Database Functions Improvements

Sources/StructuredQueriesCore/Documentation.docc/Articles/MigrationGuides.md

@@ -0,0 +1,17 @@
+# Migration guides
+
+Learn how to upgrade your application to the latest version of StructuredQueries.
+
+## Overview
+
+StructuredQueries is under constant development, and we are always looking for ways to simplify the
+library and make it more powerful. As such, we often need to deprecate certain APIs in favor of
+newer ones. We recommend people update their code as quickly as possible to the newest APIs, and
+these guides contain tips to do so.
+
+> Important: Before following any particular migration guide be sure you have followed all the
+> preceding migration guides.
+
+## Topics
+
+- <doc:MigratingTo0.16>

Sources/StructuredQueriesCore/Documentation.docc/Articles/MigrationGuides/MigratingTo0.16.md

@@ -0,0 +1,83 @@
+# Migrating to 0.16
+
+StructuredQueries 0.16 introduces powerful tools for user-defined SQLite functions, with some
+breaking changes for those defining custom query representations.
+
+## Overview
+
+StructuredQueries recently introduced a new module, StructuredQueriesSQLite, and with it a new macro
+for defining Swift functions that can be called from a query. It's called `@DatabaseFunction`, and
+can annotate any function that works with query-representable types.
+
+For example, an `exclaim` function can be defined like so:
+
+```swift
+@DatabaseFunction
+func exclaim(_ string: String) -> String {
+  string.localizedUppercase + "!"
+}
+```
+
+And will be immediately callable in a query by prefixing the function with `$`:
+
+```swift
+Reminder.select { $exclaim($0.title) }
+// SELECT "exclaim"("reminders"."title") FROM "reminders"
+```
+
+For the query to successfully execute, you must also add the function to your SQLite database
+connection. This can be done in [SharingGRDB] (0.7.0+) using the `Database.add(function:)` method,
+_e.g._ when you first configure things:
+
+[SharingGRDB]: https://github.com/pointfreeco/sharing-grdb
+
+```swift
+var configuration = Configuration()
+configuration.prepareDatabase { db in
+  db.add(function: $exclaim)
+}
+```
+
+> Tip: Use the `isDeterministic` parameter for functions that always return the same value from the
+> same arguments. SQLite's query planner can optimize these functions.
+>
+> ```swift
+> @DatabaseFunction(isDeterministic: true)
+> func exclaim(_ string: String) -> String {
+>   string.localizedUppercase + "!"
+> }
+> ```
+
+### Custom representations
+
+To define a type that works with a custom representation, like JSON, you can use the `as` parameter
+of the macro:
+
+```swift
+@DatabaseFunction(
+  as: (([String].JSONRepresentation) -> [String].JSONRepresentation).self
+)
+func jsonArrayExclaim(_ strings: [String]) -> [String] {
+  strings.map { $0.localizedUppercase + "!" }
+}
+```
+
+### Breaking change: user-defined representations
+
+To power things, a new initializer, ``QueryBindable/init(queryBinding:)``, was added to the
+``QueryBindable`` protocol. While most code should continue to compile, if you define your own
+query representations that conform to ``QueryRepresentable``, you will need to define this
+initializer upon upgrading.
+
+For example, `JSONRepresentation` added the following initializer:
+
+```swift
+public init?(queryBinding: QueryBinding) {
+  guard case .text(let json) = queryBinding else { return nil }
+  guard let queryOutput = try? jsonDecoder.decode(
+    QueryOutput.self, from: Data(json.utf8)
+  )
+  else { return nil }
+  self.init(queryOutput: queryOutput)
+}
+```

Sources/StructuredQueriesCore/Documentation.docc/StructuredQueriesCore.md

@@ -140,3 +140,7 @@ reading to learn more about building SQL with StructuredQueries.
 
