first steps to allow easy functors via macros

compiler/parser.nim

@@ -846,6 +846,7 @@ type
   TDeclaredIdentFlag = enum
     withPragma,               # identifier may have pragma
     withBothOptional          # both ':' and '=' parts are optional
+    withDot                   # allow 'var ident.ident = value'
   TDeclaredIdentFlags = set[TDeclaredIdentFlag]
 
 proc parseIdentColonEquals(p: var TParser, flags: TDeclaredIdentFlags): PNode =
@@ -859,7 +860,7 @@ proc parseIdentColonEquals(p: var TParser, flags: TDeclaredIdentFlags): PNode =
   while true:
     case p.tok.tokType
     of tkSymbol, tkAccent:
-      if withPragma in flags: a = identWithPragma(p)
+      if withPragma in flags: a = identWithPragma(p, allowDot=withdot in flags)
       else: a = parseSymbol(p)
       if a.kind == nkEmpty: return
     else: break
@@ -1889,7 +1890,7 @@ proc parseVarTuple(p: var TParser): PNode =
   optInd(p, result)
   # progress guaranteed
   while p.tok.tokType in {tkSymbol, tkAccent}:
-    var a = identWithPragma(p)
+    var a = identWithPragma(p, allowDot=true)
     addSon(result, a)
     if p.tok.tokType != tkComma: break
     getTok(p)
@@ -1905,7 +1906,7 @@ proc parseVariable(p: var TParser): PNode =
   #| colonBody = colcom stmt doBlocks?
   #| variable = (varTuple / identColonEquals) colonBody? indAndComment
   if p.tok.tokType == tkParLe: result = parseVarTuple(p)
-  else: result = parseIdentColonEquals(p, {withPragma})
+  else: result = parseIdentColonEquals(p, {withPragma, withDot})
   result{-1} = postExprBlocks(p, result{-1})
   indAndComment(p, result)
 

compiler/semexprs.nim

@@ -880,20 +880,6 @@ proc lookupInRecordAndBuildCheck(c: PContext, n, r: PNode, field: PIdent,
     if r.sym.name.id == field.id: result = r.sym
   else: illFormedAst(n)
 
-proc makeDeref(n: PNode): PNode =
-  var t = skipTypes(n.typ, {tyGenericInst, tyAlias})
-  result = n
-  if t.kind == tyVar:
-    result = newNodeIT(nkHiddenDeref, n.info, t.sons[0])
-    addSon(result, n)
-    t = skipTypes(t.sons[0], {tyGenericInst, tyAlias})
-  while t.kind in {tyPtr, tyRef}:
-    var a = result
-    let baseTyp = t.lastSon
-    result = newNodeIT(nkHiddenDeref, n.info, baseTyp)
-    addSon(result, a)
-    t = skipTypes(baseTyp, {tyGenericInst, tyAlias})
-
 const
   tyTypeParamsHolders = {tyGenericInst, tyCompositeTypeClass}
   tyDotOpTransparent = {tyVar, tyPtr, tyRef, tyAlias}
@@ -920,7 +906,7 @@ proc readTypeParameter(c: PContext, typ: PType,
 
       else:
         discard
-  
+
   if typ.kind != tyUserTypeClass:
     let ty = if typ.kind == tyCompositeTypeClass: typ.sons[1].skipGenericAlias
              else: typ.skipGenericAlias
@@ -2285,14 +2271,14 @@ proc semExpr(c: PContext, n: PNode, flags: TExprFlags = {}): PNode =
       pragma = n[1]
       pragmaName = considerQuotedIdent(pragma[0])
       flags = flags
-    
+
     case whichKeyword(pragmaName)
     of wExplain:
       flags.incl efExplain
     else:
       # what other pragmas are allowed for expressions? `likely`, `unlikely`
       invalidPragma(n)
-    
+
     result = semExpr(c, n[0], flags)
   of nkPar:
     case checkPar(n)

compiler/semstmts.nim

@@ -465,6 +465,38 @@ proc hasEmpty(typ: PType): bool =
     for s in typ.sons:
       result = result or hasEmpty(s)
 
+proc makeDeref(n: PNode): PNode =
+  var t = skipTypes(n.typ, {tyGenericInst, tyAlias})
+  result = n
+  if t.kind == tyVar:
+    result = newNodeIT(nkHiddenDeref, n.info, t.sons[0])
+    addSon(result, n)
+    t = skipTypes(t.sons[0], {tyGenericInst, tyAlias})
+  while t.kind in {tyPtr, tyRef}:
+    var a = result
+    let baseTyp = t.lastSon
+    result = newNodeIT(nkHiddenDeref, n.info, baseTyp)
+    addSon(result, a)
+    t = skipTypes(baseTyp, {tyGenericInst, tyAlias})
+
+proc fillPartialObject(c: PContext; n: PNode; typ: PType) =
+  if n.len == 2:
+    let x = semExprWithType(c, n[0])
+    let y = considerQuotedIdent(n[1])
+    let obj = x.typ.skipTypes(abstractPtrs)
+    if obj.kind == tyObject and tfPartial in obj.flags:
+      let field = newSym(skField, getIdent(y.s & $obj.n.len), obj.sym, n[1].info)
+      field.typ = skipIntLit(typ)
+      field.position = sonsLen(obj.n)
+      addSon(obj.n, newSymNode(field))
+      n.sons[0] = makeDeref x
+      n.sons[1] = newSymNode(field)
+    else:
+      localError(n.info, "implicit object field construction " &
+        "requires a .partial object, but got " & typeToString(obj))
+  else:
+    localError(n.info, "nkDotNode requires 2 children")
+
 proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
   var b: PNode
   result = copyNode(n)
@@ -529,6 +561,11 @@ proc semVarOrLet(c: PContext, n: PNode, symkind: TSymKind): PNode =
       message(a.info, warnEachIdentIsTuple)
 
     for j in countup(0, length-3):
+      if a[j].kind == nkDotExpr:
+        fillPartialObject(c, a[j],
+          if a.kind != nkVarTuple: typ else: tup.sons[j])
+        addToVarSection(c, result, n, a)
+        continue
       var v = semIdentDef(c, a.sons[j], symkind)
       if sfGenSym notin v.flags and not isDiscardUnderscore(v):
         addInterfaceDecl(c, v)

compiler/semtypes.nim

@@ -152,6 +152,8 @@ proc semAnyRef(c: PContext; n: PNode; kind: TTypeKind; prev: PType): PType =
           message n[i].info, errGenerated, "region needs to be an object type"
         addSonSkipIntLit(result, region)
     addSonSkipIntLit(result, t)
+    if tfPartial in result.flags:
+      if result.lastSon.kind == tyObject: incl(result.lastSon.flags, tfPartial)
     #if not isNilable: result.flags.incl tfNotNil
 
 proc semVarType(c: PContext, n: PNode, prev: PType): PType =

tests/fields/timplicitfieldswithpartial.nim

@@ -0,0 +1,19 @@
+discard """
+  out: '''(foo0: 38, other1: string here)
+43'''
+"""
+
+type
+  Base = ref object of RootObj
+  Foo {.partial.} = ref object of Base
+
+proc my(f: Foo) =
+  #var f.next = f
+  let f.foo = 38
+  let f.other = "string here"
+  echo f[]
+  echo f.foo0 + 5
+
+var g: Foo
+new(g)
+my(g)