CLI Tools

Kodo provides built-in functions for reading command-line arguments, standard input, and controlling process exit. Combined with File I/O and JSON, you can build complete CLI tools.

Command-Line Arguments

args() -> List<String>

Returns all command-line arguments as a List<String>, including the binary name as the first element.

module cli_args {
    meta {
        purpose: "demonstrates reading command-line arguments"
        version: "0.1.0"
    }

    fn main() -> Int {
        let arg_list: List<String> = args()
        println("arguments received")
        return 0
    }
}

Compile and run:

kodoc build cli_args.ko -o cli_args
./cli_args foo bar baz

Standard Input

readln() -> String

Reads a single line from standard input, stripping the trailing newline.

println("Enter your name:")
let name: String = readln()
println(f"Hello, {name}!")

Process Exit

exit(code: Int)

Exits the process immediately with the given exit code.

if error_occurred {
    println("fatal error")
    exit(1)
}

File I/O

Kodo provides a complete set of file and directory operations:

Builtin	Parameters	Returns	Description
file_read	path: String	Result<String, String>	Read file contents
file_write	path: String, content: String	Result<String, String>	Write file (overwrite)
file_append	path: String, content: String	Result<String, String>	Append to file
file_exists	path: String	Bool	Check if file exists
file_delete	path: String	Int (0=ok)	Delete a file
dir_list	path: String	List<String>	List directory entries
dir_exists	path: String	Bool	Check if directory exists

Extended Math

Builtin	Parameters	Returns	Description
sqrt	x: Float64	Float64	Square root
pow	base: Float64, exp: Float64	Float64	Power
sin	x: Float64	Float64	Sine
cos	x: Float64	Float64	Cosine
log	x: Float64	Float64	Natural logarithm
floor	x: Float64	Float64	Floor
ceil	x: Float64	Float64	Ceiling
round	x: Float64	Float64	Round to nearest
rand_int	min: Int, max: Int	Int	Random integer in range

Next Steps

• HTTP, JSON & Networking — HTTP client and server, JSON parsing and building
• Modules and Imports — multi-file programs and the standard library