Module Modeling.QualifierParser

This module is where any Qualifier strings are interpreted and turned into real qualifier.

It is still unfinished: built qualifiers are not optimal at all. For example, the expression "NOT ( name=='truc' AND age>30 AND age<65 )" builts two AndQualifier, the first one joining "name=='truc' AND age>30", the second one joining the result of the latter with "age < 65". There should better be one AndQualifier joining the three sub-expression.

This was primarily derived from the calculator example given in package 'spark'. For sure the big part was to handle parens... I did not manipulate grammars for years and I did not get back to the theory before doing this, hence purists will surely get mad looking at this. If you are one and wanna give a helpful hand, you're welcome here!

The grammar used here is the following:

qual ::= qual operator qual qual ::= paren_open qual paren_close qual ::= expr expr ::= expr comp_op expr expr ::= paren_open expr paren_close expr ::= term expr ::= not_expr term ::= number term ::= float term ::= string term ::= keypath not_expr ::= not_operator qual comp_op ::= + comp_op ::= * comp_op ::= < comp_op ::= > comp_op ::= == comp_op ::= >= comp_op ::= <= comp_op ::= != comp_op ::= IN comp_op ::= NOT IN operator ::= AND operator ::= OR not_operator ::= NOT

(Refer to the QualifierScanner class for a 'regexp-description' of literals

like 'string', 'keypath', etc.)