Prompt > Simple console demo of word whisperer

[Petr Schreiber]

Sometimes we are (read "I am") lazy to write long words, and the laziness can affect even console type scripts. So I tried to implement something similar to Google "whisperer".

How does it work
I created simple Prompt procedure, which takes as input:

• prompt for user
• array full off possible suggestions

The function returns the string once user hits the Return (Enter) key.

To be able to "guess" what user wants to type, I need to check what user does character by character - this is possible thanks to Console_Waitkey (Console_Read and Console_ReadLine return after press of Enter, no sooner).

Once I detect the user pressed down arrow, I check if there is an suggestion active, and if yes, I fill it for the (lazy ) user.

How to test
To test the procedure, I prepaired little example. The suggestions are stored in array named ... suggestions. They possible words are (feel free to modify):

the
thin
turtle
terrific
thinbasic

When you start the program, just type the letter "t", and you will see it will immediately offer you the word "terrific" (as it is the first match in alphabetical order), as you type other letters, you get the other suggestions or none (if there is no match).

Feel free to play with it, modify, use as you need. The possible uses could be help with typing directory name or other cases, when input can be partially predicted. You just need to fill array of suggestions and pass it to the function, the rest should be done automagically by the "engine".

Example

'
' Smart Prompt Test 
'
' version 1.0
' Petr Schreiber 2012           
'

Uses "console"

String suggestions(5) = "the", "thin", "turtle", "terrific", "thinbasic"

String sRetVal = Prompt("Enter the keyword: ", suggestions)

PrintL "You wrote " + sRetVal
PrintL
PrintL "Press any key to quit"
WaitKey


Function Prompt(sQuestion As String, suggestions() As String ) As String
  
  ' -- Let's keep the suggestions sorted for faster search
  Array Sort suggestions()
  
  ' -- Print the question first
  Print sQuestion
  
  ' -- Set contrast color for user reply
  Console_SetTextAttribute(%CONSOLE_FOREGROUND_BLUE | %CONSOLE_FOREGROUND_GREEN | %CONSOLE_FOREGROUND_RED | %CONSOLE_FOREGROUND_INTENSITY)
   
  String sRetVal
  String sChar, sSuggestion                       
  Long   xPos, yPos, j, found, offset  
  
  ' -- Keep reading till user presses Return (aka Enter)  
  While sChar <> "RETURN"     
    ' -- Store cursor position for later
    xPos = Console_GetCursorX
    yPos = Console_GetCursorY
    
    ' -- Read new characer
    sChar = Grab$(Console_WaitKey(), "[", "]")
    
    ' -- If it is normal, just write it to terminal
    If Len(sChar) = 1 Then
      sRetVal += sChar  
      Print sChar                                  
      
    ' -- If it is down key, user wants to fill in the suggestion  
    ElseIf sChar = "DOWN" Then                                 
      If Len(sSuggestion) Then
        Console_SetCursorPosition(Len(sQuestion)+1, ypos+1) 
        Print sSuggestion
        Console_SetCursorPosition(Len(sQuestion)+Len(sSuggestion)+1, ypos+1) 
        
        sRetVal = sSuggestion
      End If
    
    ' -- Special handling for deleting  
    ElseIf sChar = "DELETE" Then      
      
      If xPos > Len(sQuestion) Then
        Console_PrintAt(" ", xPos,ypos+1)
                                      
        Console_SetCursorPosition(xpos, ypos)
        sRetVal = LEFT$(sRetVal, Len(sRetVal)-1)
      End If
    End If 
    
    ' -- Here we do the dynamic search (very suboptimal :)) for suggestions            
    ' -- Only if user already entered something
    If Len(sRetVal) Then
      
      found = FALSE       
      
      ' -- We search whole passed array
      For j = LBound(suggestions) To UBound(suggestions)
          
          ' -- If the entered thing matches pattern of suggestion, it could be it!
          If IsLike(suggestions(j), sRetVal+"*" , FALSE) Then
            
            ' -- Store suggestion for later use and print it on the screen
            sSuggestion = suggestions(j)
            offset      = Len(sQuestion) + Len(sSuggestion) 
            Console_PrintAt($SPC(Len(sQuestion))+sSuggestion + $SPC(80-offset), 1,ypos+2)
            found = TRUE
            Exit For
          End If
        
      Next    

      ' -- If nothing was found, then erase the suggestion line
      If found = FALSE Then
        Console_PrintAt($SPC(80), 1,ypos+2)
        sSuggestion = ""
      End If 
      
    Else
        Console_PrintAt($SPC(80), 1,ypos+2)
        sSuggestion = ""

    End If
    
  Wend  
  
  ' -- Clean up after the suggester, if somehing was left on the screen to not waste one line  
  Console_PrintAt($SPC(80), 1,ypos+2)
  
  ' -- Force continuing on next line after question
  PrintL
  
  ' -- Reset color back to normal 
  Console_SetTextAttribute(%CONSOLE_FOREGROUND_BLUE | %CONSOLE_FOREGROUND_GREEN | %CONSOLE_FOREGROUND_RED )
  
  ' -- Return the value  
  Return sRetVal
  
End Function

Petr