io

close

function io.close(file?: file*)
  -> suc: boolean?
  2. exitcode: ("exit"|"signal")?
  3. code: integer?

Close file or default output file.

exitcode:
    | "exit"
    | "signal"

flush

function io.flush()

Saves any written data to default output file.

input

function io.input(file: string|file*)

Sets file as the default input file.

lines

function io.lines(filename?: string, ...string|integer|"L"|"a"|"l"...(+1))
  -> fun():any, ...unknown

---

for c in io.lines(filename, ...) do
    body
end

...(param):
    | "n" -- Reads a numeral and returns it as number.
    | "a" -- Reads the whole file.
   -> "l" -- Reads the next line skipping the end of line.
    | "L" -- Reads the next line keeping the end of line.

open

function io.open(filename: string, mode?: "a"|"a+"|"a+b"|"ab"|"r"...(+7))
  -> file*?
  2. errmsg: string?

Opens a file, in the mode specified in the string mode.

mode:
   -> "r" -- Read mode.
    | "w" -- Write mode.
    | "a" -- Append mode.
    | "r+" -- Update mode, all previous data is preserved.
    | "w+" -- Update mode, all previous data is erased.
    | "a+" -- Append update mode, previous data is preserved, writing is only allowed at the end of file.
    | "rb" -- Read mode. (in binary mode.)
    | "wb" -- Write mode. (in binary mode.)
    | "ab" -- Append mode. (in binary mode.)
    | "r+b" -- Update mode, all previous data is preserved. (in binary mode.)
    | "w+b" -- Update mode, all previous data is erased. (in binary mode.)
    | "a+b" -- Append update mode, previous data is preserved, writing is only allowed at the end of file. (in binary mode.)

output

function io.output(file: string|file*)

Sets file as the default output file.

popen

function io.popen(prog: string, mode?: "r"|"w")
  -> file*?
  2. errmsg: string?

Starts program prog in a separated process.

mode:
    | "r" -- Read data from this program by `file`.
    | "w" -- Write data to this program by `file`.

read

function io.read(...string|integer|"L"|"a"|"l"...(+1))
  -> any
  2. ...any

Reads the file, according to the given formats, which specify what to read.

...(param):
    | "n" -- Reads a numeral and returns it as number.
    | "a" -- Reads the whole file.
   -> "l" -- Reads the next line skipping the end of line.
    | "L" -- Reads the next line keeping the end of line.

tmpfile

function io.tmpfile()
  -> file*

In case of success, returns a handle for a temporary file.

type

function io.type(file: file*)
  -> "closed file"|"file"|`nil`

Checks whether obj is a valid file handle.

return #1:
    | "file" -- Is an open file handle.
    | "closed file" -- Is a closed file handle.
    | `nil` -- Is not a file handle.

write

function io.write(...any)
  -> file*
  2. errmsg: string?

Writes the value of each of its arguments to default output file.