The-LOOP-LANG

https://en.wikipedia.org/wiki/LOOP_(programming_language)

Installing and usage: CLICK HERE

An attempt to build an interpreter for the theoretical LOOP language.

Default grammar of loop:

P := Xi := Xj + c
   | Xi := Xj - c
   | P;P
   | "LOOP" Xi "DO" P "END"

(where i,j are natural numbers)

Features of the interpreter:

The interpreter has some additional features which may simplify writing programs:

• Arbitrary long expressions when assigning variables like: X4 := X3 - 2 + A42 + 123 + 314159
• The interpreter supports variable names starting with a capital letter followed by 1 to 2 digits, e.g.: X12, A2, G34, ...
  • Not allowed are names like: X, R342, HE, %§&, ...
• As in the original language, programs need to be separated by a semicolon
• Variables are initialized to 0 by default
• Output variable is always X0
• Values of input variables (starting with X1, X2, ...) need to be specified by the input parameter: -in=VALUE1,VALUE2,...
• LOOP statements can handle expressions as condition like: LOOP 4 + X1 DO ...

Upcoming features:

! CURRENTLY THE PROJECT IS DISCONTINUED !

• Custom definition of new keywords and reuse of programs
• Library support
• Debugging mode where a program is interpreted step-by-step

Internal grammar of this interpreter:

program   -> statement ( ";" statement )* ;

statement -> loop
             | assign ;

loop    -> "LOOP" var "DO" program "END" ;
assign  -> var ":=" expr ;

expr    -> add ;
add     -> primary ( ("+"|"-") primary )* ;
primary -> var | number ;

var     -> {A,...,Z} x {0,...,99} ;
number -> {0,...} ;