Reference for stackexchange question

qdgc_get_recursivestring.sql

-- FUNCTION: public.qdgc_get_recursivestring(double precision, double precision, integer, text)

DROP FUNCTION public.qdgc_get_recursivestring(double precision, double precision, integer, text);

CREATE OR REPLACE FUNCTION public.qdgc_get_recursivestring(
	lon_value double precision,
	lat_value double precision,
	depthlevel integer,
	square text)
    RETURNS text
    LANGUAGE 'plpython3u'
    COST 100
    VOLATILE PARALLEL UNSAFE
AS $BODY$

if  lon_value >1:
	lon_value = lon_value - math.floor(lon_value)
elif (lon_value<-1):
	lon_value = lon_value + abs(math.ceil(lon_value))

if  lat_value >1:
	lat_value = lat_value - math.floor(lat_value)
elif (lat_value<-1):
	lat_value = lat_value + abs(math.ceil(lat_value))

if ((lon_value>=0) and (lat_value>=0)):

	if ((lon_value <0.5) and (lat_value>=0.5)):
		square =  square + 'A'

		lon_value=lon_value*2
		lat_value=(lat_value-0.5)*2

	elif ((lon_value>=0.5) and (lat_value>=0.5)):
		square = square + 'B'

		lon_value=(lon_value-0.5)*2
		lat_value=(lat_value-0.5)*2

	elif ((lon_value<0.5) and (lat_value<0.5)):
		square = square + 'C'

		lat_value=lat_value*2
		lon_value=lon_value*2

		
	elif ((lon_value>=0.5) and (lat_value<0.5)):
		square =  square + 'D'

		lon_value=(lon_value-0.5)*2
		lat_value=lat_value*2


elif ((lon_value>=0) and (lat_value<=0)):

	if ((lon_value <0.5) and (lat_value>-0.5)):
		square = square + 'A'

		lon_value=lon_value*2
		lat_value=lat_value*2
		
	elif ((lon_value>=0.5) and (lat_value>-0.5)):
		square = square + 'B'

		lon_value=(lon_value-0.5)*2
		lat_value=lat_value*2

	elif ((lon_value<0.5) and (lat_value<=-0.5)):
		square = square + 'C'

		lon_value=lon_value*2
		lat_value=(lat_value+0.5)*2
		
	elif ((lon_value>=0.5) and (lat_value<=-0.5)):
		square = square + 'D'

		lon_value=(lon_value-0.5)*2
		lat_value=(lat_value+0.5)*2
		
elif ((lon_value<=0) and (lat_value<=0)):

	if ((lon_value<=-0.5) and (lat_value>-0.5)):
		square = square + 'A'

		lon_value=(lon_value+0.5)*2
		lat_value=lat_value*2
		
	elif ((lon_value>-0.5) and (lat_value>-0.5)):
		square = square + 'B'

		lon_value=lon_value*2
		lat_value=lat_value*2
		
	elif ((lon_value<=-0.5) and (lat_value<=-0.5)):
		square = square + 'C'

		lon_value=(lon_value+0.5)*2
		lat_value=(lat_value+0.5)*2

	elif ((lon_value>-0.5) and (lat_value<=-0.5)):
		square = square + 'D'

		lon_value=lon_value*2
		lat_value=(lat_value+0.5)*2


elif ((lon_value<=0) and (lat_value>=0)):

	if ((lon_value <=-0.5) and (lat_value>=0.5)):
		square = square + 'A'

		lon_value=(lon_value+0.5)*2
		lat_value=(lat_value-0.5)*2

	elif ((lon_value>-0.5) and (lat_value>=0.5)):
		square = square + 'B'

		lon_value=lon_value*2
		lat_value=(lat_value-0.5)*2

	elif ((lon_value<=-0.5) and (lat_value<0.5)):
		square = square + 'C'

		lon_value=(lon_value+0.5)*2
		lat_value=(lat_value)*2

	elif ((lon_value>-0.5) and (lat_value<0.5)):
		square = square + 'D'

		lon_value=lon_value*2
		lat_value=lat_value*2

stringlength = len(square)

if (stringlength < depthlevel):
	r_lon_value = lon_value
	r_lat_value = lat_value
	
	return qdgc_get_recursivestring(r_lon_value,r_lat_value,depthlevel,square)
	
else
	return square    
	
$BODY$;

ALTER FUNCTION public.qdgc_get_recursivestring(double precision, double precision, integer, text)
    OWNER TO postgres;