lib/effs/io.bend source

lib/effs/io.bend on the hub · documented module

import Base# V's I/O: run a program (a C effect, see proc_run.c) and write a file (Bend's File API).def Proc.run(cmd: String) -> IO(Result<&1, &1, U32 & String, String>):  import "./proc_run.c"# Standard output of a command; "" if it failed.def out_of(r: Result<&1, &1, U32 & String, String>) -> String:  match r:    case Done{v}:      v    case Fail{_}:      ""def ok_of(r: Result<&1, &1, U32 & String, String>) -> Bool:  match r:    case Done{_}:      True{}    case Fail{_}:      False{}def sh(cmd: String) -> IO(String):  do IO<String>:    r : Result<&1, &1, U32 & String, String> <- Proc.run(cmd)    return out_of(r)def ok(cmd: String) -> IO(Bool):  do IO<Bool>:    r : Result<&1, &1, U32 & String, String> <- Proc.run(cmd)    return ok_of(r)def after_write(r: File & Result<&1, &1, U32 & String, Unit>) -> IO(Unit):  match r:    case (f, _):      File.close(f)def write_opened(r: Result<&1, &1, U32 & String, File>, text: String) -> IO(Unit):  match r:    case Done{f}:      do IO<Unit>:        w : File & Result<&1, &1, U32 & String, Unit> <- File.write(f, text)        after_write(w)    case Fail{_}:      IO.die(Unit, 1, "cannot write file")def write_file(path: String, text: String) -> IO(Unit):  do IO<Unit>:    r : Result<&1, &1, U32 & String, File> <- File.open(path, "w")    write_opened(r, text)