slc

slc, Switching Logic Circuit.

Prolog interpreter easing verifying and modeling of switching logic and PLC programs.

You could get more info at https://j2e2xae.wordpress.com/slc-interprete-prolog/, a blog in spanish language.

Operators and syntax

slc is a stateful interpreter, the internal state comprises the flags FC,First Consult, and RLO, Result of Last Operation.

FC, determines when logic chain starts so RLO should be loaded.

RLO, works as an accumulator.

The operators ( a, an ) are the only load enabled operators and should begin a logic chain if FC is false, from there on, the rest operators in the chain update RLO.

The store operators and terms, ( =, \=, s, r ), resets FC, so a new chain will start at the next ( a, an ).

Flag RLO could be assigned with the terms ( set, clr ).

There are support for parens evaluation on operators ( a, o, x ).

The values 1/0 mean true/false.

Basic operators

( a, an, o, on, =, \= )

a, an : conjunction operations.

Also works as load when found at the first operation in a logic chain.

o, on : or-inclusive operations.

= : store operation.

\= : store, negated, operation.

Parens

Parens are based on lists, so our parens are square parens.

( a[ ], o[ ] )

a[ ] : and-before-or.

o[ ] : or-before-and.

Additional operators and terms

( x[ ], xn )

x[ ] : xor operation, could use parens.

xn : dual of xor.

( s, r, p, n )

s : set operation.

r : reset operation.

p : rising edge evaluation.

n : falling edge evaluation.

( set, clr )

set : sets RLO flag.

clr : clears RLO flag.

Calling prolog terms

( cal, calc, caln )

cal : unconditional call.

calc : call if true.

caln : call if false.

Examples

To be done.