Pascal Super Library

home *** CD-ROM | disk | FTP | other *** search

/ Pascal Super Library / Pascal Super Library (CW International)(1997).bin / REFERENC / TPR / TPR2.TXT < prev next >

Wrap

Text File | 1992-10-19 | 76KB | 1,474 lines

Chapter 2 of the Turbo Pascal Reference The Integrated Development Environment This chapter is part of the Turbo Pascal Reference electronic freeware book (C) Copyright 1992 by Ed Mitchell. This freeware book contains supplementary material to Borland Pascal Developer's Guide, published by Que Corporation, 1992. However, Que Corporation has no affiliation with nor responsibility for the content of this free book. Please see Chapter 1 of the Turbo Pascal Reference for important information about your right to distribute and use this material freely. If you find this material of use, I would appreciate your purchase of one my books, such as the Borland Pascal Developer's Guide or Secrets of the Borland C++ Masters, Sams Books, 1992. Thank you. Using the Integrated Development Environment Turbo Pascal provides two independent methods of creating Pascal programs. You can use your own editor and the Turbo Pascal stand-alone compiler, or you can use the integrated development system that incorporates a powerful text editor, Pascal compiler, linker and debugging system all within a convenient and efficient framework for program development. This integrated system is called the Integrated Development Environment or IDE. From the user's standpoint, the IDE looks like a text editor that just happens to include a Compile command and associated Debug functions. This means you never have to switch gears - you type in your source, compile, fix errors and compile again without having to switch back and forth from the editor to the compiler. During program execution, the IDE provides a source level debugger. Using the IDE debugger, you can move the editor cursor to specific source lines and set break points to temporarily stop program execution, and then single step through the source, checking the values of variables in the Watch window. You can even change the values of variables during program execution. When to Use the IDE? Generally speaking, you will want use the IDE as much as possible. However, depending upon the size of your program and the amount and type of memory available on your computer, your application may exceed the constraints imposed by the IDE. If your computer has Extended Memory (EMS) RAM, the IDE will be able to compile and execute extremely large programs. If your computer has only 640k of RAM, you can still develop sizeable applications but you may encounter Out of Memory errors. When this occurs, you can separate the program into smaller units or use the standalone compiler package. The standalone compiler is included in the Turbo Pascal 6.0, 7.0 and Borland Pascal pacakges, and includes a compiler, linker and Make facility. Turbo Pascal 6.0 Professional and Borland Pascal also include the Turbo Debugger and Turbo Profiler (see Chapters 7 and 8 of the Borland Pascal Developer's Guide for details). The standalone compiler is described in Chapter 10, "Turbo Pascal Standalone Programs" of the Developer's Guide. Starting Turbo Pascal's IDE Assuming that you have installed the Turbo Pascal system into subdirectory \TP, as shown in this example, you will type Turbo to access the IDE: C:\TP> TURBO If you have installed Turbo Pascal to some other directory then be certain that you have either placed that directory into your DOS Path statement or that you have changed directories to that the Turbo Pascal directory. After initialization, the IDE displays a menu bar across the top of the screen, and a status line at the bottom of the screen. The following text describes the use of the Turbo Pascal 6.0 IDE; however, the Turbo Pascal 7.0 and Borland Pascal IDE's are nearly identical. Some of the menu items have been slightly rearranged from Turbo Pascal 6.0. Selecting Menu Items You can select items from the menu bar in several ways. The easiest is to use the mouse; move the mouse pointer to the item you wish to select and click the mouse button. A pulldown menu of selections will appear and you can drag the mouse (by holding down the mouse button) to whichever selection you desire. Or, you can move the mouse pointer, without holding down any buttons, and then double click on the appropriate selection. Figure 2.1 shows the IDE menu bar, with the file Compile options menu dropped down below. Using the keyboard, you can access a pulldown menu by pressing the Alt key, and simultaneously pressing the highlighted letter of the menu item. Then,use the arrow keys to move the menu cursor up or down amongst the items. Pressing the Enter key selects the item that the cursor located on. You can also select pulldown menu items by pressing the keyboard key that matches the highlighted letter on the menu, or by pressing the short cut key shown to the right of some of the menu items. Lastly, if you prefer, you can access the menu bar by pressing the F10 key. This highlights the File menu at the upper left. Use the left or right arrow keys to move the menu bar cursor to other menu bar selections. Pressing the Enter key causes the selected menu to be displayed. ***02tpr01.pcx*** Figure 2.1. An illustration of the IDE, showing the Compile options menu overlapping an edit window. Editing, Saving and Compiling a Program To create a new program, select the New function from the File menu. An empty window will appear on the screen, with the title NONAME00.PAS centered in the upper window border. The text cursor will appear at the upper left corner of the window. You may now type a new Pascal program directly into the IDE editor. Since its become a tradition to learn a new language by writing a "Hello World" program, we'll do the same in this simple example: Program Hello; begin Writeln('Hello, world'); end; After typing this program into the editor, you can save it by choosing Save As from the File menu. A dialog box will display asking you to enter the name of the file where this program should be saved. Type a program file name, and then either press the Tab key twice to reach the OK button, and press Enter. Or, you can use the mouse to double click on the OK button. Either way, the result is the same: your newly entered program is saved to disk. Dialog Boxes Dialog boxes are used throughout the IDE and all Turbo Pascal utilities for providing input and making selections. Dialogs contain several types of input controls, including: Input line or edit fields for typing in text responses Radio buttons for selecting just one item from a group of items Check boxes for enabling or disabling a large number of options Lists, for displaying, selecting and scrolling through lists of information Buttons, such as OK or Cancel. Most dialogs are modal dialogs meaning that while they are displayed you cannot perform any other function than to complete the dialog box. When the dialog is first displayed, the cursor is either visible in an input field, or some other highlight is used to indicate the current focus within the dialog. See Figure 2.2. ***02tpr02.pcx*** Figure 2.2. Dialog boxes are used throughout the IDE to obtain user input. When you have finished entering or editing data in the dialog box, choose either the Okay or Cancel buttons to exit. For example, when the cursor is at a check box, you can see the cursor flashing between the brackets '[ ]' that delineate the check box selection. Generally, you press the Tab key to move between dialog box controls or use the mouse to click on a particular selection. However, groups of radio buttons and checkboxes are treated as a single control, so pressing the Tab key while within a group moves to the next control, and not the next selection within the group. Hence, use the arrow keys to move around within a group of radio buttons or check boxes, and use the Tab key to move from one control or group to another control or group. See Table 2.1 for a list of available dialog box controls and explanations for their usage. Table 2.1. Summary of Dialog Box Navigation and Usage Tab key Move forward to next control in sequence Shift-Tab Move backward to previous control in sequence Arrow keys Move between selections in checkboxes and radio buttons SpaceBar Select or deselect a radio button or checkbox item Enter key Select a button control Mouse click Enables or disables radio button and checkbox items, selects button controls,moves the current focus to