MY-BASIC

[John]

It's a bug in Script BASIC I need to fix.

I have known about it for years. 

[wangrenxin]

Hi,

I found a way to simulate SELECT CASE in MY-BASIC without adding new keywords. Implemented as a select function as follow, which accepts a variable argument list with a boolean expression, a lambda expression, another boolean expression, and another lambda... The advantage is it accepts not only one constant equivalence case condition, but also a boolean expression with more sub conditions for one case; the disadvantage is it requires a very ugly single line code calling the select function. Maybe it's necessary to add multi-line code linking to MB now, just like what the underline _ does in VB.

Code: Text

1. default = true ' For the default case
2. def select(...)
3.         l = len(...)
4.         if l mod 2 <> 0 then
5.                 print "Parameters not matched.";
6.                 return
7.         endif
8.         for i = 0 to l - 1 step 2
9.                 if ... then ' Evaluates a condition
10.                         _ = ... ' Gets a lambda and executes it
11.                         _()
12.                         return
13.                 else
14.                         _ = ... ' Ignores a lambda argument
15.                 endif
16.         next
17. enddef
18. a = 85
19. select(a >= 85, lambda () (print "A";), a >= 75, lambda () (print "B";), a >= 60, lambda () (print "C";), default, lambda () (print "D";))
20.  

[John]

Script BASIC doesn't have a SELECT/CASE structure either. It does have a flexible IF that works just as well. Actually better as it doesn't have the traditional CASE compare / range / type restrictions.

Code: ScriptBasic

1. a = 85
2. IF a >= 85 THEN
3.   PRINT "A\n"
4. ELSE IF a >= 75 THEN
5.   PRINT "B\n"
6. ELSE IF a >= 60 THEN
7.   PRINT "C\n"
8. ELSE
9.   PRINT "D\n"
10. END IF
11.  

jrs@laptop:~/sb/sb22/test$ scriba simcase.sb
A
jrs@laptop:~/sb/sb22/test$

Code: ScriptBasic

1. DECLARE SUB mb_init ALIAS "mbas_init" LIB "mb"
2. DECLARE SUB mb_dispose ALIAS "mbas_dispose" LIB "mb"
3. DECLARE SUB mb_open ALIAS "mbas_open" LIB "mb"
4. DECLARE SUB mb_close ALIAS "mbas_close" LIB "mb"
5. DECLARE SUB mb_load_str ALIAS "mbas_load_str" LIB "mb"
6. DECLARE SUB mb_run ALIAS "mbas_run" LIB "mb"
7.  
8. mb_code = """
9.    default = true ' For the default case
10.    def select(...)
11.            l = len(...)
12.            if l mod 2 <> 0 then
13.                    print "Parameters not matched.";
14.                    return
15.            endif
16.            for i = 0 to l - 1 step 2
17.                    if ... then ' Evaluates a condition
18.                            _ = ... ' Gets a lambda and executes it
19.                            _()
20.                            return
21.                    else
22.                            _ = ... ' Ignores a lambda argument
23.                    endif
24.            next
25.    enddef
26.    a = 85
27.    select(a >= 85, lambda () (print "A";), a >= 75, lambda () (print "B";), a >= 60, lambda () (print "C";), default, lambda () (print "D";))
28. """
29. mb_init()
30. mb_open()
31. mb_load_str(mb_code)
32. mb_run()
33. mb_close()
34. mb_dispose()
35.  

jrs@laptop:~/sb/sb22/mybasic$ scriba mbcase.sb
A
jrs@laptop:~/sb/sb22/mybasic$

[wangrenxin]

It does have a flexible IF that works just as well. Actually better as it doesn't have the traditional CASE compare / range / type restrictions.

Yes, I can't agree more. IF has done it well.

John, does SB support separating a single statement into multi-lines? I'm a little bit refusing to add these features; but not quite sure.

[John]

does SB support separating a single statement into multi-lines?

Yes it does with the _ character.

Code: ScriptBasic

1. FUNCTION test (arg1, _
2.                arg2, _
3.                arg3)
4.  

[wangrenxin]

Finally, I added Unicode token support to MY-BASIC! For instance I can use Chinese variable now:

Code: Text

1. &#21464;&#37327; = 22
2. &#21478;&#19968;&#20010;&#21464;&#37327; = 7
3. print &#21464;&#37327; / &#21478;&#19968;&#20010;&#21464;&#37327;;
4.  

[wangrenxin]

Finally, I added Unicode token support to MY-BASIC! For instance I can use Chinese variable now:

Code: Text

1. &#21464;&#37327; = 22
2. &#21478;&#19968;&#20010;&#21464;&#37327; = 7
3. print &#21464;&#37327; / &#21478;&#19968;&#20010;&#21464;&#37327;;
4.  

Well, I meant this:

[wangrenxin]

Added an inline data sequence module, now it has a simple equivalent to retro DATA, READ, RESTORE statements

[John]

Great to see you still plugging away at the project. This is a nice enhancement for retro style BASIC compatibility.

Thanks for keeping us in the loop here on All BASIC.

[wangrenxin]

Yep, more stuff to add, although the procedure is very slow
BTW. it also supports REM statement now for comment.

[John]

I recompiled the My-BASIC extension module for Script BASIC and all seems to have went well. The only thing I had to do is add the extra true argument to the mb_run() function wrapper.

Can you give us an update where things are with My-BASIC?

[wangrenxin]

Sure.

There are some minor bugfix, and some other major improvements for MY-BASIC since my last updating here.

   * Added support for applying `ITERATOR/MOVE_NEXT` and `FOR x IN y/NEXT` for collections, class and referenced usertype. https://github.com/paladin-t/my_basic/wiki/Use-iterators
   * Added support for using a non-referenced usertype larger than `sizeof(void*)`. https://github.com/paladin-t/my_basic/wiki/Use-usertype-values#structure
   * Added interpreter forking functions.
   * Added a structured exception handling ability with interpreter forking. https://github.com/paladin-t/my_basic/wiki/Structured-exception-handling
   * Added a multiple condition branching, which is implemented in MY-BASIC code. https://github.com/paladin-t/my_basic/wiki/Multiple-condition
   * Added support for defining an alias for the `LAMBDA` keyword, which is helpful to write neat code. https://github.com/paladin-t/my_basic/wiki/Lambda-abstraction

Recently I'm working on an App powered by MY-BASIC, which will allow users to write game or application in an IDE with modern BASIC syntax. It's aimed to be similar as PICO-8. I'll initially release it for desktop (Windows), still WIP, yet details and releasing date are TBD.

There are also few API changes, which are easy to figure out.

BTW. don't forget to share your use cases with us via https://github.com/paladin-t/my_basic/issues/13.