1. A method for processing handwritten equations on a computer system comprising the steps of: receiving an input pattern comprising an equation which was derived from user handwritten strokes on a graphical user input device; parsing said input pattern utilizing a defined constrained attribute grammar to determine if said input pattern defines a valid pattern within said constrained attribute grammar, said valid pattern including a set of subpatterns satisfying constraints of production rules included in said constrained attribute grammar, said constraints being used by said parsing step to establish correspondence between said subpatterns and said production rules, said constraints including keywords to be identified within said subpatterns; providing a parsed tree from said step of parsing said input pattern when said input pattern is determined to be a valid pattern in said parsing step; deriving and displaying said equation and a result of said equation utilizing said parsed tree by executing an operator at nodes of said parsed tree using operands included in said parsed tree, wherein said receiving, parsing, providing, and deriving steps are performed on said computer system; detecting an edit made to said displayed equation having said result; and editing said parsed tree associated with said equation in response to said edit made to said displayed equation and without changing a structure of said parsed tree when said edit changes only a value or an operator of said equation.
1. A method for processing handwritten equations on a computer system comprising the steps of: receiving an input pattern comprising an equation which was derived from user handwritten strokes on a graphical user input device; parsing said input pattern utilizing a defined constrained attribute grammar to determine if said input pattern defines a valid pattern within said constrained attribute grammar, said valid pattern including a set of subpatterns satisfying constraints of production rules included in said constrained attribute grammar, said constraints being used by said parsing step to establish correspondence between said subpatterns and said production rules, said constraints including keywords to be identified within said subpatterns; providing a parsed tree from said step of parsing said input pattern when said input pattern is determined to be a valid pattern in said parsing step; deriving and displaying said equation and a result of said equation utilizing said parsed tree by executing an operator at nodes of said parsed tree using operands included in said parsed tree, wherein said receiving, parsing, providing, and deriving steps are performed on said computer system; detecting an edit made to said displayed equation having said result; and editing said parsed tree associated with said equation in response to said edit made to said displayed equation and without changing a structure of said parsed tree when said edit changes only a value or an operator of said equation. 10. A method as recited in claim 1 wherein said step of identifying a subpattern further comprises examining a relevance measure of each of said keywords to determine the relevance of said keywords and the order of keywords to be matched to said subpattern.