# types Expr, Calcscanner defined in exprtrees.rs
!use bumpalo::Bump;
!use crate::bxprtrees::*; /* ! lines are injected verbatim into parser */
!use crate::bxprtrees::Expr::*;
!use rustlr::{LC,Bumper};

lifetime 'lt
absyntype Expr<'lt>
externtype Bumper<'lt,()>
nonterminals E ES
terminals + - * / ( ) = ;
terminals let in
typedterminal int i64
typedterminal var &'lt str
topsym ES
resync ;

left * 500
left / 500
left + 400
left - 400
nonassoc = 300

lexvalue int Num(n) n
lexvalue var Alphanum(x) x
lexattribute set_line_comment("#")

E --> int:m { Val(m) }
E --> var:s { Var(s) }
E --> E:e1 + E:e2 { Plus(e1.make(parser.exstate.get()),e2.make(parser.exstate.get())) }
E --> E:e1 - E:e2 { Minus(e1.make(parser.exstate.get()),e2.make(parser.exstate.get())) }
E --> E:e1 * E:e2 { Times(e1.make(parser.exstate.get()),e2.make(parser.exstate.get())) }
#E --> E:e1 / E:e2 { Divide(e1.make(parser.exstate.get()),e2.make(parser.exstate.get())) }
E --> E:e1 / E:e2 { Divide(e1.make(parser.exstate.get()),parser.exstate.make(parser.lc(2,e2))) }
E(600) --> - E:e { Negative(parser.exstate.make(parser.lc(1,e))) }
E --> let var:x = E:e in E:b {Letexp(x,e.make(parser.exstate.get()),b.make(parser.exstate.get()))}
E --> ( E:e )  { e }

ES ==> E:n ; {
  let bump = &parser.exstate;
  let mut v1 = Vec::new(); /* not bump-allocated */
  v1.push(bump.make(parser.lc(0,n)));
  Seq(v1)
  } <==
  
ES ==> ES:@Seq(mut v)@  E:e ;  {
   v.push(parser.exstate.make(parser.lc(1,e)));
   Seq(v)
   } <==

EOF