| 摘要 |
The invention relates to calculation expression management. In general terms, a calculation expression is a union of variables, constants, operators, functions, delimiter characters and other possible elements, which can be used to produce a result. A sample calculation expression is as follows: 2*3+A*(2+B+C) . The uses of calculation expressions include the creation of formulae, the formation of strings and the implementation of searches for databases. The invention facilitates the implementation of sophisticated calculation expressions. For said purpose, the invention consists in constructing and evaluating calculation expressions from graphical structures representing trees. The graphical structures can be of various different types. |
