SCI Programming Language/Definitions
define
The define statement allows you to define a symbol which will stand for a string of text:
(define symbol lots of text)
will replace symbol, wherever it is encountered as a token, with lots of text and then continue scanning at the beginning of the replacement text. Thus, if we write:
(define symbol some text)
(define same even more)
then:
(symbol)
will become:
(some text)
which then becomes:
(even more text)
enum
The enum statement eases the definition of the various states of a state-variable. Say you want to walk an actor from the door of a room across the floor, up the stairs, and through another door. You have a state-variable called actor-pos which will take on a number of values. These could be defined with defines as follows:
Code:(local actorPos define AT FRONT DOOR 0) define IN ROOM 1) define ON STAIRS 2) define TOP OF STAIRS 3) define UPPER DOOR 4) )or you could get the same result with enum:
Code:(local actor-pos (enum AT FRONT DOOR IN ROOM ON STAIRS TOP OF STAIRS UPPER DOOR ) )Enum defaults its first symbol to O. If you want a different starting value, put it right after the word enum:
Code:(enum 7 AT FRONT DOOR IN ROOM ON STAIRS TOP OF STAIRS UPPER DOOR )sets
AT FRONT_ DOOR
to 7,IN _ ROOM
to 8, etc.The value of an enum may also be defined by an expression, as follows:
Code:(enum AT FRONT DOOR = (+ AT REAR DOOR 1) )Note: Define and enum statements may be included within both global and local variable definitions.
- Notes
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