the item clicked on. Highlight key Items that contain a highlighted key can be selected by pressing the highlighted key directly, which also moves the current focus to the selected item. Radio buttons Radio buttons allow one and only one item amongst a group of items to be selected. When you select a radio button by pressing the space bar, or with a mouse click, or by pressing the item's highlighted letter, any other selected radio button within the same group of radio buttons, becomes deselected. Within each group, only one button at a time can be selected, much like the radio station "preset" quick selection buttons on automobile radio receivers. See Figure 2.2 for an example of radio buttons. Checkboxes Checkboxes provide for enabling or disabling any number of items. Thecheckboxes are typically grouped together and you can use the arrow keys to move amonst them. Press the SpaceBar to select a checkbox item, or when the item is already selected, press the SpaceBar to clear the selection. Input fields Input fields allow you to enter aribtrary text information and to use the left and right arrow keys to move within the text, the Backspace and Delete keys to delete text, the Home key to move to the beginning of the field and the End key to move to the rightmost end of the field. Many of the fields provide horizontal scrolling, enabling you to type text wider than the displayed input field. When this occurs, either or both ends of the input field will display left and right arrows to show that more text exists on either side of the input area. Use the left and right arrow keys to scroll through the text, or click the mouse pointer on the arrows. List Boxes List boxes are used to select from a large list of items. See figure 2.3, showing the Open file dialog of the IDE. A typical use is for opening a file, where the contents of the disk directory are displayed in the list box. If there are more items than will fit within the list box, a scroll bar displays either on the bottom or the right hand side of the list box. To use a list box, use the Tab key to move the cursor to the list box, or use the mouse to click on an item within the list box. Once inside the list box, you can use the standard keyboard navigations keys to move around: the arrow keys, PgUp, PgDn, Home and End, and by pressing a single letter, many lists boxes will automatically scroll to the first item beginning with the letter that you pressed. Once the cursor is positioned on the correct in the list box, you can select the item by pressing the Enter key. ***02tpr03.pcx*** Figure 2.3. The Open file dialog box uses a list box to display the files in the current directory. Use the Ins key to toggle between insert and overstrike modes. If you need to enter a control-key combination into an input field, you should prefix the control-key by pressing Ctrl-P and then the control-key you wish to enter. For example, to enter ^F into an edit field, type ^P^F. Lastly, some input fields provide access to previously entered values by displaying a history list. For example, when opening a file in the IDE, you may wish to switch back to the file that you had previously worked on. Input fields that allow you to do this display a downwards pointing arrow at the right most end. By selecting the arrow icon with the mouse, or by pressing the down arrow key, a small list box of previous inputs drops down below the input field where you can quickly choose data that was previously entered. Move the highlight bar to the desired item and press the Enter key, or use the mouse to select the item from the history list. Using the Editor The IDE's editor is where you will spend most of your time, typing new code, editing existing programs, and fixing program bugs or defects. You access the editor by selecting New from the File menu, or by opening an existing file, also from the File menu. Alternatively, you can open an existing file by specifying a filename on the command line when you first start the IDE by typing: C:\TP> TURBO SHELL.PAS which starts up Turbo and loads the existing program SHELL.PAS for editing. Borland Pascal users should type BP to access the Borland Pascal IDE. Once in the editor, a variety of keyboard commands, mouse movements and menu selections provide a full featured programmer's editing system. As you type text into the text editor window, the cursor moves across the screen and to the right. Press the Enter key when you have reached the end of your line, although the editor will scroll horizontally if you need to type source code or data files that are wider than the screen's width. Text entry can occur in either Insert mode or Overstrike mode. In Insert mode, new text is inserted in front of existing text, pushing it further along the line. In overstrike mode, text that you type is written over or replaces any other text at the cursor's location. You can toggle back and forth between insert and overstrike modes by pressing the Ins key (or for WordStar fans, by pressing Ctrl-V). Navigating in the Editor A horizontal scroll bar displays the current position of the file, relative to the start and end of its lines, and a vertical scroll bar displays the current position of the file, relative to the first and last lines in the file. Each scroll bar displays a square marker, which you can drag with the mouse to rapidly move to other locations in the file. To move line by line, press the up or down arrow keys, or click on the up or down arrow icons on the scroll bar. To page through the file, a screenful at a time, press the PgUp or PgDn keys, or click the mouse on the empty space between the scroll bar marker and the top or bottom of the scroll bar (or left and right sides if clicking on the horizontal scroll bar). Table 2.2 summarizes the editor keyboard commands. If you are familiar with older versions of WordStar, or Borland's SideKick, nearly all of the original ctrl-key combinations are also supported in the IDE and are shown in the table. Table 2.2. Editor Navigation Keystrokes. Up arrow or Ctrl-E Move up one line Down arrow or Ctrl-X Move down one line Left arrow or Ctrl-S Move left one character Right arrow or Ctrl-D Move right one character Ctrl-Left arrow or Ctrl-A Move one word to the left Ctrl-Right arrow or Ctrl-F Move one word to the right PgUp or Ctrl-R Move up one screen full PgDn or Ctrl-C Move down one screen full Home Move to beginning of current line End Move to the end of the current line Ctrl-W Scroll the screen up by one line Ctrl-Z Scroll the screen down by one line Ctrl-Home Move to the top of current edit window Ctrl-End Move to the bottom of the current edit window Ctrl-PgUp or Ctrl-Q-R Move to the beginning of the file Ctrl PgDn or Ctrl-Q-C Move to the end of the current file Ctrl-Q-B Move to the beginning of a selected text block Ctrl-Q-K Move to the end of a selected text block Tab or Ctrl-I Moves to the next tab stop on the line Ctrl-O-I Switches between tabs every 5 characters or every 8 characters. You can also set tabs to any value between 2 and 16 using the Options/Environment/Editor menu selection. Selecting Text and Text Block Operations By selecting text, you can perform operations such as Cut and Copy on entire text blocks. To select text with the mouse, move the mouse pointer to the start of the text block, and then, while pressing down on the mouse button, drag the mouse to the end of the text block that you wish to select. The text will be highlighted as you drag the mouse. Using the keyboard, you select text by pressing the Shift key, and then, while simultaneously holding down the Shift key, press keyboard navigation keys including the arrows, PgUp and PgDn. As you move the cursor with the Shift key depressed, your selection is highlighted. Text blocks may also marked by moving the cursor to the beginning of the block, pressing Ctrl-K-B, to mark the block's beginning, and then pressing Ctrl-K-K to mark the block's end. Turbo Pascal maintains a "clipboard" to which selected text can be cut or copied. When an item is Cut, it is deleted from the current file and placed on the clipboard. An item that is copied remains in the current file and a copy of the selection is placed on to the clipboard. Use Cut to delete text blocks or temporarly move them to the clipboard for later pasting to another location. Use Copy to duplicate text without deleting it. To choose either Cut or Copy, select the desired operation from the Edit pulldown menu or press the keystroke combinations shown to the right of the