Add support for WebAssembly Interface Types

.gitmodules

@@ -1254,6 +1254,9 @@
 [submodule "vendor/grammars/vscode-vlang"]
 	path = vendor/grammars/vscode-vlang
 	url = https://github.com/0x9ef/vscode-vlang
+[submodule "vendor/grammars/vscode-wit"]
+	path = vendor/grammars/vscode-wit
+	url = https://github.com/bytecodealliance/vscode-wit.git
 [submodule "vendor/grammars/vscode-wren"]
 	path = vendor/grammars/vscode-wren
 	url = https://github.com/Nelarius/vscode-wren.git

grammars.yml

@@ -1127,6 +1127,8 @@ vendor/grammars/vscode-slice:
 - source.slice
 vendor/grammars/vscode-vlang:
 - source.v
+vendor/grammars/vscode-wit:
+- source.wit
 vendor/grammars/vscode-wren:
 - source.wren
 vendor/grammars/vscode-yara:

lib/linguist/languages.yml

@@ -7339,6 +7339,18 @@ WebAssembly:
   codemirror_mode: commonlisp
   codemirror_mime_type: text/x-common-lisp
   language_id: 956556503
+WebAssembly Interface Type:
+  type: data
+  color: "#6250e7"
+  extensions:
+  - ".wit"
+  aliases:
+  - wit
+  ace_mode: text
+  tm_scope: source.wit
+  codemirror_mode: webidl
+  codemirror_mime_type: text/x-webidl
+  language_id: 134534086
 WebIDL:
   type: programming
   extensions:

