_destroy();
    die('');
} elseif (isset($_SESSION['HTTP_USER_AGENT'])) {
    if ($_SESSION['HTTP_USER_AGENT'] != md5($_SERVER['HTTP_USER_AGENT'])) {
     session_destroy();
     die('');
    }
}
// At end of page, let's regenerate the session ID
if(isset($_SESSION['username'])) {
    session_regenerate_id(TRUE);
} 
?>

Validation

<?php
// Numeric validation
is_int($var)
is_numeric($var)
?>

Export to CSV

<?php
header("Expires: 0");
header("Cache-control: private");
header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
header("Content-Description: File Transfer");
header("Content-Type: text/csv");
header("Content-disposition: attachment; filename=rawlogs.csv");
?>

Get filename

<?php
$FILE_NAME = basename($_SERVER["PHP_SELF"]);
?>

Return multiple values

<?php
function mult() {
    return array(0, 1);
}

list ($zero, $one) = mult();
?>

Create an array of objects

<?php
$allCars=array();
$result = mysql_query($SQL);

while ($rowInfo = mysql_fetch_assoc($result))
{ 
     $tempCar=new Car();

     $tempCar->setMake($rowInfo['car_make']);
     $tempCar->setModel($rowInfo['car_model']);
     $tempCar->setColor($rowInfo['car_color']);

     $allCars[]=$tempCar;
}
?>

SQLite

Initializing

<?php
/**
 * Simple example of extending the SQLite3 class and changing the __construct
 * parameters, then using the open method to initialize the DB.
 */
class MyDB extends SQLite3
{
    function __construct()
    {
        $this->open('mysqlitedb.db');
    }
}

$db = new MyDB();

$db->exec('CREATE TABLE foo (bar STRING)');
$db->exec("INSERT INTO foo (bar) VALUES ('This is a test')");

$result = $db->query('SELECT bar FROM foo');
var_dump($result->fetchArray());
?>

Reading values

<?php
//read data from database
$query = "SELECT * FROM Movies";
if($result = $database->query($query, SQLITE_BOTH, $error))
{
  while($row = $result->fetch())
  {
    print("Title: {$row['Title']} <br />" .
          "Director: {$row['Director']} <br />".
          "Year: {$row['Year']} <br /><br />");
  }
}
else
{
  die($error);
}
?>

Scrape $_GET parameters

If mod_rewrite or some other mechanism is preventing the filling of the $_GET array, use this:

<?php
parse_str($_SERVER['QUERY_STRING'], $_GET);
?>

Convert command line arguments into GET variables

<?php
parse_str(implode('&amp;', array_slice($argv, 1)), $_GET);
?>

Redirect to a different URL

<?php
header("Location: https://example.org/"); 
?>

Insecurity

PHP has more than a few security pitfalls, this is just a quick list of ways it can bite you.

$FILES tmp_name usage

tmp_name is untrusted input and should be sanitized before doing any file operations (like move_uploaded_file)

exif_imagetype is not validation

If you’re testing a file to ensure it’s an image, exif_imagetype alone is inadequate, as it can be easily bypassed with a magic string like “BM” (for bitmap)

PDO

// simple query
<?php
$sql = "SELECT max(id) FROM table";
$sth = $DB->prepare($sql);
$sth->execute();
$max_id= $sth->fetchColumn();
?>

Binary

Read a binary file

<?php
$handle = fopen('/path/to/file', 'rb');
$contents = fread($handle, filesize($filename));
fclose($handle);
?>

Binary craziness

<?php
bindec();
decbin();
?>

Playing with endianness

<?php
// For changing endianness, just use strrev()
// %016b for 16-bit, %032b for 32-bit
strrev(sprintf("%016b", $int));
?>

Unpacking binary file formats

<?php
// For parsing binary file formats,
// use pack/unpack
function get_gif_header($image_file)
{

    /* Open the image file in binary mode */
    if(!$fp = fopen ($image_file, 'rb')) return 0;

    /* Read 20 bytes from the top of the file */
    if(!$data = fread ($fp, 20)) return 0;

