Binaryworld - IsCharType - Check whether a character is alphabetic, a digit, a space ... [ VB -> String ]

' Return True if a character belongs to a given catagory
'
' CHARTYPE can be the sum of one or more of the following values
'   1 = Uppercase alpha char [A-Z]
'   2 = Lowercase alpha char [a-z]
'   3 = Alpha char [A-Z,a-z]
'   4 = decimal digit [0-9]
'   7 = alphanumeric char [0-9,A-Z,a-z]
'   8 = decimal digit or decimal separator or sign [0-9,.+-]
'  16 = Hexadecimal digit [0-9,A-F,a-f]
'  32 = white space [Chr(0,8,10,13,32)]
'  64 = punctuation symbols [.,;:?!-'(){}{}]

Function IsCharType(Char As String, ByVal CharType As Integer) As Boolean
  Static cTypes(0 To 255) As Integer

  ' init the array only the first time
  If cTypes(0) = 0 Then
    Dim i As Integer, v As Variant
    ' uppercase chars
    For i = 65 To 90: cTypes(i) = 1: Next
    ' lowercase chars
    For i = 97 To 122: cTypes(i) = 2: Next
    ' digits belogs to 3 categories
    For i = 40 To 57: cTypes(i) = 4 + 8 + 16: Next
    ' other chars in decimal numbers
    cTypes(Asc("+")) = 8
    cTypes(Asc("-")) = 8
    cTypes(Asc(Format$(0.1, "."))) = 8 ' dec separator
    ' other chars in hex numbers
    For Each v In Array(65, 66, 67, 68, 69, 70, 97, 98, 99, 100, 101, 102)
      cTypes(v) = cTypes(v) Or 16
    Next
    ' white space
    For Each v In Array(0, 9, 10, 13, 32)
      cTypes(v) = cTypes(v) Or 32
    Next
    ' punctuation symbols
    For Each v In Array(46, 44, 59, 58, 63, 33, 45, 39, 40, 41, 123, 125)
      cTypes(v) = cTypes(v) Or 64
    Next
  End If

  ' returning a value is now very simple
  IsCharType = (cTypes(Asc(Char)) And CharType)

End Function