Engine02 Game Creation - Keywords and Expressions

Keywords and Expressions

Introduction

Variable Type Identifiers

Available Keywords

Eval()

If()

Else

EndIf

Introduction

Keywords can be used in place of certain Commands within

Functions

Variable Type Identifiers

Because there is no clearly-identifiable context for every type of

variable/value

Type		Meaning
R		Identifies the variable as a "Game Variable"/"Register"
P		Identifies the variable as a "Player Variable"
O		Identifies the variable as an "Object Variable"
C		Identifies the value as a "Constant Value" (an explicit number value)

Available Keywords

The following is a list of available Keywords and their uses:

Eval()

Short for "Evaluate", this Keyword signifies that the following string is a Math Expression. This Keyword can be used for writing expressions containing one, two, or three variables in the following formats (using the

Variable Type Identifiers

~Eval(RPC)	R  = P + C
~Eval(RC)	R  = C
~Eval(RO)	R += O
~Eval(R)	R++

Variable Alias Names and Constant Values

~Eval(RPC)	U_TempReg  = A_Player_X_Pos + 160
~Eval(RC)	U_TempReg  = 32
~Eval(RO)	U_TempReg += _Object_X_Pos
~Eval(R)	U_TempReg++

Remember that standard Player Fetching and Object Fetching rules apply when using Player and/or Object Variables.

Operator		Meaning
=		Assignment- The result of the operation on the right will be placed into the variable on the left
+		Addition- The values to the left and right of this operator are added together
-		Subtraction- The value to the right of this operator is subtracted from the value to the left of this operator
*		Multiplication- The values to the left and right of this operator are multiplied together
/		Division- The value to the left of this operator is divided by the value to the right of this operator
<<		Arithmetic Left Shift- The bits of the value to the left of this operator are shifted left the number of times described by the value to the right of this operator. This is a signed operation
>>		Arithmetic Right Shift- The bits of the value to the left of this operator are shifted right the number of times described by the value to the right of this operator. This is a signed operation
&		Logical AND- The value to the left of this operator is ANDed by the value to the right of this operator
\|		Logical OR- The value to the left of this operator is ORed by the value to the right of this operator
^		Logical XOR- The value to the left of this operator is XORed by the value to the right of this operator
%		Modulus- The result of this operation is the remainder of division of the value to the left of this operator by the value to the right of this operator
+=		Addition Assignment- The value of the variable to the left of this operator is increased by the value to the right of this operator
-=		Subtraction Assignment- The value of the variable to the left of this operator is increased by the value to the right of this operator
*=		Multiplication Assignment- The value of the variable to the left of this operator is multiplied by the value to the right of this operator
/=		Division Assignment- The value of the variable to the left of this operator is divided by the value to the right of this operator
<<=		Arithmetic Left Shift Assignment- The bits of the value of the variable to the left of this operator are shifted left the number of times described by the value to the right of this operator. This is a signed operation
>>=		Arithmetic Right Shift Assignment- The bits of the value of the variable to the left of this operator are shifted right the number of times described by the value to the right of this operator. This is a signed operation
&=		Logical AND Assignment- The value of the variable to the left of this operator is ANDed by the value to the right of this operator
\|=		Lorical OR Assignment- The value of the variable to the left of this operator is ORed by the value to the right of this operator
^=		Logical XOR Assignment- The value of the variable to the left of this operator is XORed by the value to the right of this operator
%=		Modulus Assignment- The value of the variable to the left of this operator is made equal to the remainder of division of itself by the value to the right of this operator
++		Increment- The value of the variable to the left of this operator is increased by 1
--		Decrement- The value of the variable to the left of this operator is decreased by 1

If()

This keyword signifies that the following expression is an

"If" Conditional

Variable Type Identifiers

~If(RC)		R <= C

Variable Alias Names and Constant Values

~If(RC)		U_TempReg <= 512

Remember that standard Player Fetching and Object Fetching rules apply when using Player and/or Object Variables.

Operator		Meaning
<		Less Than- This condition is considered true if the value to the left of this operator is less than the value to the right of this operator
>		Greater Than- This condition is considered true if the value to the left of this operator is greater than the value to the right of this operator
<=		Less Than or Equal To- This condition is considered true if the value to the left of this operator is either less than or equal to the value to the right of this operator
>=		Greater Than or Equal To- This condition is considered true if the value to the left of this operator is greater less than or equal to the value to the right of this operator
==		Equal To- This condition is considered true if the values to the left and right of this operator are equal
!=		Not Equal To- This condition is considered true if the values to the left and right of this operator are not equal

Else

This Keyword functions the same as the "

_Else

If Block

~Else

EndIf

This Keyword functions the same as the "

_EndIf

If Block

~EndIf