cursor.md

Cursor

Methods

cursor:iterator([handler])

Returns an iterator function and cursor itself so that the statement

for value in cursor:iterator() do ... end

will iterate over all values from the cursor.

This method is semantically equivalent to:

function cursor:iterator(handler)
    return function (cursor)
        return cursor:value(handler)
    end,
    cursor
end

cursor:more()

Checks if cursor allows for more documents to be acquired. Useful for tailable cursors.

cursor:next()

Iterates cursor and returns the next BSON document from it or nil if there are no more documents to read. On error, returns nil and the error message.

cursor:value([handler])

Iterates cursor and returns the next value from it or nil if there are no more documents to read. On error, exception is thrown.

This method is semantically equivalent to:

function cursor:value(handler)
    local bson, err = cursor:next()
    if bson then
        return bson:value(handler)
    end
    if err then
        error(err)
    end
    return nil
end

except that it avoids creating a temporary BSON document.