    /* Create a format specifier */
    $header_format = 
            'A6Version/' . # Get the first 6 bytes
            'C2Width/' .   # Get the next 2 bytes
            'C2Height/' .  # Get the next 2 bytes
            'C1Flag/' .    # Get the next 1 byte
            '@11/' .       # Jump to the 12th byte
            'C1Aspect';    # Get the next 1 byte

    /* Unpack the header data */
    $header = unpack ($header_format, $data);

    $ver = $header['Version'];

    if($ver == 'GIF87a' || $ver == 'GIF89a') {
        return $header;
    } else {
        return 0;
    }
}

/* Run our example */
print_r(get_gif_header("aboutus.gif"));

/*
Array
(
    [Version] => GIF89a
    [Width1] => 97
    [Width2] => 0
    [Height1] => 33
    [Height2] => 0
    [Flag] => 247
    [Aspect] => 0
)
*/
?>

Barcodes

Get a UPC check digit

<?php
function get_ean_checkdigit($barcode){
        $sum = 0;
        for($i=(strlen($barcode));$i>0;$i--){
         $sum += (($i % 2) * 2 + 1 ) * substr($barcode,$i-1,1);
        }
        return (10 - ($sum % 10));
}
?>

libraries

composer

Composer homepage

Require a package

composer require repo/package

Will drop composer.json and composer.lock

Load vendor directory

<?php
require __DIR__ . '/vendor/autoload.php';

Create a barcode with Image_Barcode2 (PEAR)

<?php
require_once 'Image/Barcode2.php';
$bc = new Image_Barcode2;
$bc->draw($_GET['bctext'], "int25", "png");
?>

Include PEAR (Dreamhost)

<?php
//Include my PEAR path
set_include_path("." . PATH_SEPARATOR . ($UserDir = dirname($_SERVER['DOCUMENT_ROOT'])) . "/pear/php" . PATH_SEPARATOR . get_include_path());
?>

node.js

NodeJS ECMAScript Support

overview

Debugging

node --inspect ...

Can also be turned on with SIGUSR1

Node <7 - Debugger API

Node >8 - Inspector API

Debugger

Connect with node inspect HOST:PORT

Debug directly with node inspect file.js

Inserting debugger; in your code sets a breakpoint

Stepping

cont, c Continue execution
next, n Step next
step, s Step in
out, o Step out
pause Pause running code (like pause button in Developer Tools)

Breakpoints

setBreakpoint(), sb() Set breakpoint on current line
setBreakpoint(line), sb(line) Set breakpoint on specific line
setBreakpoint(‘fn()’), sb(…) Set breakpoint on a first statement in functions body
setBreakpoint(‘script.js’, 1), sb(…) Set breakpoint on first line of script.js
clearBreakpoint(‘script.js’, 1), cb(…) Clear breakpoint in script.js on line 1

Information

backtrace, bt Print backtrace of current execution frame
list(5) List scripts source code with 5 line context (5 lines before and after)
watch(expr) Add expression to watch list
unwatch(expr) Remove expression from watch list
watchers List all watchers and their values (automatically listed on each breakpoint)
repl Open debugger’s repl for evaluation in debugging script’s context
exec expr Execute an expression in debugging script’s context

Execution control

run Run script (automatically runs on debugger’s start)
restart Restart script
kill Kill script

Various

scripts List all loaded scripts
version Display V8’s version

left-pad

Rust

resources

official website

docs website

editor support

Ferris the crab

https://rustacean.net/

overview

syntax cheatsheet

//! You can create a description for your crate using two slashes and an exclamation mark

// Add debugging info to struct
// Trait is std::fmt::Debug
/// Documentation comments use three slashes and Markdown
#[derive(Debug)]
struct Rectangle {
    width: u32,
    height: u32,
}

// use impl (implementation) block to create methods
impl Rectangle {
  fn area(&self) -> u32 {
    self.width * self.height
  }
  fn is_square(&self) -> bool {
    self.width == self.height
  }
  // associated functions
  #[allow(dead_code)]
  fn square(size: u32) -> Rectangle {
    Rectangle { width: size, height: size }
  }
}

fn main() {
  let mut a = 1; // mut makes the value mutable
  println!("{}", a);
  a = 2;
  println!("{}", a);

