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Text File | 1990-06-21 | 15.5 KB | 361 lines

Ed - An Editor for C source code VERSION 0.2 Wed,20 Jun 1990 CONTENTS 1) COMMANDS 1.1) STARTING Ed 1.2) ENTERING TEXT 1.3) MOVING AROUND 1.4) FOLDING 1.5) THE MARK 1.6) DELETION 1.7) NOTES 1.8) FILE OPERATIONS 1.9) PRINTING 1.10) SEARCHING 1.11) OS COMMANDS 1.12) CONTROL CHARACTERS 1.13) MEMORY 2) COMMENTS 2.1) PHILOSOPHY 2.2) WARNINGS 2.3) RECONSTRUCTING THE OBJECT CODE 2.4) HOW IT WORKS 2.5) KNOWN PROBLEMS 2.6) CHANGES FROM VERSION 0.0 2.7) TO DO 2.8) COMMENTS PLEASE STARTING Ed Ed is a standard RISC_OS application. It is started by double clicking on its icon, it then installs itself as an icon on the iconbar. Ed needs the filer to have seen !System, and to find version 3.50 or later of the shared c library in the system:modules directory. To create a new text file click on the iconbar icon. To load a text file double click on its icon while Ed is on the iconbar. To load any date stamped file drag it onto the iconbar icon. You can also start Ed from the command line with *Run !Ed.!Run <filename> ... <filename> The named files are loaded into Ed. If you want to load Ed automatically when you double click on a text file take a copy of the !Edit.!Boot file from Edit and put it into the !Ed directory. Ed is controlled by keypresses and two menus, one for each window and one on the iconbar icon. The keypresses are directed to the window that contains the caret. This is identified by a buff coloured title bar. You can place the caret in the text by clicking select. The line containing the caret is called the current line, the window containing this line the current window, and the document displayed in this window the current document. To avoid confusion between Ed and Edit I have used green scroll bar backgrounds in Ed. If you don't like this you can edit the Templates file. You can get a keystrip for Ed by printing the Draw file !Ed.Strip . You can recreate or alter !Ed.Strip from !Ed.EdStrip if you have my DrawStrip application. ENTERING TEXT You can enter text at the caret by typing. The maximum length of a line is 108 characters. If you try to enter more than this Ed will beep and ignore you. <Insert> Start a new line below the current line. F7 Split the current line at the caret position. <Return> Usually as <Insert> - see CONTROL CHARACTERS below. <Shift>F7 Join the current line to the line above. The above keys attempt to indent the line suitably. <Shift>F8 Attempt to tidy the indentation from the current line to the next blank line, folded line or note. <Ctrl>Fn 1<=9<=9 Enter the function key string. <CtrlShift>Fn 1<=n<=9 Set the function key string to the text of the current line. Control codes and top bit set characters cannot be entered into the text. If you try to enter a top bit set character (e.g. using !Chars) the corresponding \xNN escape sequence is entered. MOVING AROUND You can move around the file using the standard keys. cursor keys Up,down,left or right one space control cursor keys Start,end,start of line or end of line. page up / down Page up / down ! F2 Go to the marked line. (see below) F4 Go to the next note. (see below) You can go to a line number from the window menu. FOLDING In order to get as much code on the screen as possible Ed implements a simple form of folding. A fold of text is retained in the document, but only the top line is visible on the screen. A folded line is displayed in dark blue. Ed folds the document at blank lines. If you fold the whole document each fold consists of a block of non-blank lines and all the blank lines that follow it. Folding is to one level only. F9 Fold the whole document. <shift>F9 Unfold the whole document. F10 Unfold the current line. <shift>F10 Fold the largest possible block of unfolded lines around the current line. F11 Fold between the mark and the current line. THE MARK A line can be marked in each document. The marked line is indicated by a grey background. It is used with the current line to delineate blocks. F1 Set mark. <Shift>F1 Clear mark. F2 Go to the mark. F5 Copy the marked line after the current line. <shift>F5 Move the marked line after the current line. Block moves and copies can be made by moving or copying a folded line. Copy and move use the most recently marked line to decide which document to use, allowing copy or move between documents. After copy or move the mark and current line are moved on one line, so you can copy or move a small block by repeatedly pressing F5 or <shift>F5. DELETION <delete> Delete the character to the left of the caret. F6 Delete all characters to the left of the caret. <Shift>F6 Delete all characters to the right of the caret. F8 Delete the current line. NOTE if this line is folded the whole fold is deleted! NOTES Temporary notes can be inserted in the file. They are whole lines. They can be