, .
.
trace . .
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:
- "CALL" ( ) ; *
- "FAIL" , ;
- "RETURN" , . , , ("*");
- "REDO" , .
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nowarnings , - . . , ("WARNING: The variable is only used once") , , .
include .
, , (Options Compiler Directives). , , , , .
, CONSTANTS, . :
< >=<>
, , , .
.
:
CONSTANTS
pi=3.14
bgi_path="c:\\prolog\\bgi"
, . , - .
, .