by Ethan Nicholas
A high-level, general-purpose multiparadigm programming language.

Frost is a high-level, general-purpose multiparadigm programming language with support for:

  • First-class immutable objects and value types
  • First-class functions and closures
  • Type inference
  • Non-nullable references, static proofs of null safety
  • Contracts (preconditions and postconditions)
  • Tuples
  • Actor model threading
Simple version of the Unix `head` utility. Reads a file
and outputs the first `count` lines from it to the
standard output stream.

@param path the file to read
@param count the number of lines to display
method head(path:File, count:Int) {
    try {
    fail(error) {

method abort(msg:String) {

method main(args:ListView<String>) {
    if args.count != 3 {
        abort("usage: head <path> <count>")
    def count := args[2].asInt
    if count == null {
        abort("error: '\{args[2]}' is not an integer")
    head(File(args[1]), count)
Information updated 07/18/20
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