C# Class Kooboo.Commerce.Rules.Conditions.Parsing.Parser

Grammer: expression : term [ OR term ]... term : factor [ AND factor ] factor : leaf_condition | ( expression ) comparison : identifier comparison_op comparison_value comparison_op : identifier in the available comparison operator list comparison_value : string_literal | number Notes: - leaf_condition means the condition expression without nesting expressions; - term and factor are temp non-terminals used to handle operator (AND, OR) precedence. Expressions could be simply expressed as: condition OR/AND condition, but with this grammer, we are not able to handle operator precendence. We have to split each operator: - Lower precedence operator first, and the operands should be the production rule of a higher precedence operator. - Because precedence(OR) is smaller than precendence(AND), so OR first and we write: expression: term [ OR term] - Then write the 'term' production rule with the higher precedence operator, that is, 'AND', so then we write: term: factor [ AND factor]