  // shadowing
  let x = 2;
  let x = x + 2;

  eprinln!("Use this to print to stderr");

  loop {
    println!("simple loop");
    break;
  }

  println!("easy as");
  for number in 1..4 {
    println!("{}", number);
  }

  let rect = Rectangle { width: 10, height: 20 };
  // get struct details for debugging
  println!("rect is {:?}", rect);
  println!("pretty print rect is {:#?}", rect);

  // using match
  let thing = 5;
  match thing {
     5 => println!("five!"),
     6 => {
         println!("six?");
         println!("why six?");
     },
     _ => (), // wildcard, don't do anything
  }
  // or using if let
  if let 5 = thing {
    println!("still five");
  } else {
    println!("not five");
  }

  // make a vector
  let mut v = vec![1,2,3];
  for i in 4..11 {
    v.push(i);
  }
  for (j, l) in v.iter().enumerate() {
    println!("index {}: {}", j, l);
  }
}

CLI

Cargo

# New project
cargo new project_name --bin
# Build a release
cargo build --release
# Test a build
cargo check
# Create documentation and open it in a browser
cargo doc --open
# Build the executable, run it
cargo run

rustc

# Build a library
rustc --crate-type=lib thing.rs

testing

If the function passes, the test passes

#[test]
fn this_tests_code(){
  println!("");
  if 1 == 0 {
    fail!("This should never happen");
  }
}

To compile the tests and replace main with test runner:

rustc --test test.rs

https://doc.rust-lang.org/stable/book/testing.html

Macros

Macro Description
print!(“text”) Print a line to STDOUT
println!(“text”) Print a line to STDOUT followed by a newline

Nightly rust

# Install nightly toolchain
rustup toolchain install nightly
# Use nightly toolchain by default
rustup default nightly

Cargo

Cargo watch

cargo watch -x check -x test

Platform support

Cross-compilation

rustup target list
rustup target add x86_64-unknown-linux-musl
cargo build --target x86_64-unknown-linux-musl

If you’re working on Mac and compiling for Linux, you’ll also want:

brew install x86_64-elf-binutils

And using that specific linker:

[target.x86_64-unknown-linux-musl]
linker = "x86_64-elf-ld"

iOS

# Be able to create iOS executables
cargo install cargo-lipo
# Install targets
rustup target add aarch64-apple-ios x86_64-apple-ios

Windows

Rust on Windows

Webassembly

async

https://areweasyncyet.rs/

Lua

overview

syntax cheatsheet

function function_name ( args ) body end

while exp do block end

for variable = from_exp , to_exp [, step_exp] do block end
(foreach) for var {, var} in explist do block end

repeat block until exp

if exp then block { elseif exp then block } [ else block ] end

Iterate through file

for line in io.lines("my.txt") do print(line) end

Rexx

https://en.wikipedia.org/wiki/Rexx

JavaScript

resources

specifications

JavaScript deobfuscator

jq

overview

syntax

var vs. let

Use let, since it limits the scope to the block. const is also block-scoped.

Classes

ES6 Modules

<script type="module">
import * as FOO from './lib/foo.js';
import { baz, bax } from './lib/bar.js';
// ...
</script>

All modules are parsed with strict mode

MDN Modules

Strict Mode

'use strict'

MDN Strict Mode docs

Debugger

debugger;

libraries

jQuery

https://jquery.com

No-conflict mode

var $j = jQuery.noConflict();

Append a node to the DOM

$('#thing').append('<p>blerg</p>');'</p>')

Get first element of several

CSS pseudo-selectors $(“.stuff li:first”);

DOM traversal $(“.stuff”).first();

Searches for the closest ancestor that matches

.closest()

Objects

Use $(this) instead of this - it’s a jQuery object

Get custom data attributes from the DOM

date(name)

Get direct children from an element

$("ul").children("li");

Get parent element of a node

$("#thing").parent();

d3js

Tangle

http://worrydream.com/Tangle/guide.html

React

https://reactjs.org/

React Native

Typescript

CoffeeScript

Elixer

Ruby/Lisp-alike run on Erlang BEAM

Crystal

resources

official website

libraries

Kemal

Sinatra-ish web framework

https://kemalcr.com/guide/

OCaml

resources

official website

Clojure

resources

official website

language reference

community

The Clojure Toolbox

Starlark

A subset of Python intended as a configuration language

resources

specifications

Nim

resources

official website