Lua evolved from a data-entry language devised for PETROBRAS,
the Brazilian oil company in the early 1990s. Its keynote has been
simplicity. The term Lua refers to a
C library and to a programming language which the library implements.
Both aspects have been designed for portability, extendibility and
is a dialect of Lua for RISC OS, which can be
downloaded from this site. The sources can also be downloaded.
It differs from standard Lua in its treatment of arithmetic,
and has built-in libraries giving access to software interrupts.
In consequence it can be used for writing wimp programs.