Syntax for extension methods

Author: odersky

docs/docs/internals/syntax.md

@@ -316,6 +316,11 @@ ValDcl            ::=  ids ‘:’ Type
 VarDcl            ::=  ids ‘:’ Type                                             PatDef(_, ids, tpe, EmptyTree)
 DefDcl            ::=  DefSig [‘:’ Type]                                        DefDef(_, name, tparams, vparamss, tpe, EmptyTree)
 DefSig            ::=  id [DefTypeParamClause] DefParamClauses
+                    |  DefParamClause ‘.’
+                       id [DefTypeParamClause] DefParamClauses
+                    |  DefParamClause
+                       id [DefTypeParamClause] DefParamClause DefParamClauses
+
 TypeDcl           ::=  id [TypTypeParamClause] [‘=’ Type]                       TypeDefTree(_, name, tparams, tpt)
                     |  id [HkTypeParamClause] TypeBounds                        TypeDefTree(_, name, tparams, bounds)
 
@@ -329,7 +334,6 @@ PatDef            ::=  Pattern2 {‘,’ Pattern2} [‘:’ Type] ‘=’ Expr
 VarDef            ::=  PatDef
                     |  ids ‘:’ Type ‘=’ ‘_’
 DefDef            ::=  DefSig [‘:’ Type] ‘=’ Expr                               DefDef(_, name, tparams, vparamss, tpe, expr)
-                    |  DefSig [nl] ‘{’ Block ‘}’                                DefDef(_, name, tparams, vparamss, tpe, Block)
                     |  ‘this’ DefParamClause DefParamClauses                    DefDef(_, <init>, Nil, vparamss, EmptyTree, expr | Block)
                        (‘=’ ConstrExpr | [nl] ConstrBlock)