1.3 Advantages

Comparing FEMLISP with other PDE toolboxes, we observe the following advantages which cannot be easily obtained using conventional languages like Fortran, C, or C++:

1. FEMLISP is interactive. Toolboxes written in conventional languages have to implement this feature themselves or to be linked with some scripting language like Perl or Python. In either case, an artificial interface between scripting level and application language appears, which is not easy to maintain.
2. The editor is integrated in a way that is very difficult to achieve for conventional languages. For example, argument lists of functions appear when typing, and the documentation of functions and variables is available at a keystroke. Also, the debug cycle is as short as it can possibly be: changing a function, recompiling it separately, and testing it in the running environment is usually a matter of only a few keystrokes and fractions of a second.
3. Lisp is very expressive, and programming techniques can be used which would introduce a large overhead in conventional languages. This leads to a concise representation of the underlying mathematical ideas and therefore to a very short and maintainable source code. To achieve maximum benefit, the FEMLISP source code is available under a liberal open source license.