The Script Programming Language/Definitions

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The Script Programming Language

Definitions

Author: Jeff Stephenson

 


Definitions


define:

The define statement allows you to define a symbol which will stand for a string of text:

Code:
(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

Code:
(define symbol some text) 
(define some even more)

then

Code:
(symbol)

will become

Code:
(some text)

which then becomes

Code:
(even more text)


enum:

A construct for easing the definition of various states of a state-variable is enum. 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, which could be defined with defines:

Code:
(local    actor-pos 
     (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 0. 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.


synonyms:

The synonyms statement defines synonyms of words. All words must have been defined in the vocabulary file (see separate Vocabulary documentation). The statement

Code:
(synonyms 
     (main-word  synonym1 synonym2 ...) 
     ... 
)

defines the words synonym1, synonym2, etc. to be synonyms of main-word. In input being interpreted by the script in which the synonym statement is defined, user input of synonym1 will be interpreted as if the user had typed main-word.


 

Notes


 

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