-- MiniJS, a tiny programming language à la Straightline (Andrew Appel).
--
-- The language features basic computation with integers and floating-point numbers,
-- variable assignment, and a print statement.
--
-- The concrete syntax is compatible with JavaScript.

-- Programs are lists of statements.

Prg. Program ::= [Stm] ;

-- Statements are either assignments or print statements.
-- Statements are terminated by a semicolon

SAssign.  Stm ::= Ident "=" Exp ;
SPrint.   Stm ::= "console.log" "(" Exp ")" ;

terminator Stm ";" ;

-- Expressions are operator trees over variables and literals.

EVar.    Exp2 ::= Ident;
EInt.    Exp2 ::= Integer;
EDouble. Exp2 ::= Double;

ETimes.  Exp1 ::= Exp1 "*" Exp2 ;
EDiv.    Exp1 ::= Exp1 "/" Exp2 ;

EPlus.   Exp ::= Exp "+" Exp1 ;
EMinus.  Exp ::= Exp "-" Exp1 ;

coercions Exp 2;