The PC-SIG Library 10

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ced 1.0 User's Guide Table of Contents Purpose . . . . . . . . . . . . . . 1 System Requirements . . . . . . . . 1 Terminology . . . . . . . . . . . . 1 Installation . . . . . . . . . . . . 2 Command line editor . . . . . . . . 2 DOS command stack . . . . . . . . . 3 Application command stack . . . . . 5 Pcall function . . . . . . . . . . . 5 Synonyms . . . . . . . . . . . . . . 6 Command chaining . . . . . . . . . . 7 Command parameters . . . . . . . . . 9 Ignoring commands . . . . . . . . . 10 Ignoring individual commands . . . . 11 Clearing ced objects . . . . . . . . 11 Configuration files . . . . . . . . 12 Changing default buffer sizes . . . 13 Status display . . . . . . . . . . . 15 Multiple definitions . . . . . . . . 15 User Commands . . . . . . . . . . . 16 Subfunction 0: Enqueue . . . . 16 Subfunction 1: Dequeue . . . . 17 Return registers . . . . . . . 17 Command processor . . . . . . . 17 Problem reporting . . . . . . . . . 18 Copyright and Disclaimer . . . . . . 19 Appendix A: Command summary . . . . 20 Appendix B: Order of Processing . . 22 Appendix C: Limitations . . . . . . 23 Appendix D: User Command Demo . . . 24 1 === ced 1.0 User's Guide === Purpose ------- Ced (which stands for Command EDitor) provides the following functions at the DOS prompt, or from within certain applications programs: -- Complete command line editing facility. -- Recall of previously issued commands for re-entry. -- Command synonyms, which may include "chaining" of a series of commands. -- Parameterization of synonym commands. -- Recall of parameters for previously issued commands. -- User-settable buffer sizes for all functions. -- For programmers, a facility to add new "resident" commands to the DOS shell. Ced is an evolutionary development of two earlier programs by another author: DOSEDIT, and RETRIEVE (an IBM copyrighted product). It performs all of the functions of both programs, and has a number of enhancements. Both DOSEDIT and RETRIEVE were written by Jack Gersbach. System Requirements ------------------- Ced was written for an IBM PC/XT/AT or compatible machine. However, it uses no hardware-specific functions, so it will probably work with any MS-DOS machine. Ced requires DOS Version 2.00 or later. It increases the size of resident DOS by about 14K bytes after installation with default buffer sizes (this can be reduced). Terminology ----------- This document will usually refer to "commands" or "DOS commands" as ced targets; you should take this to mean either (a) actual DOS commands, or (b) input to ced-compatible programs (for example, DEBUG commands). Key names are as follows: 2 === ced 1.0 User's Guide === <Up> The up-arrow key on the numeric keypad. <Down> The down-arrow key on the numeric keypad. <Left> The left-arrow key on the numeric keypad. <Right> The right-arrow key on the numeric keypad. <Backspace> The large left-arrow key, next to NumLock. A carat (^) means to press the Ctrl key in conjunction with a named key; for example, <^End> means "press and hold the Ctrl key, then press <End>". Words in CAPS are ced keywords and must be typed exactly as shown (they need not be capitalized when you use them). Words in [brackets] are optional elements of a command. Installation ------------ Installation (in its simplest form) is accomplished by typing "ced" at the DOS prompt, or including the statement "ced" in your AUTOEXEC.BAT file. There are optional parameters when installing ced; these will be covered later. After ced is installed, everything will appear to be normal, but you now have many new features when entering DOS commands. The remainder of this document will describe these features. Ced is active either at the DOS prompt, or when an application program requests buffered keyboard input from DOS (DOS function 0AH). There are a few such programs (DEBUG and EDLIN are two); but the main use of ced is at the DOS prompt. Once ced has been installed, the command "CED" becomes an internal DOS command. Thus, when you want to issue ced commands (as explained below), you will type "CED <command>", but the program file (CED.COM) need NOT be available on disk. Ced becomes fully memory resident and is an extension to DOS after installation. In particular, this means that you should NOT include a drive or path in issuing CED commands after initial installation. A command like "C:CED SYN d dir" will reload ced, which is probably not what you intend. Command line editor ------------------- Ced provides a new "editor" for DOS commands. The DOS editing keys (F3 for copy-to-end-of-line, for example) are no longer available. Instead, the following keys may be used: <Home> Cursor to home position (first character). 