algo-lang

Algorithmic natural language interpreter (language using french keywords)

Usage

Installation

npm install -g algo-lang

Command line

Basic usage:

algo-lang path/to/file.algo

Pretty print your file in console:

algo-lang --pretty-print path/to/file.algo

Language

Quick example

algorithme test
  variables
    entier i, j

  algorithme procedure swap
    parametres globaux
      entier i, j

    variables
      entier tmp

  debut
    tmp ← i
    i ← j
    j ← tmp
  fin algorithme procedure swap

debut
  i ← 2
  j ← 4
  swap(i, j)
  afficher(chaine(i) + chaine(j)) /* prints 42 */
fin algorithme test

Language documentation

Documentation in french

Note

selon expressions differ slightly from the previous documentation. There is a cas keyword added in the mix to allow LALR parsing :

selon expression faire
  cas val1, val2: expr1
                  expr2
        autrement expr3
                  expr4
fin selon

Good to know

Operator aliases

Some operators have aliases to ease development:

• <- is equivalent to ←
• ^ is equivalent to ↑

nul

There is a special nul keyword to assign the null pointer to any pointer variable and check if a pointer is null.

Available types

Only those base types are available:

• booleen (defined just like booleen = (faux, vrai))
• caractere (can be cast with system routines to: chaine, entier)
• chaine (can be cast with system routines to: entier, reel)
• entier (can be cast with system routines to: caractere, chaine, reel)
• reel (can be cast with system routines to: chaine, entier)

System routines

There are some system routines you can use:

• afficher(chaine): prints the string on stdout (no endline is added automatically)
• allouer(pointer): allocate memory for the pointed value
• caractere(value): try to cast value in caractere
• chaine(value): try to cast value in chaine
• entier(value): try to cast entier in chaine
• liberer(pointer): free memory pointed by the provided pointer, do nothing if pointer is nul, resets pointer to nul
• longueur(chaine): returns the length of the string

Operator []

The operator also allows you to access characters (caractere) in a string (chaine) like in:

afficher("toto"[1])

Important note: In this language, index are from 1 to n and not from 0 to n − 1!