#
#
#           The Nim Compiler
#        (c) Copyright 2015 Andreas Rumpf
#
#    See the file "copying.txt", included in this
#    distribution, for details about the copyright.
#

# This include file implements the semantic checking for magics.
# included from sem.nim

proc semAddrArg(c: PContext; n: PNode; isUnsafeAddr = false): PNode =
  let x = semExprWithType(c, n)
  if x.kind == nkSym:
    x.sym.flags.incl(sfAddrTaken)
  if isAssignable(c, x, isUnsafeAddr) notin {arLValue, arLocalLValue}:
    # Do not suggest the use of unsafeAddr if this expression already is a
    # unsafeAddr
    if isUnsafeAddr:
      localError(c.config, n.info, errExprHasNoAddress)
    else:
      localError(c.config, n.info, errExprHasNoAddress & "; maybe use 'unsafeAddr'")
  result = x

proc semTypeOf(c: PContext; n: PNode): PNode =
  var m = BiggestInt 1 # typeOfIter
  if n.len == 3:
    let mode = semConstExpr(c, n[2])
    if mode.kind != nkIntLit:
      localError(c.config, n.info, "typeof: cannot evaluate 'mode' parameter at compile-time")
    else:
      m = mode.intVal
  result = newNodeI(nkTypeOfExpr, n.info)
  let typExpr = semExprWithType(c, n[1], if m == 1: {efInTypeof} else: {})
  result.add typExpr
  result.typ = makeTypeDesc(c, typExpr.typ)

type
  SemAsgnMode = enum asgnNormal, noOverloadedSubscript, noOverloadedAsgn

proc semAsgn(c: PContext, n: PNode; mode=asgnNormal): PNode
proc semSubscript(c: PContext, n: PNode, flags: TExprFlags): PNode

proc skipAddr(n: PNode): PNode {.inline.} =
  (if n.kind == nkHiddenAddr: n.sons[0] else: n)

proc semArrGet(c: PContext; n: PNode; flags: TExprFlags): PNode =
  result = newNodeI(nkBracketExpr, n.info)
  for i in 1..<n.len: result.add(n[i])
  result = semSubscript(c, result, flags)
  if result.isNil:
    let x = copyTree(n)
    x.sons[0] = newIdentNode(getIdent(c.cache, "[]"), n.info)
    bracketNotFoundError(c, x)
    #localError(c.config, n.info, "could not resolve: " & $n)
    result = n

proc semArrPut(c: PContext; n: PNode; flags: TExprFlags): PNode =
  # rewrite `[]=`(a, i, x)  back to ``a[i] = x``.
  let b = newNodeI(nkBracketExpr, n.info)
  b.add(n[1].skipAddr)
  for i in 2..n.len-2: b.add(n[i])
  result = newNodeI(nkAsgn, n.info, 2)
  result.sons[0] = b
  result.sons[1] = n.lastSon
  result = semAsgn(c, result, noOverloadedSubscript)

proc semAsgnOpr(c: PContext; n: PNode): PNode =
  result = newNodeI(nkAsgn, n.info, 2)
  result.sons[0] = n[1]
  result.sons[1] = n[2]
  result = semAsgn(c, result, noOverloadedAsgn)

proc semIsPartOf(c: PContext, n: PNode, flags: TExprFlags): PNode =
  var r = isPartOf(n[1], n[2])
  result = newIntNodeT(ord(r), n, c.graph)

proc expectIntLit(c: PContext, n: PNode): int =
  let x = c.semConstExpr(c, n)
  case x.kind
  of nkIntLit..nkInt64Lit: result = int(x.intVal)
  else: localError(c.config, n.info, errIntLiteralExpected)