3 === ced 1.0 User's Guide === <End> Cursor to end position (following last character displayed). <Left> Cursor left one character position. This does not erase any characters, it simply moves the cursor. <Right> Cursor right one position. <^Left> Cursor left one word. <^Right> Cursor right one word. <Ins> Enter/exit Insert mode. When Insert is on, new characters will be inserted at the current cursor position. When Insert is off, new characters will type over the character at the cursor position. <Del> Delete the character at the cursor position. <Backspace> Delete the character to the left of the cursor position (destructive backspace). <^End> Delete all characters from cursor position to end of line. <Esc> Cancel: erase all data and start over. When you have completed entering and editing the command, press <Enter> as usual to execute. DOS command stack ----------------- Ced keeps a record of each command you enter. You can retrieve and re-enter these commands by using the <Up> and <Down> keys to display the old commands, then pressing <Enter> when the desired command is displayed (the command can be edited, of course). You can visualize the stored data as a "stack" of commands. Ced keeps a pointer to somewhere in this stack. The pointer always points to a location "between" two commands; when you press <Up>, ced displays the command "above" the pointer, then moves the pointer up one command. When you press <Down>, ced displays the command "below" the pointer, then moves the pointer down one command. For example, suppose you have entered commands A, B, and C. The stack will appear as follows: 4 === ced 1.0 User's Guide === +-------------+ | A | +-------------+ | B | +-------------+ | C | +-------------+ <-- pointer The stack is circular in nature; thus, if the pointer points "below" the last command in the stack (as it does above), it is actually between the last command (C) and the first command (A). In the situation above, pressing <Up> will display command C and leave the pointer between B and C. Pressing <Down> will display command A, and leave the pointer between A and B. When you recall an old command and re-enter it without editing, the re-entered command is not added to the stack, and the pointer will drop one level. Suppose, for example, that you press <Up> twice from the position above (pointer below C): B is displayed, and the stack looks like this: +-------------+ | A | +-------------+ <-- pointer | B | +-------------+ | C | +-------------+ If you now press <Enter> (without editing the command), command B will be sent to DOS, and the pointer will drop to point between B and C. From there, <Up> will display B again, and <Down> will display C. Thus you can "recycle" a series of commands by pressing <Up> until you see the first command, <Enter> to execute it, then a series of <Down><Enter> sequences to re-execute the commands in the original order. If you retrieve an old command and edit it before execution, the newly edited command is added to the bottom of the stack, and the pointer will point just below it. Ced will not stack any commands of two characters or less (the theory being that it's easier to retype than to go searching through the stack). This is one of those computer gizmos that's easier to use than it is to explain. Just play with <Up> and <Down>; you'll get the idea. 5 === ced 1.0 User's Guide === You can remove a command from the stack by displaying it and pressing <PgDn>, and you can clear the entire stack by pressing <PgUp>. The actual number of commands which will be held in the stack is a function of the length of the commands and the size of the stack (which can be increased; see below for details). Application command stack ------------------------- Ced actually keeps two complete command stacks: one is for DOS commands, the other for commands entered into compatible appli- cations programs (DEBUG, et al). Thus, DOS commands will not appear in the command stack while in DEBUG, and vice versa. Pcall function -------------- "Pcall" stands for parameter recall; this is a second way to quickly retrieve old commands. Pcall simply remembers old parameters to specific commands. For example, suppose you have an editor called "edit", and the last time you executed it, you used "edit c:\util\foo.doc". If you now enter "edit" without any parameters, ced will assume that you want to edit the same file and will supply the "c:\util\foo.doc" for you. You could, of course, scroll back through the command buffer to find the old command, but it might take a while to find it (and the command might be missing if it was too long ago). Because many commands are best used WITHOUT parameter recall (FORMAT and ERASE are good examples), ced will only use pcall on commands that you specify. To make a command "pcallable", type CED PCALL <command> at the DOS prompt. For example, if you want to make "edit" a pcall command, type CED PCALL edit (Remember that the ced diskette need not be available). If you wish to issue a command for which pcall is enabled, but you do not want it to have parameters, add a space after the command. For example, suppose you have issued a "CED PCALL dir" command and your last dir was a "dir *.exe". If you now type "dir", ced will add the "*.exe" automatically. However, if you type "dir " (note the space), ced will not add the "*.exe", and you'll get a full directory. 