I wonder the meaning of MACRO

i wonder the meaning of covermode and MACRO

treenode current = ownerobject(c); //current conveyor object
treenode item = parnode(1); //flowitem that is covering the photoeye
int photoeye = parval(2); //photoeye number (row in the table)
int covermode = parval(3); //mode 1 = green to yellow, mode 2 = yellow to red

#define GreenToYellow 1
#define YellowToRed 2
#define either covermode

Hello kim,
Flexscript follows c syntax rules,so #define preprocessor directive can also be used in Flexscript.
#define directive allows the definition of macros within your source code.These macro definitions allow constant values to be declared for use throughout the code. Macro definitions are not variables and cannot be changed by your program code like variables. You normally use this syntax when creating constants that represent numbers, strings or expressions.See global macros in the manual for more information