Radio Shack TRS-80 PC-3 Owner's Manual page 230

Precautions
Programs for the PC-1, when loaded from its tape, can be used with the PC-3. When entering the PC-1 programs into this unit
from PC-3 keyboard, however, the following precautions should be observed:
For example, the following are keyed-in for program entry:
10 IF N
=
LPRINT A
(ENTER)
With the PC-1, this results in a command for "If N = L, display A"
(I F N= L PR INT A). With the PC-3, however, it becomes a command for "If N =, print A" (I F N= LPRINT A), causing a syntax
error (ERROR 1) to occur when executed. This is because the PC-3 has an LPRINT command unavailable from the PC-1.
Therefore, an IF statement should be keyed-in as:
10 IF N=L THEN PRINT A
Thus, a character string for "variable and command" with the PC-1 may be regarded as "a command".
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