blambeau/qrb

require 'finitio/syntax/lexer'
require 'finitio/syntax/literals'

grammar Finitio::Syntax::Expressions
  include Finitio::Syntax::Lexer
  include Finitio::Syntax::Literals

  rule expr
    logic_or_expr
  end

  ### Boolean logic

  rule logic_or_expr
      (left:logic_and_expr op:or_operator right:logic_or_expr)
      <Finitio::Syntax::Expr::LogicDyadic>
    | logic_and_expr
  end

  rule or_operator
    spaces? ('or' | '||') spaces?
  end

  rule logic_and_expr
      (left:logic_not_expr op:and_operator right:logic_and_expr)
      <Finitio::Syntax::Expr::LogicDyadic>
    | logic_not_expr
  end

  rule and_operator
    spaces? ('and' | '&&') spaces?
  end

  rule logic_not_expr
      (not_operator term:logic_term)
      <Finitio::Syntax::Expr::LogicNot>
    | logic_term
  end

  rule not_operator
    spaces? ('!' | 'not') spaces?
  end

  rule logic_term
    comparison_expr
  end

  ### Comparisons

  rule comparison_expr
      (left:arith_expr op:comparison_operator right:comparison_expr)
      <Finitio::Syntax::Expr::Comparison>
    | arith_expr
  end

  rule comparison_operator
    spaces? ('==' | '!=' | '<=' | '>=' | '<' | '>' | '=~') spaces?
  end

  ### Arithmetic

  rule arith_expr
    arith_plusminus_expr
  end

  rule arith_plusminus_expr
      (left:arith_multdiv_expr op:plusminus_operator right:arith_plusminus_expr)
      <Finitio::Syntax::Expr::ArithOp>
    | arith_multdiv_expr
  end

  rule plusminus_operator
    spaces? ('+' | '-') spaces?
  end

  rule arith_multdiv_expr
      (left:arith_term_expr op:multdiv_operator right:arith_multdiv_expr)
      <Finitio::Syntax::Expr::ArithOp>
    | arith_term_expr
  end

  rule multdiv_operator
    spaces? ('*' | '/') spaces?
  end

  rule arith_term_expr
      ('-' term:arith_term_expr)
      <Finitio::Syntax::Expr::UnaryMinusOp>
    | oo_call
  end

  ### Function calls

  rule oo_call
      (left:fn_call ('.' right:identifier_expr)+)
      <Finitio::Syntax::Expr::OOCall>
    | fn_call
  end

  rule fn_call
      (fn:term_expr '(' spaces? expr? (comma expr)* spaces? ')')
      <Finitio::Syntax::Expr::FnCall>
    | term_expr
  end

  ###

  rule term_expr
      identifier_expr
    | literal_expr
    | parenthesized_expr
  end

  rule identifier_expr
    (!keyword /[a-zA-Z_][a-zA-Z0-9_]*/)
    <Finitio::Syntax::Expr::Identifier>
  end

  rule literal_expr
    (!eof literal)
    <Finitio::Syntax::Expr::Literal>
  end

  rule parenthesized_expr
    ('(' spaces? expr spaces? ')')
    <Finitio::Syntax::Expr::Parenthesized>
  end

end