menu selections: Shift-Del to Cut the text, Ctrl-Ins to copy the text to the clipboard. The contents of the clipboard may be pasted to a new location, or even another file, by choosing the Paste command from the Edit menu, or by pressing Shift-Ins. Use the Show Clipboard command to look at the current contents of the clipboard. If you wish to cut out a section of marked text without copying to the clipboard, choose the Clear command from the Edit menu. Use caution: When you cut text with the Clear command, the text is gone forever - it is not copied to the clipboard and there is no way to undo this operation. One use of the Clear command is to select text within the Show Clipboard window itself, and then use Clear to selectively delete a portion of the Clipboard. The Editor also contains a set of WordStar compatible text block manipulation routines that perform similar functions to using the clipboard for block copying, moving and deleting. For example, when a text block is selected, you can move the cursor to some other location in the file, and press Ctrl-K-V and the selected text block will move to the location of the cursor and will remain highlighted. If you move the cursor and press Ctrl-K-C, a new copy of the selected text is inserted. Other block operations are shown in Table 2.3. Table 2.3. Table of Text Block Operations Shift-Del Cuts the selected text from the file and places it on the clipboard. Ctrl-Ins Places a copy of the selected text on to the clipboard. Shift-Ins Pastes the contents of the clipboard at the current cursor location. Ctrl-K-B Sets the current cursor location as the start of text block. Ctrl-K-K Sets the cursor location as the end of a text block. Using Ctrl-K-B and Ctrl-K-K, you can quickly delimit a large block of text. Move to the start of the block, press Ctrl-K-B, then move to the block's end and press Ctrl-K-K. The selected block will now be highlighted. Ctrl-K-H Turns off a selected block's highlighting; or turn's highlighting back on if the selected block's highlighting was turned off by a previous Ctrl-K-H. Ctrl-K-C Copies the selected text block to the current cursor location. To use this function, select a text block using any of the available methods (Ctrl-K-B and Ctrl-K-K, the mouse or Shift-direction keys). Then, move the cursor to the new location where you wish to make a copy of the selected text. Press Ctrl-K-C and the selected text will be copied to this location. Ctrl-K-V Like Ctrl-K-C, except that the entire block is moved from the old location to the new location indicated by the cursor. Ctrl-K-P Pressing Ctrl-K-P causes the selected text block to printed. Ctrl-K-W Use Ctrl-K-W to write the selected block to a disk file. After pressing Ctrl-K-W, a prompt will display asking for the destination filename. Ctrl-K-R Use Ctrl-K-R to read in a new file and insert it into the current file at the location of the cursor. After pressing Ctrl-K-R a prompt will display asking for the name of the file to insert. Ctrl-K-I Pressing Ctrl-K-I slides all of the selected text one space to the right. Use Ctrl-K-I and Ctrl-K-U, as needed, to adjust the indentation of program source. Ctrl-K-U Pressing Ctrl-K-U slides all of the selected text one space to the left. Specific Editing Commands Other editing command are provided for searching for specific text (see The Search Menu), and character, word and line deletion. Table 2.4 summarizes these other functions. Table 2.4. Editing Commands Del or Ctrl-G Deletes the character to the right of the cursor Backspace or Ctrl-H Deletes the character to the left of the cursor Ctrl-Q-Y Deletes from the cursor to the end of the line Ctrl-Y Deletes the entire line that cursor is on Ctrl-Q-L Restores a previously deleted line (from any of the delete commands) Ctrl-T Deletes the entire word to the right of the cursor Ctrl-N Inserts a blank line Ins or Ctrl-V Toggles between insert and overstrike typing modes Ctrl-O-I Toggles automatic indentation on or off Ctrl-Q-F Find command (See The Search Menu). Ctrl-Q-A Find & replace command (See The Search Menu) Ctrl-L Search again for last Find string (See The Search Menu) Ctrl-K-n Set marker #n at current cursor location (n is from 0 to 9). Ctrl-Q-n Jump to marker #n. Ctrl-Q-[ and Ctrl-Q-] When the cursor is located on a parenthesis, pressing one of these keystroke combinations will find and reposition the cursor to the matching parenthesis. The IDE Help System The IDE provides a convenient on-line help system, providing fully indexed help to both the IDE and the Pascal programming language. The IDE's help system is also context sensitive meaning that you can directly select help corresponding to the current menu or dialog selection, or even look up Pascal keywords based on the location of the cursor. To use Help, press Alt-H or select the Help item from the menu bar. You can obtain help as follows: Function Shortcut key Contents Display a book-like table of contents, organized by general subjects, such as "Editor". Index Shift-F1 Displays a detailed index of every item in the help system. This includes every entry, including IDE functions as well as every Pascal language keyword, procedure and function, including the Turbo Vision object oriented windowing interface. Topic Search Ctrl-F1 To look up information about a specific Pascal keyword, procedure or function, put the cursor somewhere on the the word for which you need help, and then choose Topic Search. The IDE Help system will immediately display a window of information about the keyword that the cursor is located on. Previous Topic Alt-F1 The help system is a hyper-text system. Wherever you see highlighted text within the help text, if you click on the highlighted text, the help system will zip across to that subject heading. To return to a previous heading, choose Previous Topic. Copying Text from the Help system A unique feature of the IDE Help system is the ability to copy sections of text from the on-line help message and paste that text into the IDE Editor window. For example, if you are trying to match up a list of parameters in a function call, you can easily copy the function header from the help text and paste it right into your program. Many of the help items include sample program source which can be easily copied to your programs. To copy text, select the text from the help window, using either the mouse or the usual keyboard selection keys. Then choose the Copy option from the Edit pulldown. After closing the Help window, move to the appropriate location in the Editor window and choose Paste. The File Menu The File menu is used for getting existing program files, saving files to disk, creating new editor files, and printing. File Menu/Open To open an existing file, you can either specify the filename on the command line when you start Turbo Pascal, or you can use the Open command from the File menu. The Open command displays a standard file dialog, showing matching files in the current directory, and providing a prompt line where you can enter a new filename. Figure 2.3 shows the Open A File dialog. Like most dialogs, you can either use the mouse to click in a particular control, or use the Tab key to move from one control to the next. Normally, you will likely type the name of the file you wish to open, or press Tab to move to the Files listbox. In the list box, you can use the arrow keys - or the mouse - to point to a specific file - and then choose the Okay or Replace buttons to open the file. To move quickly through the Files listbox, use the PgDn or PgUp keys, mouse clicks on the scroll bar, or type single letter keys to quickly jump to the first filename beginning with that letter. Lower case letters will match to filenames, and upper case letters will quickly jump to subdirectory names. The difference between Okay and Replace is that when you choose Okay, the IDE will create a new editor window before opening the file. This let's you have multiple files visible in separate edit windows at the same time. If you choose Replace, the file will be loaded into the existing edit window, or if there are multiple edit windows, the file will load into the currently active window. When the dialog first appears, the cursor is initially located in the Name input field with the filename pattern *.PAS highlighted. You can delete this pattern by pressing any key and typing a specific filename, or you can type a new filename pattern using the standard DOS ? and * wildcard characters to display a new list of files in the Files