1 files changed, 151 insertions, 0 deletions
diff --git a/compiler/semtypinst.nim b/compiler/semtypinst.nim
new file mode 100755
index 000000000..b6126e285
--- /dev/null
+++ b/compiler/semtypinst.nim
@@ -0,0 +1,151 @@
+#
+#
+#           The Nimrod Compiler
+#        (c) Copyright 2011 Andreas Rumpf
+#
+#    See the file "copying.txt", included in this
+#    distribution, for details about the copyright.
+#
+
+# This module does the instantiation of generic procs and types.
+
+import ast, astalgo, msgs, types, semdata
+
+proc checkConstructedType*(info: TLineInfo, t: PType) = 
+  if tfAcyclic in t.flags and skipTypes(t, abstractInst).kind != tyObject: 
+    LocalError(info, errInvalidPragmaX, "acyclic")
+  elif computeSize(t) < 0: 
+    LocalError(info, errIllegalRecursionInTypeX, typeToString(t))
+  elif t.kind == tyVar and t.sons[0].kind == tyVar: 
+    LocalError(info, errVarVarTypeNotAllowed)
+  when false:
+    if t.kind == tyObject and t.sons[0] != nil:
+      if t.sons[0].kind != tyObject or tfFinal in t.sons[0].flags: 
+        localError(info, errInheritanceOnlyWithNonFinalObjects)
+    
+proc containsGenericTypeIter(t: PType, closure: PObject): bool = 
+  result = t.kind in GenericTypes
+
+proc containsGenericType*(t: PType): bool = 
+  result = iterOverType(t, containsGenericTypeIter, nil)
+
+proc searchInstTypes(tab: TIdTable, key: PType): PType = 
+  # returns nil if we need to declare this type
+  result = PType(IdTableGet(tab, key))
+  if (result == nil) and (tab.counter > 0): 
+    # we have to do a slow linear search because types may need
+    # to be compared by their structure:
+    for h in countup(0, high(tab.data)): 
+      var t = PType(tab.data[h].key)
+      if t != nil: 
+        if key.containerId == t.containerID: 
+          var match = true
+          for j in countup(0, sonsLen(t) - 1): 
+            # XXX sameType is not really correct for nested generics?
+            if not sameType(t.sons[j], key.sons[j]): 
+              match = false
+              break 
+          if match: 
+            return PType(tab.data[h].val)
+
+type
+  TReplTypeVars* {.final.} = object 
+    c*: PContext
+    typeMap*: TIdTable        # map PType to PType
+    symMap*: TIdTable         # map PSym to PSym
+    info*: TLineInfo
+
+proc ReplaceTypeVarsT*(cl: var TReplTypeVars, t: PType): PType
+proc ReplaceTypeVarsS(cl: var TReplTypeVars, s: PSym): PSym
+proc ReplaceTypeVarsN(cl: var TReplTypeVars, n: PNode): PNode = 
+  if n != nil: 
+    result = copyNode(n)
+    result.typ = ReplaceTypeVarsT(cl, n.typ)
+    case n.kind
+    of nkNone..pred(nkSym), succ(nkSym)..nkNilLit: 
+      nil
+    of nkSym: 
+      result.sym = ReplaceTypeVarsS(cl, n.sym)
+    else: 
+      var length = sonsLen(n)
+      if length > 0: 
+        newSons(result, length)
+        for i in countup(0, length - 1): 
+          result.sons[i] = ReplaceTypeVarsN(cl, n.sons[i])
+  
+proc ReplaceTypeVarsS(cl: var TReplTypeVars, s: PSym): PSym = 
+  if s == nil: return nil
+  result = PSym(idTableGet(cl.symMap, s))
+  if result == nil: 
+    result = copySym(s, false)
+    incl(result.flags, sfFromGeneric)
+    idTablePut(cl.symMap, s, result)
+    result.typ = ReplaceTypeVarsT(cl, s.typ)
+    result.owner = s.owner
+    result.ast = ReplaceTypeVarsN(cl, s.ast)
+
+proc lookupTypeVar(cl: TReplTypeVars, t: PType): PType = 
+  result = PType(idTableGet(cl.typeMap, t))
+  if result == nil: 
+    GlobalError(t.sym.info, errCannotInstantiateX, typeToString(t))
+  elif result.kind == tyGenericParam: 
+    InternalError(cl.info, "substitution with generic parameter")
+  
+proc ReplaceTypeVarsT*(cl: var TReplTypeVars, t: PType): PType = 
+  var body, newbody, x, header: PType
+  result = t
+  if t == nil: return 
+  case t.kind
+  of tyGenericParam: 
+    result = lookupTypeVar(cl, t)
+  of tyGenericInvokation: 
+    body = t.sons[0]
+    if body.kind != tyGenericBody: InternalError(cl.info, "no generic body")
+    header = nil
+    for i in countup(1, sonsLen(t) - 1): 
+      if t.sons[i].kind == tyGenericParam: 
+        x = lookupTypeVar(cl, t.sons[i])
+        if header == nil: header = copyType(t, t.owner, false)
+        header.sons[i] = x
+      else: 
+        x = t.sons[i]
+      idTablePut(cl.typeMap, body.sons[i - 1], x)
+    if header == nil: header = t
+    result = searchInstTypes(gInstTypes, header)
+    if result != nil: return 
+    result = newType(tyGenericInst, t.sons[0].owner)
+    for i in countup(0, sonsLen(t) - 1): 
+      # if one of the params is not concrete, we cannot do anything
+      # but we already raised an error!
+      addSon(result, header.sons[i])
+    idTablePut(gInstTypes, header, result)
+    newbody = ReplaceTypeVarsT(cl, lastSon(body))
+    newbody.n = ReplaceTypeVarsN(cl, lastSon(body).n)
+    addSon(result, newbody)   
+    #writeln(output, ropeToStr(Typetoyaml(newbody)));
+    checkConstructedType(cl.info, newbody)
+  of tyGenericBody: 
+    InternalError(cl.info, "ReplaceTypeVarsT: tyGenericBody")
+    result = ReplaceTypeVarsT(cl, lastSon(t))
+  else: 
+    if containsGenericType(t): 
+      result = copyType(t, t.owner, false)
+      for i in countup(0, sonsLen(result) - 1): 
+        result.sons[i] = ReplaceTypeVarsT(cl, result.sons[i])
+      result.n = ReplaceTypeVarsN(cl, result.n)
+      if result.Kind in GenericTypes: 
+        LocalError(cl.info, errCannotInstantiateX, TypeToString(t, preferName))
+        #writeln(output, ropeToStr(Typetoyaml(result)))
+        #checkConstructedType(cl.info, result)
+
+proc generateTypeInstance*(p: PContext, pt: TIdTable, arg: PNode, 
+                           t: PType): PType = 
+  var cl: TReplTypeVars
+  InitIdTable(cl.symMap)
+  copyIdTable(cl.typeMap, pt)
+  cl.info = arg.info
+  cl.c = p
+  pushInfoContext(arg.info)
+  result = ReplaceTypeVarsT(cl, t)
+  popInfoContext()
+