Reserved_words
A: abs() acos() and and() arraydim() arraysize() asc() asin() at() atan() 
B: beep bell bin$() break 
C: chr$() circle clear circle clear rect clear screen clear window close close printer close window colour color compile continue cos() curve 
D: date$ data dec() dim doc docu docu$() dot 
E: else elsif end endif end sub eof() eor() error euler execute execute$ exit exp() export 
F: fi fill for frac() 
G: getbit$() getscreen$() glob() gosub goto 
H: hex$() 
I: ifimport inkey$ input input at input # instr() int() interrupt 
J: 
K: 
L: label left$() len() line line input line to locallog() lower$() ltrim$() 
M: map() mapx() mapy() max() mid$() min() mod() mouseb mousex mousey 
N: new curve next not numparams 
O: on gosub on goto open open printer open window or or() origin 
P: pause peek peek$ pi poke print print at print using print # printer putbit putscreen 
Q: 
R: ran() rectangle read rem redim repeat restore return reverse right$() rinstr() rtrim$() 
S: seek() sig() sin() static step split() sqr() sqrt() str$() subsystem() system$() 
T: tan() tell text then time$ token() trim$() 
U: until upper$() using 
V: val() 
W: wait wend while window window origin 
X: xor() 
Y: 
Z:
+ - * / ^ ?@:#,;

Expressions used by Yabasic that should not be used as any  argument 
 arraysize 
 at 
 backspace 
 cc 
 cb 
 circledate$ 
 debug del 
 down 
 end 
 enter 
 error 
 esc 
 fatal 
 fontheight f1...f12 
 home 
 infolevel 
 ins 
 interrupt 
 left 
 library 
 lower$ main 
 maxnum 
 note 
 new curve 
 numparams 
 on 
 origin 
 os pi 
 printer 
 rc 
 rightscreen 
 screenheight 
 screenwidth 
 scrdown 
 scrup static 
 tab 
 textalign 
time$ 
 up 
 upper$ 
 version 
 warning window