Adding Builders

• Start with the language grammar from the book

  • exp = term | exp + term | exp - term
  • term = fac | fac * atom | fac / atom
  • atom = id | ( exp )

• Add builder symbols; points during parsing where tree nodes are built

  • exp = term | exp + term OP | exp - term OP
  • term = fac | fac * atom OP | fac / atom OP
  • atom = id | ( exp ) BR

• This needs doing first, otherwise you lose info, eg about associativity