Ideas for Roguelike

For Roguelike:

Draw the character on top of the map.

Collision detection: make TYPES for the tiles. If the type is a wall or water, keep the player at its current tile position, else do the move. This can be done with a function call. If is_passable() == true, then move, else stay.

FUNCTION is_passable(x AS INTEGER, y AS INTEGER) AS BOOLEAN
      DIM tile_type AS INTEGER
      tile_type = floor(rows, cols)
      IF tile_type = "floor"
            RETURN true
      ELSE
            RETURN false
      END IF
END FUNCTION

Going off the map entirely can be solved by walling the border or making maps that don't touch the border

To move with collision detection:
. . .
SELECT key_code
. . .
    CASE key_up
        IF is_passable() = 1
            BREAK
        ELSE
            player.y -= 1
        END IF
. . .
END SELECT

Drawing the map:

This can be done with types:

ENUMERATION
    TILE_FLOOR
    TILE_WALL
    TILE_TREE
    TILE_WATER
    TILE_BUILDING
    TILE_NPC
END ENUMERATION

TYPE tile_type
    character AS CHAR
    color_code AS SHORT
    passable AS BOOLEAN
END TYPE

 DIM AS tile_type() current_tile = {
'Character, is passable
".", true, 'floor
"#", false, 'wall
"¥", false, 'tree
"~", true, 'water
"%", false, 'building
"&", false 'npc
}

FUNCTION is_passable(x, y) AS BOOLEAN
    tile_value AS INTEGER = floor(y, x)
    RETURN current_tile(tile_type).passable
END FUNCTION

Shorten up case statement:

DIM delta_x, delta_y, end_loop AS INTEGER
'x is ahead of you, y is ahead of you
end_loop= 0
DO
SELECT key_code
CASE up
    delta_x = 0
    delta_y = -1
CASE down
    delta_x = 0
    delta_y = 1
CASE left
    delta_x = -1
    delta_y = 0
CASE right
    delta_x = 1
    delta_y = 0
CASE escape
    End
CASE not any of above
    delta_x = 0
    delta_y = 0
END SELECT
LOOP UNTIL end_loop = 1
IF is_passable(player.x+delta_x, player.y+delta_y) THEN
    player.x += delta_x
    player.y += delta_y
END IF

Interacting with items:

Add more things to the enumeration I made before:

TILE_OPENDOOR
TILE_CLOSEDDOOR
TILE_OPENCHEST
TILE_CLOSEDCHEST
TILE_DOWNSTAIRCASE
TILE_UPSTAIRCASE

and add things to the Select/Case statement:

CASE c
IF floor/map(player.x+delta_x, player.y+delta_y) is OPENDOOR THEN
    floor/map(player.x+delta_x, player.y+delta_y) is CLOSEDDOOR
END IF
. . .