microsoft-visualbasic-runtime/Extensions/Reflection/ScriptMeta.vb

Imports System.ComponentModel
Imports System.Reflection
Imports System.Runtime.CompilerServices
Imports Microsoft.VisualBasic.CommandLine.Reflection

Public Module ScriptMeta

    ''' <summary>
    '''
    ''' </summary>
    ''' <param name="type"></param>
    ''' <param name="[nameOf]"></param>
    ''' <returns></returns>
    <Extension>
    Public Function API(type As Type, [nameOf] As String, Optional strict As Boolean = False) As String
#If NET_40 = 0 Then
        Dim methods = type.GetMethods(BindingFlags.Public Or BindingFlags.Static)
        Dim mBase As MethodInfo = (From m As MethodInfo In methods
                                   Where String.Equals([nameOf], m.Name)
                                   Select m).FirstOrDefault
        Dim APIExport As ExportAPIAttribute

        If mBase Is Nothing Then
NULL:       If Not strict Then
                Return [nameOf]
            Else
                Return ""
            End If
        Else
            APIExport = mBase.GetCustomAttribute(Of ExportAPIAttribute)

            If APIExport Is Nothing Then
                GoTo NULL
            Else
                Return APIExport.Name
            End If
        End If
#Else
        Throw New NotSupportedException
#End If
    End Function

    ''' <summary>
    ''' 获取得到定义该类型成员之上的<see cref="DescriptionAttribute"/>值或者默认定义
    ''' </summary>
    ''' <param name="m"></param>
    ''' <param name="default$"></param>
    ''' <returns></returns>
    <Extension>
    Public Function Description(m As MemberInfo, Optional default$ = Nothing) As String
        Dim customAttrs() = m.GetCustomAttributes(GetType(DescriptionAttribute), inherit:=False)

        If Not customAttrs.IsNullOrEmpty Then
            Return DirectCast(customAttrs(Scan0), DescriptionAttribute).Description
        Else
            Return [default]
        End If
    End Function

    <Extension>
    Public Function Category(m As MemberInfo, Optional default$ = Nothing) As String
        Dim customAttrs() = m.GetCustomAttributes(GetType(CategoryAttribute), inherit:=False)

        If Not customAttrs.IsNullOrEmpty Then
            Return DirectCast(customAttrs(Scan0), CategoryAttribute).Category
        Else
            Return [default]
        End If
    End Function

    ''' <summary>
    ''' Get object usage information
    ''' </summary>
    ''' <param name="m"></param>
    ''' <returns></returns>
    <Extension>
    Public Function Usage(m As MemberInfo) As String
        Try
            Dim attr As UsageAttribute = m.GetCustomAttribute(Of UsageAttribute)
            Return attr.UsageInfo
        Catch ex As Exception
            Return Nothing
        End Try
    End Function

    ''' <summary>
    ''' Get example code of the <see cref="Usage"/>
    ''' </summary>
    ''' <param name="m"></param>
    ''' <returns></returns>
    <Extension>
    Public Function ExampleInfo(m As MemberInfo) As String
        Try
            Dim attr As ExampleAttribute = m.GetCustomAttribute(Of ExampleAttribute)
            Return attr.ExampleInfo
        Catch ex As Exception
            Return Nothing
        End Try
    End Function

    ''' <summary>
    ''' Get the scripting namespace value from <see cref="[Namespace]"/>
    ''' </summary>
    ''' <param name="app"></param>
    ''' <returns></returns>
    '''
    <ExportAPI("Get.API.Namespace")>
    <Extension>
    Public Function NamespaceEntry(app As Type, Optional nullWrapper As Boolean = False) As [Namespace]
        Dim attr As Object() = Nothing

        Try
            attr = app.GetCustomAttributes(GetType([Namespace]), True)
        Catch ex As Exception
            Call LogException(New Exception(app.FullName, ex))
        End Try

        If attr.IsNullOrEmpty Then
            Dim descr$ = app.FullName
            If nullWrapper Then
                descr = $"< {descr} >"
            End If
            Return New [Namespace](app.Name, descr, True)
        Else
            Return DirectCast(attr(Scan0), [Namespace])
        End If
    End Function
End Module