Parses the chart code
parse_chartcode(chartcode = NULL)the chart code, usually constructed by create_chartcode()
The function returns a list with the following components:
populationA string identifying the population,
e.g. 'NL','MA', 'TU' or 'PT'.
sexA string "male", "female" or
"undifferentiated".
designA letter indicating the chart design: 'A' = 0-15m,
'B' = 0-4y, 'C' = 1-21y, 'D' = 0-21y, 'E' =
0-4ya.
sideA string indicating the side or yname:
'front', 'back', 'both', 'hgt',
'wgt', 'hdc', 'bmi', 'wfh', 'dsc'
languageThe language in which the chart is drawn. Currently only
"dutch" charts are implemented, but for population == "PT" we
may also have "english".
weekA scalar indicating the gestational age at birth.
Only used if population == "PT".