samples/WebAssembly Interface Type/wasi-io.wit

@@ -0,0 +1,259 @@
+// From: https://github.com/WebAssembly/wasi-io/tree/e6bcf18ac5e2d2deee5016fc4b6e260fc14d4bdc/wit 
+
+default world example-world {
+    import streams: self.streams
+}
+
+/// WASI I/O is an I/O abstraction API which is currently focused on providing
+/// stream types.
+///
+/// In the future, the component model is expected to add built-in stream types;
+/// when it does, they are expected to subsume this API.
+default interface streams {
+    use self.poll.{pollable}
+
+    /// An error type returned from a stream operation. Currently this
+    /// doesn't provide any additional information.
+    record stream-error {}
+
+    /// An input bytestream. In the future, this will be replaced by handle
+    /// types.
+    ///
+    /// This conceptually represents a `stream<u8, _>`. It's temporary
+    /// scaffolding until component-model's async features are ready.
+    ///
+    /// `input-stream`s are *non-blocking* to the extent practical on underlying
+    /// platforms. I/O operations always return promptly; if fewer bytes are
+    /// promptly available than requested, they return the number of bytes promptly
+    /// available, which could even be zero. To wait for data to be available,
+    /// use the `subscribe-to-input-stream` function to obtain a `pollable` which
+    /// can be polled for using `wasi_poll`.
+    ///
+    /// And at present, it is a `u32` instead of being an actual handle, until
+    /// the wit-bindgen implementation of handles and resources is ready.
+    ///
+    /// This [represents a resource](https://github.com/WebAssembly/WASI/blob/main/docs/WitInWasi.md#Resources).
+    type input-stream = u32
+
+    /// Read bytes from a stream.
+    ///
+    /// This function returns a list of bytes containing the data that was
+    /// read, along with a bool which, when true, indicates that the end of the
+    /// stream was reached. The returned list will contain up to `len` bytes; it
+    /// may return fewer than requested, but not more.
+    ///
+    /// Once a stream has reached the end, subsequent calls to read or
+    /// `skip` will always report end-of-stream rather than producing more
+    /// data.
+    ///
+    /// If `len` is 0, it represents a request to read 0 bytes, which should
+    /// always succeed, assuming the stream hasn't reached its end yet, and
+    /// return an empty list.
+    ///
+    /// The len here is a `u64`, but some callees may not be able to allocate
+    /// a buffer as large as that would imply.
+    /// FIXME: describe what happens if allocation fails.
+    read: func(
+        this: input-stream,
+        /// The maximum number of bytes to read
+        len: u64
+    ) -> result<tuple<list<u8>, bool>, stream-error>
+
+    /// Read bytes from a stream, with blocking.
+    ///
+    /// This is similar to `read`, except that it blocks until at least one
+    /// byte can be read.
+    blocking-read: func(
+        this: input-stream,
+        /// The maximum number of bytes to read
+        len: u64
+    ) -> result<tuple<list<u8>, bool>, stream-error>
+
+    /// Skip bytes from a stream.
+    ///
+    /// This is similar to the `read` function, but avoids copying the
+    /// bytes into the instance.
+    ///
+    /// Once a stream has reached the end, subsequent calls to read or
+    /// `skip` will always report end-of-stream rather than producing more
+    /// data.
+    ///
+    /// This function returns the number of bytes skipped, along with a bool
+    /// indicating whether the end of the stream was reached. The returned
+    /// value will be at most `len`; it may be less.
+    skip: func(
+        this: input-stream,
+        /// The maximum number of bytes to skip.
+        len: u64,
+    ) -> result<tuple<u64, bool>, stream-error>
+
+    /// Skip bytes from a stream, with blocking.
+    ///
+    /// This is similar to `skip`, except that it blocks until at least one
+    /// byte can be consumed.
+    blocking-skip: func(
+        this: input-stream,
+        /// The maximum number of bytes to skip.
+        len: u64,
+    ) -> result<tuple<u64, bool>, stream-error>
+
+    /// Create a `pollable` which will resolve once either the specified stream
+    /// has bytes available to read or the other end of the stream has been
+    /// closed.
+    subscribe-to-input-stream: func(this: input-stream) -> pollable
+
+    /// Dispose of the specified `input-stream`, after which it may no longer
+    /// be used.
+    drop-input-stream: func(this: input-stream)
+
+    /// An output bytestream. In the future, this will be replaced by handle
+    /// types.
+    ///
+    /// This conceptually represents a `stream<u8, _>`. It's temporary
+    /// scaffolding until component-model's async features are ready.
+    ///
+    /// `output-stream`s are *non-blocking* to the extent practical on
+    /// underlying platforms. Except where specified otherwise, I/O operations also
+    /// always return promptly, after the number of bytes that can be written
+    /// promptly, which could even be zero. To wait for the stream to be ready to
+    /// accept data, the `subscribe-to-output-stream` function to obtain a
+    /// `pollable` which can be polled for using `wasi_poll`.
+    ///
+    /// And at present, it is a `u32` instead of being an actual handle, until
+    /// the wit-bindgen implementation of handles and resources is ready.
+    ///
+    /// This [represents a resource](https://github.com/WebAssembly/WASI/blob/main/docs/WitInWasi.md#Resources).
+    type output-stream = u32
+
+    /// Write bytes to a stream.
+    ///
+    /// This function returns a `u64` indicating the number of bytes from
+    /// `buf` that were written; it may be less than the full list.
+    write: func(
+        this: output-stream,
