Introduces Bytes class (#1019)

This introduces a new `Bytes` standard library class, for working with
binary data.

* Add Bytes class to the standard library
* Change CLI to eval `output.bytes`
* Change code generators to map Bytes to respective underlying type
* Add subscript and concat operator support
* Add binary encoding for Bytes
* Add PCF and Plist rendering for Bytes

Co-authored-by: Kushal Pisavadia <kushi.p@gmail.com>

docs/modules/ROOT/partials/component-attributes.adoc

@@ -138,6 +138,7 @@ endif::[]
 :uri-stdlib-Function3: {uri-stdlib-baseModule}/Function3
 :uri-stdlib-Function4: {uri-stdlib-baseModule}/Function4
 :uri-stdlib-Function5: {uri-stdlib-baseModule}/Function5
+:uri-stdlib-Bytes: {uri-stdlib-baseModule}/Bytes
 :uri-stdlib-Resource: {uri-stdlib-baseModule}/Resource
 :uri-stdlib-outputFiles: {uri-stdlib-baseModule}/ModuleOutput#files
 

docs/modules/bindings-specification/pages/binary-encoding.adoc

@@ -161,6 +161,24 @@ The array's length is the number of slots that are filled. For example, xref:{ur
 |
 |
 |
+
+|link:{uri-stdlib-Function}[Function]
+|`0xE`
+|
+|
+|
+|
+|
+|
+
+|link:{uri-stdlib-Bytes}[Bytes]
+|`0xF`
+|link:{uri-messagepack-bin}[bin]
+|Binary contents
+|
+|
+|
+|
 |===
 
 [[object-members]]

docs/modules/language-reference/pages/index.adoc

@@ -3684,6 +3684,41 @@ res5 = map.getOrNull("Falcon") // <5>
 <4> result: `2`
 <5> result: `null`
 
+[[bytes]]
+=== Bytes
+
+A value of type `Bytes` is a sequence of `UInt8` elements.
+
+`Bytes` can be constructed by passing byte values into the constructor.
+
+[source,pkl]
+----
+bytes1 = Bytes(0xff, 0x00, 0x3f) // <1>
+bytes2 = Bytes() // <2>
+----
+<1> Result: a `Bytes` with 3 elements
+<2> Result: an empty `Bytes`
+
+`Bytes` can also be constructed from a base64-encoded string, via `base64DecodedBytes`:
+
+[source,pkl]
+----
+bytes3 = "cGFycm90".base64DecodedBytes // <1>
+----
+<1> Result: `Bytes(112, 97, 114, 114, 111, 116)`
+
+==== `Bytes` vs `List<UInt8>`
+
+`Bytes` is similar to `List<UInt8>` in that they are both sequences of `UInt8` elements.
+However, they are semantically distinct.
+`Bytes` represent binary data, and is typically rendered differently.
+For example, they are rendered as `<data>` tags when using `PListRenderer`.
+
+`Bytes` also have different performance characteristics; a value of type `Bytes` tends to be managed as a contiguous memory block.
+Thus, they are more compact and consume less memory.
+However, they are not optimized for transformations.
+For example, given two values of size `M` and `N`, concatenating two `Bytes` values allocates O(M + N) space, whereas concatenating two `List` values allocates O(1) space.
+
 [[regular-expressions]]
 === Regular Expressions
 
@@ -4671,6 +4706,10 @@ The following types are iterable:
 |entry key (`Key`)
 |entry value (`Value`)
 
+|`Bytes`
+|element index (`Int`)
+|element value (`UInt8`)
+
 |`Listing<Element>`
 |element index (`Int`)
 |element value (`Element`)
@@ -4751,6 +4790,9 @@ The following table describes how different iterables turn into object members:
 
 | `IntSeq`
 | Element
+
+| `Bytes`
+| Element
 |===
 
 These types can only be spread into enclosing objects that support that member type.