 - <doc:FullTextSearch>
 - <doc:Integration>
+
+### Migration guides
+
+- <doc:MigrationGuides>

Sources/StructuredQueriesCore/Internal/Deprecations.swift

@@ -169,6 +169,14 @@ extension Date.ISO8601Representation: QueryBindable {
   public var queryBinding: QueryBinding {
     .text(queryOutput.iso8601String)
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard
+      case .text(let iso8601String) = queryBinding,
+      let queryOutput = try? Date(iso8601String: iso8601String)
+    else { return nil }
+    self.init(queryOutput: queryOutput)
+  }
 }
 
 @available(
@@ -226,6 +234,14 @@ extension UUID.LowercasedRepresentation: QueryBindable {
   public var queryBinding: QueryBinding {
     .text(queryOutput.uuidString.lowercased())
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard
+      case .text(let uuidString) = queryBinding,
+      let uuid = UUID(uuidString: uuidString)
+    else { return nil }
+    self.init(queryOutput: uuid)
+  }
 }
 
 @available(

Sources/StructuredQueriesCore/QueryBindable+Foundation.swift

@@ -5,6 +5,11 @@ extension Data: QueryBindable {
     .blob([UInt8](self))
   }
 
+  public init?(queryBinding: QueryBinding) {
+    guard case .blob(let bytes) = queryBinding else { return nil }
+    self.init(bytes)
+  }
+
   public init(decoder: inout some QueryDecoder) throws {
     try self.init([UInt8](decoder: &decoder))
   }
@@ -15,6 +20,11 @@ extension URL: QueryBindable {
     .text(absoluteString)
   }
 
+  public init?(queryBinding: QueryBinding) {
+    guard case .text(let string) = queryBinding else { return nil }
+    self.init(string: string)
+  }
+
   public init(decoder: inout some QueryDecoder) throws {
     guard let url = Self(string: try String(decoder: &decoder)) else {
       throw InvalidURL()

Sources/StructuredQueriesCore/QueryBindable.swift

@@ -16,11 +16,6 @@ public protocol QueryBindable: QueryRepresentable, QueryExpression where QueryVa
 
 extension QueryBindable {
   public var queryFragment: QueryFragment { "\(queryBinding)" }
-
-  public init?(queryBinding: QueryBinding) {
-    guard let queryValue = QueryValue(queryBinding: queryBinding) else { return nil }
-    self.init(queryBinding: queryValue.queryBinding)
-  }
 }
 
 extension [UInt8]: QueryBindable, QueryExpression {
@@ -53,22 +48,42 @@ extension Date: QueryBindable {
 
 extension Float: QueryBindable {
   public var queryBinding: QueryBinding { .double(Double(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .double(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension Int: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension Int8: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension Int16: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension Int32: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension Int64: QueryBindable {
@@ -89,14 +104,26 @@ extension String: QueryBindable {
 
 extension UInt8: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension UInt16: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension UInt32: QueryBindable {
   public var queryBinding: QueryBinding { .int(Int64(self)) }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding else { return nil }
+    self.init(value)
+  }
 }
 
 extension UInt64: QueryBindable {
@@ -107,6 +134,10 @@ extension UInt64: QueryBindable {
       return .int(Int64(self))
     }
   }
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let value) = queryBinding, value >= UInt64.min else { return nil }
+    self.init(value)
+  }
 }
 
 extension UUID: QueryBindable {
@@ -146,8 +177,16 @@ extension DefaultStringInterpolation {
 
 extension QueryBindable where Self: LosslessStringConvertible {
   public var queryBinding: QueryBinding { description.queryBinding }
+  public init?(queryBinding: QueryBinding) {
+    guard let description = String(queryBinding: queryBinding) else { return nil }
+    self.init(description)
+  }
 }
 
 extension QueryBindable where Self: RawRepresentable, RawValue: QueryBindable {
   public var queryBinding: QueryBinding { rawValue.queryBinding }
+  public init?(queryBinding: QueryBinding) {
+    guard let rawValue = RawValue(queryBinding: queryBinding) else { return nil }
+    self.init(rawValue: rawValue)
+  }
 }

