Associative Arrays (Rosetta)

[Charles Pegge]

Very basic implementation:

Code: OxygenBasic

1.  
2. def n 200
3.  
4.  
5. Class AssociativeArray
6. '=====================
7.  
8.   indexbase 1
9.   string s[n]
10.   sys    max
11.  
12.   method find(string k) as sys
13.   sys i,e
14.   e=max*2
15.   for i=1 to e step 2
16.     if k=s[ i ] then return i
17.   next
18.   end method
19.  
20.   method dat(string k) as string
21.   sys i=find(k)
22.   if i then return s[ i+1]
23.   end method
24.  
25.   method dat(string k, d) as sys
26.   sys i=find(k)
27.   if i=0 then
28.     if max>=n
29.       print "Array overflow" : return 0
30.     end if
31.     max+=1
32.     i=max*2-1
33.     s[ i ]=k
34.   end if
35.   s[ i+1]=d
36.   return i
37.   end method
38.  
39. end class
40.  
41.  
42. '====
43. 'TEST
44. '====
45.  
46. AssociativeArray A
47.  
48. 'fill
49. A.s<={"shoes","LC1",  "ships","LC2",  "sealingwax","LC3",  "cabbages","LC4",  "kings","LC5"}
50. A.max=5
51. 'access
52. print A.dat("ships")       'result LC2
53. A.dat("computers")="LC99"  '
54. print A.dat("computers")   'result LC99
55.  
56.  

http://rosettacode.org/wiki/Associative_arrays/Creation


Charles

[Aurel]

hi Charles
What you think about using associative array as container for array in interpreter?

[Charles Pegge]

I think they are good for small data sets. not very efficient but easy to use.

Here is another implementation, using only 1 string for storage. The storage capacity is flexible, and easy to store.

Code: OxygenBasic

1. Class AssociativeArray  
2. '=====================  
3.  
4.   bstring s,c1,c2,c3
5.   sys     max  
6.   '
7.  method find(string k) as sys  
8.   sys i=instr(s, c1+k+c2)
9.   if i>max then i=0
10.   return i
11.   end method  
12.   '
13.  method dat(string k) as string
14.   'GET  
15.  sys i=find k
16.   if i then
17.     i=instr i,s,c2
18.     sys j=instr(i,s,c3)
19.     if j then return mid s,i+1,j-i-1
20.   end if
21.   end method  
22.   '
23.  method dat(string k, d) as sys
24.   'PUT
25.  sys i
26.   if max=0 then
27.     'SET FIELD MARKERS
28.    c1=chr(1) : c2=chr(2) : c3=chr(3)
29.   else
30.     i=find k
31.   end if
32.   if i=0 then
33.     'APPEND
34.    sys m=max+len(k)+len(d)+3
35.     if m>len s then
36.       s+=nuls 0x1000+m-max 'stretch at least 4k
37.    end if
38.     mid s,max+1,c1+k+c2+d+c3
39.     i=max
40.     max=m
41.   else
42.     'REPLACE
43.    i+=len(k)+2
44.     sys j=instr(i,s,c3)
45.     if j then
46.       'INSERT DATA
47.      s=left(s,i-1)+d+c3+mid(s,j+1)
48.       max=len s
49.     end if
50.   end if  
51.   return i  
52.   end method
53.  
54.   method clear()
55.   s="" : c1="" : c2="" : c3="" : max=0
56.   end method
57.  
58.   method fill(sys n,...)
59.   sys i
60.   indexbase 0
61.   bstring w at @param
62.   n+=n
63.   for i=1 to n step 2
64.     dat w(i),w(i+1)
65.   next
66.   end method
67.  
68. end class  
69.  
70.  
71. '====  
72. 'TEST  
73. '====  
74.  
75. AssociativeArray A  
76.  
77. A.fill 5,"shoes","LC1",  "ships","LC2",  "sealingwax","LC3",  "cabbages","LC4",  "kings","LC5"
78. 'print A.s
79. print A.dat("ships")       'result LC2  
80. A.dat("computers")="LC99"  '  
81. print A.dat("computers")  'result LC99
82. A.clear()
83.  

[kryton9]

I missed this post somehow. Good thing I clicked on Home instead of just Show unread posts...visit.

