Merge pull request #7 from ahmedk92/int_conversion

Int type tolerance, and better SQLDataType conversion requirements and conveniences

Author: kean

Sources/SwiftSQL/SQLDataType.swift

@@ -12,10 +12,7 @@ import SQLite3
 public protocol SQLDataType {
     func sqlBind(statement: OpaquePointer, index: Int32)
     static func sqlColumn(statement: OpaquePointer, index: Int32) -> Self
-}
-
-public extension SQLDataType {
-    static func convert(from value: Any) -> Self? { value as? Self }
+    static func convert(from value: Any) -> Self?
 }
 
 extension Int: SQLDataType {
@@ -26,6 +23,11 @@ extension Int: SQLDataType {
     public static func sqlColumn(statement: OpaquePointer, index: Int32) -> Int {
         Int(sqlite3_column_int64(statement, index))
     }
+    
+    public static func convert(from value: Any) -> Int? {
+        guard let int64 = value as? Int64 else { return nil }
+        return Int(int64)
+    }
 }
 
 extension Int32: SQLDataType {
@@ -36,6 +38,11 @@ extension Int32: SQLDataType {
     public static func sqlColumn(statement: OpaquePointer, index: Int32) -> Int32 {
         sqlite3_column_int(statement, index)
     }
+    
+    public static func convert(from value: Any) -> Self? {
+        guard let int64 = value as? Int64 else { return nil }
+        return Int32(int64)
+    }
 }
 
 extension Int64: SQLDataType {
@@ -46,6 +53,8 @@ extension Int64: SQLDataType {
     public static func sqlColumn(statement: OpaquePointer, index: Int32) -> Int64 {
         sqlite3_column_int64(statement, index)
     }
+    
+    public static func convert(from value: Any) -> Self? { value as? Self }
 }
 
 extension Double: SQLDataType {
@@ -56,6 +65,8 @@ extension Double: SQLDataType {
     public static func sqlColumn(statement: OpaquePointer, index: Int32) -> Double {
         sqlite3_column_double(statement, index)
     }
+    
+    public static func convert(from value: Any) -> Self? { value as? Self }
 }
 
 extension String: SQLDataType {
@@ -67,6 +78,8 @@ extension String: SQLDataType {
         guard let pointer = sqlite3_column_text(statement, index) else { return "" }
         return String(cString: pointer)
     }
+    
+    public static func convert(from value: Any) -> Self? { value as? Self }
 }
 
 extension Data: SQLDataType {
@@ -81,6 +94,8 @@ extension Data: SQLDataType {
         let count = Int(sqlite3_column_bytes(statement, Int32(index)))
         return Data(bytes: pointer, count: count)
     }
+    
+    public static func convert(from value: Any) -> Self? { value as? Self }
 }
 
 private let SQLITE_TRANSIENT = unsafeBitCast(-1, to: sqlite3_destructor_type.self)

Sources/SwiftSQLExt/SwiftSQLExt.swift

@@ -71,7 +71,11 @@ public struct SQLRow {
     ///
     /// - parameter index: The leftmost column of the result set has the index 0.
     public subscript<T: SQLDataType>(index: Int) -> T {
-        T.convert(from: values[index]!)!
+        let value = values[index]!
+        guard let convertedValue = T.convert(from: value) else {
+            fatalError("Could not convert \(type(of: value)). Make sure target type (\(T.self)) correctly implements convert(from:).")
+        }
+        return convertedValue
     }
 
     /// Returns a single column of the current result row of a query. If the

Tests/SwiftSQLExtTests/SwiftSQLExtTests.swift

@@ -141,13 +141,13 @@ private extension SQLConnection {
         """)
 
         try insertUsersStatement
-            .bind("Alice", Int64(80))
+            .bind("Alice", 80)
             .execute()
 
         try insertUsersStatement.reset()
 
         try insertUsersStatement
-            .bind("Bob", Int64(90))
+            .bind("Bob", 90)
             .execute()
 
         let insertPersonsStatement = try self.prepare("""
@@ -170,9 +170,9 @@ private extension SQLConnection {
 
 private struct User: Hashable, SQLRowDecodable {
     let name: String
-    let level: Int64
+    let level: Int
 
-    init(name: String, level: Int64) {
+    init(name: String, level: Int) {
         self.name = name
         self.level = level
     }