Sources/StructuredQueriesCore/QueryRepresentable/Codable+JSON.swift

@@ -6,15 +6,6 @@ public struct _CodableJSONRepresentation<QueryOutput: Codable>: QueryRepresentab
   public init(queryOutput: QueryOutput) {
     self.queryOutput = queryOutput
   }
-
-  public init(decoder: inout some QueryDecoder) throws {
-    self.init(
-      queryOutput: try jsonDecoder.decode(
-        QueryOutput.self,
-        from: Data(String(decoder: &decoder).utf8)
-      )
-    )
-  }
 }
 
 extension Decodable where Self: Encodable {
@@ -46,6 +37,24 @@ extension _CodableJSONRepresentation: QueryBindable {
       return .invalid(error)
     }
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard case .text(let value) = queryBinding else { return nil }
+    guard let queryOutput = try? jsonDecoder.decode(QueryOutput.self, from: Data(value.utf8))
+    else { return nil }
+    self.init(queryOutput: queryOutput)
+  }
+}
+
+extension _CodableJSONRepresentation: QueryDecodable {
+  public init(decoder: inout some QueryDecoder) throws {
+    self.init(
+      queryOutput: try jsonDecoder.decode(
+        QueryOutput.self,
+        from: Data(String(decoder: &decoder).utf8)
+      )
+    )
+  }
 }
 
 extension _CodableJSONRepresentation: SQLiteType {

Sources/StructuredQueriesCore/QueryRepresentable/Date+JulianDay.swift

@@ -30,6 +30,11 @@ extension Date.JulianDayRepresentation: QueryBindable {
   public var queryBinding: QueryBinding {
     .double(2440587.5 + queryOutput.timeIntervalSince1970 / 86400)
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard case .double(let value) = queryBinding else { return nil }
+    self.init(queryOutput: Date(timeIntervalSince1970: (value - 2440587.5) * 86400))
+  }
 }
 
 extension Date.JulianDayRepresentation: QueryDecodable {

Sources/StructuredQueriesCore/QueryRepresentable/Date+UnixTime.swift

@@ -30,6 +30,11 @@ extension Date.UnixTimeRepresentation: QueryBindable {
   public var queryBinding: QueryBinding {
     .int(Int64(queryOutput.timeIntervalSince1970))
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard case .int(let timeIntervalSince1970) = queryBinding else { return nil }
+    self.init(queryOutput: Date(timeIntervalSince1970: Double(timeIntervalSince1970)))
+  }
 }
 
 extension Date.UnixTimeRepresentation: QueryDecodable {

Sources/StructuredQueriesCore/QueryRepresentable/UUID+Bytes.swift

@@ -30,6 +30,16 @@ extension UUID.BytesRepresentation: QueryBindable {
   public var queryBinding: QueryBinding {
     .blob(withUnsafeBytes(of: queryOutput.uuid, [UInt8].init))
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard case .blob(let bytes) = queryBinding else { return nil }
+    guard bytes.count == 16 else { return nil }
+    self.init(
+      queryOutput: bytes.withUnsafeBytes {
+        UUID(uuid: $0.load(as: uuid_t.self))
+      }
+    )
+  }
 }
 
 extension UUID.BytesRepresentation: QueryDecodable {

Sources/StructuredQueriesCore/QueryRepresentable/UUID+Uppercased.swift

@@ -27,6 +27,14 @@ extension UUID? {
 }
 
 extension UUID.UppercasedRepresentation: QueryBindable {
+  public init?(queryBinding: QueryBinding) {
+    guard
+      case .text(let uuidString) = queryBinding,
+      let uuid = UUID(uuidString: uuidString)
+    else { return nil }
+    self.init(queryOutput: uuid)
+  }
+
   public var queryBinding: QueryBinding {
     .text(queryOutput.uuidString)
   }

Sources/StructuredQueriesCore/TableAlias.swift

@@ -193,6 +193,11 @@ extension TableAlias: QueryBindable where Base: QueryBindable {
   public var queryBinding: QueryBinding {
     base.queryBinding
   }
+
+  public init?(queryBinding: QueryBinding) {
+    guard let base = Base(queryBinding: queryBinding) else { return nil }
+    self.init(base: base)
+  }
 }
 
 extension TableAlias: QueryDecodable where Base: QueryDecodable {