used for reminders or to help find your place. They are not saved when the file is saved. Notes are displayed in red. Folded notes are in green. You can insert a file of notes after given line numbers. The main use of this is to read the error messages from the Acorn ANSI c compiler as notes. Each note goes after the line it applies to. To do this take the Note option from the window menu. The named file is searched for lines begining with a given prefix followed by a line number. The default filename is the same as the source file with the last letter of the directory changed to l. The default prefix is " "name" line ",where name is (the last letter of the directory).leafname . If you spool the error messages from the c compiler to a file with the same name as the source file but the last letter of the directory changed to l you will only need to click on <OK>. See !Ed.Makefile for one way to do this.The line numbers will only be correct if the source file has not been edited or folded. You may need to alter the filename or prefix for errors in a #include file, or if you include notes from one of the unix type utilities that produce similar lists. The program can be set to ignore case in the prefix, or to attempt to use #line directives. F3 Start a new note line. <Shift>F2 Make a text line into a note line. <Shift>F3 Make a note line into a text line. <Shift>F4 Make consecutive note lines from the current line on into a comment. F4 Go to the next note. FILE OPERATIONS Text files can be included at the caret position by dragging their icon into the current window. A document can be saved from the window menu using the usual RISC_OS method. When a document is saved all blank lines are stripped from the end unless they contain the caret or the mark. If you save a folded document the folded text is included. A line can also be saved from the window menu. Folded lines can be saved to save a block. PRINTING <Print> Print the document the current document. <ShiftPrint> Print the marked line. You can also print by saving to a printer driver. SEARCHING Various searching options are avaliable from the find option of the window menu. The previous ten search criteria are stored and can be stepped through using [Previous] and [Next]. If the [List] option is chosen a new document is created containing all the lines found containing the search string. If the [Comments] option is not chosen the search attempts to exclude comments and strings. If the [Name] option is chosen the search only matches strings that are not preceded or succeeded by a letter, number or underline. If the [Whole] option is chosen, or the caret is not in the window selected the search starts at the start of the document, otherwise it starts at the beginning of the line containing the caret. If the [Folded] option is chosen the search includes folded text. When a match is found the caret is placed before it, and you have the usual replacement options. If the match is inside a fold you have the additional option of unfolding to see it. OS COMMANDS Ed allows the usual F12 option to obtain a command line. You can also execute a (possibly folded) line of a document as a command. The resulting screen output can be redirected to an Ed document. The line is saved as an obey file <EdTemp $Dir>.ToDo and * obeyed possibly with redirection to <EdTemp$Dir>.Output. The system variable <EdTemp$Dir> is presently set in !Run to RAM:. If you do not have a ram disk configured you will need to set this to some other suitable directory. F12 Open command line. <Shift>F11 Obey a line. <Shift>F12 Obey a line and spool output to a new Ed window. CONTROL CHARACTERS The <Ctrl>X keys look for a system variable Ed$X and pass it to Ed's key interpreter, X can be a letter or [\]^_. You can enter text or other control characters. The string &XXX where XXX are THREE hex digits are interpreted as the key press with code XXX so you can use any of Ed's key commands.&& is interpreted as &. At present a few of these are defined in the !Run file. You can edit these to suit.The present ones are:- <Ctrl>B Start a c block. <Ctrl>T Enter the time. <Ctrl>D Enter the date. <Ctrl>Y Enter the year. <Ctrl>C Enter a copyright message (You will need to change this!) <Ctrl>M This is equivalent to <Return> and is set to the <Insert> key. If you would prefer <Return> to use the 'split' key F7, so that return operates as in Edit, rather than as in the BASIC editor, you can change the line in the !Run file to :- Set Ed$M &187 Some other examples Set Ed$\ &181&1AF&18E&18EMODIFIED |D&182&191 Makes <Ctrl>\ put a modification date in the 4th line of the program. Set Ed$Z &1CDWIPE :4 ~CFR~V &1DB&188 Makes <Ctrl>Z wipe your hard disk for you ! MEMORY Ed obtains memory for documents from the wimp pool. It does not give this back unless you close all documents. ( A document is closed when all its windows are