if 454 > 45 then
   msgbox "hola"
else if 41 = 41 then
   msgbox "adios"
else
   msgbox "error"
end if

Option Explicit

Private Sub Form_Load()
Const CODIGO As String = "if (-1 < 1)) {" & vbCrLf & "msgbox hola" & vbCrLf & "}"
    MsgBox CBool(validateCondition(itsIF(getLine(CODIGO, 0))))
End Sub

Public Static Function TextBetweenWords$(ByRef sText$, ByVal sWord1$, ByVal sWord2$)
Dim lPos1&, lPos2&, lStart&
    If LenB(sText) Then
        lPos1 = InStrB(1, sText, sWord1, vbBinaryCompare)
        If lPos1 Then
            lStart = lPos1 + LenB(sWord1)
            lPos2 = InStrB(lStart, sText, sWord2, vbBinaryCompare)
            If lPos2 Then TextBetweenWords = MidB$(sText, lStart, lPos2 - lStart)
        End If
    End If
End Function

Public Function getLine(ByRef sStr As String, ByVal lLine As Long) As String
Dim sVar()      As String
    sVar = Split(sStr, vbCrLf)
    If (UBound(sVar) < lLine) Then
        getLine = sVar(UBound(sVar))
    Else
        getLine = sVar(lLine)
    End If
End Function

Public Function itsIF(ByVal sLine As String) As String
Dim i As Long
    For i = 1 To Len(sLine)
        If (LCase$(MidB$(sLine, i, 4)) = "if") Then
            itsIF = TextBetweenWords$(sLine, "(", ")")
            Exit Function
        End If
    Next
End Function

Public Function validateCondition(ByRef sCondition As String) As Long
Dim sStr As String
Dim lIndex As Long
    
    sStr = TextBetweenWords$(sCondition, "(", ")")
    Do Until (sStr = vbNullString)
        sStr = TextBetweenWords$(sCondition, "(", ")")
        If Not (sStr = vbNullString) Then
            sCondition = Replace$(sCondition, "(" & sStr & ")", validateCondition(sStr), 1, 1, vbTextCompare)
        End If
    Loop
    
    sCondition = Trim$(sCondition)
    lIndex = InStr(1, sCondition, "=", vbTextCompare)
    If lIndex > 0 Then
        validateCondition = Trim$(MidB$(sCondition, 1, (lIndex - 1) * 2)) = Trim$(MidB$(sCondition, (lIndex * 2) + 3))
        Exit Function
    End If
    
    lIndex = InStr(1, sCondition, ">", vbTextCompare)
    If lIndex > 0 Then
        validateCondition = MidB$(sCondition, 1, lIndex) > Trim$(MidB$(sCondition, lIndex + 1))
        Exit Function
    End If
    
    lIndex = InStr(1, sCondition, "<", vbTextCompare)
    If lIndex > 0 Then
        validateCondition = MidB$(sCondition, 1, lIndex) < Trim$(MidB$(sCondition, lIndex + 1))
        Exit Function
    End If
    
    ' //  ...
End Function