list box. You can also change to a different subdirectory by typing the subdirectory pathname in the Name field; however, this only changes the default directory temporarily. Use the Change dir command on the File menu to change the default directory for the entire time that you are using the IDE. If you've previously opened other files, then the down arrow icon at the right of the Name field will display a list box showing the previous filenames. This is a quick way to reopen a file that you had used previously. File Menu/New Choose New to open a new, empty edit window and begin typing a new program file. The new edit window will have the default name NONAMExx.PAS, where xx is from 00 to 99. File Menu/Save functions To save the contents of an edit window to the disk, choose one of the Save commands: Save, Save as, or Save all. If you have been typing a new file, or wish to save the edit window to a new filename, choose the Save as menu item. At the prompt, you can enter a new filename where the contents of the edit will be saved. Choose Save to quickly save the active edit window to disk, using the name that has already been assigned to the file. If the edit window has the name NONAMExx.PAS, the IDE will automatically display the Save as prompt asking you to specify a unique name for the file. You can press F2 as a shortcut key, to perform a quick save while editing. The Save all menu item saves each and every one of the edit windows that have been modified. File Menu/Change dir Use Change dir to select a new disk drive and subdirectory to become the current working subdirectory. Change dir displays a dialog box with a prompt field for typing a new directory, and includes a list box display of the disk's subdirectory structure. You can choose a new name by typing the subdirectory name or by moving to the Directory Tree list box and selecting fromn the directories that are displayed. After selecting a new directory with Change dir, the new directory becomes the default directory. File Menu/Print Use the Print function to copy the contents of the active window to the DOS PRN: printer device (usually equivalent to LPT1:). If you wish to print only a subsection of text, first select the text and then use the Ctrl-K-P editor command keys File Menu/Get Info Choose Get Info to obtain information about the current IDE environment, including the size of the compiled code, the amount of memory required for data storage, the number of lines in the program's source, and the amount of low memory and EMS memory used by DOS and Turbo Pascal. File Menu/DOS Shell Choose DOS Shell to temporarily leave Turbo Pascal and return to the DOS command line prompt. From the DOS command line, you can use all of the standard DOS commands and even run other programs provided that they fit within the available memory. To return to Turbo Pascal, type Exit at the command line prompt. File Menu/Exit To exit from Turbo Pascal choose the Exit option or press the Alt-X shortcut key combination. If you have not saved any of the files that you have modified, Turbo Pascal will prompt you, asking if you want to have them saved before exitting. The Search Menu The Search menu provides functions for locating text quickly, automatically replacing existing text with new text, jumping to specific line in the text, and find the location of errors. Search Menu/Find (Ctrl-Q-F) To search through the current file, choose the Find option and type the text you wish to locate at the Text to find field. Press Enter to accept the default options, shown below the input field, and the IDE will quickly scan through the file looking for the text. By default, Find matches the text, ignoring the case of both the pattern and the text in the edit window. In other words, lower case text will match upper case text. Find also has a neat shortcut for text entry: In the Text to find field, pressing the right arrow key copies characters, one by one, from the current position in the edit window. The Find dialog presents a variety of options as to how the search will be performed. These options are shown in Table 2.3. Table 2.3. Find Dialog Options. Case sensitive If checked, any lower case letters that you enter in the search pattern will match only lower case letters, and upper case letters will match only upper case letters. Whole words only By setting this option, Find will only match an item if it appears as a separate word. If you look for the word "win" with this option set, you will only find occurrences of "win" as a standalone word, and you will not locate any occurrences of words like "window" or "winner". Regular expression Choose this option to enter a fairly complex "text searching expression", known as a regular expression. When this option is set, you can embed special characters into the search pattern that are interpreted according to the the following rules: ^ Placing a circumflex at the start of the string forces the search pattern to only match items that begin at the start of a line. $ The dollar sign is the opposite of the circumflex and forces the pattern to match items that fall at the end of a line. . Use a period to match any character value. This is equivalent to the DOS ? wildcard for matching any single character in the string. * The asterisk matches an entire string of characters (like the DOS * wildcard) and is used, for example, in looking for quickly matching any characters before or after a specific character set: CA* matches Call, California, Cauliflower and even just CA. The asterisk, unlike the + symbol, will even match if there are no characters following the primary search string. + Behaves like the asterisk, except that there must be at least one character for the + symbol. CA+ does not match CA but does match Call or California. [ ] Use brackets to specify a list of single characters that may appear in this position. For example, ABC[DEF] will match the following: ABCD, ABCE, ABCF, but not ABCG or any other character not including D, E or F in the 4th position. You can also search for a character match not appearing in the bracketed list by placing a circumflex as the first character. ABC[^DEF] means find all strings beginning with ABC and not ending in D, E or F. - To match a range of character values, place a hyphen between the first and last characters in the range. ABC[D-F] is equivalent to ABC[DEF] because this hyphenated list matches all characters beginning with D and up to and including F. \ When you need to search for one of the special characters, ^, $, ., *, + or brackets, prefex the special character with the backslash. Example, /$ lets you search for the dollar sign character. Direction Choose Forward to search towards the end of the file or Backward to search towards the beginning of the file. Scope You can confine the search to just the area of text that is currently selected. Normally the search will take place over the entire text file or selection. Origin Choose From cursor to start the search at the current cursor location, or choose Entire Scope to search over the entire file or the entire selected region. Search Menu/Replace (Ctrl-A) Use the Replace command to replace existing text with new text. The Replace function displays a dialog box resembling the Find dialog box, except for the addition of a New text field, a Prompt on replace option, and a Change All button. To use Replace, type in text to search for at the Text to find field, a replacement string at the New text field, and then choose Ok. The default operation is to stop at each occurrence of the Text to find string and prompt to ask you if its okay to change this occurrence to the New text string. If you press the Change all button, then every occurrence of the Text to find string will be changed to the New text string value. The remaining Replace options behave the same as those in the Find dialog. Search Menu/Search Again (Ctrl-L) After completing a search or replace of an item, you can resume the previous search or replace by choosing Search again. Search Menu/Go to Line Number While you are editing, the line number that the cursor is on is displayed in the lower left corner of the editing window. Choose Go to Line Number to quickly jump to a specific line within the current edit window. Go to Line Number displays a dialog box with one input field asking for the line number. Search Menu/Find Procedure When you are running a program through the built-in IDE debugger, you can search for specific procedure declarations by procedure name. This