# Unambiguous LR grammar for simple calculator.
# F# first test

valuetype int
nonterminals E T F
#nonterminal E int
#nonterminal T int
#nonterminal F int
terminals + *
# these will be used later...
# The first two args are same as for rust, third is string representing
# type of token returned by lexer, last arg is a function of type
# string -> value to be applied to the string text of the parsed token
#valueterminal realnum ~ float ~ Float ~ float
valueterminal number ~ int ~ Num ~ (fun x->int x)
lexterminal LPAREN (
lexterminal RPAREN )
topsym E

E --> E:e + T:t { e + t }
E --> T:t { t }
#T --> T:t * F:f { t*f }
T ==> T:t * F:f {
  let tf = t*f
  if f<>0 && ((tf%f)+tf/f<>t) then
    let (ln,cl) = parser.position(1)
    printfn "Warning: arithmetic overflow line %d, column %d" ln cl
  t*f
  } <==
T --> F:f { f }
F --> LPAREN E:e RPAREN  { e }
F --> number:n { n }

EOF