Documentation

Init.System.IO

Like https://hackage.haskell.org/package/ghc-Prim-0.5.2.0/docs/GHC-Prim.html#t:RealWorld. Makes sure we never reorder IO operations.

TODO: mark opaque

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    def EIO (ε : Type) :
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      instance instMonadEIO {ε : Type} :
      Monad (EIO ε)
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      instance instMonadExceptOfEIO {ε : Type} :
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      instance instOrElseEIO {ε α : Type} :
      OrElse (EIO ε α)
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      • instOrElseEIO = { orElse := MonadExcept.orElse }
      instance instInhabitedEIO {ε α : Type} [Inhabited ε] :
      Inhabited (EIO ε α)
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      def BaseIO :

      An EIO monad that cannot throw exceptions.

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        @[inline]
        def BaseIO.toEIO {α ε : Type} (act : BaseIO α) :
        EIO ε α
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          • instMonadLiftBaseIOEIO = { monadLift := fun {α : Type} => BaseIO.toEIO }
          @[inline]
          def EIO.toBaseIO {ε α : Type} (act : EIO ε α) :
          BaseIO (Except ε α)
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            @[inline]
            def EIO.catchExceptions {ε α : Type} (act : EIO ε α) (h : εBaseIO α) :
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              @[reducible, inline]
              abbrev IO :
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                @[inline]
                def BaseIO.toIO {α : Type} (act : BaseIO α) :
                IO α
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                  @[inline]
                  def EIO.toIO {ε α : Type} (f : εIO.Error) (act : EIO ε α) :
                  IO α
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                    @[inline]
                    def EIO.toIO' {ε α : Type} (act : EIO ε α) :
                    IO (Except ε α)
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                    • act.toIO' = liftM act.toBaseIO
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                      @[inline]
                      def IO.toEIO {ε α : Type} (f : IO.Errorε) (act : IO α) :
                      EIO ε α
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                        @[inline]
                        unsafe def unsafeBaseIO {α : Type} (fn : BaseIO α) :
                        α
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                          @[inline]
                          unsafe def unsafeEIO {ε α : Type} (fn : EIO ε α) :
                          Except ε α
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                            @[inline]
                            unsafe def unsafeIO {α : Type} (fn : IO α) :
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                              @[extern lean_io_timeit]
                              opaque timeit {α : Type} (msg : String) (fn : IO α) :
                              IO α
                              @[extern lean_io_allocprof]
                              opaque allocprof {α : Type} (msg : String) (fn : IO α) :
                              IO α
                              @[extern lean_io_initializing]

                              Programs can execute IO actions during initialization that occurs before the main function is executed. The attribute [init <action>] specifies which IO action is executed to set the value of an opaque constant.

                              The action initializing returns true iff it is invoked during initialization.

                              @[extern lean_io_as_task]
                              opaque BaseIO.asTask {α : Type} (act : BaseIO α) (prio : Task.Priority := Task.Priority.default) :

                              Run act in a separate Task. This is similar to Haskell's unsafeInterleaveIO, except that the Task is started eagerly as usual. Thus pure accesses to the Task do not influence the impure act computation. Unlike with pure tasks created by Task.spawn, tasks created by this function will be run even if the last reference to the task is dropped. The act should manually check for cancellation via IO.checkCanceled if it wants to react to that.

                              @[extern lean_io_map_task]
                              opaque BaseIO.mapTask {α : Type u_1} {β : Type} (f : αBaseIO β) (t : Task α) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :

                              See BaseIO.asTask.

                              @[extern lean_io_bind_task]
                              opaque BaseIO.bindTask {α : Type u_1} {β : Type} (t : Task α) (f : αBaseIO (Task β)) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :

                              See BaseIO.asTask.

                              def BaseIO.mapTasks {α : Type u_1} {β : Type} (f : List αBaseIO β) (tasks : List (Task α)) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :
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                                def BaseIO.mapTasks.go {α : Type u_1} {β : Type} (f : List αBaseIO β) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :
                                List (Task α)List αBaseIO (Task β)
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                                  @[inline]
                                  def EIO.asTask {ε α : Type} (act : EIO ε α) (prio : Task.Priority := Task.Priority.default) :
                                  BaseIO (Task (Except ε α))

                                  EIO specialization of BaseIO.asTask.

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                                  • act.asTask prio = act.toBaseIO.asTask prio
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                                    @[inline]
                                    def EIO.mapTask {α : Type u_1} {ε β : Type} (f : αEIO ε β) (t : Task α) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :
                                    BaseIO (Task (Except ε β))

                                    EIO specialization of BaseIO.mapTask.