function displays a dialog box asking for the name of the procedure. If, for instance, you type AddFiles as the procedure name to look for, Find Procedure scans through the edit window until find where AddFiles is defined. Find Procedure does not locate instances where AddFiles is called, but only where it is specifically defined. Search Menu/Find Error (Alt-F8) If, while running a program, a run-time error occurs, the IDE automatically places the cursor at the location in the source where the problem occurred. Later, during editing in the IDE edit window, to relocate the problem spot, choose Find Error and the cursor will again be placed at the location where the run-time error occurred. The Run Menu The Run menu provides options to start and control execution of your program. You can use the Run options after compiling the program (see the Compile Menu), or you can run the program directly by choosing Run. If the program has not been compiled since the last editing changes then it will be compiled for you. Run Menu/Run (Alt-R) If the program source needs compiling, the Run command will invoke the compiler. Then, your program will begin exeucution. You can press Ctrl-Break once or twice, as needed, to stop program execution. The IDE will then position the cursor at the location where the program was halted. If the program is temporarily stopped during use of the built-in debugger, choose the Run command to resume program execution. See also Run Menu/Parameters and Options Menu/Compiler, Memory sizes, Linker and Debugger for additional items that affect the execution of the program. Run Menu/Program Reset (Ctrl-F2) While using the debugging features of the IDE, you can completely halt and reset the program's execution by choosing this command from the Run Menu. Once selected, you can no longer resume execution except by choosing the Run command and restarting the program from the beginning. Run Menu/Go to Cursor (F4) At any time that you would use the Run command to start execution of your program, you can choose Go to Cursor to execute the program up to the location of the cursor in the IDE. Once execution reaches the cursor location, the program will stop and you can use the debugging facilities to observe the values of variables or continue debugging of the program. Alternatively, you could set a breakpoint (see Debug/Breakpoints) and Run the program until it halted at the breakpoint. The difference is that Go to Cursor is only a temporary breakpoint, while a set breakpoint remains until it is cleared. Run Menu/Trace Into (F7) and Step Over (F8) To single step execute through the source code, line by line, choose either the Trace Into or the Step Over commands. Trace Into and Step Over operate similarly except that Trace Into will continue to execute line by line as it enters lower-level procedures that the debugger has access to, and Step Over will call the procedure but will not trace through the procedure and will not halt until the next line after the procedure call. Run Menu/Parameters If your program makes use of command line parameters, you can use the Parameters command to set up the parameters for program execution. When the program is started, these parameters are available as if they had been typed on the DOS command line. The Compile Menu The compile menu is used to compile and link the executable program. See also the Run Menu and the Options Menu for items that can affect the compilation process. Compile Menu/Compile (Alt-F9) Use Compile to compile the current edit window. Use Build or Make or the Run menu's Run command when you also need to recompile other source files that will be used in the final link. Compile Menu/Make (F9) Use Make to compile and link a complete executable .EXE file. Make automatically checks and compiles, if necessary, any dependent program unit files (*.TPU), external object files (*.OBJ), and even included files within units. Whenever the Make function finds a source file that is older than the current compiled file (either the .OBJ or .TPU file), then those files are automatically recompiled so that their compiled form is brought up to date with the latest changes. Make is a "smart" function in that it only compiles those files that need to be compiled; unchanged units are not recompiled. Compile Menu/Build The Build command is like Make, except that Build recompiles every dependent unit, regardless of whether or not recompilation is needed. See also the Destination and the Primary File commands. Compile Menu/Destination Use this function to tell the IDE to either compile and link the program directly to memory, which is fastest, or to create an .EXE executable file on disk. Regardless of this setting, all units that create .TPU files are always compiled to disk. With either selection, you can run the program using the Run Menu/Run command. Also see Options Menu/Directories. Compile Menu/Primary File When writing programs that make use of several units and related include files, particularly when several of them are loaded simultaneously into multiple edit windows, you need to tell the compiler which of the files is the primary or main file. Use the Primary File command to mark which files is the main file that references all the others. The Make and Build commands reference this filename to determine which file owns which units, and to perform "smart" recompilation of the source. The Debug Menu and the Built-in Debugger The Debug menu provides access to the built-in debugging features of the IDE. In conjunction with the single step execution features on the Run menu, the built-in debugger let's you carefully step through your program, line by line, observing and changing variables as you proceed, and setting breaktpoints to stop execution and specific locations. Also see the Options/Compile and Options/Debugger features. The options values are set, by default, to enable use of the IDE's built-in debugger. However, its important that the Compiler Options be set to enable debugging information and usually, to retain local symbol information (see Options/Compile). Using the Options/Debugger command you should insure that the Debugging mode is set to "Integrated" mode (the standalone debugger is described in Chapter 9). The two features that will most often be used are the Breakpoints option, to set program stopping points, and the Watches function, to examine the values of variables. You can change variable values using the Evaluate/Modify command. Debug Menu/Evaluate/Modify (Ctrl-F4) Use this feature to evaluate an expression, referencing existing variable values, and optionally to assign new values to program variables during program execution. Evaluate/Modify displays a dialog box prompting for an Expression, and displaying the evaluated result in the Result field (which is also editable). You can type a new value or expression in the New value field and select the Modify button to update the contents of variable (must be a variable or array element) entered in the Expression field. The expression evaluator can format the results according to the format specifiers shown inTable 2-11. For arrays, you can specify a repeat count expression to enumerate many elements of the array by following the array or pointer name with a comma, and a repeat count expression. For example: XArray[0], 3 displays the first 3 elements of XArray. Table 2-11 Evaluate/Modify Format Specifiers , (comma) Is used following an array or pointer variable to specify a display repeat count. See the example given in the text. C Normally, ASCII characters in the range of 0 to 31 are displayed using the notation #nn to indicate which ASCII value is stored in the byte. By adding ,C after the expression, these values will display as actual characters. D Use ,D to display all integer values as decimal numbers. Fn Use ,Fn to change the default floating point digits display of 11 digits to the number specified by n, where n is from 2 to 18. M By adding ,M after an expression, the value of the expression is used as a memory address (the expression must evaluate to a variable address or pointer reference as if it were being used on the left side of the := assignment operator). Normally, the ,M format will display one memory byte in Hex. However, by following ,M with one of the other format specifiers, you can display the following bytes as if they contain an integer, real, pointer or string value. P By default, pointer values are displayed as Ptr(segment, offset). By specifying ,P after the