Quote patterns: syntax and parsing

Author: odersky

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -1478,9 +1478,8 @@ object Parsers {
 
     /** SimpleExpr    ::= ‘new’ (ConstrApp [TemplateBody] | TemplateBody)
      *                 |  BlockExpr
-     *                 |  ‘'’ ‘{’ Block ‘}’
-     *                 |  ‘'’ ‘[’ Type ‘]’
      *                 |  ‘$’ ‘{’ Block ‘}’
+     *                 |  Quoted
      *                 |  quoteId
      *                 |  SimpleExpr1 [`_']
      *  SimpleExpr1   ::= literal
@@ -1490,6 +1489,8 @@ object Parsers {
      *                 |  SimpleExpr `.' id
      *                 |  SimpleExpr (TypeArgs | NamedTypeArgs)
      *                 |  SimpleExpr1 ArgumentExprs
+     *  Quoted        ::= ‘'’ ‘{’ Block ‘}’
+     *                 |  ‘'’ ‘[’ Type ‘]’
      */
     def simpleExpr(): Tree = {
       var canApply = true
@@ -1827,6 +1828,7 @@ object Parsers {
 
     /** SimplePattern    ::= PatVar
      *                    |  Literal
+     *                    |  Quoted
      *                    |  XmlPattern
      *                    |  `(' [Patterns] `)'
      *                    |  SimplePattern1 [TypeArgs] [ArgumentPatterns]
@@ -1853,6 +1855,8 @@ object Parsers {
         } else wildIndent
       case LPAREN =>
         atSpan(in.offset) { makeTupleOrParens(inParens(patternsOpt())) }
+      case QUOTE =>
+        simpleExpr()
       case XMLSTART =>
         xmlLiteralPattern()
       case _ =>

docs/docs/internals/syntax.md

@@ -209,9 +209,8 @@ InfixExpr         ::=  PrefixExpr
 PrefixExpr        ::=  [‘-’ | ‘+’ | ‘~’ | ‘!’] SimpleExpr                       PrefixOp(expr, op)
 SimpleExpr        ::=  ‘new’ (ConstrApp [TemplateBody] | TemplateBody)          New(constr | templ)
                     |  BlockExpr
-                    |  ‘'’ ‘{’ Block ‘}’
-                    |  ‘'’ ‘[’ Type ‘]’
                     |  ‘$’ ‘{’ Block ‘}’
+                    |  Quoted
                     |  quoteId     // only inside splices
                     |  SimpleExpr1 [‘_’]                                        PostfixOp(expr, _)
 SimpleExpr1       ::=  Literal
@@ -222,6 +221,8 @@ SimpleExpr1       ::=  Literal
                     |  SimpleExpr (TypeArgs | NamedTypeArgs)                    TypeApply(expr, args)
                     |  SimpleExpr1 ArgumentExprs                                Apply(expr, args)
                     |  XmlExpr
+Quoted            ::=  ‘'’ ‘{’ Block ‘}’
+                    |  ‘'’ ‘[’ Type ‘]’
 ExprsInParens     ::=  ExprInParens {‘,’ ExprInParens}
 ExprInParens      ::=  PostfixExpr ‘:’ Type
                     |  Expr
@@ -261,6 +262,7 @@ InfixPattern      ::=  SimplePattern { id [nl] SimplePattern }
 SimplePattern     ::=  PatVar                                                   Ident(wildcard)
                     |  Literal                                                  Bind(name, Ident(wildcard))
                     |  ‘(’ [Patterns] ‘)’                                       Parens(pats) Tuple(pats)
+                    |  Quoted
                     |  XmlPattern
                     |  SimplePattern1 [TypeArgs] [ArgumentPatterns]
 SimplePattern1    ::=  Path