Cool stuff Charles, but I should never be surprised by what you come up with.

[Charles Pegge]

They are useful for typeless languages - less so for languages that support types and OOP.

[Frankolinox]

the last "Class AssociativeArray" example doesn't run here, I dont know why? Is there a new oxygen dll needed for running? I've got an error about "class" thingy, oxygen cannot read that one.

[Aurel]

work for me...
To better understand how this work and how this can be used
i little bit rearange fill method...well oxygen have really really almost the best way
i have ever see for OOP stuff,even i don't get some things i know something about UDT 

Code: [Select]

Class AssociativeArray 
'===================== 
 
  bstring s,c1,c2,c3
  sys     max 
  '
  method find(string k) as sys 
  sys i=instr(s, c1+k+c2)
  if i>max then i=0
  return i
  end method 
  '
  method dat(string k) as string
  'GET 
  sys i=find k
  if i then
    i=instr i,s,c2
    sys j=instr(i,s,c3)
    if j then return mid s,i+1,j-i-1
  end if
  end method 
  '
  method dat(string k, d) as sys
  'PUT
  sys i
  if max=0 then
    'SET FIELD MARKERS
    c1=chr(1) : c2=chr(2) : c3=chr(3)
  else
    i=find k
  end if
  if i=0 then
    'APPEND
    sys m=max+len(k)+len(d)+3
    if m>len s then
      s+=nuls 0x1000+m-max 'stretch at least 4k
    end if
    mid s,max+1,c1+k+c2+d+c3
    i=max
    max=m
  else
    'REPLACE
    i+=len(k)+2
    sys j=instr(i,s,c3)
    if j then
      'INSERT DATA
      s=left(s,i-1)+d+c3+mid(s,j+1)
      max=len s
    end if
  end if 
  return i 
  end method

  method clear()
  s="" : c1="" : c2="" : c3="" : max=0
  end method

  method fill(sys n,...)
  sys i
  indexbase 0
  bstring w at @param
  n+=n
  for i=1 to n step 2
    dat w(i),w(i+1)
  next
  end method
 
end class 
 
 
'==== 
'TEST 
'==== 
 
AssociativeArray A 
 'fill key-value pair
A.fill 1,"shoes","LC1" 
A.fill 1,"ships","LC2"
A.fill 1,"sealingwax","LC3"
A.fill 1,"cabbages","LC4"
A.fill 1,"kings","LC5"

'print A.s
print A.dat("ships")       'result LC2 
A.dat("computers")="LC99"  ' 
print A.dat("computers")  'result LC99
A.clear()


[Aurel]

I think that this can be very good container...

Code: [Select]

Class AssociativeArray 
'===================== 
 
  bstring s,c1,c2,c3
  sys     max 
  '
  method find(string k) as sys 
  sys i=instr(s, c1+k+c2)
  if i>max then i=0
  return i
  end method 
  '
  method dat(string k) as string
  'GET 
  sys i=find k
  if i then
    i=instr i,s,c2
    sys j=instr(i,s,c3)
    if j then return mid s,i+1,j-i-1
  end if
  end method 
  '
  method dat(string k, d) as sys
  'PUT
  sys i
  if max=0 then
    'SET FIELD MARKERS
    c1=chr(1) : c2=chr(2) : c3=chr(3)
  else
    i=find k
  end if
  if i=0 then
    'APPEND
    sys m=max+len(k)+len(d)+3
    if m>len s then
      s+=nuls 0x1000+m-max 'stretch at least 4k
    end if
    mid s,max+1,c1+k+c2+d+c3
    i=max
    max=m
  else
    'REPLACE
    i+=len(k)+2
    sys j=instr(i,s,c3)
    if j then
      'INSERT DATA
      s=left(s,i-1)+d+c3+mid(s,j+1)
      max=len s
    end if
  end if 
  return i 
  end method

  method clear()
  s="" : c1="" : c2="" : c3="" : max=0
  end method

  method fill(sys n,...)
  sys i
  indexbase 0
  bstring w at @param
  n+=n
  for i=1 to n step 2
    dat w(i),w(i+1)
  next
  end method
 
end class 
 
 
'==== 
'TEST 
'==== 
 
AssociativeArray A 
 'fill key-value pair
A.fill 1,"shoes","LC1" 
A.fill 1,"ships","LC2"
A.fill 1,"sealingwax","LC3"
A.fill 1,"cabbages","LC4"
A.fill 1,"kings","LC5"

