parser.mly~

%{
    open Ast
%}

%token <int> NUM
%token <string> IDENT
%token TRUE FALSE
%token IF
%token PLUS MINUS TIMES DIV
%token LPAR RPAR
%token EOL

%start line

%type <Ast.expr> line

%%
line:
expr EOL                     { $1 }
;

expr:
    NUM                           { ASTNum($1) }
  | IDENT                         { ASTId($1) }
  | TRUE                          { ASTBool(true) }
  | FALSE                         { ASTBool(false) }
  | LPAR IF expr expr expr RPAR   { ASTIf($3, $4, $5) }
  | LPAR PLUS expr expr RPAR      { ASTPrim(Ast.Add, $3, $4) }
  | LPAR MINUS expr expr RPAR     { ASTPrim(Ast.Sub, $3, $4) }
  | LPAR TIMES expr expr RPAR     { ASTPrim(Ast.Mul, $3, $4) }
  | LPAR DIV expr expr RPAR       { ASTPrim(Ast.Div, $3, $4) }

exprs:
    expr                          { $1 } 
  | expr exprs                    { ASTExpressions($1, $2) }
;