Function isDigit(ch As String) As Boolean
    Return ch >= "0" And ch <= "9"
End Function

Function to_snake_case(s As String) As String
    Dim As Integer l = Len(s)
    Dim As String snake = Trim(s), tmp = snake

    For i As Integer = 1 To Len(snake)
        If isDigit(Mid(snake, i, 1)) Then
            Continue For
        Elseif Instr(Mid(snake, i, 1), " ") Then
            Mid(snake, i) = "_"
            Continue For
        Elseif Instr(Mid(snake, i, 1), Any "\:/-_!.") Then
            Continue For
        Elseif Mid(snake, i, 1) = Ucase(Mid(snake, i, 1))  Then
            tmp = Lcase(Mid(snake, i,1))
            Mid(snake, i) = "_"
            snake = Left(snake, i) & tmp & Mid(snake, i+1)
        End If
    Next i
    Return snake
End Function

Function toCamelCase(s As String) As String
    Dim As Integer l = Len(s)
    Dim As String camel = Trim(s), tmp = camel

    For i As Integer = 1 To Len(camel)
        If Instr(Mid(camel, i, 1), Any ":/!.") Then
            Continue For
        Elseif Instr(Mid(camel, i, 1), Any " _-") Then
            camel = Left(camel, i-1) & Ucase(Mid(camel, i+1,1)) & Mid(camel, i+2)
        End If
    Next i
    Return camel
End Function

Dim Shared tests(1 To ...) As String*33 => {_
"snakeCase", "snake_case", "variable_10_case", "variable10Case", _
"\u025brgo rE tHis", "ergo rE tHis", "hurry-up-joe!", _
"c://my-docs/happy_Flag-Day/12.doc", "  spaces  "}

Sub test0(title As String, fn As String)
    Print title
    For i As Integer = 1 To Ubound(tests)
        Dim As String texto = tests(i) & " ===> " & to_snake_case(tests(i))
        Locate i+1, 41 - Len(texto) / 2 : Print texto
    Next i
End Sub

Sub test1(title As String, fn As String)
    Print title
    For i As Integer = 1 To Ubound(tests)
        Dim As String texto = tests(i) & " ===> " & toCamelCase(tests(i))
        Locate i+12, 41 - Len(texto) / 2 : Print texto
    Next i
End Sub

test0 "to_snake_case:", "to_snake_case"
Print
test1 "toCamelCase:", "toCamelCase"

Sleep