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                                      @[inline]
                                      def EIO.bindTask {α : Type u_1} {ε β : Type} (t : Task α) (f : αEIO ε (Task (Except ε β))) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :
                                      BaseIO (Task (Except ε β))

                                      EIO specialization of BaseIO.bindTask.

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                                        @[inline]
                                        def EIO.mapTasks {α : Type u_1} {ε β : Type} (f : List αEIO ε β) (tasks : List (Task α)) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :
                                        BaseIO (Task (Except ε β))

                                        EIO specialization of BaseIO.mapTasks.

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                                          def IO.ofExcept {ε : Type u_1} {α : Type} [ToString ε] (e : Except ε α) :
                                          IO α
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                                            def IO.lazyPure {α : Type} (fn : Unitα) :
                                            IO α
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                                              @[extern lean_io_mono_ms_now]

                                              Monotonically increasing time since an unspecified past point in milliseconds. No relation to wall clock time.

                                              @[extern lean_io_mono_nanos_now]

                                              Monotonically increasing time since an unspecified past point in nanoseconds. No relation to wall clock time.

                                              @[extern lean_io_get_random_bytes]
                                              opaque IO.getRandomBytes (nBytes : USize) :

                                              Read bytes from a system entropy source. Not guaranteed to be cryptographically secure. If nBytes = 0, return immediately with an empty buffer.

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                                                @[inline]
                                                def IO.asTask {α : Type} (act : IO α) (prio : Task.Priority := Task.Priority.default) :

                                                IO specialization of EIO.asTask.

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                                                  @[inline]
                                                  def IO.mapTask {α : Type u_1} {β : Type} (f : αIO β) (t : Task α) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :

                                                  IO specialization of EIO.mapTask.

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                                                    @[inline]
                                                    def IO.bindTask {α : Type u_1} {β : Type} (t : Task α) (f : αIO (Task (Except IO.Error β))) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :

                                                    IO specialization of EIO.bindTask.

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                                                      @[inline]
                                                      def IO.mapTasks {α : Type u_1} {β : Type} (f : List αIO β) (tasks : List (Task α)) (prio : Task.Priority := Task.Priority.default) (sync : Bool := false) :

                                                      IO specialization of EIO.mapTasks.

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                                                        @[extern lean_io_check_canceled]

                                                        Check if the task's cancellation flag has been set by calling IO.cancel or dropping the last reference to the task.

                                                        @[extern lean_io_cancel]
                                                        opaque IO.cancel {α : Type u_1} :

                                                        Request cooperative cancellation of the task. The task must explicitly call IO.checkCanceled to react to the cancellation.

                                                        inductive IO.TaskState :

                                                        The current state of a Task in the Lean runtime's task manager.

                                                        • waiting: IO.TaskState

                                                          The Task is waiting to be run. It can be waiting for dependencies to complete or sitting in the task manager queue waiting for a thread to run on.

                                                        • running: IO.TaskState

                                                          The Task is actively running on a thread or, in the case of a Promise, waiting for a call to IO.Promise.resolve.

                                                        • finished: IO.TaskState

                                                          The Task has finished running and its result is available. Calling Task.get or IO.wait on the task will not block.

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                                                            @[extern lean_io_get_task_state]
                                                            opaque IO.getTaskState {α : Type u_1} :

                                                            Returns current state of the Task in the Lean runtime's task manager.

                                                            @[inline]
                                                            def IO.hasFinished {α : Type u_1} (task : Task α) :

                                                            Check if the task has finished execution, at which point calling Task.get will return immediately.

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                                                              @[extern lean_io_wait]
                                                              opaque IO.wait {α : Type} (t : Task α) :

                                                              Wait for the task to finish, then return its result.

                                                              @[extern lean_io_wait_any]
                                                              opaque IO.waitAny {α : Type} (tasks : List (Task α)) (h : tasks.length > 0 := by exact Nat.zero_lt_succ _) :

                                                              Wait until any of the tasks in the given list has finished, then return its result.

                                                              @[extern lean_io_get_num_heartbeats]

                                                              Helper method for implementing "deterministic" timeouts. It is the number of "small" memory allocations performed by the current execution thread.

                                                              @[extern lean_io_add_heartbeats]

                                                              Adjusts the heartbeat counter of the current thread by the given amount. This can be useful to give allocation-avoiding code additional "weight" and is also used to adjust the counter after resuming from a snapshot.

                                                              inductive IO.FS.Mode :

                                                              The mode of a file handle (i.e., a set of open flags and an fdopen mode).

