Merge pull request #47 from kareman/Readme-require-Swift-5.3

Readme: require Swift 5.3.
Add part about pattern input types.
Split up readme unit test to avoid warning about it taking too long to type check.

Author: kareman

README.md

@@ -1,6 +1,6 @@
 <p align="center">
    <a href="https://developer.apple.com/swift/">
-      <img src="https://img.shields.io/badge/Swift-5.2-orange.svg?style=flat" alt="Swift 5.2">
+      <img src="https://img.shields.io/badge/Swift-5.3-orange.svg?style=flat" alt="Swift 5.3">
    </a>
    <a href="https://github.com/apple/swift-package-manager">
       <img src="https://img.shields.io/badge/Swift%20Package%20Manager-compatible-brightgreen.svg" alt="SPM">
@@ -17,6 +17,10 @@ For general information about PEGs, see [the original paper](https://dl.acm.org/
 
 To try out Patterns in a playground, open Playground/Playground.xcworkspace in Xcode.
 
+### Note
+
+Patterns requires Swift 5.3, which is currently in beta. If using Xcode, version 12 (also in beta) is required. 
+
 ## Example
 
 ```swift
@@ -183,6 +187,30 @@ let pointsAsSubstrings = parser.matches(in: text).map { match in
 
 You can also use `match[multiple: name]` to get an array if captures with that name may be matched multiple times. `match[one: name]` only returns the first capture of that name.
 
+### Inputs
+
+By default, patterns have `String` as their input type. But you can use any `BidirectionalCollection` with `Hashable` elements for input. Just explicitly specify the input type of the first pattern, and the rest should get it automatically:
+
+```swift
+let text = "This is a point: (43,7), so is (0, 5). But my final point is (3,-1).".utf8
+
+let digit = OneOf<String.UTF8View>(UInt8(ascii: "0")...UInt8(ascii: "9"))
+let number = ("+" / "-" / "") • digit+
+let point = "(" • Capture(name: "x", number)
+	• "," • " "¿ • Capture(name: "y", number) • ")"
+
+struct Point: Codable {
+	let x, y: Int
+}
+
+let parser = try Parser(search: point)
+let pointsAsSubstrings = parser.matches(in: text).map { match in
+	(text[match[one: "x"]!], text[match[one: "y"]!])
+}
+```
+
+`Parser.decode` can (currently) only take String as input, but `.matches` handles all types.
+
 ## Setup
 
 ### [Swift Package Manager](https://swift.org/package-manager/)

Tests/PatternsTests/PatternTests.swift

@@ -307,48 +307,67 @@ class PatternTests: XCTestCase {
 		assertCaptures(point, input: text, result: [["43", "7"], ["0", "5"], ["3", "-1"]])
 	}
 
-	func testReadme() throws {
-		do {
-			let l = OneOf(description: "ten") { character in
-				character.wholeNumberValue == 10
-			}
-
-			let arithmetic = Grammar { g in
-				g.all <- g.expr • !any
-				g.expr <- g.sum
-				g.sum <- g.product • (("+" / "-") • g.product)*
-				g.product <- g.power • (("*" / "/") • g.power)*
-				g.power <- g.value • ("^" • g.power)¿
-				g.value <- digit+ / "(" • g.expr • ")"
-			}
-
-			let parser = try Parser(search: l)
-			for match in parser.matches(in: "text") {
-				_ = match
-				// ...
-			}
-			_ = arithmetic
+	func testReadme1() throws {
+		let l = OneOf(description: "ten") { character in
+			character.wholeNumberValue == 10
 		}
 
-		do {
-			let text = "This is a point: (43,7), so is (0, 5). But my final point is (3,-1)."
+		let arithmetic = Grammar { g in
+			g.all <- g.expr • !any
+			g.expr <- g.sum
+			g.sum <- g.product • (("+" / "-") • g.product)*
+			g.product <- g.power • (("*" / "/") • g.power)*
+			g.power <- g.value • ("^" • g.power)¿
+			g.value <- digit+ / "(" • g.expr • ")"
+		}
+
+		let parser = try Parser(search: l)
+		for match in parser.matches(in: "text") {
+			_ = match
+			// ...
+		}
+
+		_ = arithmetic
+	}
+
+	func testReadme2() throws {
+		let text = "This is a point: (43,7), so is (0, 5). But my final point is (3,-1)."
+
+		let number = ("+" / "-" / "") • digit+
+		let point = "(" • Capture(name: "x", number)
+			• "," • " "¿ • Capture(name: "y", number) • ")"
+
+		struct Point: Codable {
+			let x, y: Int
+		}
+
+		let parser = try Parser(search: point)
+		let points = try parser.decode([Point].self, from: text)
 
-			let number = ("+" / "-" / "") • digit+
-			let point = "(" • Capture(name: "x", number)
-				• "," • " "¿ • Capture(name: "y", number) • ")"
+		let pointsAsSubstrings = parser.matches(in: text).map { match in
+			(text[match[one: "x"]!], text[match[one: "y"]!])
+		}
+
+		_ = (points, pointsAsSubstrings)
+	}
 
-			struct Point: Codable {
-				let x, y: Int
-			}
+	func testReadme3() throws {
+		let text = "This is a point: (43,7), so is (0, 5). But my final point is (3,-1).".utf8
 
-			let parser = try Parser(search: point)
-			let points = try parser.decode([Point].self, from: text)
+		let digit = OneOf<String.UTF8View>(UInt8(ascii: "0") ... UInt8(ascii: "9"))
+		let number = ("+" / "-" / "") • digit+
+		let point = "(" • Capture(name: "x", number)
+			• "," • " "¿ • Capture(name: "y", number) • ")"
 
-			let pointsAsSubstrings = parser.matches(in: text).map { match in
-				(text[match[one: "x"]!], text[match[one: "y"]!])
-			}
+		struct Point: Codable {
+			let x, y: Int
+		}
 
-			_ = (points, pointsAsSubstrings)
+		let parser = try Parser(search: point)
+		let pointsAsSubstrings = parser.matches(in: text).map { match in
+			(text[match[one: "x"]!], text[match[one: "y"]!])
 		}
+
+		_ = pointsAsSubstrings
 	}
 }