expression, the pointer value will be displayed as segment:offset. R Record variables are displayed showing the values of each field separated by commas. By adding ,R, the record is output to include variable names. S Forces string and character values in the range 0 to 31 ASCII to display as #nn. When used with the ,M format, S causes the memory bytes to be interpreted as a string. $, H, or X Displays all integer values as hexidecimal, such as $1A. Debug Menu/Watches Using the Watches function, you can add variables and expressions to a watch window, where their contents will be displayed at all times. Selecting Watches displays a sub menu containing Add Watch, Delete Watch, Edit Watch and Remove all watches. These functions are described below. Debug/Watches - Add Watch (Ctrl-F7) Choose Add Watch to type a new variable or watch expression to be added to the watch window. Typically you will type a simple variable name, such as Filename, or pointer reference such as List^.Name, or even a record name. You can also enter expressions, such as I*J or whatever is appropriate. In addition to the Ctrl-F7 shortcut key for adding watch values, if the Watch window is the active or focused window, you can press the Ins key to insert watch expressions, one after another. Debug Menu/Watches - Delete Watch When the watch window is the active window, you can delete individual watch expressions by moving the cursor to the item to be deleted and choosing the Delete Watch item, or pressing either the Del or Ctrl-Y keys. Debug Menu/Watches - Edit Watch To change an existing watch expression, choose Edit Watch and type the new expression in the Edit Watch dialog prompt. For fastest access, just move the cursor over an existing watch expression in the Watch window and press the Enter key. This immediately displays the Edit Watch window. Debug Menu/Watches-Remove all Watches Use Remove all Watches to erase the contents of the Watch window. Debug Menu/Toggle Breakpoint (Ctrl-F8) To set a breakpoint, choose Toggle Breakpoint. If the cursor is on a highlighted line already containing a break point, choosing Toggle Breakpoint clears that breakpoint. Debug Menu/Breakpoints The Breakpoints command is used to edit or add breakpoints to the list of currently active breakpoints, to delete breakpoints or to quickly locate and view the source code where a breakpoint is set. The Breakpoints command brings up a dialog box showing the current list of breakpoints (the line number where its set and any conditions assigned to the breakpoint), and a set of buttons to perform operations on the list. Edit Breakpoints Button Choose the Edit Breakpoints button to change an existing breakpoint or to add a new one. Edit Breakpoints displays a subdialog on top of the Breakpoints dialog with the following fields: Condition field: You can enter a conditional test in this field, such as I>10, which limits the breakpoint to having an effect only when the variable I is greater than 10. Pass count: By entering a value in the Pass count field, the break point will be skipped this number of times before actually stopping at the break point. This feature is especially useful when debugging items in the middle of a loop. Filename: This is the name of the source file that contains this breakpoint. Line number: Specifies the line number at which the break point is located. Delete Button Within the list of breakpoints, move the highlight bar cursor to the breakpoint you wish to delete, and then choose the Delete button. Note that the Breakpoints dialog has no Cancel button so that any breakpoints you clear are gone for good. View Button To locate a specific breakpoint's source code, point to the breakpoint in the breakpoints list and select the View button. This switches the active window to the file containing the breakpoint and displays the source line where the breakpoint is set. Clear All Button Use Clear All to erase all breakpoints from the program. The Options Menu The options menu provides a way to set compiler, linker, and debugger options, and to establish default directories and memory allocations. You can also customize various features of the IDE, including startup defaults, color selections, mouse behaviour and so on. Options Menu/Compiler The Compiler Options are shown in Table 2.4 Many of these options can also be set using imbedded $ comment directives. $ comnment directives are place inside your Turbo Pascal source, as a comment. By beginning the comment with a $ character, a compiler option character, and then optional parameters, you can turn various features on or off throughout the program's compilation. For example, to enable range checking, so that the compiler will check on array indices before use to insure that they fall within the bounds defined for the array, you would insert a comment into your program's source, like this: {$R+} To disable range checking, you type {$R-}. Using this feature, you can selectively enable and disable features at various places in the program. In general, following the compiler directive with a + plus symbol to enable the feature and a - minus symbol to disable the feature, or, for item requiring a numeric parameter, follow the compiler directive with the value of the parameter. Table 2.4. Compiler Options. Force far calls ($F compiler directive) Normally, the compiler generates near calls for all procedure and functions in the current file. You can force far call generation by selecting this option. Overlays allowed ($O compiler directive) You must set this option for all units that will subsequently be overlaid. Its also okay to set this option for units that are not overlaid as it merely adds some additional run time checks to the generated code. Word align data ($A compiler directive) Normally, the compiler generates byte aligned data assignments. Setting this option forces the compiler to generate word aligned assignments, so that if one value ends on an odd byte, the compiler will skip a byte to insure that the next assignment is made to an even byte position. The 80x86 CPUs, including the 8086, operate slightly faster when fetching word-aligned data than when fetching byte aligned data. 286 instructions ($G compiler directive) Compiles using the 80286 instruction set. Programs created with this option will not run on 8088 or 8086 processors. Range checking ($R compiler directive) Range checking can be performed on all array and string subscript values. If the index is out of range, then a run time error occurs and the program halts. Set this option to enable range checking, and clear this option to disable range checking. Programs may run noticeably faster with range checking turned off. Stack checking ($S compiler directive) When this option is set, the compiler generates extra code for every procedure and function call to insure that adequate memory remains in the stack area. If the call would cause the program to run out of memory, the program is halted with a run-time error. I/O checking ($I compiler directive) The default setting is to have the compiler check for input/output errors on all input/output operations, such as reading or writing to a file. However, usually you will want to have your own checks for such errors so you will want to disable this option, or use the $I- compiler directive to locally disable I/O checking. You can then check the value of the IOResult function to determine if an error occurred. Strict var-strings ($V compiler directive) Most Pascal compilers will not let you pass a string variable as a VAR parameter unless both VAR parameters are exactly the same type and length. For example, you normally cannot pass a STRING[80] typed variable to a procedure having a VAR parameter defined (via a type declaration) as STRING[128]. However, clearing this option, Turbo Pascal will allow you to pass mismatched string types. Complete Boolean evaluation ($B compiler directive) The Turbo Pascal compiler normally performs short-circuited boolean expression evaluation. This means that, as the expression is evaluated at run time, as soon the result is definitely known the remainder of the expression will be ignored. This is particularly useful in testing an index value before using it in an array subscript, in for example, if Index < 10 and (X[Index]=9) then... If Index is 10 or greater, the program will not execute the array subscript. However, by enabling this compiler option, you can force the program to always fully evaluate the expression. This might be used when calling a function within an expression, and your program must use an intended side affect of the function call. Extended syntax ($X compiler directives) When this option is set, Turbo Pascal will let you call a function just like it was a procedure. In effect, the result of the function will be ignored and thrown away. This feature does not apply to any System unit functions. 