10 REM PC-BASIC test 
20 REM DEF FN, DEF SEG, DEF USR syntax
30 OPEN "OUTPUT.TXT" FOR OUTPUT AS 1
40 ON ERROR GOTO 1000
50 DEF
60 DEF FN
70 DEF SEG
80 DEF USR
90 DEF METAL
100 DEF FNA
110 DEF FNA(X)
105 DEF FNA(X)=
120 DEF FNA(X)=1
130 DEF SEG=
140 DEF SEG=1
150 DEF SEG = -1
160 DEF SEG =32768
170 DEF SEG = -32768
180 DEF SEG=65535
190 DEF SEG=65536
200 DEF SEG="a"
230 DEF USR=
240 DEF USR=1
250 DEF USR = -1
260 DEF USR =32768
270 DEF USR = -32768
280 DEF USR=65535
290 DEF USR=65536
300 DEF USR0=0
305 DEF USR 0=0
310 DEF USR9=0
320 DEF USR A=0
330 DEF USR (1-1) = 0
340 DEF USR -1=0
345 DEF USR "a"=0
350 DEF USR0="a"
999 END
1000 PRINT#1, ERR, ERL
1010 RESUME NEXT
