constraint now part of the parameter symbol and not of the type

compiler/ast.nim

@@ -624,6 +624,7 @@ type
     loc*: TLoc
     annex*: PLib              # additional fields (seldom used, so we use a
                               # reference to another object to safe space)
+    constraint*: PNode        # additional constraints like 'lit|result'
   
   TTypeSeq* = seq[PType]
   TType* = object of TIdObj   # types are identical iff they have the
@@ -650,7 +651,6 @@ type
     align*: int               # the type's alignment requirements
     containerID*: int         # used for type checking of generics
     loc*: TLoc
-    constraint*: PNode        # additional constraints like 'lit|result'
 
   TPair*{.final.} = object 
     key*, val*: PObject

compiler/parampatterns.nim

@@ -48,8 +48,8 @@ proc add(code: var TPatternCode, op: TOpcode) {.inline.} =
   add(code, chr(ord(op)))
 
 proc whichAlias*(p: PSym): TAliasRequest =
-  if p.typ.constraint != nil:
-    result = TAliasRequest(p.typ.constraint.strVal[0].ord)
+  if p.constraint != nil:
+    result = TAliasRequest(p.constraint.strVal[0].ord)
 
 proc compileConstraints(p: PNode, result: var TPatternCode) =
   case p.kind

compiler/patterns.nim

@@ -71,8 +71,8 @@ proc inSymChoice(sc, x: PNode): bool =
   
 proc checkTypes(c: PPatternContext, p: PSym, n: PNode): bool =
   # check param constraints first here as this is quite optimized:
-  if p.typ.constraint != nil:
-    result = matchNodeKinds(p.typ.constraint, n)
+  if p.constraint != nil:
+    result = matchNodeKinds(p.constraint, n)
     if not result: return
   if isNil(n.typ):
     result = p.typ.kind in {tyEmpty, tyStmt}

compiler/rodread.nim

@@ -330,9 +330,6 @@ proc decodeType(r: PRodReader, info: TLineInfo): PType =
   if r.s[r.pos] == '@': 
     inc(r.pos)
     result.containerID = decodeVInt(r.s, r.pos)
-  if r.s[r.pos] == '`':
-    inc(r.pos)
-    result.constraint = decodeNode(r, UnknownLineInfo())
   decodeLoc(r, result.loc, info)
   while r.s[r.pos] == '^': 
     inc(r.pos)
@@ -423,6 +420,9 @@ proc decodeSym(r: PRodReader, info: TLineInfo): PSym =
     result.offset = - 1
   decodeLoc(r, result.loc, result.info)
   result.annex = decodeLib(r, info)
+  if r.s[r.pos] == '#':
+    inc(r.pos)
+    result.constraint = decodeNode(r, UnknownLineInfo())
   if r.s[r.pos] == '(':
     if result.kind in routineKinds:
       result.ast = decodeNodeLazyBody(r, result.info, result)

compiler/rodwrite.nim

@@ -233,9 +233,6 @@ proc encodeType(w: PRodWriter, t: PType, result: var string) =
   if t.containerID != 0: 
     add(result, '@')
     encodeVInt(t.containerID, result)
-  if t.constraint != nil:
-    add(result, '`')
-    encodeNode(w, UnknownLineInfo(), t.constraint, result)
   encodeLoc(w, t.loc, result)
   for i in countup(0, sonsLen(t) - 1): 
     if t.sons[i] == nil: 
@@ -295,6 +292,9 @@ proc encodeSym(w: PRodWriter, s: PSym, result: var string) =
     encodeVInt(s.offset, result)
   encodeLoc(w, s.loc, result)
   if s.annex != nil: encodeLib(w, s.annex, s.info, result)
+  if s.constraint != nil:
+    add(result, '#')
+    encodeNode(w, UnknownLineInfo(), s.constraint, result)
   # lazy loading will soon reload the ast lazily, so the ast needs to be
   # the last entry of a symbol:
   if s.ast != nil:

compiler/semtypes.nim

@@ -635,6 +635,13 @@ proc liftParamType(c: PContext, procKind: TSymKind, genericParams: PNode,
         genericParams.addSon(newSymNode(s))
         result = typeClass
 
+proc semParamType(c: PContext, n: PNode, constraint: var PNode): PType =
+  if n.kind == nkCurlyExpr:
+    result = semTypeNode(c, n.sons[0], nil)
+    constraint = semNodeKindConstraints(n)
+  else:
+    result = semTypeNode(c, n, nil)
+
 proc semProcTypeNode(c: PContext, n, genericParams: PNode, 
                      prev: PType, kind: TSymKind): PType = 
   var
@@ -660,13 +667,14 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
     checkMinSonsLen(a, 3)
     var
       typ: PType = nil
-      def: PNode = nil      
+      def: PNode = nil
+      constraint: PNode = nil
       length = sonsLen(a)
       hasType = a.sons[length-2].kind != nkEmpty
       hasDefault = a.sons[length-1].kind != nkEmpty
 
     if hasType:
-      typ = semTypeNode(c, a.sons[length-2], nil)
+      typ = semParamType(c, a.sons[length-2], constraint)
       
     if hasDefault:
       def = semExprWithType(c, a.sons[length-1]) 
@@ -689,6 +697,7 @@ proc semProcTypeNode(c: PContext, n, genericParams: PNode,
                                     arg.name.s, arg.info).skipIntLit
       arg.typ = finalType
       arg.position = counter
+      arg.constraint = constraint
       inc(counter)
       if def != nil and def.kind != nkEmpty: arg.ast = copyTree(def)
       if ContainsOrIncl(check, arg.name.id): 
@@ -839,11 +848,6 @@ proc semTypeNode(c: PContext, n: PNode, prev: PType): PType =
         result = semTypeExpr(c, n)
     else:
       result = semTypeExpr(c, n)
-  of nkCurlyExpr:
-    result = semTypeNode(c, n.sons[0], nil)
-    if result != nil:
-      result = copyType(result, getCurrOwner(), true)
-      result.constraint = semNodeKindConstraints(n)
   of nkWhenStmt:
     var whenResult = semWhen(c, n, false)
     if whenResult.kind == nkStmtList: whenResult.kind = nkStmtListType

todo.txt

@@ -1,8 +1,8 @@
 version 0.9.2
 =============
 
-- overloading based on ASTs: 'constraint' should not be in PType but for the
-  parameter *symbol*
+- overloading based on ASTs
+- implement generic converters
 
   - implement ``partial`` pragma for partial evaluation: easily done with AST
     overloading
@@ -20,7 +20,7 @@ version 0.9.X
 =============
 
 - implement the missing features wrt inheritance
-- implement generic methods and generic converters
+- implement generic methods
 - improve the compiler as a service
 - ``=`` should be overloadable; requires specialization for ``=``
 - implement constructors + full 'not nil' checking