'print A.s
print A.dat("ships")       'result LC2 
A.dat("computers")="LC99"  ' 
print A.dat("computers")  'result LC99
A.clear()

'new
AssociativeArray arr01

arr01.fill 1,"a","10"
arr01.fill 1,"b","20"
arr01.fill 1,"c","10"

print arr01.dat("b")  ' res 20
arr01.dat("d") = "40"
print arr01.dat("d")  'res 40

[Aurel]

And another small example with asci char map with assoc-array

Code: [Select]

Class AssociativeArray 
'===================== 
 
  bstring s,c1,c2,c3
  sys     max 
  '
  method find(string k) as sys 
  sys i=instr(s, c1+k+c2)
  if i>max then i=0
  return i
  end method 
  '
  method dat(string k) as string
  'GET 
  sys i=find k
  if i then
    i=instr i,s,c2
    sys j=instr(i,s,c3)
    if j then return mid s,i+1,j-i-1
  end if
  end method 
  '
  method dat(string k, d) as sys
  'PUT
  sys i
  if max=0 then
    'SET FIELD MARKERS
    c1=chr(1) : c2=chr(2) : c3=chr(3)
  else
    i=find k
  end if
  if i=0 then
    'APPEND
    sys m=max+len(k)+len(d)+3
    if m>len s then
      s+=nuls 0x1000+m-max 'stretch at least 4k
    end if
    mid s,max+1,c1+k+c2+d+c3
    i=max
    max=m
  else
    'REPLACE
    i+=len(k)+2
    sys j=instr(i,s,c3)
    if j then
      'INSERT DATA
      s=left(s,i-1)+d+c3+mid(s,j+1)
      max=len s
    end if
  end if 
  return i 
  end method

  method clear()
  s="" : c1="" : c2="" : c3="" : max=0
  end method

  method fill(sys n,...)
  sys i
  indexbase 0
  bstring w at @param
  n+=n
  for i=1 to n step 2
    dat w(i),w(i+1)
  next
  end method
 
end class 
 
 
'==== 
'TEST 
'==== 
 
'new
AssociativeArray arr01
int n
string cr=chr(13)
string ch="",value,buff=""
'A-Z
'n=65
For n=65 to 90
  value = str(n)
  ch    = chr(n)
    arr01.fill 1,ch,value
    buff = buff + ch + " " + arr01.dat(ch) + cr   
Next n
'asci map from 65-90
print buff


[Frankolinox]

my mistake, the problems was caused by the numbers (1.,2.,3. ..) in front of codelines, I deleted all and array example works fine.

[Aurel]

They are useful for typeless languages

Hello Charles

Let say that i want to add Lists() of elements in my interpreter.
Can i use associative array that i can hold different types of elements in that list like:

List{a} = [ "mystring", myInt, myFloat]

[Brian Alvarez]

I like them, but they are not for exactly fitted executables. The main problem with associative arrays
in executables is that they could raise runtime errors. I have a half baked implementation:

Code: [Select]

DIM Arr(10) AS ASSOCIATIVE
This way you can do something like:

Code: [Select]

Arr("name") = "Brian"
Arr(0)   = "Something else"
Arr(10) = 29883
But you wouldnt be able to do, for example:

Code: [Select]

FOR Arr(10) = 1 to 10
    ' Some code.
NEXT
 This had a good purpose for CGI scripting though. I will see if i can finish the implementation for Oxygen.

[Aurel]

Hi Brian

The main problem with associative arrays
in executables is that they could raise runtime errors

After i finish core with expression parser and vars,loops i will try to add it .
of course they need test..

runtime errors that is not fine ,they are UDT so that is a problematic part
i will see...
to have List in lang would be fine !

[Brian Alvarez]

 I implemented them for simple purposes. Direct values.

 They still dont support storing UDT's or Arrays in them though.

[Brian Alvarez]

In the image it does not show, but Ar("something") is also supported.