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IO

I/O is, in PHP (and really many Programming Languages) often capricious. The IO monad abstracts I/O in accordance with Functional Programming principles: it performs unsafe operations in a controlled environment. It is therefore apt for things like printing to Standard Output (STDOUT), and interacting with the filesystem among other impure actions. To follow is a set of IO primitives available in bingo-functional.

IO#

IO(unsafe)
IO :: a -> IO ()

Calls the IO monad constructor thereby initializing a value of type IO.

Since:

  • bingo-functional - v1.11.0
  • bingo-functional-js - v0.1.0

Argument(s):

  • unsafe - Unsafe IO operation
use function Chemem\Bingo\Functional\Functors\Monads\IO\IO;
$unsafe = IO(fn (): string => 'foo');

putChar#

putChar(char)
putChar :: Char -> IO ()

Writes a character to the Standard Output Device (STDOUT).

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • char - The character to write
use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(IO\getChar, IO\putChar);
$io(IO\IO(fn (): string => 'x'));

putStr#

putStr(str)
putStr :: String -> IO ()

Writes a string to the Standard Output Device.

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • str - The string to write
use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(IO\getLine, IO\putStr);
$io(IO\IO(fn (): string => 'IO > '));

putStrLn#

putStrLn(str)
putStr :: String -> IO ()

Works like putStr() but appends a new line to STDOUT output.

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • str - The string to write
use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(IO\getLine, IO\putStrLn);
$io(IO\IO(fn (): string => 'IO > '));

getChar#

getChar()
getChar :: IO Char

Reads character from Standard Input Device (STDIN).

Since:

  • bingo-functional - v1.11.0

Argument(s):

None

use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(IO\getChar, IO\putChar);
$io(IO\IO(fn (): string => 'x'));

getLine#

getLine()
getLine :: IO String

Reads a line from the Standard Input Device (STDIN).

Since:

  • bingo-functional - v1.11.0

Argument(s):

None

use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(IO\getLine, IO\putStr);
$io(IO\IO(fn (): string => 'IO > '));

interact#

interact(function)
interact :: (String -> String) -> IO ()

Takes a function with a String -> String signature, parses Standard Input device input and conveys output to same standard device.

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • function - An arbitrary string-transforming function
use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(  fn ($_) => IO\interact(fn ($str) => printf('%s', strtoupper($str))),  IO\putStr);
$io(IO\IO(fn (): string => 'IO > '));

_print#

_print(printable)
_print :: Show a => a -> IO ()

Outputs a value of any printable type to the Standard Output device (STDOUT).

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • printable - An IO instance with printable data
use function Chemem\Bingo\Functional\Functors\Monads\IO\{IO, _print};
$io = _print(IO('foo'));

IOException#

IOException(message)
IOException :: String -> IO ()

Throws an IO Exception in controlled environment.

Since:

  • bingo-functional - v1.11.0
  • bingo-functional-js - v0.1.0

Argument(s):

  • message - An arbitrary IO Exception message
use function Chemem\Bingo\Functional\Functors\Monads\IO\IOException;
$err = IOExcpetion('An error occurred!');

catchIO#

catchIO(operation)
catchIO :: IO () -> IO ()

Catches an IO Exception in a controlled environment.

Since:

  • bingo-functional - v1.11.0
  • bingo-functional-js - v0.1.0

Argument(s):

  • operation - An IO instance containing an IO Exception
use function Chemem\Bingo\Functional\Functors\Monads\IO\{catchIO, IOException};
$err = catchIO(IOExcpetion('An error occurred!'));$err->exec();

readFile#

readFile(file)
readFile :: String -> IO String

Reads a file and returns the contents of the file as a string.

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • file - Path to file
use function Chemem\Bingo\Functional\Functors\Monads\mcompose;use Chemem\Bingo\Functional\Functors\Monads\IO;
$io = mcompose(IO\getLine, IO\putStr, IO\readFile);
$io(IO\IO(fn (): string => 'path/to/file'));

writeFile#

writeFile(file, contents)
writeFile :: String -> String -> IO ()

Writes a string to a file.

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • file - Path to file
  • contents - Contents to write to file
use function Chemem\Bingo\Functional\{  Functors\Monads\mcompose,  Algorithms\partialRight};use Chemem\Bingo\Functional\Functors\Monads\IO;
const TEXT = 'foo, bar, baz';
$write = mcompose(  fn (bool $res) => IO\IO($res ? TEXT : 'A write error occurred'),  partialRight(IO\writeFile, TEXT));
$write(IO\IO(fn (): string => 'path/to/file'));

appendFile#

appendFile(file, contents)
appendFile :: String -> String -> IO ()

Appends a string to a file.

Since:

  • bingo-functional - v1.11.0

Argument(s):

  • file - Path to file
  • contents - Contents to append to file
use function Chemem\Bingo\Functional\{  Functors\Monads\mcompose,  Algorithms\partialRight};use Chemem\Bingo\Functional\Functors\Monads\IO;
const TEXT = 'foo, bar, baz';
$write = mcompose(  fn (bool $res) => IO\IO($res ? TEXT : 'A write error occurred'),  partialRight(IO\appendFile, TEXT));
$write(IO\IO(fn (): string => 'path/to/file'));