More smart PrettyPrinter formatting

Sources/TSCodeModule/Basic/PrettyPrinter.swift

@@ -10,6 +10,13 @@ extension PrettyPrintable {
     }
 }
 
+public enum BlockScope {
+    case global
+    case function
+    case `class`
+    case interface
+}
+
 public final class PrettyPrinter {
     private var level: Int = 0
 
@@ -19,9 +26,13 @@ public final class PrettyPrinter {
 
     public private(set) var line: Int = 1
 
+    public private(set) var blockScope: BlockScope
+
     public var smallNumber: Int = 3
 
-    public init() {}
+    public init(initialScope: BlockScope = .global) {
+        blockScope = initialScope
+    }
 
     public func write(_ text: String) {
         indentIfStartOfLine()
@@ -62,6 +73,13 @@ public final class PrettyPrinter {
         return try f()
     }
 
+    public func with<R>(blockScope: BlockScope, _ f: () throws -> R) rethrows -> R {
+        let prev = self.blockScope
+        defer { self.blockScope = prev }
+        self.blockScope = blockScope
+        return try f()
+    }
+
     private func indentIfStartOfLine() {
         guard isStartOfLine else { return }
         isStartOfLine = false

Sources/TSCodeModule/Code/TSBlockItem.swift

@@ -41,10 +41,13 @@ extension [TSBlockItem] {
     public func print(printer: PrettyPrinter) {
         for (index, item) in enumerated() {
             if index > 0,
-               let decl = self[index - 1].decl,
-               decl.wantsTrailingNewline
+               let prevDecl = self[index - 1].decl,
+               let itemDecl = item.decl
             {
-                printer.writeLine("")
+                let isSame = isSameKind(lhs: prevDecl, rhs: itemDecl)
+                if !isSame || itemDecl.wantsNewlineBetweenSiblingDecl(scope: printer.blockScope) {
+                    printer.writeLine("")
+                }
             }
 
             item.print(printer: printer)

Sources/TSCodeModule/Code/TSCode.swift

@@ -8,6 +8,8 @@ public struct TSCode: PrettyPrintable {
     public var items: [TSBlockItem]
 
     public func print(printer: PrettyPrinter) {
-        items.print(printer: printer)
+        printer.with(blockScope: .global) {
+            items.print(printer: printer)
+        }
     }
 }

Sources/TSCodeModule/Decl/TSClassDecl.swift

@@ -39,11 +39,11 @@ public struct TSClassDecl: PrettyPrintable {
         }
         printer.writeUnlessStartOfLine(" ")
         printer.writeLine("{")
-
-        printer.nest {
-            items.print(printer: printer)
+        printer.with(blockScope: .class) {
+            printer.nest {
+                items.print(printer: printer)
+            }
         }
-
         printer.writeLine("}")
     }
 }

Sources/TSCodeModule/Decl/TSDecl.swift

@@ -20,16 +20,41 @@ public enum TSDecl: PrettyPrintable {
         case .method(let d): d.print(printer: r)
         case .namespace(let d): d.print(printer: r)
         case .type(let d): d.print(printer: r)
-        case .var(let d): d.print(printer: r)
+        case .`var`(let d): d.print(printer: r)
         case .custom(let d): d.print(printer: r)
         }
     }
 
-    public var wantsTrailingNewline: Bool {
+    public func wantsNewlineBetweenSiblingDecl(scope: BlockScope) -> Bool {
         switch self {
-        case .`var`(let d): return d.wantsTrailingNewline
-        case .custom: return false
-        default: return true
+        case .class:
+            return true
+        case .field:
+            return false
+        case .import:
+            return false
+        case .interface:
+            return true
+        case .method, .function:
+            switch scope {
+            case .interface:
+                return false
+            default:
+                return true
+            }
+        case .namespace:
+            return true
+        case .type:
+            return true
+        case .var:
+            switch scope {
+            case .global:
+                return true
+            default:
+                return false
+            }
+        case .custom:
+            return true
         }
     }
 
