Hey y'all ![;-)]( "Wink")
I'm aware that BBC Basic heap management isn't the best, so rather than allocate new space for a string every time I redefine it, I thought I'd just define 256 bytes as a string buffer and work in that when appropriate (indirecting with $strBuff%="...." or similar)
This was initially working fine, but I've now run in to a situation where I am getting 'No Such Variable' errors when trying to indirect into this buffer inside a PROC.
I'm assigning the buffer _after_ MODE change, I've tried DIMing and directly assigning an address, and ensured HIMEM and TOP aren't interfering, but to no avail.
Here's my code; lines 40-70 are my initial test case, but the problems arrive at line 630...Which gives me "No such variable at line 630" and sure enough, when I get the prompt back 'P. strBuff%' says 'No such variable' (although I'm kinda sure that I've had the 'No such variable' error but been able to 'P. strBuff%' successfully on occasion - I might be wrong though)
I'm obviously doing something incredibly stupid here; would any of you be good enough to point out my mistake?![;-)]( "Wink")
Many Thanks In Advance,
Neal
I'm aware that BBC Basic heap management isn't the best, so rather than allocate new space for a string every time I redefine it, I thought I'd just define 256 bytes as a string buffer and work in that when appropriate (indirecting with $strBuff%="...." or similar)
This was initially working fine, but I've now run in to a situation where I am getting 'No Such Variable' errors when trying to indirect into this buffer inside a PROC.
I'm assigning the buffer _after_ MODE change, I've tried DIMing and directly assigning an address, and ensured HIMEM and TOP aren't interfering, but to no avail.
Here's my code; lines 40-70 are my initial test case, but the problems arrive at line 630...
Code:
10REM>SpdAtLat 20MODE1 30VDU19,1,4;0; 40REM DIM strBuff% 255 41strBuff%=&900 60$strBuff%="TEST" 70PROCshwHlt(2,1) 80 90REMPROCsetVars 100REMPROCtitle 110REMPROCscrLayout 120PROCshwUnits 130REMPROCshowVars 140 150END 160 170DEF FNgetArsyOSCol(N%) 180IFN%=0 =0 190IFN%=15 =1 200IFN%=240 =2 210IFN%=255 =3 220=129 230 240DEF PROCshwHlt(P%,C%) 250LOCAL N%,F% 260F%=FNgetArsyOSCol(?&357) 270FOR N%=1 TO LEN($strBuff%) 280IFP%=N% THEN COLOUR C% ELSE COLOUR F% 290PRINTMID$($strBuff%,N%,1); 300NEXT 310ENDPROC 320 330DEF PROCtitle 340COLOUR 131:COLOUR0 350PRINT"Speed At Latitude" 360PRINT"=================" 370COLOUR128:COLOUR2 380PRINTTAB(17,0);" Calculate speed for a" 390PRINTTAB(17,1);" planetary latitude" 400ENDPROC 410 420DEF PROCscrLayout 430GCOL0,3 440MOVE0,0 450DRAW0,960 460DRAW1279,960 470DRAW1279,0 480DRAW0,0 490ENDPROC 500 510DEF PROCshwHlt(P%,C%) 520LOCAL N%,F% 530REM F%=FNgetArsyOSCol(?&357) 540FOR N%=1 TO LEN($strBuff%) 550IFP%=N% THEN COLOUR 3 ELSE COLOUR F% 560PRINTMID$($strBuff%,N%,1); 570NEXT 580ENDPROC 590 600DEF PROCshwUnits 610COLOUR131:COLOUR0 620PRINTTAB(0,2)"Units: "; 630$scrBuff%="units: " 640PROCshwHlt(0,1) 650ENDPROCI'm obviously doing something incredibly stupid here; would any of you be good enough to point out my mistake?
Many Thanks In Advance,
Neal
Statistics: Posted by NealC — Mon Feb 02, 2026 6:04 pm