                                                              All modes do not translate line endings (i.e., O_BINARY on Windows) and are not inherited across process creation (i.e., O_NOINHERIT on Windows, O_CLOEXEC elsewhere).

                                                              References:

                                                              • read: IO.FS.Mode

                                                                File opened for reading. On open, the stream is positioned at the beginning of the file. Errors if the file does not exist.

                                                                • open flags: O_RDONLY
                                                                • fdopen mode: r
                                                              • write: IO.FS.Mode

                                                                File opened for writing. On open, truncate an existing file to zero length or create a new file. The stream is positioned at the beginning of the file.

                                                                • open flags: O_WRONLY | O_CREAT | O_TRUNC
                                                                • fdopen mode: w
                                                              • writeNew: IO.FS.Mode

                                                                New file opened for writing. On open, create a new file with the stream positioned at the start. Errors if the file already exists.

                                                                • open flags: O_WRONLY | O_CREAT | O_TRUNC | O_EXCL
                                                                • fdopen mode: w
                                                              • readWrite: IO.FS.Mode

                                                                File opened for reading and writing. On open, the stream is positioned at the beginning of the file. Errors if the file does not exist.

                                                                • open flags: O_RDWR
                                                                • fdopen mode: r+
                                                              • append: IO.FS.Mode

                                                                File opened for writing. On open, create a new file if it does not exist. The stream is positioned at the end of the file.

                                                                • open flags: O_WRONLY | O_CREAT | O_APPEND
                                                                • fdopen mode: a
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                                                                structure IO.FS.Stream :

                                                                A pure-Lean abstraction of POSIX streams. We use Streams for the standard streams stdin/stdout/stderr so we can capture output of #eval commands into memory.

                                                                • flush : IO Unit
                                                                • read : USizeIO ByteArray

                                                                  Read up to the given number of bytes from the stream. If the returned array is empty, an end-of-file marker has been reached. Note that EOF does not actually close a stream, so further reads may block and return more data.

                                                                • write : ByteArrayIO Unit
                                                                • getLine : IO String

                                                                  Read text up to (including) the next line break from the stream. If the returned string is empty, an end-of-file marker has been reached. Note that EOF does not actually close a stream, so further reads may block and return more data.

                                                                • putStr : StringIO Unit
                                                                • isTty : BaseIO Bool

                                                                  Returns true if a stream refers to a Windows console or Unix terminal.

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                                                                  • IO.FS.instInhabitedStream = { default := { flush := default, read := default, write := default, getLine := default, putStr := default, isTty := default } }
                                                                  @[extern lean_get_stdin]
                                                                  @[extern lean_get_stdout]
                                                                  @[extern lean_get_stderr]
                                                                  @[extern lean_get_set_stdin]

                                                                  Replaces the stdin stream of the current thread and returns its previous value.

                                                                  @[extern lean_get_set_stdout]

                                                                  Replaces the stdout stream of the current thread and returns its previous value.

                                                                  @[extern lean_get_set_stderr]

                                                                  Replaces the stderr stream of the current thread and returns its previous value.

                                                                  @[specialize #[]]
                                                                  partial def IO.iterate {α β : Type} (a : α) (f : αIO (α β)) :
                                                                  IO β
                                                                  @[extern lean_io_prim_handle_mk]
                                                                  @[extern lean_io_prim_handle_lock]
                                                                  opaque IO.FS.Handle.lock (h : IO.FS.Handle) (exclusive : Bool := true) :

                                                                  Acquires an exclusive or shared lock on the handle. Will block to wait for the lock if necessary.

                                                                  NOTE: Acquiring a exclusive lock while already possessing a shared lock will NOT reliably succeed (i.e., it works on Unix but not on Windows).

                                                                  @[extern lean_io_prim_handle_try_lock]
                                                                  opaque IO.FS.Handle.tryLock (h : IO.FS.Handle) (exclusive : Bool := true) :

                                                                  Tries to acquire an exclusive or shared lock on the handle. Will NOT block for the lock, but instead return false.

                                                                  NOTE: Acquiring a exclusive lock while already possessing a shared lock will NOT reliably succeed (i.e., it works on Unix but not on Windows).

                                                                  @[extern lean_io_prim_handle_unlock]

                                                                  Releases any previously acquired lock on the handle. Will succeed even if no lock has been acquired.

                                                                  @[extern lean_io_prim_handle_is_tty]

                                                                  Returns true if a handle refers to a Windows console or Unix terminal.

