ARGS

Command Line Argument Parsing in Vint

Vint now provides built-in support for parsing command line arguments, making it easy to build CLI applications.

Basic Usage

Get All Arguments

// Get all command line arguments as an array
let allArgs = args()
print(allArgs)  // ["input.txt", "--verbose", "--output", "result.txt"]

Using the CLI Module

import cli

// Get all arguments (same as args())
let cliArgs = cli.args()

// Get only positional arguments (non-flags)
let positional = cli.getPositional()
print(positional)  // ["input.txt", "extra_file.txt"]

// Get flags as a dictionary
let flags = cli.getFlags()
print(flags)  // {verbose: true, output: "result.txt"}

// Check if a specific flag is present
if (cli.hasArg("--verbose")) {
    print("Verbose mode enabled")
}

// Get the value of a specific flag
let outputFile = cli.getArgValue("--output")
if (outputFile) {
    print("Output file:", outputFile)
}

Supported Flag Formats

• --flag - Boolean flags (sets to true)
• --flag value - Flag with value (space-separated)
• --flag=value - Flag with value (equals-separated)
• -v - Short flags (boolean)

Complete Example

// example: vint myapp.vint input.txt --output result.txt --verbose --format json

import cli

// Check for help
if (cli.hasArg("--help")) {
    print("Usage: myapp <input> [options]")
    exit(0)
}

// Get input file from positional arguments
let positional = cli.getPositional()
let inputFile = positional[0] || "stdin"

// Get options
let outputFile = cli.getArgValue("--output") || "stdout"
let format = cli.getArgValue("--format") || "txt"
let verbose = cli.hasArg("--verbose")

if (verbose) {
    print("Processing", inputFile, "->", outputFile, "in", format, "format")
}

Available Functions

Built-in Functions

• args() - Returns array of all command line arguments

CLI Module Functions

• cli.args() - Same as args()
• cli.getPositional() - Returns array of positional arguments
• cli.getFlags() - Returns dictionary of flags
• cli.hasArg(flag) - Checks if flag is present
• cli.getArgValue(flag) - Gets value of flag
• cli.prompt(message) - Prompts user for input
• cli.confirm(message) - Prompts for yes/no confirmation
• cli.execCommand(cmd) - Executes shell command
• cli.cliExit(code) - Exits with status code

Notes

• Positional arguments are those that don't start with - or --
• Flag values are automatically detected (space or equals separated)
• Boolean flags are set to true when present
• The args() builtin and cli.args() return the same result
• All functions handle quotes in arguments properly