Ltrim$ returns a copy of the string StrExpr in which the left
blanks have been trimmed, leading spaces removed. If StrExpr consists
entirely of blanks, ltrim$ returns the empty string.
EXAMPLE
The program
a$ = " Space: The Final Frontier "
b$ = ltrim$(a$)
print ">" a$ "<"
print ">" b$ "<"
produces
> Space: The Final Frontier <
>Space: The Final Frontier <