NAME
ReadArgs - Parse the command line input (V36)
SYNOPSIS
result = ReadArgs(template, array, rdargs)
D0 D1 D2 D3
struct RDArgs * ReadArgs(STRPTR, LONG *, struct RDArgs *)FUNCTION
Parses and argument string according to a template. Normally gets the arguments by reading buffered IO from Input, but also can be made to parse a string. MUST be matched by a call to FreeArgs.
ReadArgs() parses the commandline according to a template that is passed to it. This specifies the different command-line options and their types. A template consists of a list of options. Options are named in "full" names where possible (for example, "Quick" instead of "Q"). Abbreviations can also be specified by using "abbrev=option" (for example, "Q=Quick").
Options in the template are separated by commas. To get the results of ReadArgs(), you examine the array of longwords you passed to it (one entry per option in the template). This array should be cleared (or initialized to your default values) before passing to ReadArgs(). Exactly what is put in a given entry by ReadArgs() depends on the type of option. The default is a string (a sequence of non-whitespace characters, or delimited by quotes, which will be stripped by ReadArgs()), in which case the entry will be a pointer.
Options can be followed by modifiers, which specify things such as the type of the option. Modifiers are specified by following the option with a '/' and a single character modifier. Multiple modifiers can be specified by using multiple '/'s. Valid modifiers are:
/S - Switch. This is considered a boolean variable, and will be set if the option name appears in the command-line. The entry is the boolean (0 for not set, non-zero for set).
/K - Keyword. This means that the option will not be filled unless the keyword appears. For example if the template is "Name/K", then unless "Name=<string>" or "Name <string>" appears in the command line, Name will not be filled.
/N - Number. This parameter is considered a decimal number, and will be converted by ReadArgs. If an invalid number is specified, an error will be returned. The entry will be a pointer to the longword number (this is how you know if a number was specified).
/T - Toggle. This is similar to a switch, but when specified causes the boolean value to "toggle". Similar to /S.
/A - Required. This keyword must be given a value during command-line processing, or an error is returned.
/F - Rest of line. If this is specified, the entire rest of the line is taken as the parameter for the option, even if other option keywords appear in it.
/M - Multiple strings. This means the argument will take any number of strings, returning them as an array of strings. Any arguments not considered to be part of another option will be added to this option. Only one /M should be specified in a template. Example: for a template "Dir/M,All/S" the command-line "foo bar all qwe" will set the boolean "all", and return an array consisting of "foo", "bar", and "qwe". The entry in the array will be a pointer to an array of string pointers, the last of which will be NULL.
There is an interaction between /M parameters and /A parameters. If there are unfilled /A parameters after parsing, it will grab strings from the end of a previous /M parameter list to fill the /A's. This is used for things like Copy ("From/A/M,To/A").
ReadArgs() returns a struct RDArgs if it succeeds. This serves as an "anchor" to allow FreeArgs to free the associated memory. You can also pass in a struct RDArgs to control the operation of ReadArgs() (normally you pass NULL for the parameter, and ReadArgs() allocates one for you). This allows providing different sources for the arguments, providing your own string buffer space for temporary storage, and extended help text. See <dos/rdargs.h> for more information on this. Note: if you pass in a struct RDArgs, you must still call FreeArgs to release storage that gets attached to it, but you are responsible for freeing the RDArgs yourself.
See BUGS regarding passing in strings.
INPUTS
template - formatting string array - array of longwords for results, 1 per template entry rdargs - optional rdargs structure for options. AllocDosObject should be used for allocating them if you pass one in.
RESULT result - a struct RDArgs or NULL for failure.
BUGS In V36, there were a couple of minor bugs with certain argument combinations (/M/N returned strings, /T didn't work, and /K and /F interacted). Also, a template with a /K before any non-switch parameter will require the argument name to be given in order for line to be accepted (i.e. "parm/K,xyzzy/A" would require "xyzzy=xxxxx" in order to work - "xxxxx" would not work). If you need to avoid this for V36, put /K parameters after all non-switch parameters. These problems should be fixed for V37.
Currently (V37 and before) it requires any strings passed in to have newlines at the end of the string. This may or may not be fixed in the future.
SEE ALSO