rule returns [double value]
    : exp=multiplyExp { $value = $exp.value; }
    ;


multiplyExp returns [double value]
    :    a1=additionExp     {$value = $a1.value;}
         ( '*' a2=additionExp {$value *= $a2.value;}
         | '/' a2=additionExp {$value /= $a2.value;}
         )*
    ;

additionExp returns [double value]
    :    m1=involutExp      {$value = $m1.value;}
         ( '+' m2=involutExp  {$value += $m2.value;}
         | '-' m2=involutExp  {$value -= $m2.value;}
         )*
    ;

involutExp returns [double value]
    : i1=radicalExp {$value = $i1.value;}
        ( '^' i2=radicalExp {$value = Math.pow($value, $i2.value);}
        )*
    ;

radicalExp returns [double value]
    : r1=logExp {$value = $r1.value;}
        ( 'N' r2=logExp{$value = Math.pow($value, 1.0/$r2.value);}
        )*
    ;

logExp returns [double value]
    : l1 = cosPars {$value = $l1.value;}
    ( 'log' l2=cosPars{$value=Math.log10($l2.value);}
    )*
    ;

cosPars returns [double value]
    :c1 = atomExp {$value = $c1.value;}
    ('cos' c2=atomExp {$value=Math.cos($c2.value);})*
    ;

atomExp returns [double value]
  : primaryExp              {$value = $primaryExp.value;}
  | '(' exp=additionExp ')' {$value = $exp.value;}
  ;

primaryExp returns [double value]
    : Number    {$value = Double.parseDouble($Number.text);}
    | 'pi'      {$value = Math.PI;}
    | 'sin'     {$value = Math.sin($value);}
    ;

Number
    :    ('0'..'9')+ ('.' ('0'..'9')+)?
    ;

WS
    :   (' ' | 't' | 'r'| 'n') {$channel=HIDDEN;}
    ;