parser: understand nested template strings

ScalablyTyped · Sep 29, 2022 · aad3cd9 · aad3cd9
1 parent 46c5867
commit aad3cd9
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Showing 4 changed files with 83 additions and 10 deletions.
diff --git a/importer/src/test/scala/org/scalablytyped/converter/internal/ts/parser/LexerTests.scala b/importer/src/test/scala/org/scalablytyped/converter/internal/ts/parser/LexerTests.scala
@@ -19,12 +19,6 @@ final class LexerTests extends AnyFunSuite with Matchers {
     )
   }
 
-  test("string literal") {
-    shouldParseAs("`a`", TsLexer.stringLiteral)(
-      TsLexer.StringLit("a"),
-    )
-  }
-
   test("-readonly") {
     shouldParseAs("-readonly", TsLexer.token)(
       TsLexer.Keyword("-readonly"),
@@ -42,4 +36,48 @@ final class LexerTests extends AnyFunSuite with Matchers {
       TsLexer.Shebang("#!/bin/bash"),
     )
   }
+
+  test("template") {
+    shouldParseAs("`a`", TsLexer.stringTemplateLiteral)(
+      TsLexer.StringTemplateLiteral(List(Left('a'))),
+    )
+    shouldParseAs("`a${'b'}c${d}`", TsLexer.stringTemplateLiteral)(
+      TsLexer.StringTemplateLiteral(
+        List(Left('a'), Right(List(TsLexer.StringLit("b"))), Left('c'), Right(List(TsLexer.Identifier("d")))),
+      ),
+    )
+  }
+
+  test("nested template strings") {
+    val nested = TsLexer.StringTemplateLiteral(
+      List(
+        Left('b'),
+        Right(List(TsLexer.Identifier("c"))),
+      ),
+    )
+    shouldParseAs("`a${`b${c}`}`", TsLexer.stringTemplateLiteral)(
+      TsLexer.StringTemplateLiteral(List(Left('a'), Right(List(nested)))),
+    )
+  }
+
+  test("nested template strings (sample)") {
+    val nested = TsLexer.StringTemplateLiteral(
+      List(
+        Left('['),
+        Right(List(TsLexer.Identifier("Middle"))),
+        Left(']'),
+        Right(List(TsLexer.Identifier("Tail"))),
+      ),
+    )
+
+    shouldParseAs("`${Head}.${FixPathSquareBrackets<`[${Middle}]${Tail}`>}`", TsLexer.stringTemplateLiteral)(
+      TsLexer.StringTemplateLiteral(
+        List(
+          Right(List(TsLexer.Identifier("Head"))),
+          Left('.'),
+          Right(List(TsLexer.Identifier("FixPathSquareBrackets"), TsLexer.Keyword("<"), nested, TsLexer.Keyword(">"))),
+        ),
+      ),
+    )
+  }
 }
diff --git a/importer/src/test/scala/org/scalablytyped/converter/internal/ts/parser/ParserTests.scala b/importer/src/test/scala/org/scalablytyped/converter/internal/ts/parser/ParserTests.scala
@@ -3100,4 +3100,13 @@ export {};
       ),
     )
   }
+
+  test("nested template strings") {
+    shouldParseAs(
+      "`${Head}.${FixPathSquareBrackets<`[${Middle}]${Tail}`>}`",
+      TsParser.tsType,
+    )(
+      TsTypeLiteral(TsLiteral.Str("${Head}.${FixPathSquareBrackets<[${Middle}]${Tail}>}")),
+    )
+  }
 }
diff --git a/ts/src/main/scala/org/scalablytyped/converter/internal/ts/parser/TsLexer.scala b/ts/src/main/scala/org/scalablytyped/converter/internal/ts/parser/TsLexer.scala
@@ -22,6 +22,15 @@ object TsLexer extends Lexical with StdTokens with ParserHelpers with ImplicitCo
   }
   final case class Shebang(chars: String) extends Token
 
+  final case class StringTemplateLiteral(tokens: List[Either[Char, List[Token]]]) extends Token {
+    def chars =
+      tokens
+        .map {
+          case Left(str)     => str.toString
+          case Right(tokens) => tokens.flatMap(_.chars).mkString("${", "", "}")
+        }
+        .mkString("")
+  }
   implicit def FromString[T](p: Parser[T]): String => ParseResult[T] =
     (str: String) => p.apply(new CharSequenceReader(str))
 
@@ -108,7 +117,20 @@ object TsLexer extends Lexical with StdTokens with ParserHelpers with ImplicitCo
     def quoted(quoteChar: Char): Parser[String] =
       quoteChar ~> stringOf(inQuoteChar(quoteChar)) <~ quoteChar
 
-    (quoted('\"') | quoted('\'') | quoted('`')) ^^ StringLit
+    (quoted('\"') | quoted('\'')) ^^ StringLit
+  }
+
+  lazy val stringTemplateLiteral: Parser[StringTemplateLiteral] = {
+    val templateQuote = '`'
+    val interpolationStart: Parser[Char] = '$' ~> '{'
+    val interpolationEnd:   Parser[Char] = '}'
+    val nonInterpolationEndToken = token.filter { case Keyword("}") => false; case _ => true }
+
+    val either: Parser[Either[Char, List[Token]]] =
+      interpolationStart.flatMap(_ => (rep(nonInterpolationEndToken) <~ interpolationEnd).map(Right.apply)) |
+        chrExcept(templateQuote).map(Left.apply)
+
+    templateQuote ~> rep(either) <~ templateQuote ^^ StringTemplateLiteral.apply
   }
 
   val delim: Parser[Keyword] = {
@@ -182,8 +204,8 @@ object TsLexer extends Lexical with StdTokens with ParserHelpers with ImplicitCo
     not(directive) ~> oneLine | block
   }
 
-  override val token: Parser[Token] = {
-    val base = identifier | directive | comment | numericLiteral | stringLiteral | delim | shebang | EofCh ^^^ EOF
+  override lazy val token: Parser[Token] = {
+    val base = identifier | directive | comment | numericLiteral | stringLiteral | stringTemplateLiteral | delim | shebang | EofCh ^^^ EOF
 
     val ignore = (newLine | whitespaceChar).*
 

diff --git a/ts/src/main/scala/org/scalablytyped/converter/internal/ts/parser/TsParser.scala b/ts/src/main/scala/org/scalablytyped/converter/internal/ts/parser/TsParser.scala
@@ -652,7 +652,11 @@ class TsParser(path: Option[(os.Path, Int)]) extends StdTokenParsers with Parser
   }
 
   lazy val tsLiteralString: Parser[TsLiteral.Str] =
-    stringLit ^^ TsLiteral.Str.apply
+    elem("string literal", {
+      case _: TsLexer.StringLit             => true
+      case _: TsLexer.StringTemplateLiteral => true
+      case _ => false
+    }) ^^ (lit => TsLiteral.Str(lit.chars))
 
   lazy val tsIdentModule: Parser[TsIdentModule] =
     tsLiteralString ^^ ModuleNameParser.apply