Swift 5.7 Improvements (#261)

* Swift 5.7 Improvements

While we have some ideas to take Swift 5.7 even further, we need more
time to let the details bake. Till then, we can still offer a
quality-of-life improvement for folks using Swift 5.7, especially those
working on Advent of Code 2022!

Improving Parsing's builder limits
----------------------------------

This is perhaps the most notable improvement for now.

Currently, Parsing's builders limits the number of parsers allowed in a
block because of how many overloads need to be maintained and generated.

Using Swift 5.7's new [`buildPartialBlock`][se-0348], we can greatly
improve upon this limit:

| Builder          | Block limit `swift(<5.7)` | Block limit `swift(>=5.7)` |
| ---------------- | ------------------------- | -------------------------- |
| `OneOfBuilder`   | 10                        | ∞                          |
| `ParserBuilder`  | 6                         | 10–∞*                      |

\* Up to 10 non-`Void` captures in a block, plus unlimited `Void`
captures.

This should make working with larger builders much easier. The limit of
10 captures is arbitrary and could be expanded. If you hit it, please
[let us know][discussions]!

[se-0348]: https://github.com/apple/swift-evolution/blob/main/proposals/0348-buildpartialblock.md
[discussions]: https://github.com/pointfreeco/swift-parsing/discussions

Adding primary associated types
-------------------------------

We've added primary associated types to a number of protocols:

  * `Parser<Input, Output>`
  * `ParserPrinter<Intput, Output>`
  * `Conversion<Input, Output>`
  * `PrependableCollection<Element>`

This will allow you to express and constrain these protocols in a more
lightweight, natural manner.

Formatter parser-printer support
--------------------------------

We've added support for using formatters directly in your parser
printers with the `Formatted` parser-printer:

```swift
let total = ParsePrint {
  "TOTAL: "
  Formatted(.currency(code: "USD"))
}

try total.parse("TOTAL: $42.42")  // 42.42
try total.print(99.95)            // "TOTAL: $99.95"
```

`Formatted` takes any of the many formatters shipping in iOS 15 and more
recently.

---

We have more plans for Parsing in the coming months to take even greater
advantage of modern Swift features, and we hope to explore them soon!

* Fix

* wip

* Clean up schemes

* wip

* remove 5.6 docs

Co-authored-by: Brandon Williams <[email protected]>

.gitignore

@@ -1,5 +1,6 @@
 .DS_Store
 /.build
+/.swiftpm
 /Packages
 /*.xcodeproj
 xcuserdata/

Makefile

@@ -9,12 +9,15 @@ benchmarks:
 
 test:
 	xcodebuild test \
+		-workspace Parsing.xcworkspace \
 		-scheme Parsing \
 		-destination platform="$(PLATFORM_IOS)"
 	xcodebuild test \
+		-workspace Parsing.xcworkspace \
 		-scheme Parsing \
 		-destination platform="$(PLATFORM_MACOS)"
 	xcodebuild test \
+		-workspace Parsing.xcworkspace \
 		-scheme Parsing \
 		-destination platform="$(PLATFORM_TVOS)"
 

Parsing.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>