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Set managment in MLC, new instructions


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I have added instructions to manage sets in MLC and the PreCompiler.

A set is an interval of integers, for example

DIMSET 5 160 A

defines A as a set that can contain 156 numbers from 5 to 160.

Each element is stored in a single bit, so that is the main advantage: you can manage large sets without taking much memory.


ELEMENT+ A 12	; add element 12 in set A
ELEMENT- A 100	; remove element 100 from set A
ELEMENT? A 12	; test if 12 is in set A
; here actions if element is in set
; here if it is not in the set

As you can see, adding, removing and testing elements is easy, you don't have to manage yourself the bit level.


SETFILL A	; fills A, all elements present
SETCLEAR A	; clear A all elements removed
SETCARD A B	; returns in B the cardinal of A (number of elements present)
SETCOMP A	; turns A into its complement
SETFINDNEXT A B ; search in A the next element present starting from B, and returns it in B
; here actions if an element was found
; here if no more element was found


If you have several sets you can do unions, intersections, differences


SET+ A B	; A = A union B
SET* A B	; A = A inter B
SET- A B	; A = A - B


As an example, I have written the program to search for prime numbers from 2 to 32767. (this set is only 4KB long to manage 32766 numbers).


It takes only 22 seconds to find the 3512 prime numbers.


100 CALL CLEAR::DIM A$(48)
$MLC F 110 10 3000
320 PRINT C;" prime numbers"::PRINT "from 2 to 32767."
330 END
DIMSET 2 32767 A		; a is a set with elements from 2 to 32767
SETFILL A			   ; all elements in A
LET B 2				 ; first element to find
	SETFINDNEXT A B	 ; start looking for an element in A starting from B
WHILE=				  ; if found, then B=element number, and B is PRIME
	LET C B			 ; take the prime number
		ADD C B		 ; computes 2*B, 3*B, 4*B, etc...
	WHILE>			  ; when it's over 32767, it is considered as negative.
		ELEMENT- A C	; and remove this list from A
	INC B			   ; see if there is another prime number after B
SETCARD A C			 ; computes cardinal of set A
PUTPARAM 1 C			; and return the cardinal




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The idea of using bit sets is very cool. Like it!


Thanks! I think this is important on a machine with precious free bytes !!



After a problem on my WEB page, everything has been now updated:


For MLC with its documentation:

http://gtello.pagesperso-orange.fr/mlc_f.htm (français)

http://gtello.pagesperso-orange.fr/mlc_e.htm (english)


For the PreCompiler with on line documentation:

http://gtello.pagesperso-orange.fr/precompiler.htm (Fra & Eng)



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