spongebobify.rs

use std::env;

fn print_spongebob(vals: &[String]) {
    let statement = vals.join(" ");
    let mut lower = true;
    for c in statement.chars() {
        let new_c = if lower { c.to_lowercase().next() }
                        else { c.to_uppercase().next() };
        if let Some(c) = new_c {
            print!("{}", c);
        }
        lower = !lower;
    }
    print!("\n");
}

fn main() {
    let args: Vec<_> =  env::args().collect();
    if let Some((_, tail)) = args.split_first() {
        print_spongebob(tail);
    } else {
        println!("usage: spongebobify [statement...]")
    }
}

Haskell version:

import Data.Char
import System.Environment
import Data.List

spongebobify s = spongebobify' s True
  where spongebobify' "" _ = ""
        spongebobify' (x:xs) lower = (flipC lower x) : spongebobify' xs (not lower)
        flipC True = toLower
        flipC False = toUpper

main = getArgs >>= putStrLn . spongebobify . intercalate " "