KEY_ADD

Syntax

KEY_ADD (keyword$)

Location

BeuleTools

This function returns the start address of where the machine code routine for the given keyword is stored. If the keyword is unrecognised by the system, 0 will be returned. This command will work from MultiBASICs and Multiple SBASICs.

Example 1

The file server functions of Toolkit II will only work if the code is in ROM, on an EPROM cartridge, under SMS or on a Trump Card for example.

Nevertheless, the FSERVE command is also found in the configurable software version. You can easily check what version of Toolkit II is present by looking at the base address of TK2_EXT and then adapt your program to take account of the system configuration.

100 TK2_location=KEY_ADD("TK2\_EXT")
105 FILE_SERVER=0
110 SELect ON TK2_location
120   = 48*1024 TO 64*1024: FILE_SERVER=1
130   = REMAINDER: IF VER$='HBA': FILE_SERVER=1
140 END SELect
150 :
160 IF FILE_SERVER THEN
170   FSERVE
180 ELSE PRINT "Sorry, no ROM based file server."
190 END IF

Example 2

KEY_ADD does not produce an error (unlike ELIS) when a keyword is not found, and is therefore ideal to check if a certain Toolkit, command or function is present. This can be used within programs to adapt to available facilities.

In this example the internal date and time is saved as a hexadecimal number (this is more precise) if the necessary functions are present, otherwise it saves it as a floating point number.

The load routine then checks if the DATE was stored as a hexadecimal or decimal number, taking whatever action is necessary.

100 DateFile$="flp1_LastDATE_dat"
110 :
120 DEFine PROCedure WRITE\_DATE
130   IF KEY_ADD("OPEN_OVER") THEN
140   OPEN_OVER#3,DateFile$
150   ELSE OPEN#3,DateFile$
160   END IF
170   IF KEY_ADD("HEX$") AND KEY_ADD("HEX") THEN
180     PRINT#3,"$" & HEX$(DATE,32)
190   ELSE PRINT#3,DATE
200   END IF
210   CLOSE#3
220 END DEFine WRITE_DATE
230 :
240 DEFine PROCedure READ_DATE
250   LOCal d$
260   OPEN_IN#3,DateFile$
270   INPUT#4,d$: CLOSE#3
280   IF d$(1)="$" THEN
290   IF NOT KEY_ADD("HEX") THEN RETurn
300   d$=HEX(d$(2 TO))
310   END IF
320   ADATE d$-DATE
330 END DEFine READ_DATE

CROSS-REFERENCE

ELIS differs from KEY_ADD in that it returns zero if the keyword is not found, rather than an error message. See also KEYW and LOOKUP%. FIND and FLIS are also useful.