Operators: Difference between revisions

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{
{
   print( "This line DOES get printed." );
   print( "This line DOES get printed." );
   // evaluated right-to-left
   // && has highest precedence
   // true or (true && false) returns true
   // true or (true && false) returns true
}
}

Revision as of 16:54, 26 January 2011

Mathematical Operators

The following mathematical operators are used in KoLmafia:

+ AdditionPerforms addition and string concatenation
- SubtractionPerforms subtraction
* MultiplicationPerforms multiplication
/ DivisionPerforms division
 % ModuloReturns the remainder after division
** ExponentPerforms exponentiation

Note that, with the exception of using "+" for string concatenation, these operators can only be used on int or float datatypes.

Bitwise Operators

The following mathematical operators are used for operating on the bits of integers. The operands must be integers; no coercion is allowed:

& anda & b
| ora | b
~ not~a
<< left shifta << b
>> right shifta >> b
&= anda &= b --> a = a & b
|= ora |= b --> a = a | b
>>> unsigned right shifta >>> b


Assignment Operators

The following assignment operators are used in KoLmafia (let a = left operand, b = right operand):

= a = b
+= a = a + b
-= a = a - b
*= a = a * b
/= a = a / b
 %= a = a % b
**= a = a ** b
>>= a = a >> b
>>>= a = a >>> b

Of these, only += and = are usable for strings. See Mathematical Operators for information regarding the basic Mathematical Operators.

Relational Operators

To follow these examples, a basic understanding of the concepts found on Control Structures would be helpful.

In order to create more complex if statements, we need to understand the basic relational operators:

== equal to
 != not equal to
< less than
> greater than
<= less than or equal to
>= greater than or equal to

Note that you cannot mix datatypes within a comparison or KoLmafia will abort with an error, with the exception of mixing types int and float, where KoLmafia will do a transparent type conversion behind-the-scenes. If you need to compare different datatypes, use one or more of the Datatype Conversion functions. Also, == is case-insensitive with respect to strings.


if ( true == true )
{
   print( "This line DOES get printed." );
}
if ( true == false )
{
   print( "This line does NOT get printed." );
}
if ( 1 == 1.0 )
{
   print( "This line DOES get printed." );
}
if ( 1 == 2 )
{
   print( "This line does NOT get printed." );
}
if ( "Hello" == "hello" )
{
   print( "This line DOES get printed." );
}

Boolean Operators

&& and
|| or
 ! not

Note that the above operators only work with boolean values & datatypes. To make use of them with other datatypes, you will either need to first perform a Datatype Conversion, or you will need to nest your operations such that a boolean value is used with the boolean operators.

if ( true && true )
{
   print( "This line DOES get printed (both possibilities proved true)." );
}
if ( true && false )
{
   print( "This line does NOT get printed (only one possibility proved true)." );
}
if ( true || false )
{
   print( "This line DOES get printed (since at least one of the possibilities proved true)." );
}
if ( ! false )
{
   print( "This line DOES get printed (since the not operator converted false to true)." );
}


Operator Precedence

KoLmafia follows Java's Operator Precedence rules with a few exceptions.

(The exceptions being operators that exist in only one or the other; operators that exist in both have the same precedence in both.)

14 (reserved for postfix ++ and --)
13 ! ~ contains remove (reserved for prefix ++ and --)
12 **
11 * / %
10 + -
9 << >> >>>
8 < > <= >=
7 == !=
6 &
5 ^ (xor)
5 |
3 &&
2 ||
1(reserved for ?:(ternary conditional))
0 (reserved for assignments)


Statements inside a () pair are always evaluated first, then in order of precedence as listed above (highest number precedence first), then left-to-right.

if ( true || true && false )
{
   print( "This line DOES get printed." );
   // && has highest precedence
   // true or (true && false) returns true
}
if ( ( true && false ) && true )
{
   print( "This line does NOT get printed." );
   // ( true && false ) is evaluated first since it is inside of parentheses
   // so we end up evaluating ( false && true ) which returns false
}
if ( true && ! ( true && false ) )
{
   print( "This line DOES get printed." );
   // ( true && false ) is evaluated first since it is inside of parentheses
   // the ! operator converts the false from ( true && false ) to true
   // ( true && true ) returns true
}