9.
ARexx
9.5.5
AmigaDOS Inside and Out
COMMANDS & FUNCTIONS Since the main purpose of ARexx is to serve as a utility language, it is especially adept at handling text and numbers. ARexx includes specific text-handling functions to perform such esoteric tasks as centering a line, stripping out substrings, deleting words, and even reversing a string of characters. ARexx number-handling functions have the ability to convert among decimal, hexadecimal, and binary, find the maximum or minimum in a list, and even set the number of digits of precision in ARexx math operations. (This function is called "FUZZ".) Of course, ARexx is also equipped with a full complement of program control functions. Our little one-line example demonstrated an elementary DO loop; SELECT-WHEN-OTHERWISE and DF-THENELSE conditionals are also supported, in addition to others. A list of the ARexx commands can be found at the end of this chapter. You should refer to this list as you encounter various commands in the examples.
ARexx programs can even issue AmigaDOS commands or launch other programs, so they are really limited only by the imagination of the programmer. Advanced programmers can make use of a full range of highly sophisticated ARexx commands that control interrupts, alter the system configuration, and even access machine addresses. They can also call support libraries that allow opening screens and windows and creating gadgets.
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