proc semInstantiationInfo(c: PContext, n: PNode): PNode =
  result = newNodeIT(nkTupleConstr, n.info, n.typ)
  let idx = expectIntLit(c, n.sons[1])
  let useFullPaths = expectIntLit(c, n.sons[2])
  let info = getInfoContext(c.config, idx)
  var filename = newNodeIT(nkStrLit, n.info, getSysType(c.graph, n.info, tyString))
  filename.strVal = if useFullPaths != 0: toFullPath(c.config, info) else: toFilename(c.config, info)
  var line = newNodeIT(nkIntLit, n.info, getSysType(c.graph, n.info, tyInt))
  line.intVal = toLinenumber(info)
  var column = newNodeIT(nkIntLit, n.info, getSysType(c.graph, n.info, tyInt))
  column.i<style>pre { line-height: 125%; }
td.linenos .normal { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
span.linenos { color: inherit; background-color: transparent; padding-left: 5px; padding-right: 5px; }
td.linenos .special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
span.linenos.special { color: #000000; background-color: #ffffc0; padding-left: 5px; padding-right: 5px; }
.highlight .hll { background-color: #ffffcc }
.highlight .c { color: #888888 } /* Comment */
.highlight .err { color: #a61717; background-color: #e3d2d2 } /* Error */
.highlight .k { color: #008800; font-weight: bold } /* Keyword */
.highlight .ch { color: #888888 } /* Comment.Hashbang */
.highlight .cm { color: #888888 } /* Comment.Multiline */
.highlight .cp { color: #cc0000; font-weight: bold } /* Comment.Preproc */
.highlight .cpf { color: #888888 } /* Comment.PreprocFile */
.highlight .c1 { color: #888888 } /* Comment.Single */
.highlight .cs { color: #cc0000; font-weight: bold; background-color: #fff0f0 } /* Comment.Special */
.highlight .gd { color: #000000; background-color: #ffdddd } /* Generic.Deleted */
.highlight .ge { font-style: italic } /* Generic.Emph */
.highlight .ges { font-weight: bold; font-style: italic } /* Generic.EmphStrong */
.highlight .gr { color: #aa0000 } /* Generic.Error */
.highlight .gh { color: #333333 } /* Generic.Heading */
.highlight .gi { color: #000000; background-color: #ddffdd } /* Generic.Inserted */
.highlight .go { color: #888888 } /* Generic.Output */
.highlight .gp { color: #555555 } /* Generic.Prompt */
.highlight .gs { font-weight: bold } /* Generic.Strong */
.highlight .gu { color: #666666 } /* Generic.Subheading */
.highlight .gt { color: #aa0000 } /* Generic.Traceback */
.highlight .kc { color: #008800; font-weight: bold } /* Keyword.Constant */
.highlight .kd { color: #008800; font-weight: bold } /* Keyword.Declaration */
.highlight .kn { color: #008800; font-weight: bold } /* Keyword.Namespace */
.highlight .kp { color: #008800 } /* Keyword.Pseudo */
.highlight .kr { color: #008800; font-weight: bold } /* Keyword.Reserved */
.highlight .kt { color: #888888; font-weight: bold } /* Keyword.Type */
.highlight .m { color: #0000DD; font-weight: bold } /* Literal.Number */
.highlight .s { color: #dd2200; background-color: #fff0f0 } /* Literal.String */
.highlight .na { color: #336699 } /* Name.Attribute */
.highlight .nb { color: #003388 } /* Name.Builtin */
.highlight .nc { color: #bb0066; font-weight: bold } /* Name.Class */
.highlight .no { color: #003366; font-weight: bold } /* Name.Constant */
.highlight .nd { color: #555555 } /* Name.Decorator */
.highlight .ne { color: #bb0066; font-weight: bold } /* Name.Exception */
.highlight .nf { color: #0066bb; font-weight: bold } /* Name.Function */
.highlight .nl { color: #336699; font-style: italic } /* Name.Label */
.highlight .nn { color: #bb0066; font-weight: bold } /* Name.Namespace */
.highlight .py { color: #336699; font-weight: bold } /* Name.Property */
.highlight .nt { color: #bb0066; font-weight: bold } /* Name.Tag */
.highlight .nv { color: #336699 } /* Name.Variable */
.highlight .ow { color: #008800 } /* Operator.Word */
.highlight .w { color: #bbbbbb } /* Text.Whitespace */
.highlight .mb { color: #0000DD; font-weight: bold } /* Literal.Number.Bin */
.highlight .mf { color: #0000DD; font-weight: bold } /* Literal.Number.Float */
.highlight .mh { color: #0000DD; font-weight: bold } /* Literal.Number.Hex */
.highlight .mi { color: #0000DD; font-weight: bold } /* Literal.Number.Integer */
.highlight .mo { color: #0000DD; font-weight: bold } /* Literal.Number.Oct */
.highlight .sa { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Affix */
.highlight .sb { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Backtick */
.highlight .sc { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Char */
.highlight .dl { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Delimiter */
.highlight .sd { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Doc */
.highlight .s2 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Double */
.highlight .se { color: #0044dd; background-color: #fff0f0 } /* Literal.String.Escape */
.highlight .sh { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Heredoc */
.highlight .si { color: #3333bb; background-color: #fff0f0 } /* Literal.String.Interpol */
.highlight .sx { color: #22bb22; background-color: #f0fff0 } /* Literal.String.Other */
.highlight .sr { color: #008800; background-color: #fff0ff } /* Literal.String.Regex */
.highlight .s1 { color: #dd2200; background-color: #fff0f0 } /* Literal.String.Single */
.highlight .ss { color: #aa6600; background-color: #fff0f0 } /* Literal.String.Symbol */
.highlight .bp { color: #003388 } /* Name.Builtin.Pseudo */
.highlight .fm { color: #0066bb; font-weight: bold } /* Name.Function.Magic */
.highlight .vc { color: #336699 } /* Name.Variable.Class */
.highlight .vg { color: #dd7700 } /* Name.Variable.Global */
.highlight .vi { color: #3333bb } /* Name.Variable.Instance */
.highlight .vm { color: #336699 } /* Name.Variable.Magic */
.highlight .il { color: #0000DD; font-weight: bold } /* Literal.Number.Integer.Long */</style><div class="highlight"><pre><span></span><span class="k">discard</span><span class="w"> </span><span class="s2">&quot;&quot;&quot;</span>
<span class="s">  file: &quot;tstmtexp.nim&quot;</span>
<span class="s">  line: 8</span>
<span class="s">  errormsg: &quot;expression &#39;5&#39; is of type &#39;int literal(5)&#39; and has to be discarded&quot;</span>
<span class="s2">&quot;&quot;&quot;</span>
<span class="c"># Test 3</span>