closed) . PHILOSOPHY Ed is designed specifically for the editing of c source code. In fact for editing code in the way I write c. One of the major problems with programming at the keyboard is the amount of code you can fit on the screen at once, folding is one way of avoiding this. As nothing other than the text can be saved I decided to split the folds at blank lines. I only put blank lines between procedures so this works fairly well. I did try recursive folding using multiple blank lines, but this was far too confusing to use. I have tried to make Ed as similar to Edit as possible. One major question was the operation of <Return>. In the end I decided let it create a new blank line like the BASIC editor rather than split as in Edit, if you don't like this see CONTROL CHARACTERS above. If you don't like my other key assignments you can change them by editing the procedure keyop(int) in c.Edkeys. Another important point was the [Name] option in the search menu. I was fed up with using Edit to search for all instances of variable a, and having it stop three times in each occurrence of variable aardvark. WARNINGS Even excluding any possible bugs Ed is a dangerous program to use. There are many possibilities for loosing your work or your files. On loading a file Ed replaces tabs by single spaces. It ignores all other control and top bit set characters except for cariage return and line feeds. It saves using only line feeds. It splits all lines that are too long for it. It deletes trailing blank lines, and trailing spaces from lines. Thus you can alter a file just by loading and immediately saving. Loading and saving a non-text file could lead to disaster. You can delete a whole block of lines just by deleting one folded line. There are no undo facilities in Ed, and no backup file system. Ed just ignores most invalid commands, it does not usually beep annoyingly at you or give error messages. RECONSTRUCTING THE OBJECT CODE Ed can be reconstructed by compiling the seven source code files using Acorn's ANSI c v3. The two header files need to be in an h directory. The RISC_OSLib headers also need to be found. The seven object files need to be linked together with RISC_OSLib and the standard c library stubs. You can use the Makefile provided. You may have to alter the directories where the libraries and their headers are found. You will need to create o and l directories. Ed was constructed on a 1Mb A310 with 20Mb hard disk. To compile on a 1Mb machine the RunMake obey file can be used to run AMU. You will need the memory fairly clear of modules. It was nice to find that I could compile successfully while Ed was present but not while Edit was present. HOW IT WORKS (Very briefly) Three structures doc,wind and line are defined in h.EdHdr. The program keeps a doubly linked list of docs,each of which points to doubly linked lists of winds and lines. These are obtained from a linked list of empty lines.The size of a line must be an exact divisor of the pagesize. It is currently 128 bytes. The size of a doc and a wind must be no more than the size of a line. Ed uses 128 bytes even to store an empty line, so it is wasteful of memory. However there should be no difficulty with source code files of any reasonable size. A fold is stored as a linked list of lines attached to the displayed top line. The current line cline and its line number clinen must be kept in sync to keep the display correct. KNOWN PROBLEMS Ed does not restart the closedown sequence after a <CtrlShift>F12 if you reply [YES] to "Quit without saving?". The indentation is not yet as desired. It could probably never be perfect, You would have to read header files and do macro expansion! I'm a bit suspicious about what happens when Ed runs out of memory. CHANGES FROM VERSION 0.0 Bug fix - the ~ character is now accepted. Bug fix - the delete character key does not leave stray characters. Copy and Move step the caret and the mark on one line. Modified files are marked with * on the title bar. Tab characters are converted to a space when a file is read. The read errors option has been moved to the window menu, to allow errors in a #include file to be read, and #line directives obeyed. The indenting algorithm now ignores { or } in "strings", 'character quotes' or /* comments */. Ed$X macros introduced, <Return> and "insert block" moved to macros. Closing a window with <Alter> opens the source directory. Squeeze option removed (buggy and not used). TO DO (?) Add a bracket checking option. Implement RAM transfer. Improve indentation. Interface, possibly through the run line option, with Unix-like utilities, in particular to search for definitions in RISC_OSLIB headers. COMMENTS PLEASE I would welcome bug reports, criticism (constructive or otherwise), modifications or suggestions for modifications. Chris Stretch Archive BBS No.62 CBTP13@JANET%UK.AC.ULSTER.UCVAX