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Hints for Efficient Balisc/Scilab 6.x Coding

• Use type instead of typeof, whenever possible.
• Use nargin, nargout instead of argn.
• Use x==[] instead of isempty(x), whenever possible.
• Use x<>[] instead of ~isempty(x), whenever possible.
• Use issquare instead of size, whenever possible.
• Use length(x) instead of size(x,'*'), whenever possible.
• Use x(length(x)) or x(size(x,'*') instead of x($), whenever possible.
• Use &&, || instead of &, |, whenever possible.
• Use ~(A || B) instead of ~A && ~B (cf. De Morgan's Laws).
• Use ~(A && B) instead of ~A || ~B (cf. De Morgan's Laws).
• Use execstr instead of evstr, whenever possible.
• Use tokens instead of strsplit, whenever possible.
• Use matrix(A,length(A),1) instead of A(:), whenever possible.
• Use A.B instead of A("B") or getfield("B",A), whenever possible.
• Use ones(m,n).*.A instead of repmat(A,m,n), whenever possible.
• Use size(x)==1 instead of isscalar(x) or size(x,'*')==1, whenever possible.
• Use A=[] instead of A(:)=[], whenever possible.
• Use .* and ./ instead * of / for integer types, whenever possible.
• Use a & b instead of bitand(a,b), whenever possible.
• Use a | b instead of bitor(a,b), whenever possible.
• Use (a | b) & ~(a & b) instead of bitxor(a,b), whenever possible.
• Use // Blah Blah only sparingly (cf. #488).
• Use eye() instead of eye(A) or eye(n,m), whenever possible.
• Use {} instead of cell(), whenever possible.
• Use a+imult(b) instead of complex(a,b), whenever possible.
• Use [f,e]=frexp(x) instead of [f,e]=log2(x), whenever possible.
• Use x instead of x<>0, whenever possible.
• Use x.^(1./n) instead of nthroot(x,n), whenever possible.
• Use a+b*%i instead of complex(a,b) or a+imult(b), whenever possible.
• Use A(:,size(A,2):-1:1) instead of flipdim(A,2), whenever possible.
• Use A==B instead of isequal(A,B), whenever possible.
• Use list(A(:),B(:)) instead of lstcat(A,B), whenever possible.
• Use a:(b-a)/(n-1):b instead of linspace(a,b,n), whenever possible.
• Use strrchr(file,'.') instead of fileparts(file,'extension')`, whenever possible.
• Use strncpy(x,n) instead of part(x,1:n), whenever possible.
• Use X=[] instead of X(:)=[] or X(:,:,...)=[], whenever possible.

"Fifty" Ways to Kill Your Scilab 6.x (and Sometimes even Balisc)

1. {1:$}
2. ~who()
3. sleep 1
4. a().b=1
5. 1|who()
6. atan(1,)
7. cell(-1)
8. sin{1}=1
9. 1.*.eye()
10. 1./.eye()
11. 1.\.eye()
12. imult(%s)
13. {1,2}'(1)
14. 1./int8(0)
15. int8(0).\1
16. x=1;x()=[]
17. p=1:$;p(:)
18. a(list())=1
19. eye()/eye()
20. eye()\eye()
21. expm(eye())
22. {list()(:)}
23. if who(),end
24. A=1;A(1,%nan)
25. for i=1:$,end
26. min(eye(),"r")
27. max(eye(),"r")
28. struct("a",{})
29. [null(),null()]
30. ereduc(eye(),1)
31. sprand(-1,1,.1)
32. while who(),end
33. for w=who(),end
34. isvector(list())
35. cumsum(eye(),"r")
36. sprand(1e3,1e3,1)
37. sparse([1 0.5],1)
38. cumprod(eye(),"r")
39. fromJSON("{""""}")
40. triu([%s+%i,1;1,1])
41. covStart(["a";"b"])
42. [insert(),insert()]
43. write(6,1:3,"(I2)")
44. matrix(1,ones(34,1))
45. s.a=1;getfield("b",s)
46. saveafterncommands(1)
47. strsubst("","","","r")
48. permute([2,2],40:-1:1)
49. strsubst('aaa','aa','a')
50. S=struct();S(2,2)=struct()
51. L=list();L(2)=insert();L(1)
52. u=["a","b"];v(1,:)=u,u(:,:)
53. gcf().color_map=rand(2e6,3)
54. a=struct("b",null());a.b=a.b
55. surf(1:2e3,1:2e3,(1:2e3)'*(1:2e3))
56. x=tlist("x");function %x_s(a),end;-x
57. f=gcf();xdel();save(TMPDIR+"/f.sod","f")
58. deff('f(a,b)','plot2d(a,a,style=b)'),f(1,)
59. A=ones(1000,1001);for i=1:1e4,try,inv(A),end,end
60. C{1}=null();save("/tmp/T","C");clear("C");load("/tmp/T")

to be continued ...

Predefined (and Protected) Variables Unique to Balisc

• %balisc

  • Useful to check whether it is Balisc, e.g. use exists("%balisc").
  • Returns a single integer (e.g. 0), which indicates the version of Balisc

• –

  • Shorthand for void()
  • Ignore outputs of functions, e.g. [–,b]=frexp(7.93) (cf. #1003)

Functions Unique to Balisc

• bitpack, bitunpack

• errmsgs

  • Returns predefined error messages and associated error numbers

• fflush

  • Flushes streams opened by mopen or popen

• flintmax

  • Return the largest integer that can be represented consecutively in a floating point value

• funname

• funref

• inner

  • Move or create a variable to or in the inner (current) scope

• intmax

  • Return the largest integer that can be represented in an integer type

• intmin

  • Return the smallest integer that can be represented in an integer type

• isprotected, protect, unprotect

  • Provide an interface to the protection mechanism of arbitrary variables
  • They supersede predef and are easy to use (cf. #420)

• macrofile

• outer

  • Move or create a variable to or in the outer (previous) scope

• popen

  • Executes a command and connects a pipe to the corresponding process

• rmfield

• swapbytes

• typecast

• void

Removed Functions and Keywords

Balisc 2

• lstcat was buggy and slow, use list
• bitstring is a very specialized function and is (now) redundant
  • e.g. use dec2base(typecast(%pi,'uint64'),2,64) instead of bitstring(%pi)
• argn was redundant and rather slow, use nargin and nargout instead.

Balisc 1

• getscilabkeywords redundant, use isprotected, librarieslist, libraryinfo, ...
• predef had limited functionality, use isprotected, protect, unprotect

Balisc 0

• banner useless, nobody needs it
• funptr outdated and useless
• getURL redundant, use http_xxx functions
• oldEmptyBehaviour was annoying, thus completely removed
• otherwise undocumented and redundant, use else
• predef had limited functionality, use isprotected, protect, unprotect
• read_csv redundant, use csvRead
• resume redundant, use return
• splitURL, use msscanf function to do the job
• switch undocumented and redundant, use select
• write_csv redundant, use csvWrite