<span class="mi">1</span><span class="o">+</span><span class="mi">4</span>
</pre></div>
</code></pre></td></tr></table>
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 a.getNode(2))

  let
    # altough we use VM callback here, it is not
    # executed like 'normal' VM callback
    idx = vm.registerCallback("bindSymImpl", bindSymWrapper)
    # dummy node to carry idx information to VM
    idxNode = newIntTypeNode(nkIntLit, idx, c.graph.getSysType(TLineInfo(), tyInt))

  result = copyNode(n)
  for x in n: result.add x
  result.add n # info node
  result.add idxNode

proc semShallowCopy(c: PContext, n: PNode, flags: TExprFlags): PNode

proc semOf(c: PContext, n: PNode): PNode =
  if sonsLen(n) == 3:
    n.sons[1] = semExprWithType(c, n.sons[1])
    n.sons[2] = semExprWithType(c, n.sons[2], {efDetermineType})
    #restoreOldStyleType(n.sons[1])
    #restoreOldStyleType(n.sons[2])
    let a = skipTypes(n.sons[1].typ, abstractPtrs)
    let b = skipTypes(n.sons[2].typ, abstractPtrs)
    let x = skipTypes(n.sons[1].typ, abstractPtrs-{tyTypeDesc})
    let y = skipTypes(n.sons[2].typ, abstractPtrs-{tyTypeDesc})

    if x.kind == tyTypeDesc or y.kind != tyTypeDesc:
      localError(c.config, n.info, "'of' takes object types")
    elif b.kind != tyObject or a.kind != tyObject:
      localError(c.config, n.info, "'of' takes object types")
    else:
      let diff = inheritanceDiff(a, b)
      # | returns: 0 iff `a` == `b`
      # | returns: -x iff `a` is the x'th direct superclass of `b`
      # | returns: +x iff `a` is the x'th direct subclass of `b`
      # | returns: `maxint` iff `a` and `b` are not compatible at all
      if diff <= 0:
        # optimize to true:
        message(c.config, n.info, hintConditionAlwaysTrue, renderTree(n))
        result = newIntNode(nkIntLit, 1)
        result.info = n.info
        result.typ = getSysType(c.graph, n.info, tyBool)
        return result
      elif diff == high(int):
        if commonSuperclass(a, b) == nil:
          localError(c.config, n.info, "'$1' cannot be of this subtype" % typeToString(a))
        else:
          message(c.config, n.info, hintConditionAlwaysFalse, renderTree(n))
          result = newIntNode(nkIntLit, 0)
          result.info = n.info
          result.typ = getSysType(c.graph, n.info, tyBool)
  else:
    localError(c.config, n.info, "'of' takes 2 arguments")
  n.typ = getSysType(c.graph, n.info, tyBool)
  result = n

proc semUnown(c: PContext; n: PNode): PNode =
  proc unownedType(c: PContext; t: PType): PType =
    case t.kind
    of tyTuple:
      var elems = newSeq[PType](t.len)
      var someChange = false
      for i in 0..<t.len:
        elems[i] = unownedType(c, t[i])
        if elems[i] != t[i]: someChange = true
      if someChange:
        result = newType(tyTuple, t.owner)
        # we have to use 'rawAddSon' here so that type flags are
        # properly computed:
        for e in elems: result.rawAddSon(e)
      else:
        result = t
    of tyOwned: result = t.sons[0]
    of tySequence, tyOpenArray, tyArray, tyVarargs, tyVar, tyLent,
       tyGenericInst, tyAlias:
      let L = t.len-1
      let b = unownedType(c, t[L])
      if b != t[L]:
        result = copyType(t, t.owner, keepId = false)
        result[L] = b
        result.flags.excl tfHasOwned
      else:
        result = t
    else:
      result = t

  result = copyTree(n[1])
  result.typ = unownedType(c, result.typ)

proc magicsAfterOverloadResolution(c: PContext, n: PNode,
                                   flags: TExprFlags): PNode =
  ## This is the preferred code point to implement magics.
  ## ``c`` the current module, a symbol table to a very good approximation
  ## ``n`` the ast like it would be passed to a real macro
  ## ``flags`` Some flags for more contextual information on how the
  ## "macro" is calld.

