Backup of Library Reference(No. 10)

Library Reference

Note: the LMNtal API is under development and its specification is subject to change.

In the following, arguments with the '+' sign are those consumed upon reaction with the library atoms, while arguments with the '-' sign are those generated by the library API. The slash (/) notation is used to indicate the arity of atoms.

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Library integer

integer.rnd(+N,-H): H is bound to a random number between 0 and N-1.
integer.srnd(+N): Initialize the random number generator using N as the new seed of random numbers.
integer.of_str(+S,-N): N is bound to an integer whose string representation is S.
integer.set(+A,+B,+G): Assume $a[A] and $b[B] are of type int and $g[G] is of type ground. Then creates a multiset $g[$a], $g[$a+1], ..., $g[$b]. For example, n=integer.set(1,100) will be reduced to n=1, ..., n=100.

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Libraty float

float.of_str(+S,-N): N is bound to a floating-point number whose string representation is S.

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Library nlmem

The library nlmem (nonlinear membrane) is used when coping or removing a cell with free links (i.e., links connected to atoms outside the membrane). When copying such cells, the free links should be split by inserting ternary atoms; when removing such cells, the free links should be terminated by a unary atom. The library nlmem contains an implementation of the following rule schemes that use aggregates:

R=nlmem.copy(X,a), {$p[X|*Z]} :-
   R=copied(X1,X2),
   {$p[X1|*Z1]}, {$p[X2|*Z2]},
   a(*Z1,*Z2,*Z).
nlmem.kill(X,b), {$p[X|*Z]} :- b(*Z).

They are rule schemes in the sense that a and b are metasymbols to be replaced by any symbolic names.

nlmem.copy(+{P},+a,-R): An abbreviated form of (nlmem.copy(R0,a,R), {+R0,P}). Creates two copies of the cell {+R0,P} with all its free links renamed, and connects R and the two fresh copies of R0 using a ternary atom with the name a. Furthermore, for each free link L of the original cell {+R0, P} (except R0 that will disappear together with the '+'), nlmem.copy connects the two fresh copies of L and the original L via the ternary atom a.
nlmem.copy(+{P},-R): Same as {nlmem.copy({P},copied,R).
nlmem.kill(+{P},+b): An abbreviated form of (nlmem.kill(R0,b), {+R0,P}). Connects each free link L of the cell {+R0, P} (except R0 that will disappear together with the '+') to the unary atom b.
nlmem.kill(+{P}): Same as nlmem.kill({P},killed).

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Library seq

Library seq is to apply sets of rules R1,..., Rn sequentially to a graph G, that is, rules Rn+1 are applied only after rules in Rn becomes non-applicable.

Each set of rules Rk is specified as a cell containing rules, while the initial graph G is specified as a cell containing G. For instance,

r=seq.run({a}, [{a:-b}, {b:-c. a:-never.}, {c:-d. b:-never.}])

is reduced to

r={d}

r=seq.run(+M,+Rs): M is a cell (called a data cell) and Rs is a list of cells (called rull cells) each containing rules. Applies rules in Rs to the data cell M sequentially from left to right. When reaction terminates for the rules in some rule cell, these rules are removed and the rules in the next rule cell are inserted into the data cell. Stops execution when stop_seq/0 appears in the cell.

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Library io

Input/output in SLIM is done through ports. An operation on a port will return a new port to be used for future operations on the port. A simple program that copies stdin to stdout can be written as:

main.
main :-
  io.read_token(io.stdin, I, S),
  loop(S, eof, I, io.stdout).
        
loop(S, EOF, I, O) :- S == EOF |
  io.free_port(I), io.free_port(O).
loop(S0, EOF, I0, O0) :- S0 \== EOF | 
  io.print_line(O0, S0, O),
  io.read_token(I0, I, S),
  loop(S, EOF, I, O).