How to do a bubble sort in Occam

Question

I am trying to program in occam, and I think that it is not so easy to understand because the documentation is not so good. Anyway, I hope someone to help me.

I am trying just to learn how make a simple program. A bubble sort in occam.

#INCLUDE "course.module"
[32]INT x:
INT aux:   
BOOL flag:    
flag:= TRUE    
aux:=0

--put values on the array    
SEQ k=0 for 10    
  x[i] = -x[i]

-- bubble sort
WHILE (flag)      
  SEQ i = 0 for 9      
    IF    
      x[i] > x[i+1]    
        aux:= x[i]    
        x[i]:= x[i+1]    
        x[i+1] := aux    
  flag:= false    
:

I got this image on the terminal: What is wrong with this code?

Answer 1

occam-pi is indentation sensitive

A few hints in the code may help and courtesy of TiO-IDE may provide a place for online experimentation:

#INCLUDE "course.module"
PROC main( CHAN BYTE keyboard, screen, error )

  [32]INT  x:
  INT      aux:
  BOOL     flag:

  SEQ -- ------------------------- BoSEQ:
    SEQ i = 0 FOR 31   -- SEQ used as <-an-iterator->
      x[i] :=    i        -- put values on the array

    SEQ i = 0 FOR 10   -- SEQ used as <-an-iterator->
      x[i] := -x[i]       -- put values on the array

    flag   := TRUE

    WHILE ( flag )     -- WHILE
      SEQ                 -- SEQ as a bubble sort
        SEQ i = 0 FOR 10     -- SEQ used as <-an-iterator->
          IF                    -- IF
            x[i] > x[i+1]          -- CASE: x[i] > x[i+1]
              SEQ                     -- SEQ of steps
                aux    := x[i]           -- 1
                x[i]   := x[i+1]         -- 2
                x[i+1] := aux            -- 3
                -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
                -- INTERESTING [occam-pi] FEATURE IS, THAT
                --             [occam-pi] CAN _SWAP_ IN-PLACE
                --             USING JUST x[i], x[i+1] := x[i+1], x[i]
            TRUE                   -- OTHERWISE:
              SKIP
        -- SEQ used above as <-an-iterator-> got exhausted
        flag := FALSE        -- SET FALSE
    -- ----------------------------- EoSEQ:
: -- main()