Learning to Program with the Cybiko Handheld Computer Using B2C

Chapter 4 : Editing Your First Program

Introduction

The process for any B2C program is simple: Edit, Compile, Download, Run, and Repeat.  In this chapter we'll look at the first part: Editing.

 There are many good editors for use on the PC.  Every programmer has a favorite editor. Here, we will discuss the Notepad editor for Windows, and the Edit program for MS-DOS.  You will also be introduced to the MS-DOS Command Prompt, since you will spend much of your time there.

Notepad

The Notepad editor is a bare-essentials editor, which is precisely what we need for editing B2C programs.  You can run Notepad by selecting the "Start" menu and pulling-right on "Accessories".  Pull-down to the "Notepad" icon.  Here is a summary of the Notepad menu options:

Run Notepad and type the following…

print "hello world"
dim b as int
input b

Now exit the Notepad selecting the File->Exit menu and answer "Yes" when it asks you if you want to save the file.  Use the filename "hello.b2c".

MS-DOS and Edit

The MS-DOS Edit command is a more powerful alternative to the Notepad editor.  It offers a more professional set of features than Notepad.  As a programmer, these features give you an easier path from your ideas to your code.  The faster you can type your ideas into the editor, the more ideas you can code.  So what features do we need in an editor? Here is a list of the bare essentials:
  

• open file
• save file
• enter and edit text
• cut, copy and paste of text
• tab or indent
• search
• search & replace

 You may desire other features, but I find these to be the minimum. Notepad (for Windows 9x) does not have a search & replace and line numbering.

MSDOS as Your Working Environment

The MS-DOS (Microsoft Disk Operating System) Prompt is still delivered with all MS Windows operating systems. This is a viable working environment for our needs.

You may want to modify some of the properties of the MS-DOS window. For example, the default setting is for a 24-line display. I like more lines of text when using the text editor. To change the properties, click the left mouse button over the MS-DOS logo in the upper-left corner of the window - this will display a menu. Select "Properties" at the bottom of the menu.

Here are the settings I like to use for MS-DOS:

MS-DOS Commands

There are relatively few MS-DOS commands that you will need to know in this tutorial. Fortunately, the majority of tasks can be handled in Windows. Nevertheless it is useful to know how to do certain, fundamental operations. The following table summarizes them:

Introducing MS-DOS Edit

print "hello world"
dim b as int
input b

MS-DOS Edit Commands

MS-DOS Edit is a very straightforward editor with a few hidden options.  It is "mouse-enabled," meaning that if you click on the menu bar, the expected Windows-like thing will happen. Clicking on some text in the Editor window will move the cursor to that position. You can drag the mouse over text and it will select the text.

If you would rather, you can use the keyboard for menu operations by holding down the ALT key (at the bottom of the keyboard, next to the space bar). When you hold down the ALT key, the menu "lights up" and you may press the highlighted character to drop-down the selected menu. For example, selecting ALT-F drops-down the File menu. Also, holding down the SHIFT key and moving the arrow keys will select text for cut and paste operations.

In dialog boxes, the TAB key usually will move you from field to field. The arrow keys will move you up, down, left, and right. If you select text in the Editor window and hit the TAB key, the selected region will be indented one tab stop (usually 8 characters). Holding down the SHIFT key and hitting TAB will "outdent" one tab stop.

MS-DOS Edit Menu commands

The File->Open and File->Save As menu options will display a dialog box with ...

• Filename input field - can hold wildcard (*) patterns or filenames
• Current Working Directory
• Filename listbox - showing all files matching the pattern in the Filename input field
• Directories listbox - showing the parent dir (..), any directories, and other devices ([-A-], [-C-], [-D-], etc...)
• Open Read Only Checkbox - select this if you don’t want to modify the file when you open it (either click on it with the mouse, or tab over to it and hit the space bar)
• Open Binary Checkbox - select this if you want to open files with other than ASCII data (like .app files)
• Line Width - for binary files only, the number of characters per line to display

 The File-Print menu option will give you the option of printing selected text or the entire file.

 The Search->Find menu option will display a dialog box with ...

• Find What - the text string you want to find
• Match whole word only checkbox - use this to find the search string as a word (surrounded by white space - space characters, tabs, newlines)
• Match case - use this to force upper and lower case letters to match

The Search->Replace menu option will display a dialog box with ...

• Find What - the text string you want to replace
• Replace With - the text string you want to replace the search string with
• Match whole word only checkbox - use this to find the search string as a word
• Match case - use this to force upper and lower case letters to match
• Replace Button - replace a single occurrence of the search string
• Replace All - replace all occurrences in the currently selected file

The View->Split option splits the current window into 2 panes. You are free to open a second, different file into the second window. You may resize the panes by selecting View->Size Window and moving the "center bar" up and down with the arrow keys. Or, you can use the mouse pointer to grab the "center bar" and drag it to the size you like. Selecting View->Close Window will return the Editor to single-pane viewing.

 The Options->Settings will display a dialog box with ...

• Tab Stop (defaults to 8, but I recommend 4) - the number of spaces to indent when TAB is entered.
• Colors - allows you to change many color parameters in the Editor. I recommend keeping the defaults. If you get lost, you can always come here and click on "Defaults".

The Help->Commands menu option displays a dialog box with a listing of many "hidden" keyboard commands. I won't repeat their descriptions here. Most of them are obvious (like Home to return to the beginning of a line). But there are a few surprises (like CTRL-Y to delete a line). Use the Page-Up and Page-Down keys to scroll through the list.