8087/80287 ($N compiler directive) When set, this results in the compiler generating code for the 8087 or 80x87 math coprocessor chip. This option is often used in conjunction with the Emulation mode option; see below. Emulation ($E compiler directive) When this option is set, the compiler will link in routines that automatically detect the prescence or abscence of the floating point processors. If the math processor is installed, then it will be used; if the math processor is not installed, the routines that simulate the processor are called instead. To generate code for all types of machines, regardless of whether or not they have a floating point chip, select both the 8087/80287 and the Emulation options. If you know that the target machine definitely has a coprocessor, then disable this option but enable the 8087/80287 option. Debug information ($D compiler directive) If you are going to use either the built-in or the standalone debuggers, set this option on so that the compiler will generate internal line number tables to assist in matching generated code to program source statements. You can selectively disable debug information on a per unit basis; such units cannot have their procedures or functions traced into. Local symbols ($L compiler directive) This option should be set so that the compiler builds a table of all local variables and constant identifiers. You can then refer to these during a debugging session. Conditional defines In Turbo Pascal programs, you can conditionally compile sections of the program depending upon the settings or definition of certain symbols. A common use is to create an identifier called Debug. Special debug code is then inserted into the program source, surrounded by the conditional compilation instructions, {$IFDEF Debug} and {$ENDIF}. If Debug is defined in a $DEFINE statement, then the code is generated. If Debug is not defined, such as when the program has been completed and thoroughly tested, then the special debugging code will not be generated as part of the final executable. Use this input field in the Compiler Options box to define any particular symbols that your program references. Multiple symbols may be separated by semicolons. Important note: Symbols used as part of the $IFDEF check are not the same as symbols used as program constants and variables. Options Menu/Memory sizes The Memory sizes dialog displays prompts for Stack size, Low heap limit and High heap limit. You can enter new values that are appropriate for your program. For example, the TVSHELL program described in the Borland Pascal Developer's Guide, Chapters 11-12, "Turbo Vision Tutorial" loads and executes other programs. If the High heap limit is set to the maximum default value, no memory would be available to load and execute another program. Many programs can execute with a relatively small heap, which is the area that dynamic variables are allocated from, and this limit can be safely set to a small value such as 8 or 16k. Options Menu/Linker On the Linker options dialog, you can indicate if you wish to produce a link map file, showing where each unit has been placed in the executable. Select one of the options Segments, Public or Detailed, or specifiy no link file by selecting Off. The linker normally links programs using a memory based buffer. However, for large programs you may need to select a disk based buffer, which is slower, but can accomodate much larger programs. Select either the Memory or the Disk radio button to choose the correct setting for your programs. Options Menu/Debugger Use this dialog to specify which debugger you plan to use: either select the Integrated debugger, which is the default, or choose the Standalone debugger. You may also select the type of display swapping in effect. If you are using a second monochrome monitor for debugging output, the Display swapping settings are ignored. Otherwise, the none selection causes the debugger to maintain control of the screen at all times. The default setting, Smart, causes the screen to display your program's output every time a procedure call is made or any time that it believes an I/O will occur to the screen. When the program encounters a break point or error, control returns to the debugger. Lastly, the Always selection forces the screen to swap back and forth between the debugger and the program at every statement execution. Generally, you will want to use the Smart swapping mode of operation. Options Menu/Directories The directories dialog specifies the location of various files. Values should be entered as follows: EXE & TPU Directory Enter the name of the subdirectory that will contain all created .EXE and .TPU files. Leave this field blank if you want to store these files at the same location as where the source is found. Include directories If this field is blank, include files will be read from the source file directory. Otherwise, you can specifiy a different directory or directories where the compiler should look for the included source files. By separating directory names with a semicolon, you can enter a large number of directories, each of which will be searched by the compiler. Unit directories Like the Include directories field, you can type multiple subdirectory names to be searched by the compiler and linker when accessing program units. Multiple directory names should be separated by semicolons. Object directories If you reference assembly language routines in your program, specify the location of the *.OBJ files using this field. Again, multiple directories may be entered by separating each name with a semicolon. Options Menu/Environment Choose this selection to set a variety of parameters including 25 or 43/50 line modes. A submenu containing Preferences, Editor, Mouse, Startup and Colors items is displayed. Options Menu/Environment - Preferences Use the Preferences dialog to choose: Use the Screen sizes option to select 25 or 43/50 line modes (CGA is always 25 lines only, EGA is 43 lines and VGA is 50 lines); Use the Auto Save selections to choose automatic saving of modified editor files each time the Run command is given; To choose automatic saving of all environment selections when you exit the IDE; and to choose saviing of the desktop so that it the desktop will be restored upon return to the IDE. Use the Source tracking option to specify how source files should be loaded when in debug mode or when a run time error occurs. For example, if you are single stepping into a procedure whose source is not currently loaded, the IDE will read in that source file. If you have selected the New window option for Source tracking a new window is created and the file loaded into that window. If the Current window option is chosed, then the contents of the top most window are replaced with the new file. Use the Desktop file options to specify that the TURBO.DSK desktop file be saved in either the Current directory or to the Configuration file directory, which is whatever directory contains the TURBO.TP configuration file. Options Menu/Environment - Editor Options Select Editor options to specify any of the following: Create backup files: If set, any file that you edit will retain the immediately preceding version in a file having the same filename but a .BAK extension. Autoindent mode: If set, the IDE editor provides an intelligent, automatic indenting feature to ease typing the standard indentation used in Pascal source. Use tab characters: Normally, the IDE editor converts tabs to spaces. However, if this option is set, then the editor inserts an actual ASCII 9 tab character into the text. See Tab size, below. Optimal fill: If this option is set, leading blanks on each line are converted, if possible, to a combination of ASCII 9 tab characters and spaces. See Tab size, below. Backspace unindents: If set, this option operates roughly the opposite of the automatic indent feature. When you backspace, the cursor will move to the preceding indent level. This is especially useful when entering lots of nested begin - end statements. Cursor through tabs: If the Use tab characters option is set, and ASCII 9 tab characters are being