mjambon

# Bash function
#
# Usage: save foo.bar
# - creates a file like foo.bar.d41d8cd,
# - overwrites previous copy if identical,
# - preserves other previous versions with very high probability
#
save() {
  file=$1
  if [[ -f "$file" ]]; then

mjambon

# Guiding principle: a shell is a domain-specific language for handling
# files and processes. These core features shall be served by a dedicated
# and already familiar syntax. Traditional programming control structures
# on the other hand are hard to use and limited in traditional shell
# languages. For this, we shall use a proper programming language, one that
# checks statically for basic programming mistakes, allows the use of rich
# data structures, and integrates well in large applications.
#
# Language properties:
#

mjambon

(*
  Sample command-line argument specified using Cmdliner's author's style.
*)

open Cmdliner

let seed_term =
  let doc = "
    Use the number $(docv) to initialize the global pseudo-random number
    generator.

mjambon

(*
   Created by Martin Jambon and placed in the Public Domain on June 1, 2019.

   Print a tree or a DAG as tree, similarly to the 'tree' command.
*)

open Printf

let rec iter f = function
  | [] -> ()

mjambon

#! /bin/bash
#
# Illustrate what happens when editing a script while it's running.
#
# This happens when saving the file in emacs, for example, but not with
# 'sed -i' because the latter deletes the old file before writing a new one.
# See https://unix.stackexchange.com/a/88572/46435 for an explanation.
#

set -eu

mjambon

#! /usr/bin/env bash
#
# Run parallel commands and fail if any of them fails.
#

set -eu

pids=()

for x in 1 2 3; do

mjambon

#! /bin/bash

x=0
y=0

read x <<EOF
1
EOF

echo 1 | read y

mjambon

#! /bin/bash

x=1

f() {
  echo "$x"
}

g() {
  local x=2

mjambon

#! /bin/bash

f() {
  echo "$x"
}

main() {
  local x=42
  f
}

mjambon

(*
   Interactive approach
   --------------------

   You can copy-paste code into `utop`, provided you load the lwt.unix
   package:

     #use "topfind";;
     #thread;;  (* only needed in the plain `ocaml` toplevel, not in `utop`. *)
     #require "lwt.unix";;