+        /// Data to write
+        buf: list<u8>
+    ) -> result<u64, stream-error>
+
+    /// Write bytes to a stream, with blocking.
+    ///
+    /// This is similar to `write`, except that it blocks until at least one
+    /// byte can be written.
+    blocking-write: func(
+        this: output-stream,
+        /// Data to write
+        buf: list<u8>
+    ) -> result<u64, stream-error>
+
+    /// Write multiple zero bytes to a stream.
+    ///
+    /// This function returns a `u64` indicating the number of zero bytes
+    /// that were written; it may be less than `len`.
+    write-zeroes: func(
+        this: output-stream,
+        /// The number of zero bytes to write
+        len: u64
+    ) -> result<u64, stream-error>
+
+    /// Write multiple zero bytes to a stream, with blocking.
+    ///
+    /// This is similar to `write-zeroes`, except that it blocks until at least
+    /// one byte can be written.
+    blocking-write-zeroes: func(
+        this: output-stream,
+        /// The number of zero bytes to write
+        len: u64
+    ) -> result<u64, stream-error>
+
+    /// Read from one stream and write to another.
+    ///
+    /// This function returns the number of bytes transferred; it may be less
+    /// than `len`.
+    ///
+    /// Unlike other I/O functions, this function blocks until all the data
+    /// read from the input stream has been written to the output stream.
+    splice: func(
+        this: output-stream,
+        /// The stream to read from
+        src: input-stream,
+        /// The number of bytes to splice
+        len: u64,
+    ) -> result<tuple<u64, bool>, stream-error>
+
+    /// Read from one stream and write to another, with blocking.
+    ///
+    /// This is similar to `splice`, except that it blocks until at least
+    /// one byte can be read.
+    blocking-splice: func(
+        this: output-stream,
+        /// The stream to read from
+        src: input-stream,
+        /// The number of bytes to splice
+        len: u64,
+    ) -> result<tuple<u64, bool>, stream-error>
+
+    /// Forward the entire contents of an input stream to an output stream.
+    ///
+    /// This function repeatedly reads from the input stream and writes
+    /// the data to the output stream, until the end of the input stream
+    /// is reached, or an error is encountered.
+    ///
+    /// Unlike other I/O functions, this function blocks until the end
+    /// of the input stream is seen and all the data has been written to
+    /// the output stream.
+    ///
+    /// This function returns the number of bytes transferred.
+    forward: func(
+        this: output-stream,
+        /// The stream to read from
+        src: input-stream
+    ) -> result<u64, stream-error>
+
+    /// Create a `pollable` which will resolve once either the specified stream
+    /// is ready to accept bytes or the other end of the stream has been closed.
+    subscribe-to-output-stream: func(this: output-stream) -> pollable
+
+    /// Dispose of the specified `output-stream`, after which it may no longer
+    /// be used.
+    drop-output-stream: func(this: output-stream)
+}
+
+/// A poll API intended to let users wait for I/O events on multiple handles
+/// at once.
+default interface poll {
+    /// A "pollable" handle.
+    ///
+    /// This is conceptually represents a `stream<_, _>`, or in other words,
+    /// a stream that one can wait on, repeatedly, but which does not itself
+    /// produce any data. It's temporary scaffolding until component-model's
+    /// async features are ready.
+    ///
+    /// And at present, it is a `u32` instead of being an actual handle, until
+    /// the wit-bindgen implementation of handles and resources is ready.
+    ///
+    /// `pollable` lifetimes are not automatically managed. Users must ensure
+    /// that they do not outlive the resource they reference.
+    ///
+    /// This [represents a resource](https://github.com/WebAssembly/WASI/blob/main/docs/WitInWasi.md#Resources).
+    type pollable = u32
+
+    /// Dispose of the specified `pollable`, after which it may no longer
+    /// be used.
+    drop-pollable: func(this: pollable)
+
+    /// Poll for completion on a set of pollables.
+    ///
+    /// The "oneoff" in the name refers to the fact that this function must do a
+    /// linear scan through the entire list of subscriptions, which may be
+    /// inefficient if the number is large and the same subscriptions are used
+    /// many times. In the future, this is expected to be obsoleted by the
+    /// component model async proposal, which will include a scalable waiting
+    /// facility.
+    ///
+    /// Note that the return type would ideally be `list<bool>`, but that would
+    /// be more difficult to polyfill given the current state of `wit-bindgen`.
+    /// See <https://github.com/bytecodealliance/preview2-prototyping/pull/11#issuecomment-1329873061>
+    /// for details.  For now, we use zero to mean "not ready" and non-zero to
+    /// mean "ready".
+    poll-oneoff: func(in: list<pollable>) -> list<u8>
+}

vendor/README.md

@@ -571,6 +571,7 @@ This is a list of grammars that Linguist selects to provide syntax highlighting
 - **Wavefront Object:** [Alhadis/language-wavefront](https://github.com/Alhadis/language-wavefront)
 - **Web Ontology Language:** [textmate/xml.tmbundle](https://github.com/textmate/xml.tmbundle)
 - **WebAssembly:** [Alhadis/language-webassembly](https://github.com/Alhadis/language-webassembly)
+- **WebAssembly Interface Type:** [bytecodealliance/vscode-wit](https://github.com/bytecodealliance/vscode-wit)
 - **WebIDL:** [andik/IDL-Syntax](https://github.com/andik/IDL-Syntax)
 - **WebVTT:** [Alhadis/language-subtitles](https://github.com/Alhadis/language-subtitles)
 - **Wget Config:** [Alhadis/language-etc](https://github.com/Alhadis/language-etc)