Jonlidgard

README.md

@@ -174,6 +174,29 @@ A `CSVReader` parses CSV data from a given input (`String`, `Data`, `URL`, or `I
 
     Loading all data into memory may provide faster iteration for small to medium size files, since you get rid of the overhead of managing an `InputStream`.
 
+-   `lastFieldDelimiterStrategy` (default `.parse`) indicates whether to ignore extra delimiters in the last field.
+
+	This can sometimes be helpful when parsing unquoted CSV, e.g. an address field that contains data such as 'Street, City, Region'.
+
+    For example:
+     ```swift
+		 $0.lastFieldDelimiterStrategy = .ignore
+     ```
+
+	The following **unquoted** text:
+	```
+    		Header1, Header2
+    		A, B, C, D
+    ```
+
+    would result in it being parsed as though it was the following quoted text:
+	```
+    		Header1, Header2
+    		"A", "B, C, D"
+    ```
+
+
+
 The configuration values are set during initialization and can be passed to the `CSVReader` instance through a structure or with a convenience closure syntax:
 
 ```swift

sources/imperative/reader/Reader.swift

@@ -109,12 +109,14 @@ extension CSVReader {
 
   loop: while true {
     let result: [String]?
+
     do {
       result = try self._parseLine(rowIndex: self.count.rows)
     } catch let error {
       self.status = .failed(error as! CSVError<CSVReader>)
       throw error
     }
+
     // If no fields were parsed, the EOF has been reached.
     guard let fields = result else {
       self.status = .finished
@@ -184,7 +186,8 @@ extension CSVReader {
       break loop
     // 7. If a regular character is encountered, an "unescaped field" is awaiting parsing.
     } else {
-      let field = try self._parseUnescapedField(starting: scalar, rowIndex: rowIndex)
+      let isLastField = self.count.fields > 0 && self.count.fields == result.count + 1
+      let field = try self._parseUnescapedField(starting: scalar, rowIndex: rowIndex, isLastField: isLastField)
       result.append(field.value)
       if field.isAtEnd { break loop }
     }
@@ -198,7 +201,7 @@ extension CSVReader {
   /// - parameter rowIndex: The index of the row being parsed.
   /// - throws: `CSVError<CSVReader>` exclusively.
   /// - returns: The parsed field and whether the row/file ending characters have been found.
-  private func _parseUnescapedField(starting: Unicode.Scalar, rowIndex: Int) throws -> (value: String, isAtEnd: Bool) {
+  private func _parseUnescapedField(starting: Unicode.Scalar, rowIndex: Int, isLastField: Bool) throws -> (value: String, isAtEnd: Bool) {
     var reachedRowsEnd = false
     self._fieldBuffer.append(starting)
 
@@ -213,9 +216,14 @@ extension CSVReader {
       if scalar == self._settings.escapingScalar {
         throw Error._invalidUnescapedField(rowIndex: rowIndex)
       // 4. If the field delimiter is encountered, return the already parsed characters.
+
       } else if try self._isFieldDelimiter(scalar) {
-        reachedRowsEnd = false
-        break fieldLoop
+        if configuration.lastFieldDelimiterStrategy == .parse || !isLastField {
+          reachedRowsEnd = false
+          break fieldLoop
+        } else { // if last field then treat delimiter as a regular scalar
+          self._fieldBuffer.append(scalar)
+        }
       // 5. If the row delimiter is encountered, return the already parsed characters.
       } else if try self._isRowDelimiter(scalar) {
         reachedRowsEnd = true

sources/imperative/reader/ReaderConfiguration.swift

@@ -15,6 +15,8 @@ extension CSVReader {
     public var headerStrategy: Strategy.Header
     /// Trims the given characters at the beginning and end of each row, and between fields.
     public var trimStrategy: CharacterSet
+    /// Ignores delimiters in last field - useful for parsing some unquoted types of CSV
+    public var lastFieldDelimiterStrategy: Strategy.lastFieldDelimiterStrategy
     /// Boolean indicating whether the data/file/string should be completely parsed at reader's initialization.
     public var presample: Bool
 
@@ -24,6 +26,7 @@ extension CSVReader {
       self.delimiters = (field: ",", row: "\n")
       self.escapingStrategy = .doubleQuote
       self.headerStrategy = .none
+      self.lastFieldDelimiterStrategy = .parse
       self.trimStrategy = CharacterSet()
       self.presample = false
     }
@@ -49,3 +52,20 @@ extension Strategy {
     }
   }
 }
+
+
+extension Strategy {
+  public enum lastFieldDelimiterStrategy: ExpressibleByNilLiteral, ExpressibleByBooleanLiteral {
+
+    case parse
+    case ignore
+
+    public init(nilLiteral: ()) {
+      self = .parse
+    }
+
+    public init(booleanLiteral value: BooleanLiteralType) {
+      self = (value) ? .ignore : .parse
+    }
+  }
+}

tests/MyCustomTests.swift

@@ -0,0 +1,31 @@
+//
+//  TestIgnoreDelimitersInLastField.swift
+//  
+//
+//  Created by Jon Lidgard on 17/04/2022.
+//
+
+import XCTest
+import CodableCSV
+
+
+class MyCustomTests: XCTestCase {
+  override func setUp() {
+    self.continueAfterFailure = false
+  }
+}
+
+
+extension MyCustomTests {
+
+  func testIgnoreExtraDelimitersInLastField() throws {
+    let input = """
+  a,b
+  §A,BC, DE
+  """
+    XCTAssertNoThrow(try CSVReader.decode(input: input) {
+      $0.headerStrategy = .firstLine
+      $0.lastFieldDelimiterStrategy = .ignore
+    })
+  }
+}