Instructions Set.

The instruction set of ORAC includes environments, commands and sub-commands. An input file is made out of a series of environments. Each environment allows a series of commands which might use a few sub-commands. Environments resembles Fortran NAMELIST, but have not been programmed as NAMELIST. The environment name is a string which always starts with a & followed by capital letters. Each environment ends with the instruction &END. Command names are characters strings all in capital letters. Each command reads a variable set of parameters which can be characters and/or numbers (real or integer). There are also commands (structured commands) which are composed of more than one input line. A structured command end with the instruction END and allows a series of sub-commands in its inside. Sub-commands are in lower case and can read sub-string of characters and/or real or integer numbers. In the following section we will describe in details all the supported instruction allow by ORAC .