JSON con asignaciones y decisiones dentro de una función, Prolog

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%commands to the interpreter are submitted from stdin input ('show input' box below)
%'halt.' will be automatically appended to stdin input.
%swi-prolog 7.6.4

%Usar 'fin.' para terminar un objeto
%Usar 'otro.' para añadir otro elemento

%Ejemplo: 
%objeto1.
%objeto.
%halt.
%mas.
%objeto2.
%cadena.
%sdsd.

objeto :- write('{'),key,write('}').
key :- read(X),(X='fin'->write('');X='halt'->write('');
                X='otro'->write(','),key;
                write('"'),write(X),write('"'),
                write(':'),valor).
valor :- read(X),(X='cadena'->cadena; 
                  X='numero'->numero; 
                  X='objeto'->objeto;
                  X='funcion'->funcion),key.
numero :- read(X),write(X).
cadena :- read(X), write('"'),write(X),write('"').
funcion :- write('"function(){'),instruccion,
           write('return '),read(Y),write(Y),write(';'),
           write('}"').
instruccion :- read(X),(X='asignacion'->asignacion;
                        X='decision'->decision;                                                
                        X='fin'->write('')).
decision :- write('if('),read(X),write(X),write(')'),verdadero,falso,instruccion.
            
verdadero :-write('{'),instruccion,write('}').
falso :- write(' else{'),instruccion,write('} '). 
asignacion :- numero,write('='),numero,write('; '),instruccion.
:- objeto.

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