inserted in the text, then and only then does this option apply. When ASCII 9 characters are embedded in the text, pressing the left or right arrow key moves across the entire gap of blanks that may appear at the site of an ASCII 9 character. If the Cursor through tabs option is set to true, the cursor key will advance across the ASCII 9 as if it was a group of blank characters. Tab size: Tab size specifies how far apart, in characters, the tab positions are located. The default value is 8 but may be set to any value from 2 to 16. Options Menu/Environment - Mouse Use the Mouse options dialog to set a function from the right mouse button (Nothing, Topic search, Go to cursor, Breakpoint, Evaluate or Add watch), to select reversal of the left and right mouse buttons (especially useful if you use the mouse with your left hand). Using the Mouse options dialog, you can also set the mouse double click rate by sliding a marker across a scroll bar ranging from Slow to Fast. Options Menu/Environment - Startup This dialog controls a variety of IDE start up options. In addition to specifying start up options here, you can append the command line switches shown below when you first start the IDE by typing, for example, TURBO /D+ where a + following the switch is equivalent to setting that option on, and a minus "-" is equivalent to turning the option off. Dual monitor support (/D): Set this option if you have both a graphics monitor for user program output and a monochrome monitor for debugging information output. You can switch which monitor is the debugging monitor using commands appropriate for your computer, before you start running Turbo Pascal. Graphics screen save (/G): If set, an additional 8k of RAM will be allocated to a buffer used for saving all of graphics memory while debugging programs that operate in graphics mode. EGA/VGA palette save (/P): This function is useful when your program manipulates the palette registers of the EGA and VGA video cards. If set, the IDE will restore the registers to their original values each time the screen switches between user output and debug output. CGA snow checking (/N): Some of the original CGA adaptors used single ported memory, where the video circuitry and the CPU would sometimes interfere with one another's access to the CGA video memory and produce a flicker effect referred to as "snow". If you are using a CGA monitor that experiences snow, this option should be set on (it is set by default). However, if your monitor does not experience snow, you should turn this option off. Monitors that do not display snow will have faster output with this option disabled. LCD color set (/L): If you are using the IDE on a typical lap top computer with an LCD screen, you should select this option to provide a more readable display. Use expanded memory (/X): If you have installed an EMS driver and have EMS memory available, Turbo Pascal will automatically attempt to use the EMS memory. The use of EMS will substantially improve the performance of Turbo Pascal, particularly when working with very large programs. Youcan also use the /S option to specify a RAM disk or other fast disk area where Turbo Pascal can locate its swap file. Load TURBO.TPL (/T): By turning this option off, you can increase the memory available for compiling, as long as you then link in the SYSTEM.TPU unit. Window heap size (/W): The window heap size specifies, in k bytes, the amount of RAM reserved to manage the windows on the desktop. If you do not normally open multiple files, you can reduce the memory allocation. Values may be in the range from 24k to 64k. Editor heap size (/E): The default value of 28k is sufficient for most users especially if you are using a RAM disk, EMS or a fast hard disk.. However, if you are swapping to a slow disk, you should set this to a much larger value, as needed, between 28k up to 128k. Overlay heap size (/O): The overlay heap size can be adjusted between 64k and 256k. If you are using EMS, you can enlarge the amount of memory available for compiling by reducing this to 64k with no degradation in performance. Swap file directory (/S): If you are not using EMS, you can specify the location of the swap by typing in the directory where the file should be created. See Use expanded memory, above. Options Menu/Environment - colors Use the colors dialog to select different colors, both foreground and background, for each component in the IDE. Selecting colors is a fairly cumbersome undertaking because of the large variety of components and possible color choices. If you elect to use this feature, you will probably want to change the colors on only a few items. Options Menu/Save options Use Save options to specify where the name and location of the TURBO.TP configuration file (you can create different and multiple configuration files if you wish). Use the Retrieve options dialog to reload a previously saved configuration file. The Window Menu Use the Window pulldown menu to manage the display of the IDE windows. From this pulldown, you can select between the active user program screen or the debugger screen, as well as access a variety of other windows and functions. Some of the functions such as Size/Move are directly accessible using the mouse and are presented on the Window menu so that keyboard-only users can perform the same functions. Size/Move (Ctrl-F5): To move the active window, select Size/Move and then use the arrow keys to drag the window. If you press Shift-arrow keys, you can change the window's size. Press Enter when you are finished making your adjustments, or press the Esc key to abandon your changes. If you are using a mouse, you can move a window by clicking and dragging on the window border, and you can adjust the windows size by clicking and dragging on the lower right corner. Zoom (F5): Zooming is the action that takes place when a small window is enlarged to cover the entire desktop. You can zoom a small window to maximum size by selecting this function, or you click the mouse on the up arrow located at the upper right corner of the window, or by double clicking on the top most line of the window (other than on the close icon). Tile: The tile function arranges the windows as if they were tiles on a floor; each window is sized and positioned so that all the windows can be seen at the same time with no overlapping windows, hence the name "tiling". Cascade: When windows are cascaded, instead of tiled, the windows are overlapped so that other than the top most window, each of the windows shows only its upper border and left side border peeking around from behind. You can select a window by clicking on it with the mouse or by using the Next command on the Window menu. Next (F6): Use Next and Previous to cycle through the list of windows, making the next or previous window in the display become the active window. Previous (Shift-F6): See above. Close (Alt-F3): To close a window, click on the window's close icon in the upper left corner, or make the window active and choose the Close function. Watch: If you have previously closed the Watch window, or if it has become hidden behind another window, select Watch to make the Watch window visible on the display. Register: Select Register to make this window, a display of CPU registers and their contents, visible on the screen. Output: Output opens a small window (whose size can be increased) displaying output from any DOS commands you may have executed by shelling to DOS (from the File menu). If your program generates simple text output using Writeln's, this output too can be seen in the Output window. If you are debugging a 25 line output application within a 50 line VGA display, you can see both your program's output and the debugger information at the same time. Call stack (Ctrl-F3): Displays a list of procedures or functions called (and currently active). You can use this procedure list to quickly jump to the corresponding source code by moving the highlight bar up or down with the arrow keys, so that it points to the item of interest, and pressing Enter. The edit window will then jump to the location where the procedure where was called. User Screen (Alt-F5): This function switches the entire screen to show your program's output only and is used frequently during debug sessions. Press any key or click the mouse to return to the IDE. List (Alt-0): Displays a window containing a list of every active window on the IDE desktop. You can jump directly to any of the windows by selecting or clicking the desired item.