GROUP Class


Parameter: a list of sub-rules enclosed in parenthesis, comma can be used as separator in the list.

Optional modifiers: PREF, SUF, SEP, NULL.

Algorithm:
Processes each sub-rule of the list; if at least one variable gives a result, processes the sub-rule specified by PREF and SUF; if at least two variables give a result, processes the sub-rule specified by SEP; then builds the result string by concatenating the PREF result, then the result of each variable for which a result exists, inserting between each pair of existing results the SEP result, and finally the SUF result. If there is no variable giving a result, processes the sub-rule specified by NULL, and returns the NULL result.

Example
col_min_max GROUP (col_len, col_dec)
PREF = "("
SEP = " AND "
SUF = ")"
NULL = "Length and number of decimals are undetermined.";

col_len ATTR ColumnLength
PREF = "$name;'s length is : ";

col_dec ATTR ColumnDecimal
PREF = "$name;'s nb of decimals is : ";


The ColumnLength and ColumnDecimal repository functions return the length of the number of decimals of a column. If the column is price, the length is 10 and the number of decimals is 5, the result will be price's length is: 10 and price's nb of decimals is: 5. If the length is undetermined, the result will be: price's nb of decimals is: 5; if both are undetermined, the result will be: length and number of decimals are undetermined.