3.1.3 Standard Parameter Names In the descriptions of the built-in functions, several generic names are used for parameters, to indicate something about the type and use of that parameter, e.g. valid range. To avoid repeating the same information for the majority of the functions, some common “rules” for the standard parameter names are stated here. These rules implicitly apply for the rest of this chapter. Note that the following list does not try to classify any general REXX “datatypes”, but provides a binding between the sub-datatypes of strings and the methodology used when naming parameters. · Length is a non-negative whole number within the internal precision of the built-in functions. Whether it denotes a length in characters or in words, depends on the context. · String can be any normal character string, including the nullstring. There are no further requirements for this parameter. Sometimes a string is called a “packed string” to explicitly show that it usually contains more than the normal printable characters. · Option is used in some of the functions to choose a particular action, e.g. in DATE() to set the format in which the date is returned. Everything except the first character will be ignored, and case does not matter. note that the string should consequently not have any leading space. · Start is a positive whole number, and denotes a start position in e.g. a string. Whether it refers to characters or words depends on the context. The first position is always numbered 1, unless explicitly stated otherwise in the documentation. Note that when return values denotes positions, the number 0 is generally used to denote a nonexistent position. · Padchar must be a string, exactly one character long. That character is used for padding. · Streamid is a string that identifies a REXX stream. The actual contents and format of such a string is implementation dependent. · Number is any valid REXX number, and will be normalized according to the settings of NUMERIC before it is used by the function. If you see one of these names having a number appended, that is only to separate several parameters of the same type, e.g. string1, string2 etc. They still follow the rules listed above. There are several parameters in the built-in functions that do not easily fall into the categories above. These are given other names, and their type and functionality will be described together with the functions in which they occur.