// Emits 01234567891011121314151617... as a Stream of runes.
func AllDigits() functional.Generator {
return functional.NewGenerator(
func(e functional.Emitter) {
for number := 0; ; number++ {
for _, ch := range strconv.Itoa(number) {
ptr := e.EmitPtr()
if ptr == nil {
return
}
*(ptr.(*rune)) = ch
}
}
})
}
// ChkbookEntries returns a Generator that emits all the entries in a
// checkbook ordered by most recent to least recent. conn is the sqlite
// connection; acctId is the id of the account for which to print entries.
// If acctId does not match a valid account, ChkbookEntries will return an
// error and nil for the Generator. If caller does not exhaust returned
// Generator, it must call Close on it to free up resources.
func ChkbkEntries(conn *sqlite.Conn, acctId int) (functional.Generator, error) {
stmt, err := conn.Prepare("select balance from balances where acct_id = ?")
if err != nil {
return nil, err
}
if err = stmt.Exec(acctId); err != nil {
stmt.Finalize()
return nil, err
}
if !stmt.Next() {
stmt.Finalize()
return nil, errors.New("No balance")
}
var bal int64
if err = stmt.Scan(&bal); err != nil {
stmt.Finalize()
return nil, err
}
stmt.Finalize()
stmt, err = conn.Prepare("select date, name, amount from entries where acct_id = ? order by date desc")
if err != nil {
return nil, err
}
if err = stmt.Exec(acctId); err != nil {
stmt.Finalize()
return nil, err
}
return functional.NewGenerator(func(emitter functional.Emitter) {
rowStream := functional.ReadRows(stmt)
for ptr := emitter.EmitPtr(); ptr != nil && rowStream.Next(ptr); ptr = emitter.EmitPtr() {
entry := ptr.(*Entry)
entry.Balance = bal
bal += entry.Amount
}
stmt.Finalize()
}), nil
}