                                                                  @[extern lean_io_prim_handle_flush]
                                                                  @[extern lean_io_prim_handle_rewind]

                                                                  Rewinds the read/write cursor to the beginning of the handle.

                                                                  @[extern lean_io_prim_handle_truncate]

                                                                  Truncates the handle to the read/write cursor.

                                                                  Does not automatically flush. Usually this is fine because the read/write cursor includes buffered writes. However, the combination of buffered writes, then rewind, then truncate, then close may lead to a file with content. If unsure, flush before truncating.

                                                                  @[extern lean_io_prim_handle_read]

                                                                  Read up to the given number of bytes from the handle. If the returned array is empty, an end-of-file marker has been reached. Note that EOF does not actually close a handle, so further reads may block and return more data.

                                                                  @[extern lean_io_prim_handle_write]
                                                                  @[extern lean_io_prim_handle_get_line]

                                                                  Read text up to (including) the next line break from the handle. If the returned string is empty, an end-of-file marker has been reached. Note that EOF does not actually close a handle, so further reads may block and return more data.

                                                                  @[extern lean_io_prim_handle_put_str]
                                                                  @[extern lean_io_realpath]

                                                                  Resolves a pathname to an absolute pathname with no '.', '..', or symbolic links.

                                                                  This function coincides with the POSIX realpath function, see there for more information.

                                                                  @[extern lean_io_remove_file]
                                                                  @[extern lean_io_remove_dir]

                                                                  Remove given directory. Fails if not empty; see also IO.FS.removeDirAll.

                                                                  @[extern lean_io_create_dir]
                                                                  @[extern lean_io_rename]
                                                                  opaque IO.FS.rename (old new : System.FilePath) :

                                                                  Moves a file or directory old to the new location new.

                                                                  This function coincides with the POSIX rename function, see there for more information.

                                                                  @[extern lean_io_create_tempfile]

                                                                  Creates a temporary file in the most secure manner possible. There are no race conditions in the file’s creation. The file is readable and writable only by the creating user ID. Additionally on UNIX style platforms the file is executable by nobody. The function returns both a Handle to the already opened file as well as its FilePath.

                                                                  Note that it is the caller's job to remove the file after use.

                                                                  @[extern lean_io_getenv]
                                                                  opaque IO.getEnv (var : String) :
                                                                  @[extern lean_io_app_path]
                                                                  @[extern lean_io_current_dir]
                                                                  @[inline]
                                                                  def IO.FS.withFile {α : Type} (fn : System.FilePath) (mode : IO.FS.Mode) (f : IO.FS.HandleIO α) :
                                                                  IO α
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                                                                    def IO.FS.withTempFile {m : TypeType u_1} {α : Type} [Monad m] [MonadFinally m] [MonadLiftT IO m] (f : IO.FS.HandleSystem.FilePathm α) :
                                                                    m α

                                                                    Like createTempFile but also takes care of removing the file after usage.

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                                                                      • h.putStrLn s = h.putStr (s.push '\n')
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                                                                                  def IO.FS.writeFile (fname : System.FilePath) (content : String) :
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                                                                                    • strm.putStrLn s = strm.putStr (s.push '\n')
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                                                                                      structure IO.FS.DirEntry :
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                                                                                        • entry.path = entry.root / { toString := entry.fileName }
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                                                                                            structure IO.FS.Metadata :
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                                                                                              @[extern lean_io_read_dir]
                                                                                              @[extern lean_io_metadata]
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                                                                                                  Return all filesystem entries of a preorder traversal of all directories satisfying enter, starting at p. Symbolic links are visited as well by default.

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                                                                                                        def IO.withStdin {m : TypeType u_1} {α : Type} [Monad m] [MonadFinally m] [MonadLiftT BaseIO m] (h : IO.FS.Stream) (x : m α) :
                                                                                                        m α
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                                                                                                          def IO.withStdout {m : TypeType u_1} {α : Type} [Monad m] [MonadFinally m] [MonadLiftT BaseIO m] (h : IO.FS.Stream) (x : m α) :
                                                                                                          m α
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                                                                                                            def IO.withStderr {m : TypeType u_1} {α : Type} [Monad m] [MonadFinally m] [MonadLiftT BaseIO m] (h : IO.FS.Stream) (x : m α) :
                                                                                                            m α
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                                                                                                              def IO.print {α : Type u_1} [ToString α] (s : α) :
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                                                                                                                def IO.println {α : Type u_1} [ToString α] (s : α) :
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                                                                                                                  def IO.eprint {α : Type u_1} [ToString α] (s : α) :
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                                                                                                                    def IO.eprintln {α : Type u_1} [ToString α] (s : α) :
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                                                                                                                        Create given path and all missing parents as directories.

