Merge pull request #2100 from ewanmellor/swift-fix-parsetreepatternmatcher

Fix ParseTreePatternMatcher.split in the Swift runtime.

runtime/Swift/Sources/Antlr4/tree/pattern/Chunk.swift

@@ -17,5 +17,12 @@
 /// regular tokens of the text surrounding the tags.
 /// 
 
-public class Chunk {
+public class Chunk: Equatable {
+    public static func ==(lhs: Chunk, rhs: Chunk) -> Bool {
+        return lhs.isEqual(rhs)
+    }
+
+    public func isEqual(_ other: Chunk) -> Bool {
+        return false
+    }
 }

runtime/Swift/Sources/Antlr4/tree/pattern/ParseTreePatternMatcher.swift

@@ -387,7 +387,7 @@ public class ParseTreePatternMatcher {
 
         let ntags = starts.count
         for i in 0..<ntags {
-            if starts[i] != stops[i] {
+            if starts[i] >= stops[i] {
                 throw ANTLRError.illegalArgument(msg: "tag delimiters out of order in pattern: " + pattern)
             }
         }
@@ -408,7 +408,7 @@ public class ParseTreePatternMatcher {
             // copy inside of <tag>
             let tag = pattern[starts[i] + start.length ..< stops[i]]
             var ruleOrToken = tag
-            var label = ""
+            var label: String?
             let colon = tag.indexOf(":")
             if colon >= 0 {
                 label = tag[0 ..< colon]
@@ -417,7 +417,7 @@ public class ParseTreePatternMatcher {
             chunks.append(try TagChunk(label, ruleOrToken))
             if i + 1 < ntags {
                 // copy from end of <tag> to start of next
-                let text = pattern[stops[i] + stop.length ..< starts[i] + 1]
+                let text = pattern[stops[i] + stop.length ..< starts[i + 1]]
                 chunks.append(TextChunk(text))
             }
         }

runtime/Swift/Sources/Antlr4/tree/pattern/TagChunk.swift

@@ -87,10 +87,19 @@ public class TagChunk: Chunk, CustomStringConvertible {
     /// returned as just the tag name.
     /// 
     public var description: String {
-        if label != nil {
-            return label! + ":" + tag
+        if let label = label {
+            return "\(label):\(tag)"
         }
-
+        else {
             return tag
         }
+    }
+
+
+    override public func isEqual(_ other: Chunk) -> Bool {
+        guard let other = other as? TagChunk else {
+            return false
+        }
+        return tag == other.tag && label == other.label
+    }
 }

runtime/Swift/Sources/Antlr4/tree/pattern/TextChunk.swift

@@ -36,15 +36,19 @@ public class TextChunk: Chunk, CustomStringConvertible {
         return text
     }
 
-    /// 
-    /// 
     ///
     /// The implementation for _org.antlr.v4.runtime.tree.pattern.TextChunk_ returns the result of
     /// _#getText()_ in single quotes.
     ///
-
-
     public var description: String {
-        return "'" + text + "'"
+        return "'\(text)'"
+    }
+
+
+    override public func isEqual(_ other: Chunk) -> Bool {
+        guard let other = other as? TextChunk else {
+            return false
+        }
+        return text == other.text
     }
 }

runtime/Swift/Tests/Antlr4Tests/ParseTreePatternMatcherTests.swift

@@ -0,0 +1,34 @@
+/// Copyright (c) 2012-2017 The ANTLR Project. All rights reserved.
+/// Use of this file is governed by the BSD 3-clause license that
+/// can be found in the LICENSE.txt file in the project root.
+
+import Foundation
+import XCTest
+import Antlr4
+
+class ParseTreePatternMatcherTests: XCTestCase {
+
+    func testSplit() throws {
+        try doSplitTest("", [TextChunk("")])
+        try doSplitTest("Foo", [TextChunk("Foo")])
+        try doSplitTest("<ID> = <e:expr> ;",
+                        [TagChunk("ID"), TextChunk(" = "), TagChunk("e", "expr"), TextChunk(" ;")])
+        try doSplitTest("\\<ID\\> = <e:expr> ;",
+                        [TextChunk("<ID> = "), TagChunk("e", "expr"), TextChunk(" ;")])
+    }
+}
+
+private func doSplitTest(_ input: String, _ expected: [Chunk]) throws {
+    let matcher = try makeMatcher()
+    XCTAssertEqual(try matcher.split(input), expected)
+}
+
+private func makeMatcher() throws -> ParseTreePatternMatcher {
+    // The lexer and parser here aren't actually used.  They're just here
+    // so that ParseTreePatternMatcher can be constructed, but in this file
+    // we're currently only testing methods that don't depend on them.
+    let lexer = Lexer()
+    let ts = BufferedTokenStream(lexer)
+    let parser = try Parser(ts)
+    return ParseTreePatternMatcher(lexer, parser)
+}