Allow more customisation of artificial environments

It is now allowed to supply a custom input stream and a custom exit
code handler to the user-exposed constructor of Env, allowing full
customisation of the artificial environment.

CHANGELOG.md

@@ -37,6 +37,7 @@ All notable changes to the Pony compiler and standard library will be documented
 - Compile error when comparing sugared constructors with 'is' or 'isnt' (#2024) ([PR #2494](https://github.com/ponylang/ponyc/pull/2494))
 - Support OpenSSL 1.1.0 ([PR #2415](https://github.com/ponylang/ponyc/pull/2415))
 - Add U64 type to `cli` package. ([PR #2488](https://github.com/ponylang/ponyc/pull/2488))
+- Allow customisation of `Env.input` and `Env.exitcode` in artificial environments
 
 ### Changed
 
@@ -46,6 +47,7 @@ All notable changes to the Pony compiler and standard library will be documented
 - Rename Date to PosixDate ([PR #2436](https://github.com/ponylang/ponyc/pull/2436))
 - Fix and re-enable dynamic scheduler scaling ([PR #2483](https://github.com/ponylang/ponyc/pull/2483))
 - Expose OutStream rather than StdStream in Env ([PR #2463](https://github.com/ponylang/ponyc/pull/2463))
+- Rename StdinNotify to InputNotify
 
 ## [0.21.3] - 2018-01-14
 

examples/commandline/main.pony

@@ -16,7 +16,7 @@ actor Main
       end
 
     let cmd =
-      match CommandParser(cs).parse(env.args, env.vars())
+      match CommandParser(cs).parse(env.args, env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
           ch.print_help(env.out)

examples/gups_basic/main.pony

@@ -18,7 +18,7 @@ class val Config
       OptionSpec.i64("updaters", "Number of updaters." where default' = 8)
     ])?.>add_help()?
     let cmd =
-      match CommandParser(cs).parse(env.args, env.vars())
+      match CommandParser(cs).parse(env.args, env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
         ch.print_help(env.out)

examples/gups_opt/main.pony

@@ -17,7 +17,7 @@ class val Config
       OptionSpec.i64("actors", "Log2 of the actor count." where default' = 2)
     ])?.>add_help()?
     let cmd =
-      match CommandParser(cs).parse(env.args, env.vars())
+      match CommandParser(cs).parse(env.args, env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
         ch.print_help(env.out)

examples/httpget/httpget.pony

@@ -24,7 +24,7 @@ class val Config
       ArgSpec.string("url", "Url to query." where default' = None)
     ])?.>add_help()?
     let cmd =
-      match CommandParser(cs).parse(env.args, env.vars())
+      match CommandParser(cs).parse(env.args, env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
         ch.print_help(env.out)

examples/mandelbrot/mandelbrot.pony

@@ -97,7 +97,7 @@ class val Config
         where short' = 'o', default' = "")
     ])?.>add_help()?
     let cmd =
-      match CommandParser(cs).parse(env.args, env.vars())
+      match CommandParser(cs).parse(env.args, env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
         ch.print_help(env.out)

examples/message-ubench/main.pony

@@ -59,7 +59,7 @@ actor Main
             ArgSpec.string_seq("", "")
           ])?.>add_help()?
       let cmd =
-      match CommandParser(cs).parse(env.args, env.vars())
+      match CommandParser(cs).parse(env.args, env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
         ch.print_help(env.out)

examples/printargs/printargs.pony

@@ -11,7 +11,7 @@ actor Main
 
     env.out.print(consume str)
 
-    let envvars = EnvVars(env.vars())
+    let envvars = EnvVars(env.vars)
 
     for (k, v) in envvars.pairs() do
       env.out.print(k + " = " + v)

examples/yield/main.pony

@@ -211,7 +211,7 @@ actor Main
     end
 
     let cmd =
-      match CommandParser(cs).parse(_env.args, _env.vars())
+      match CommandParser(cs).parse(_env.args, _env.vars)
       | let c: Command => c
       | let ch: CommandHelp =>
         ch.print_help(_env.out)

packages/buffered/reader.pony

@@ -36,7 +36,7 @@ class Reader
   use "buffered"
   use "collections"
 
-  class Notify is StdinNotify
+  class Notify is InputNotify
     let _env: Env
     new create(env: Env) =>
       _env = env

packages/builtin/env.pony

@@ -10,7 +10,7 @@ class val Env
     Can be `None` for artificially constructed `Env` instances.
     """
 
-  let input: Stdin
+  let input: InputStream
     """
     Stdin represented as an actor.
     """
@@ -24,8 +24,14 @@ class val Env
   let args: Array[String] val
     """The command line used to start the program."""
 