                                                                                                                        Fully remove given directory by deleting all contained files and directories in an unspecified order. Fails if any contained entry cannot be deleted or was newly created during execution.

                                                                                                                        @[extern lean_io_process_get_current_dir]

                                                                                                                        Returns the current working directory of the calling process.

                                                                                                                        @[extern lean_io_process_set_current_dir]

                                                                                                                        Sets the current working directory of the calling process.

                                                                                                                        @[extern lean_io_process_get_pid]

                                                                                                                        Returns the process ID of the calling process.

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                                                                                                                            • stdin : cfg.stdin.toHandleType
                                                                                                                            • stdout : cfg.stdout.toHandleType
                                                                                                                            • stderr : cfg.stderr.toHandleType
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                                                                                                                              @[extern lean_io_process_spawn]
                                                                                                                              opaque IO.Process.spawn (args : IO.Process.SpawnArgs) :
                                                                                                                              IO (IO.Process.Child args.toStdioConfig)
                                                                                                                              @[extern lean_io_process_child_wait]

                                                                                                                              Block until the child process has exited and return its exit code.

                                                                                                                              @[extern lean_io_process_child_try_wait]

                                                                                                                              Check whether the child has exited yet. If it hasn't return none, otherwise its exit code.

                                                                                                                              @[extern lean_io_process_child_kill]

                                                                                                                              Terminates the child process using the SIGTERM signal or a platform analogue. If the process was started using SpawnArgs.setsid, terminates the entire process group instead.

                                                                                                                              @[extern lean_io_process_child_take_stdin]
                                                                                                                              opaque IO.Process.Child.takeStdin {cfg : IO.Process.StdioConfig} :
                                                                                                                              IO.Process.Child cfgIO (cfg.stdin.toHandleType × IO.Process.Child { stdin := IO.Process.Stdio.null, stdout := cfg.stdout, stderr := cfg.stderr })

                                                                                                                              Extract the stdin field from a Child object, allowing them to be freed independently. This operation is necessary for closing the child process' stdin while still holding on to a process handle, e.g. for Child.wait. A file handle is closed when all references to it are dropped, which without this operation includes the Child object.

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                                                                                                                                Run process to completion and capture output. The process does not inherit the standard input of the caller.

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                                                                                                                                  Run process to completion and return stdout on success.

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                                                                                                                                    @[extern lean_io_exit]
                                                                                                                                    opaque IO.Process.exit {α : Type} :
                                                                                                                                    UInt8IO α
                                                                                                                                    structure IO.AccessRight :
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                                                                                                                                      • acc.flags = (if acc.read = true then 4 else 0).lor ((if acc.write = true then 2 else 0).lor (if acc.execution = true then 1 else 0))
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                                                                                                                                        structure IO.FileRight :
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                                                                                                                                          • acc.flags = (acc.user.flags.shiftLeft 6).lor ((acc.group.flags.shiftLeft 3).lor acc.other.flags)
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                                                                                                                                            @[extern lean_chmod]
                                                                                                                                            opaque IO.Prim.setAccessRights (filename : System.FilePath) (mode : UInt32) :
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                                                                                                                                              @[reducible, inline]
                                                                                                                                              abbrev IO.Ref (α : Type) :

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                                                                                                                                                def IO.mkRef {α : Type} (a : α) :
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                                                                                                                                                  structure IO.CancelToken :

                                                                                                                                                  Mutable cell that can be passed around for purposes of cooperative task cancellation: request cancellation with CancelToken.set and check for it with CancelToken.isSet.

                                                                                                                                                  This is a more flexible alternative to Task.cancel as the token can be shared between multiple tasks.

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                                                                                                                                                    Creates a new cancellation token.

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                                                                                                                                                      Activates a cancellation token. Idempotent.

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                                                                                                                                                        Checks whether the cancellation token has been activated.

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                                                                                                                                                          @[export lean_stream_of_handle]
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                                                                                                                                                          • IO.FS.Stream.ofHandle h = { flush := h.flush, read := h.read, write := h.write, getLine := h.getLine, putStr := h.putStr, isTty := h.isTty }
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                                                                                                                                                                def IO.FS.withIsolatedStreams {m : TypeType u_1} {α : Type} [Monad m] [MonadFinally m] [MonadLiftT BaseIO m] (x : m α) (isolateStderr : Bool := true) :
                                                                                                                                                                m (String × α)

                                                                                                                                                                Run action with stdin emptied and stdout+stderr captured into a String.

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