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Expressions

Operators

BlitzMax supports the following operators. Operators are grouped into levels of precedence, starting with the highest precedence operators:

Operator	Syntax
Sub expression	( Expression )
New object	New Typename
Literal	Value
Identifier	Value
Self object	Self
Super object	Super
Null value	Null
Pi	Pi
True	True
False	False
Member	Expression . Identifier
Index	Expression [ IndexExpressions ]
Call	Expression ( Parameters )
Posate	+ Expression
Negate	- Expression
Bitwise complement	~ Expression
Boolean not	Not Expression
Value byte size	SizeOf Expression
Variable address	Varptr Variable
Convert type expression	Type Expression
Power	Expression ^ Expression
Multiply	Expression * Expression
Divide	Expression / Expression
Remainder	Expression Mod Expression
Bitwise shift left	Expression Shl Expression
Bitwise shift right	Expression Shr Expression
Arithmetic shift right	Expression Sar Expression
Add	Expression + Expression
Subtract	Expression - Expression
Bitwise and	Expression & Expression
Bitwise or	Expression | Expression
Bitwise exclusive or	Expression ~ Expression
Equal	Expression = Expression
Not equal	Expression <> Expression
Less than	Expression < Expression
Greater than	Expression > Expression
Less than or equal	Expression <= Expression
Greater than or equal	Expression >= Expression
Conditional and	Expression And Expression
Conditional or	Expression Or Expression

In addition, the following built in functions are also supported:

Function	Syntax
Character code	Asc ( Expression )
Character	Chr ( Expression )
Value length	Len ( Expression )

Null returns 0, an empty string, an empty array, the null object or a pointer to 0 depending on context.

True and False are integer constants with the values 1 and 0, respectively.

The index operator can be used on either arrays or strings. If used on an array, the element at the specified index is returned. If used on a string, the character code of the character at the specified index is returned.

The Not operator inverts the logic of a boolean expression. If the expression evaluates to true, Not returns false and vice versa.

Asc returns the character value of the first character of a string, or -1 if the length of the string is 0.

Chr constructs a 1 character string with the specified character value.

Len can be used with either a string or array. When used with a string, Len returns the number of characters in the string. When used with an array, Len returns the number of elements in the array. In the case of multidimensional arrays, Len returns the total number of elements.

Boolean expressions

It is frequently necessary to consider an expression as true or false, for example, for use with an If statement.

The rules for determining whether an expression is true or false are:

Expression Type	Truth condition
Numeric	True if value is not equal to 0
Object	True if object is not equal to Null
String	True if length is not equal to 0
Array	True if length is not equal to 0