-  let _envp: Pointer[Pointer[U8]] val
-  let _vars: (Array[String] val | None)
+  let vars: Array[String] val
+    """The program's environment variables."""
+
+  let exitcode: {(I32)} val
+    """
+    Sets the environment's exit code. The exit code of the root environment will
+    be the exit code of the application, which defaults to 0.
+    """
 
   new _create(
     argc: U32,
@@ -44,14 +50,16 @@ class val Env
     err = StdStream._err()
 
     args = _strings_from_pointers(argv, argc.usize())
-    _envp = envp
-    _vars = None
+    vars = _strings_from_pointers(envp, _count_strings(envp))
+
+    exitcode = {(code: I32) => @pony_exitcode[None](code) }
 
-  new create(
+  new val create(
     root': (AmbientAuth | None),
-    input': Stdin, out': OutStream,
+    input': InputStream, out': OutStream,
     err': OutStream, args': Array[String] val,
-    vars': (Array[String] val | None))
+    vars': Array[String] val,
+    exitcode': {(I32)} val)
   =>
     """
     Build an artificial environment. A root capability may be supplied.
@@ -61,32 +69,14 @@ class val Env
     out = out'
     err = err'
     args = args'
-    _envp = recover Pointer[Pointer[U8]] end
-    _vars = vars'
+    vars = vars'
+    exitcode = exitcode'
 
-  fun vars(): Array[String] val =>
-    """
-    Return the environment variables as an array of strings of the form
-    "key=value".
-    """
-    match _vars
-    | let v: Array[String] val => v
-    else
-      if not _envp.is_null() then
-        _strings_from_pointers(_envp, _count_strings(_envp))
-      else
-        recover Array[String] end
-      end
+  fun tag _count_strings(data: Pointer[Pointer[U8]] val): USize =>
+    if data.is_null() then
+      return 0
     end
 
-  fun tag exitcode(code: I32) =>
-    """
-    Sets the application exit code. If this is called more than once, the last
-    value set will be the exit code. The exit code defaults to 0.
-    """
-    @pony_exitcode[None](code)
-
-  fun tag _count_strings(data: Pointer[Pointer[U8]] val): USize =>
     var i: USize = 0
 
     while
@@ -105,10 +95,8 @@ class val Env
     let array = recover Array[String](len) end
     var i: USize = 0
 
-    while
+    while i < len do
       let entry = data._apply(i = i + 1)
-      not entry.is_null()
-    do
       array.push(recover String.copy_cstring(entry) end)
     end
 

packages/builtin/stdin.pony

@@ -8,19 +8,19 @@ use @pony_asio_event_create[AsioEventID](
 use @pony_asio_event_unsubscribe[None](event: AsioEventID)
 use @pony_asio_event_destroy[None](event: AsioEventID)
 
-interface StdinNotify
+interface InputNotify
   """
-  Notification for data arriving via stdin.
+  Notification for data arriving via an input stream.
   """
   fun ref apply(data: Array[U8] iso) =>
     """
-    Called when data is available on stdin.
+    Called when data is available on the stream.
     """
     None
 
   fun ref dispose() =>
     """
-    Called when no more data will arrive on stdin.
+    Called when no more data will arrive on the stream.
     """
     None
 
@@ -30,19 +30,35 @@ interface tag DisposableActor
   """
   be dispose()
 
+interface tag InputStream
+  """
+  Asynchronous access to some input stream.
+  """
+  be apply(notify: (InputNotify iso | None), chunk_size: USize = 32)
+    """
+    Set the notifier. Optionally, also sets the chunk size, dictating the
+    maximum number of bytes of each chunk that will be passed to the notifier.
+    """
+
+  be dispose() =>
+    """
+    Clear the notifier in order to shut down input.
+    """
+    None
+
 actor Stdin
   """
   Asynchronous access to stdin. The constructor is private to ensure that
   access is provided only via an environment.
 
-  Reading from stdin is done by registering a `StdinNotify`:
+  Reading from stdin is done by registering an `InputNotify`:
 
   ```pony
   actor Main
     new create(env: Env) =>
       // do not forget to call `env.input.dispose` at some point
       env.input(
-        object iso is StdinNotify
+        object iso is InputNotify
           fun ref apply(data: Array[U8] iso) =>
             env.out.write(String.from_iso_array(consume data))
 
@@ -54,7 +70,7 @@ actor Stdin
 
   **Note:** For reading user input from a terminal, use the [readline](readline--index) package.
   """
-  var _notify: (StdinNotify | None) = None
+  var _notify: (InputNotify | None) = None
   var _chunk_size: USize = 32
   var _event: AsioEventID = AsioEvent.none()
   let _use_event: Bool
@@ -65,7 +81,7 @@ actor Stdin
     """
     _use_event = use_event
 
-  be apply(notify: (StdinNotify iso | None), chunk_size: USize = 32) =>
+  be apply(notify: (InputNotify iso | None), chunk_size: USize = 32) =>
     """
     Set the notifier. Optionally, also sets the chunk size, dictating the
     maximum number of bytes of each chunk that will be passed to the notifier.
@@ -79,7 +95,7 @@ actor Stdin
     """
     _set_notify(None)
 
-  fun ref _set_notify(notify: (StdinNotify iso | None)) =>
+  fun ref _set_notify(notify: (InputNotify iso | None)) =>
     """
     Set the notifier.
     """
@@ -99,7 +115,7 @@ actor Stdin
       end
     end
 
-    try (_notify as StdinNotify).dispose() end
+    try (_notify as InputNotify).dispose() end
     _notify = consume notify
 
   be _loop_read() =>
@@ -132,7 +148,7 @@ actor Stdin
     ourself a resume message and stop reading to avoid starving other actors.
     """
     try
-      let notify = _notify as StdinNotify
+      let notify = _notify as InputNotify
       var sum: USize = 0
 
       while true do