ExcelでネストしたIf関数をVBAでインデントして分析しやすくする

Module1のコード

プログラムのエントリーポイント(開始場所)はMainプロシージャである。

PublicEnum TokenType
    Target 'If
    BeginParen '(
    EndParen   ')
    Comma  ',
    Other
EndEnumPublicEnum CharType
    Alphabet
    Number
    BeginParen
    EndParen
    Comma
    DoubleQuote
    Other
EndEnumFunction GetCharType(c)As CharType
    Dim ret As CharType
    SelectCaseAsc(c)CaseAsc("a")ToAsc("z"),Asc("A")ToAsc("Z")
        ret = CharType.Alphabet
    CaseAsc("0")ToAsc("9")
        ret = CharType.Number
    CaseElseSelectCaseTrueCase c ="(": ret = CharType.BeginParen
            Case c =")": ret = CharType.EndParen
            Case c =",": ret = CharType.Comma
            Case c ="""": ret = CharType.DoubleQuote
            CaseElse
                ret = CharType.Other
        EndSelectEndSelect
    GetCharType = ret
EndFunctionFunction IsIn(target_,ParamArray check())AsBooleanDim i AsLong, ret AsBoolean: ret =FalseFor i =LBound(check)ToUBound(check)
        ret = ret Or check(i)= target_
    Next
    IsIn = ret
EndFunctionSub Main()Dim targetExpression As Expression: Set targetExpression =New Expression
    targetExpression.ExpressionString =InputBox("数式を入力してください。")Dim tokens As Collection
    Set tokens = GetTokens(targetExpression)Dim t As Token
    
    Dim st As Stack: Set st =New Stack
    Dim tabCount AsLongFor i =1To tokens.Count
        Debug.Print tokens(i).tString;
        SelectCase tokens(i).tType
            Case TokenType.BeginParen
                If tokens(i -1).tType = TokenType.Target Then
                    st.Push True
                    tabCount = tabCount +1Else
                    st.Push FalseEndIfCase TokenType.EndParen
                If st.Pop Then tabCount = tabCount -1Case TokenType.Comma
                If st.Top Then
                    Debug.Print
                    Debug.PrintString(tabCount,vbTab);
                EndIfCaseElseEndSelectNextEndSubFunction GetTokens(targetExpression As Expression)As Collection
    Dim ret As Collection: Set ret =New Collection
    
    Dim t As Token
    DoWhile targetExpression.hasNext
        Set t =New Token
        t.tString = targetExpression.getNext
        SelectCase GetCharType(t.tString)Case CharType.Alphabet
                DoWhile IsIn(GetCharType(targetExpression.checkNext), CharType.Alphabet, CharType.Number)
                    t.AddChar targetExpression.getNext
                LoopCase CharType.Number
                DoWhile GetCharType(targetExpression.checkNext)= CharType.Number
                    t.AddChar targetExpression.getNext
                LoopCase CharType.DoubleQuote
                DoWhile GetCharType(targetExpression.checkNext)<> CharType.DoubleQuote
                    t.AddChar targetExpression.getNext
                Loop
                t.AddChar targetExpression.getNext
            Case CharType.BeginParen
            Case CharType.EndParen
            Case CharType.Comma
            Case CharType.Other
        EndSelect
        ret.Add t
    LoopSet GetTokens = ret
EndFunction

Tokenクラスのコード

Public tString
Sub AddChar(c)
    tString = tString & c
EndSubPropertyGet tType()As TokenType
    Dim ret As TokenType
    SelectCaseUCase(tString)Case"IF": ret = TokenType.Target
        Case"(": ret = TokenType.BeginParen
        Case")": ret = TokenType.EndParen
        Case",": ret = TokenType.Comma
        CaseElse: ret = TokenType.Other
    EndSelect
    tType = ret
EndProperty

Stackクラスのコード

Private Items()AsVariantPropertyGetCount()AsIntegerCount=UBound(Items)EndPropertyPropertyGet Top()AsVariant
    Top = Items(UBound(Items))EndPropertyPublicFunction Pop()AsVariantIfUBound(Items)>0Then
        Pop = Items(UBound(Items))ReDimPreserve Items(UBound(Items)-1)Else
        Pop =EmptyEndIfEndFunctionPublicSub Push(ByRef x AsVariant)ReDimPreserve Items(UBound(Items)+1)
    Items(UBound(Items))= x
EndSubPrivateSub Class_Initialize()ReDim Items(0)EndSub