System Interaction

Some facilities have been developed to access the outside world.

sys .exit

Exists the program with the indicated error code.

0 sys .exit       # successful termination

sys .file

Creates a scope representing a file. This object supports .open, .close, .read, .write, .writeall, .eachLine. Three files sys .in, sys .out, sys .err are predefined and represent the standard input, output and error streams respectively.

sys .file ":" via
  "foo.txt" :open
  8 :read dump          # first 8 bytes of foo.txt, possibly less if foo.txt is shorter
  { dump } :eachLine    # dump each line of foo.txt (excluding the 8 bytes already read)
  :close
"Hallo Welt!\n" sys .out .writeall
Hallo Welt!

As .write directly maps to the write(2) syscall, it might not write all bytes. Instead it returns the number of bytes written as an integer. Usually, you want to use .writeall which will call write(2) repeatedly, until all bytes are written.

sys .fdToFile will create a file representing scope directly from a unix file descriptor number.

sys .freeze

To create stand-alone executables, sys .freeze takes a filename and a function object and creates an executable which will execute the function object when started.

{ "Hello World!\n" sys .out .writeall 0 sys .exit } "hello" sys .freeze

An elymas interpreter can be implemented via include easily:

{
  sys .argv len { 0 sys .argv * } { "/proc/self/fd/0" } ? * include
  0 sys .exit
} "interpreter" sys .freeze

sys .mkdir

Creates a new directory.

sys .ls / sys .readdir

List the contents of a directory. sys .ls excludes files with a leading dot.

sys .rename

Takes two filenames. Renames the first (stack second-to-top) to the second (stack top).