[Maxima-discuss] About the behaviour of read

[El O. De M. <obs...@gm...>]

Hi

I have used the command read many times and have noticed something like
data persistence.
You can try once the following attempted tic, tac, toe implementation,
which uses read.
 --> /* Tic-Tac-Toe game implementation */

/* Initialize the game state */
/*grid: matrix(["", "", ""], ["", "", ""], ["", "", ""])$*/
grid:genmatrix(lambda([x,y],""),3,3)$
player: X$
 --> /* Function to make a move */
make_move(my_row,my_col) :=
 block(if grid[my_row][my_col] = "" then
   (grid[my_row][my_col]: player,
    player: if player = X then O else X)
  else
   (print("Invalid move, try again.")))$
 --> diagonalp(grid):=is(unique(makelist(grid[i,i],i,3))#[""] and
length(unique(makelist(grid[i,i],i,3)))=1)$
 --> antidiagonalp(grid):=is(unique(makelist(grid[i,4-i],i,3))#[""] and
length(unique(makelist(grid[i,4-i],i,3)))=1)$
 --> rowp(grid):=block(
   L:[],
   for i from 1 thru 3 do if unique(flatten(args(row(grid,i))))#[""] and
       length(unique(flatten(args(row(grid,i)))))=1 then
push(row(grid,i),L),
   if L#[] then true
)$
 --> columnp(grid):=block(
   L:[],
   for i from 1 thru 3 do if unique(flatten(args(col(grid,i))))#[""] and
       length(unique(flatten(args(col(grid,i)))))=1 then
push(col(grid,i),L),
   if L#[] then true
)$
 --> check_winner(grid):=is(diagonalp(grid) or antidiagonalp(grid) or
rowp(grid) or columnp(grid))$
 --> /* Game loop */
tictactoe():=block(
   runner:true,
   while runner do (
       print(grid),
       [my_row,my_col]: read("Enter row and col (1-3) as a list: "),
       make_move(my_row,my_col),
       winner: check_winner(grid),
       if winner then (
           print("Player ", if player = X then O else X, " wins!"),
           runner:false),
       if not member("", flatten(args(grid))) then (
           print("It's a draw!"),
           runner:false
       )
   )
)$
 --> reset_game() := (
   grid: genmatrix(lambda([x,y],""),3,3),
   player: X
)$
 --> tictactoe();

After one play, if another game is initialized, a "suggestion" is shown for
the player, namely the initial for the previous play. I mean, Is it good
that while using read some "options" appear?

There is another way to see the persistence behaviour.
I could use vscode copilot in agent mode to ask it to do changes in .wxm
files. One file in which I ask for changes was one with the code above, but
after a play of tic, tac, toe additional lines were added, like:
/* [wxMaxima: input   start ] */
columnp(grid):=block(
    L:[],
    for i from 1 thru 3 do if unique(flatten(args(col(grid,i))))#[""] and
        length(unique(flatten(args(col(grid,i)))))=1 then
push(col(grid,i),L),
    if L#[] then true
)$
/* [wxMaxima: input   end   ] */

or

/* [wxMaxima: question  start ] */
<math><st>Enter column (1-3): </st><st> </st></math>
/* [wxMaxima: question  end   ] */
/* [wxMaxima: answer  start ] */
2;3;3;2;1;
/* [wxMaxima: answer  end   ] */

These lines persisted in vscode even if the wxmaxima code was returned to
an unevaluated form (all cells not evaluated) and saved.

If this kind of behavior is wanted, let me know

best regards

-- 
https://github.com/Observatorio-de-Matematica