This program will try to answer to the Gary Luckenbaugh's article about FOR…NEXT best practice under ugBASIC.

 
 CLS
 
 ''' RULE #1
 ' Always enter a FOR-NEXT loop at the FOR. Don’t even think about entering 
 ' the middle of a loop. Not surprisingly, “there be dragons here” if you 
 ' do.
 '
 ' In ugBASIC you can enter into a FOR...NEXT without problems.
 
 PRINT "RULE#1"
 PRINT
 
 DIM x1 AS BYTE
 
 x1 = 1
 
 GOTO inTheMiddle1
 
 FOR x1 = 1 TO 10
 
 inTheMiddle1:
 
 	PRINT x1;" ";
 NEXT x1
 
 PRINT
 
 ''' RULE #2
 ' Never leave a FOR-NEXT mid-flight. Use FOR-NEXT to count from the 
 ' beginning to the TO value with steps of STEP. If you feel you must 
 ' leave a FOR in mid-flight, then FOR is not the proper construct.
 '
 ' In ugBASIC you can exit out from a FOR...NEXT without problems.
 
 PRINT:PRINT "RULE #2"
 PRINT
 
 DIM x2 AS BYTE
 
 FOR x2 = 1 TO 10
 
 	PRINT x2;" ";
 	
 	IF x2 > 4 THEN GOTO outOfFor2
 	
 NEXT x2
 
 outOfFor2:
 
 PRINT
 
 ''' RULE #3
 ' If you absolutely must jump out of a FOR, then you must always 
 ' come back to where you left off. The best way to do this is 
 ' via GOSUB to jump out and then RETURN to where you were. 
 ' At the location where you jump out, there should be no 
 ' FORs with the same control variable, in this case i.
 '
 ' In ugBASIC you can jump out using GOTO (see rules #1 and #2)
 ' and you can use the same variable if you jump inside a GOSUB.
 
 ''' RULE #4
 ' Never enter a FOR loop recursively, unless you are using a modern 
 ' BASIC, and even then use recursive subs/functions and not GOTOs 
 ' or GOSUBS
 '
 ' ugBASIC does not support recursion
 
 ''' RULE #5
 ' Don’t try to change the final value or the step when a FOR-NEXT 
 ' is in-flight. You may get away with this on some BASICs and 
 ' not on others.
 '
 ' In ugBASIC you can change initial, final and step value.
 
 PRINT:PRINT "RULE #5"
 PRINT
 
 DIM x5 AS BYTE, f5 AS BYTE, t5 AS BYTE, s5 AS BYTE
 
 f5 = 1: t5 = 10: s5 = 2
 
 FOR x5 = f5 TO t5 STEP s5
 
 	PRINT x5; " ";
 	
 	IF x5 > 4 THEN
 		t5 = 10
 		s5 = 4
 	ENDIF
 	
 NEXT 
 
 PRINT
 
 ''' RULE #6
 ' Don’t change the control variable in-flight:
 '
 ' In ugBASIC you can change the contro variable, as you like.
 
 PRINT:PRINT "RULE #6"
 PRINT
 
 DIM x6 AS BYTE
 
 FOR x6 = 1 TO 10
 
 	PRINT x6;" ";
 	
 	IF x6 > 3 THEN x6 = 10
 		
 NEXT 
 
 PRINT
 
 ''' RULE #7
 ' Draw a line from each FOR to the corresponding NEXT, and make 
 ' sure no lines overlap, as depicted below:
 '
 '     +-- for i = 1 to 10
 '     |
 '+----|--------for j = 1 to 10
 '+    |
 '+    +---next i
 '+
 '+-------next j
 '
 ' Also ugBASIC respects this rule.
 
 

• contrib_for_next_bp.bas

The instructions here refer to compiling the example from the command line. For Microsoft Windows users we suggest using UGBASIC-IDE, which allows you to compile the example with just one click.

In order to compile and run the example, you need to have the Altirra emulator, and in particular that the altirra executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.atari contrib_for_next_bp.bas -o example.xex
 altirra example.xex
 
 # Windows 
 ugbc.atari.exe contrib_for_next_bp.bas -o example.xex
 altirra example.xex

In order to compile and run the example, you need to have the Altirra emulator, and in particular that the altirra executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.atarixl contrib_for_next_bp.bas -o example.xex
 altirra example.xex
 
 # Windows 
 ugbc.atarixl.exe contrib_for_next_bp.bas -o example.xex
 altirra example.xex

In order to compile and run the example, you need to have the VICE emulator, and in particular that the x64sc executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.c64 contrib_for_next_bp.bas -o example.prg
 x64sc example.prg
 
 # Windows 
 ugbc.c64.exe contrib_for_next_bp.bas -o example.prg
 x64sc example.prg

In order to compile and run the example, you need to have the VICE emulator, and in particular that the x64sc executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.c64reu contrib_for_next_bp.bas -o example.prg
 x64sc -reu example.prg
 
 # Windows 
 ugbc.c64reu.exe contrib_for_next_bp.bas -o example.prg
 x64sc -reu example.prg

In order to run the example, you need to have the YAPE emulator. In particular that the yape executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.plus4 contrib_for_next_bp.bas -o example.prg
 yape example.prg
 