  case n[0].sym.magic
  of mAddr:
    checkSonsLen(n, 2, c.config)
    result = n
    result[1] = semAddrArg(c, n[1], n[0].sym.name.s == "unsafeAddr")
    result.typ = makePtrType(c, result[1].typ)
  of mTypeOf:
    result = semTypeOf(c, n)
  of mSizeOf:
    # TODO there is no proper way to find out if a type cannot be queried for the size.
    let size = getSize(c.config, n[1].typ)
    # We just assume here that the type might come from the c backend
    if size == szUnknownSize:
      # Forward to the c code generation to emit a `sizeof` in the C code.
      result = n
    elif size >= 0:
      result = newIntNode(nkIntLit, size)
      result.info = n.info
      result.typ = n.typ
    else:
      localError(c.config, n.info, "cannot evaluate 'sizeof' because its type is not defined completely, type: " & n[1].typ.typeToString)
      result = n
  of mAlignOf:
    # this is 100% analog to mSizeOf, could be made more dry.
    let align = getAlign(c.config, n[1].typ)
    if align == szUnknownSize:
      result = n
    elif align >= 0:
      result = newIntNode(nkIntLit, align)
      result.info = n.info
      result.typ = n.typ
    else:
      localError(c.config, n.info, "cannot evaluate 'alignof' because its type is not defined completely, type: " & n[1].typ.typeToString)
      result = n
  of mOffsetOf:
    var dotExpr: PNode

    block findDotExpr:
      if n[1].kind == nkDotExpr:
        dotExpr = n[1]
      elif n[1].kind == nkCheckedFieldExpr:
        dotExpr = n[1][0]
      else:
        illFormedAst(n, c.config)

    assert dotExpr != nil

    let value = dotExpr[0]
    let member = dotExpr[1]

    discard computeSize(c.config, value.typ)

    result = newIntNode(nkIntLit, member.sym.offset)
    result.info = n.info
    result.typ = n.typ
  of mArrGet:
    result = semArrGet(c, n, flags)
  of mArrPut:
    result = semArrPut(c, n, flags)
  of mAsgn:
    if n[0].sym.name.s == "=":
      result = semAsgnOpr(c, n)
    else:
      result = semShallowCopy(c, n, flags)
  of mIsPartOf: result = semIsPartOf(c, n, flags)
  of mTypeTrait: result = semTypeTraits(c, n)
  of mAstToStr:
    result = newStrNodeT(renderTree(n[1], {renderNoComments}), n, c.graph)
    result.typ = getSysType(c.graph, n.info, tyString)
  of mInstantiationInfo: result = semInstantiationInfo(c, n)
  of mOrd: result = semOrd(c, n)
  of mOf: result = semOf(c, n)
  of mHigh, mLow: result = semLowHigh(c, n, n[0].sym.magic)
  of mShallowCopy: result = semShallowCopy(c, n, flags)
  of mNBindSym:
    if dynamicBindSym notin c.features:
      result = semBindSym(c, n)
    else:
      result = semDynamicBindSym(c, n)
  of mProcCall:
    result = n
    result.typ = n[1].typ
  of mDotDot:
    result = n
  of mRoof:
    localError(c.config, n.info, "builtin roof operator is not supported anymore")
  of mPlugin:
    let plugin = getPlugin(c.cache, n[0].sym)
    if plugin.isNil:
      localError(c.config, n.info, "cannot find plugin " & n[0].sym.name.s)
      result = n
    else:
      result = plugin(c, n)
  of mNewFinalize:
    # Make sure the finalizer procedure refers to a procedure
    if n[^1].kind == nkSym and n[^1].sym.kind notin {skProc, skFunc}:
      localError(c.config, n.info, "finalizer must be a direct reference to a procedure")
    result = n
  of mDestroy:
    result = n
    let t = n[1].typ.skipTypes(abstractVar)
    if t.destructor != nil:
      result.sons[0] = newSymNode(t.destructor)
  of mUnown:
    result = semUnown(c, n)
  else: result = n