Fixed format string parsing

CHANGELOG.md

@@ -6,7 +6,9 @@
 
 ### Bug Fixes
 
-_None_
+* Improved format string regex to handle escaped "%"s that precede a variable.  
+  [Tamas Lustyik](https://github.com/lvsti)
+  [#29](https://github.com/SwiftGen/SwiftGenKit/pull/29)
 
 ### Breaking Changes
 

Sources/Parsers/StringsFileParser.swift

@@ -124,7 +124,7 @@ public final class StringsFileParser {
 
     do {
       return try NSRegularExpression(
-        pattern: "(?<!%)%\(position)\(precision)(@|\(pattern_int)|\(pattern_float)|[csp])",
+        pattern: "(?:^|(?<!%)(?:%%)*)%\(position)\(precision)(@|\(pattern_int)|\(pattern_float)|[csp])",
         options: [.caseInsensitive]
       )
     } catch {

Tests/SwiftGenKitTests/StringsTests.swift

@@ -132,10 +132,16 @@ class StringsTests: XCTestCase {
     XCTAssertEqual(placeholders, [.Unknown, .Int, .Object, .Float, .Char])
   }
 
-  func testParseEscapePercentSign() {
+  func testParseEvenEscapePercentSign() {
     let placeholders = StringsFileParser.PlaceholderType.placeholders(fromFormat: "%%foo")
     // Must NOT map to [.Float]
     XCTAssertEqual(placeholders, [])
   }
 
+  func testParseOddEscapePercentSign() {
+    let placeholders = StringsFileParser.PlaceholderType.placeholders(fromFormat: "%%%foo")
+    // Should map to [.Float]
+    XCTAssertEqual(placeholders, [.Float])
+  }
+
 }