 # Windows 
 ugbc.plus4.exe contrib_for_next_bp.bas -o example.prg
 yape example.prg

In order to run the example, you need to have the VICE emulator. In particular that the xplus4 executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.plus4 contrib_for_next_bp.bas -o example.prg
 xplus4 example.prg
 
 # Windows 
 ugbc.plus4.exe contrib_for_next_bp.bas -o example.prg
 xplus4 example.prg

In order to compile and run the example, you need to have the XROAR emulator, and in particular that the xroar executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.d32 contrib_for_next_bp.bas -o example.bin
 xroar -rompath (your rom path) example.bin
 
 # Windows 
 ugbc.d32.exe contrib_for_next_bp.bas -o example.bin
 xroar.exe -rompath (your rom path) example.bin

In order to compile and run the example, you need to have the XROAR emulator, and in particular that the xroar executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.d64 contrib_for_next_bp.bas -o example.bin
 xroar -rompath (your rom path) example.bin
 
 # Windows 
 ugbc.d64.exe contrib_for_next_bp.bas -o example.bin
 xroar.exe -rompath (your rom path) example.bin

In order to compile and run the example, you need to have the DCMOTO emulator, and in particular that the dcmoto executable is accessible.

Then, type this command on the command line and on the emulator:

 # Linux 
 ugbc.pc128op contrib_for_next_bp.bas -o example.k7
 dcmoto
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
 
 # Windows 
 ugbc.pc128op.exe contrib_for_next_bp.bas -o example.k7
 dcmoto
 (choose example.k7)
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC

In order to compile and run the example, you need to have the DCMOTO emulator, and in particular that the dcmoto executable is accessible.

Then, type this command on the command line and on the emulator:

 # Linux 
 ugbc.pc128op contrib_for_next_bp.bas -o example.k7
 dcmoto
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC
 
 # Windows 
 ugbc.pc128op.exe contrib_for_next_bp.bas -o example.k7
 dcmoto
 (choose example.k7)
 (choose BASIC 128)
 CLEAR,&H2FFF: LOADM"CASS:",R: EXEC

In order to compile and run the example, you need to have the VICE emulator, and in particular that the xvic executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.vic20 contrib_for_next_bp.bas -o example.prg
 xvic --memory 24k example.prg
 
 # Windows 
 ugbc.vic20.exe contrib_for_next_bp.bas -o example.prg
 xvic --memory 24k example.prg

In order to compile and run the example, you need to have the Speccy emulator, and in particular that the speccy executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.zx contrib_for_next_bp.bas -o example.tap
 Speccy example.tap
 
 # Windows 
 ugbc.zx.exe contrib_for_next_bp.bas -o example.tap
 Speccy example.tap

In order to compile and run the example, you need to have the openMsx or the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.msx1 contrib_for_next_bp.bas -o example.rom
 openmsx -cart example.rom
 
 # Windows 
 ugbc.msx1.exe contrib_for_next_bp.bas -o example.rom
 openmsx -cart example.rom

 # Linux 
 ugbc.msx1 contrib_for_next_bp.bas -o example.rom
 bluemsx example.rom
 
 # Windows 
 ugbc.msx1.exe contrib_for_next_bp.bas -o example.rom
 bluemsx example.rom

In order to compile and run the example, you need to have the openMsx or the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.coleco contrib_for_next_bp.bas -o example.rom
 openmsx -machine \"COL - ColecoVision\" -cart example.rom
 
 # Windows 
 ugbc.coleco.exe contrib_for_next_bp.bas -o example.rom
 bluemsx -machine \"COL - ColecoVision\" example.rom

 # Linux 
 ugbc.coleco contrib_for_next_bp.bas -o example.rom
 bluemsx /machine \"COL - ColecoVision\" /rom1 example.rom
 
 # Windows 
 ugbc.coleco.exe contrib_for_next_bp.bas -o example.rom
 bluemsx  /machine \"COL - ColecoVision\" /rom1 example.rom

In order to compile and run the example, you need to have the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.sc3000 contrib_for_next_bp.bas -o example.rom
 bluemsx /machine \"SEGA - SC-3000\" /rom1 example.rom
 
 # Windows 
 ugbc.sc3000.exe contrib_for_next_bp.bas -o example.rom
 bluemsx  /machine \"SEGA - SC-3000\" /rom1 example.rom

In order to compile and run the example, you need to have the BlueMSX emulator, and in particular that its executable is accessible.

Then, type this command on the command line:

 # Linux 
 ugbc.sg1000 contrib_for_next_bp.bas -o example.rom
 bluemsx /machine \"SEGA - SG-1000\" /rom1 example.rom
 
 # Windows 
 ugbc.sg1000.exe contrib_for_next_bp.bas -o example.rom
 bluemsx  /machine \"SEGA - SG-1000\" /rom1 example.rom

If you have found a problem trying to run this example, if you think there is a bug or, more simply, you would like it to be improved, open an issue for this example on GitHub. Thank you!