This note provides a bit more detail for Java programmers on what is going on here; only read on if you want to understand how the use of functions in TOPCAT algebraic expressions relates to normal Java code.
The expressions which you write are compiled to Java bytecode
when you enter them (if there is a 'compilation error' it will be
reported straight away). The functions listed in the previous subsections
are all the public static methods of the classes which
are made available by default. The classes listed are all in the
packages uk.ac.starlink.ttools.func and
uk.ac.starlink.topcat.func
(uk.ac.starlink.topcat.func.Strings etc).
However, the public static methods are all imported into an anonymous
namespace for bytecode compilation, so that you write
(sqrt(x) and not Maths.sqrt(x).
The same happens to other classes that are imported (which can be
in any package or none) - their public
static methods all go into the anonymous namespace. Thus, method
name clashes are a possibility.
This cleverness is all made possible by the rather wonderful JEL.