Separators

White Space

Spaces, tabs, and new lines, frequently referred to as "white space", are treated as separators and may be used freely in problem descriptors to increase readability.  Multiple white spaces are treated by FlexPDE as a single white space.

Commas

Commas are used to separate items in a list, and should be used only where explicitly required by the descriptor syntax.

Semicolons

Semicolons are reserved to signify the end of a label or statement when it is not otherwise clear where the label or statements ends.  If, while parsing equations in a problem descriptor, FlexPDE encounters two mathematical quantities separated by a white space without an intervening mathematical operator it will interpret this to mean that one equation has ended and another equation is about to begin.  If, on the other hand, FlexPDE encounters two mathematical quantities with an intervening mathematical operator it will interpret this to mean a continuation of the equation even if the terms are placed on separate lines.  If a new equation beginning with a mathematical operator  (such as the negation operator '-') follows another equation, the first equation must be terminated with a semicolon to keep FlexPDE from interpreting the two equations as one equation.