json ejercicio Balance , Prolog

Language: Layout:

%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

progra:- write('{') ,read(X), (X='atributo' -> pvalor, write('}');
                                               write('}')).
pvalor:- read(X), (X='cadena' -> cadenaid,cadena,valor; 
                    X='numero' -> cadenaid,numero,valor; 
                    X='objeto' -> cadenaid,progra,valor; 
                    X='array' -> cadenaid,array,valor;
                    X='' -> write('')).
valor:- read(X), (X='cadena' -> write(','),cadenaid,cadena,valor; 
                    X='numero' -> write(','),cadenaid,numero,valor; 
                    X='objeto' -> write(','),cadenaid,progra,valor;
                     X='array' -> write(','),cadenaid,array,valor;
                    X='' -> write('')).
cadena:- read(X), write('"'),write(X),write('"').
cadenaid:- read(X), write('"'),write(X),write('":').
numero:- read(X), write(X).
array:- write('['),parray,write(']').
parray:- read(X), (X='cadena' -> cadena,varray; 
                    X='numero' -> numero,varray; 
                    X='objeto' -> progra,varray; 
                    X='array' -> array,varray;
                    X='' -> write('')).
varray:- read(X), (X='cadena' -> write(','),cadena,varray; 
                    X='numero' -> write(','),numero,varray; 
                    X='objeto' -> write(','),progra,varray;
                     X='array' -> write(','),array,varray;
                    X='' -> write('')).
:- progra.

[ - ] Show input
Absolute running time: 0.31 sec, cpu time: 0.15 sec, memory peak: 7 Mb, absolute service time: 0,4 sec