@@ -51,20 +76,45 @@ public enum TSDecl: PrettyPrintable {
         kind: String,
         name: String,
         type: TSType? = nil,
-        initializer: TSExpr? = nil,
-        wantsTrailingNewline: Bool = false
+        initializer: TSExpr? = nil
     ) -> TSDecl {
-        .var(TSVarDecl(
+        .`var`(TSVarDecl(
             export: export,
             kind: kind,
             name: name,
             type: type,
-            initializer: initializer,
-            wantsTrailingNewline: wantsTrailingNewline
+            initializer: initializer
         ))
     }
 
     public static func custom(_ text: String) -> TSDecl {
         .custom(TSCustomDecl(text))
     }
 }
+
+public func isSameKind(lhs: TSDecl, rhs: TSDecl) -> Bool {
+    switch (lhs, rhs) {
+    case (.`class`, .`class`):
+        return true
+    case (.field, .field):
+        return true
+    case (.function, .function):
+        return true
+    case (.`import`, .`import`):
+        return true
+    case (.interface, .interface):
+        return true
+    case (.method, .method):
+        return true
+    case (.namespace, .namespace):
+        return true
+    case (.type, .type):
+        return true
+    case (.`var`, .`var`):
+        return true
+    case (.custom, .custom):
+        return false
+    default:
+        return false
+    }
+}

Sources/TSCodeModule/Decl/TSFunctionDecl.swift

@@ -37,8 +37,10 @@ public struct TSFunctionDecl: PrettyPrintable {
         }
 
         printer.writeLine(" {")
-        printer.nest {
-            items.print(printer: printer)
+        printer.with(blockScope: .function) {
+            printer.nest {
+                items.print(printer: printer)
+            }
         }
         printer.writeLine("}")
     }

Sources/TSCodeModule/Decl/TSImportDecl.swift

@@ -8,16 +8,23 @@ public struct TSImportDecl: PrettyPrintable {
     public var from: String
 
     public func print(printer: PrettyPrinter) {
-        printer.writeLine("import {")
-        printer.nest {
-            for (i, name) in names.enumerated() {
-                printer.write(name)
-                if i < names.count - 1 {
-                    printer.write(",")
+        let isBig = names.count > printer.smallNumber
+        if isBig {
+            printer.writeLine("import {")
+            printer.nest {
+                for (i, name) in names.enumerated() {
+                    printer.write(name)
+                    if i < names.count - 1 {
+                        printer.write(",")
+                    }
+                    printer.writeLine("")
                 }
-                printer.writeLine("")
             }
+            printer.writeLine("} from \"\(from)\";")
+        } else {
+            printer.write("import { ")
+            printer.write(names.joined(separator: ", "))
+            printer.writeLine(" } from \"\(from)\";")
         }
-        printer.writeLine("} from \"\(from)\";")
     }
 }

Sources/TSCodeModule/Decl/TSInterfaceDecl.swift

@@ -32,8 +32,10 @@ public struct TSInterfaceDecl: PrettyPrintable {
         }
         printer.writeUnlessStartOfLine(" ")
         printer.writeLine("{")
-        printer.nest {
-            decls.map { TSBlockItem.decl($0) }.print(printer: printer)
+        printer.with(blockScope: .interface) {
+            printer.nest {
+                decls.map { TSBlockItem.decl($0) }.print(printer: printer)
+            }
         }
         printer.writeLine("}")
     }

Sources/TSCodeModule/Decl/TSMethodDecl.swift

@@ -44,8 +44,10 @@ public struct TSMethodDecl: PrettyPrintable {
 
         if let items {
             printer.writeLine(" {")
-            printer.nest {
-                items.print(printer: printer)
+            printer.with(blockScope: .function) {
+                printer.nest {
+                    items.print(printer: printer)
+                }
             }
             printer.writeLine("}")
         } else {

Sources/TSCodeModule/Decl/TSVarDecl.swift

@@ -4,22 +4,19 @@ public struct TSVarDecl: PrettyPrintable {
     public var name: String
     public var type: TSType?
     public var initializer: TSExpr?
-    public var wantsTrailingNewline: Bool
 
     public init(
         export: Bool = false,
         kind: String,
         name: String,
         type: TSType? = nil,
-        initializer: TSExpr? = nil,
-        wantsTrailingNewline: Bool = false
+        initializer: TSExpr? = nil
     ) {
         self.export = export
         self.kind = kind
         self.name = name
         self.type = type
         self.initializer = initializer
-        self.wantsTrailingNewline = wantsTrailingNewline
     }
 
     public func print(printer: PrettyPrinter) {

Tests/CodableToTypeScriptTests/Generate/GenerateExampleTests.swift

@@ -144,11 +144,7 @@ enum R<T> {
 }
 """,
         expecteds: ["""
-import {
-    E,
-    E_JSON,
-    E_decode
-} from "..";
+import { E, E_JSON, E_decode } from "..";
 """, """
 export type R<T> = {
     kind: "s";

Tests/CodableToTypeScriptTests/Generate/GenerateNestedTests.swift

@@ -101,9 +101,7 @@ struct C {
 """,
             typeSelector: .name("C"),
             expecteds: ["""
-import {
-    A_B
-} from "..";
+import { A_B } from "..";
 """, """
 export type C = {
     b: A_B;