parsing of user defined type classes

compiler/ast.nim

@@ -190,6 +190,7 @@ type
     nkTypeOfExpr,         # type(1+2)
     nkObjectTy,           # object body
     nkTupleTy,            # tuple body
+    nkTypeClassTy,        # user-defined type class
     nkRecList,            # list of object parts
     nkRecCase,            # case section of object
     nkRecWhen,            # when section of object

compiler/parser.nim

@@ -927,9 +927,10 @@ proc parseExpr(p: var TParser): PNode =
   of tkTry: result = parseTry(p)
   else: result = simpleExpr(p)
 
+proc parseEnum(p: var TParser): PNode
 proc parseObject(p: var TParser): PNode
 proc parseDistinct(p: var TParser): PNode
-proc parseEnum(p: var TParser): PNode
+proc parseTypeClass(p: var TParser): PNode
 
 proc primary(p: var TParser, mode: TPrimaryMode): PNode = 
   #| typeKeyw = 'var' | 'ref' | 'ptr' | 'shared' | 'type' | 'tuple'
@@ -983,6 +984,11 @@ proc primary(p: var TParser, mode: TPrimaryMode): PNode =
     else:
       result = newNodeP(nkObjectTy, p)
       getTok(p)
+  of tkGeneric:
+    if mode == pmTypeDef:
+      result = parseTypeClass(p)
+    else:
+      parMessage(p, errInvalidToken, p.tok)
   of tkDistinct:
     if mode == pmTypeDef:
       result = parseDistinct(p)
@@ -1613,6 +1619,32 @@ proc parseObject(p: var TParser): PNode =
     return
   addSon(result, parseObjectPart(p))
 
+proc parseTypeClass(p: var TParser): PNode =
+  result = newNodeP(nkTypeClassTy, p)
+  getTok(p)
+  addSon(result, p.parseSymbol)
+  if p.tok.tokType == tkCurlyDotLe and p.validInd:
+    addSon(result, parsePragma(p))
+  else:
+    addSon(result, ast.emptyNode)
+  if p.tok.tokType == tkOf and p.tok.indent < 0:
+    var a = newNodeP(nkOfInherit, p)
+    getTok(p)
+    while true:
+      addSon(a, parseTypeDesc(p))
+      if p.tok.tokType != tkComma: break
+      getTok(p)
+    addSon(result, a)
+  else:
+    addSon(result, ast.emptyNode)
+  if p.tok.tokType == tkComment:
+    skipComment(p, result)
+  # an initial IND{>} HAS to follow:
+  if not realInd(p):
+    addSon(result, emptyNode)
+  else:
+    addSon(result, parseStmt(p))
+
 proc parseDistinct(p: var TParser): PNode = 
   #| distinct = 'distinct' optInd typeDesc
   result = newNodeP(nkDistinctTy, p)

lib/core/macros.nim

@@ -59,7 +59,7 @@ type
     nnkBindStmt, nnkMixinStmt,
     nnkCommentStmt, nnkStmtListExpr, nnkBlockExpr,
     nnkStmtListType, nnkBlockType, nnkTypeOfExpr, nnkObjectTy,
-    nnkTupleTy, nnkRecList, nnkRecCase, nnkRecWhen,
+    nnkTupleTy, nnkTypeClassTy, nnkRecList, nnkRecCase, nnkRecWhen,
     nnkRefTy, nnkPtrTy, nnkVarTy,
     nnkConstTy, nnkMutableTy,
     nnkDistinctTy,