A goal of Commodities Exchange is to improve user control over input handlers. One way in which it accomplishes this is through the use of standard ToolTypes. The user will expect commodities to recognize the set of standard tool types: CX_PRIORITY CX_POPUP CX_POPKEY CX_PRIORITY lets the user set the priority of a commodity. The string "CX_PRIORITY=" is a number from -128 to 127. The higher the number, the higher the priority of the commodity, giving it access to input events before lower priority commodities. All commodities should recognize CX_PRIORITY. CX_POPUP and CX_POPKEY are only relevant to commodities with a window. The string "CX_POPUP=" should be followed by a "yes" or "no", telling the commodity if it should or shouldn't show its window when it is first launched. CX_POPKEY is followed by a st ring describing the key to use as a hot key for "popping up" the commodity's window. The description string for CX_POPKEY describes an input event. The specific format of the string is discussed later in this article. Commodities Exchange's support library functions simplify parsing arguments from either the Workbench or a CLI. A Workbench launched commodity gets its arguments directly from the tool types in the commodity's icon. CLI launched commodities get their ar guments from the command line, but these arguments look exactly like the tool types from the commodity's icon. For example, the following command line sets the priority of a commodity called HotKey to 5: HotKey "CX_PRIORITY=5" Commodities Exchange has several support library functions used to parse arguments: tooltypearray = char **ArgArrayInit(int argc, char **argv); void ArgArrayDone(void); tooltypevalue = char *ArgString(char **tooltypearray, char *tooltype, char *defaultvalue); tooltypevalue = LONG *ArgInt(char **tooltypearray, char *tooltype, LONG defaultvalue); ArgArrayInit() initializes a tool type array of strings which it creates from the startup arguments, argc and argv. It doesn't matter if these startup arguments come from the Workbench or from a CLI, ArgArrayInit() can extract arguments from either source. Because ArgArrayInit() uses some icon.library functions, a commodity is responsible for opening that library before using the function. ArgArrayInit() also uses some resources that must be returned to the system when the commodity is done. ArgArrayDone() performs this clean up. Like ArgArrayInit(), ArgArrayDone() uses icon.library, so the library has to remain open until ArgArrayDone() is finished. The support library has two functions that use the tool type array set up by ArgArrayInit(), ArgString() and ArgInt(). ArgString() scans the tool type array for a specific tool type. If successful, it returns a pointer to the value associated with that tool type. If it doesn't find the tool type, it returns the default value passed to it. ArgInt() is similar to ArgString(). It also scans the ArgArrayInit()'s tool type array, but it returns a LONG rather than a string pointer. ArgInt() extracts the i nteger value associated with a tool type, or, if that tool type is not present, it returns the default value. Of course, these tool type parsing functions are not restricted to the standard Commodities Exchange tool types. A commodity that requires any arguments should use these functions along with custom tool types to obtain these values. Because the Commodit ies Exchange standard arguments are processed as tool types, the user will expect to enter other arguments as tool types.
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