FNinput(x,y,textlimit)

Copy and paste this tool in BBC BASIC or BBCSDL and execute it
Look carefully at the code to understand what it does. I have put explanation inside to make it easier to
understand
     MODE 8 :REM a graphics screen
     VDU 5:REM makes text have graphics positioning
     REM notice that this doesnt require a loop for your message to be created?
     REM FNinput works on its own
     MOVE 10,500:GCOL 15:PRINT "Type something and press ENTER "
     REM x,y,textlimit  ----- Text limit is the longest you will be allowed to make your text
     M1$=FNinput(100,100,50)
     MOVE 10,200:GCOL 15:PRINT "Your message was: "+M1$

     END
     REM remember this allows input message to be completed before it cycles.
     REM this command takes control until message is entered.
     REM I am working on a more flexible version that can be left and revisited like in windows
     REM so sorta like live multi processes
     REM H,V,TEXTLIMIT (simpler?)
     DEF FNinput(bx,by,textlimit)
     LOCAL fill,MESSAGE$
     initialx%=0:sl%=0:key$="":MESSAGE$="":MES$=""
     initialx%=textlimit*16.2
     FOR fill=1 TO 58
       GCOL 15:LINE bx-4,by+20-fill,bx+initialx%,by+20-fill
     NEXT fill
     GCOL 0:LINE bx+3,by+20,bx+initialx%,by+20:LINE bx+3,by+20-fill,bx+initialx%,by+20-fill
     REPEAT
       REPEAT
         key$ =INKEY$(1)
         GCOL 0
         MOVE bx,by:PRINT MESSAGE$;"_" :* REFRESH
         sl%=LEN(MESSAGE$)
       UNTIL key$ <>""
       sl%=LEN(MESSAGE$)
       IF INKEY(-48) sl%=LEN(MESSAGE$)-1:key$=""
       REPEAT UNTIL INKEY(0)=-1
       IF sl%<LEN(MESSAGE$) THEN
         GCOL 15
         MOVE bx,by
         PRINT MESSAGE$;"_"
       ENDIF
       MES$=MID$(MESSAGE$,0,sl%)
       MESSAGE$=MES$
       GCOL 15:MOVE bx,by:PRINT MESSAGE$;"_"
       IF LEN(key$) = 1 THEN
         IF LEN(MESSAGE$)<textlimit THEN GCOL 15:MOVE bx,by:PRINT MESSAGE$;"_": MESSAGE$=MESSAGE$+key$:* REFRESH OFF
         REM (jump)
       ENDIF
     UNTIL INKEY(-74)
     * REFRESH ON
     =MESSAGE$