6 === ced 1.0 User's Guide === You may also bypass pcall processing through the use of the ignore character; see below, under "Ignoring Individual Commands". Synonyms -------- The synonym function allows you to define brief "synonyms" for frequently used commands. For example, suppose you invoke your communications package by typing "talk rbbs /c63". Ced allows you to abbreviate this to a shorter command, say, "bb", by typing at the DOS prompt: CED SYN bb talk rbbs /c63 The exact syntax is: CED SYN <synonym> <command> The <synonym> is the command abbreviation (which you will type at the DOS prompt), and <command> is the word or phrase which ced will substitute when it sees <synonym>. The synonym is always the first word after the keyword "syn", and <command> is always all of the remaining words. For example, "ced syn d dir" allows you to type "d" instead of "dir". You may add parameters: "d *.exe" becomes equivalent to "dir *.exe". Many people define very short synonyms for frequently used commands: CED SYN d dir CED SYN e edit CED SYN g debug CED SYN l link CED SYN rbbs talk rbbs /c63 CED SYN cc1 cc1 -bpe Note in the last example that you can use a synonym which is identical to its associated phrase and simply use it to automat- ically add parameters. Also note that synonym processing takes place AFTER pcall processing; thus if you use a command synonym and wish the command to be "pcallable", use the synonym in the pcall command. For example: CED SYN e edit CED PCALL e (not PCALL edit) 7 === ced 1.0 User's Guide === User program synonyms --------------------- Because ced "knows" whether it is being used from the DOS prompt or from an application program such as DEBUG, it is possible to define separate sets of synonyms for DOS commands and for user programs. The syntax for a "user synonym" is CED USERSYN <synonym> <command> This is identical to the SYN command except for the new keyword USERSYN. For example, if you need to frequently type the DEBUG command "d ds:1010 1200", you might use CED USERSYN d1 d es:1010 1200 (Remember that DEBUG is a ced-compatible program; thus you can type ced commands at the DEBUG prompt.) Then you could simply type "d1" to dump memory from the specified address. Note that a "d1" USERSYN is separate from a "d1" SYN; at the DOS prompt you'd get the SYN, in DEBUG or EDLIN you'd get the USERSYN. Command chaining ---------------- The command chaining feature allows you to place more than one command in a SYN or USERSYN. These commands would be passed to DOS or to the user program one at a time, as input is requested. Suppose, for example, that in order to run your communications package, you always type: cd \talk talk cis /c63 cd \ You could put this sequence into one synonym by typing CED SYN cis cd \talk^talk cis /c63^cd \ The ^ character serves as a command separator. When you type CIS at the prompt, ced will output everything up to the ^ (in this case, "cd \talk") and then simulate an <Enter>. The next time DOS requests input, it will get "talk cis /c63<Enter>", and so on. Note that ced will not pass DOS-chained commands to user programs; thus, in 8 === ced 1.0 User's Guide === CED SYN bug cd \util^debug^cd \ DEBUG would not see the trailing "cd \", which would still be held up until you return to the DOS prompt. The first of the chained commands (e.g., the first 'cd \' above) cannot itself be a synonym, but the remaining commands can. That is, if 'f' and 'g' are synonyms, the command CED SYN h dir^f^g will work as you expect. Be careful, though. A command like CED syn f dir^f will put the computer into a loop from which there is no retreat. If one of the chained commands is a synonym which itself defines more chain commands, the unused portions of the first chain will be lost. If, for example, you have defined: CED SYN f a^b^c CED SYN b x^y and you then execute "f", the commands actually executed will be a, x, and y. Command c will be not be executed. You may alter the chain character (command separator) via the ced command CED CHAINCH <char> So, for example, "CED CHAINCH &" would replace ^ with & as the command separator. The chain character can, but probably should not, be a control character. If you are typing the command directly into ced, you can just type the control character: CED CHAINCH <Ctrl-A> However, if you are setting the chain character via configuration files (below), it may not be possible to type in the control character directly. For this reason, you can also specify a control character by typing the carat (^) and a letter key. Thus, if you wanted to use ^Y as the chain character, you would use '^' and 'Y': CED CHAINCH ^Y Certain control characters should not be used as for this purpose, because they are used for other functions by DOS; among these are ^C (cancel), ^G (bell), ^H (backspace), ^I (tab), 9 === ced 1.0 User's Guide === ^L (linefeed), ^M (carriage return), ^P (printer on), and ^S (stop). The use of control characters as described has more meaningful use in setting the "ignore" and "status request" characters (below). Command parameters ------------------ This section describes how synonyms and command chaining interact with command line parameters. The simplest case is a single word synonym like CED SYN d dir which specifies no special parameter handling. In this case, any command line parameters are simply tacked on after the synonym substitution: "d *.exe /w" becomes "dir *.exe /w". If the synonym itself contains parameters: CED SYN dw dir /w a similar situation holds. For example, "dw *.asm" becomes "dir /w *.asm". You might think of these simple nonchained synonyms as just substitutions: when ced sees the synonym, it will simply substitute the replacement text, leaving the rest of the command line alone. This simple substitution, however, means that your command line parameters must always be the last text of the synonym. There would be no way, for example, to define a synonym that would obtain a directory of <name>.exe, where <name> is some filename entered on the command line and ".exe" is part of the synonym. That is, it would not be possible to define a synonym "d" such that the command d foo would result in a "dir foo.exe" command. However, ced does provide a way to substitute parameters into the middle of a synonym. Ced recognizes the "%n" dummy parameter format used by DOS batch files. %1 represents the first command line parameter, %2 is the second, and so on, up to %9. Refer to your DOS documentation (batch file section) if this is unclear. Thus, a synonym which would provide the example function is: 10 === ced 1.0 User's Guide === CED SYN d dir %1.exe When "d foo" is executed, "foo" (the first command line parameter) is substituted for the %1, resulting in the desired command "dir foo.exe". When a synonym contains chained commands, all parameter substitution is performed at one time, before the chain is started. Thus, CED SYN f a %1^b %2^c %3 when executed "f one two three" will result in three commands: a one b two c three If a chain-command synonym contains no dummy parameters (no %'s) the command line parameters will be appended to the end of the chain, i.e., as parameters to the last command. So, CED SYN f a^b^c when executed "f foo" will result in the three commands: a b c foo Ignoring commands ----------------- There may be certain commands that you do not want ced to process; for example, you might not want the ERASE command stacked. To instruct ced to ignore a command, use the ced command CED IGNORE <command> For example: CED IGNORE erase When a command is set to IGNORE, ced will not place it in the command stack, check for aliases, or perform any pcall processing (even if you have set PCALL for that command). 11 === ced 1.0 User's Guide === Ignoring individual commands ---------------------------- You may sometimes want ced to ignore processing of a specific command. For example, you may have "dir" defined as a synonym for an external program which will display a sorted directory, but on occasion want to display a standard DOS directory. To force ced to suspend all processing of a command, precede it with ^N (Ctrl-N). If the first character of input is ^N, ced will not stack the command, check for aliases, or perform any pcall processing (just as if it were IGNOREd). The Ctrl-N, of course, is not passed to DOS or to the application program. For example: ^Ndir If you find ^N inconvenient, you can change the ignore character to a different character by using the IGNORECH command: CED IGNORECH ^T CED IGNORECH ! See the section on command chaining (above) for more information on how to enter control characters in this command. Clearing ced objects -------------------- From time to time it may be useful to clear a ced "object": a pcall command, a synonym, or an ignore command. The CLEAR command allows you to do this. The formal syntax is: CED CLEAR <function> [[FROM] <name>] This looks more complex than it is. The <function> is one of SYN, USERSYN, PCALL, and IGNORE. Since the [[FROM] <name>] is optional, the simplest form of the clear command is exemplified by: CED CLEAR SYN which will clear all synonyms. Similarly, CED CLEAR PCALL clears all pcall commands. You may clear an individual item by including its name. For example: CED CLEAR USERSYN foo 12 === ced 1.0 User's Guide === clears the user synonym "foo", leaving all others synonyms undisturbed. Finally, you can clear all items FROM a specified item through the end of the list with the FROM option. For example: CED CLEAR USERSYN FROM foo would clear the user synonym "foo" and all synonyms listed after "foo". This command is particularly useful if you have loaded a temporary set of synonyms for some special purpose. Suppose, for example, that you have a set of synonyms already in memory, then you load an additional set to be used temporarily. When you are done, the command CED CLEAR SYN FROM foo would delete all of the "temporary" synonyms, assuming that the first of these was "foo". Note that SYN and USERSYN objects share storage. Thus, a CLEAR SYN FROM <item> or CLEAR USERSYN FROM <item> will clear all synonyms (of either type) FROM the named item. Similarly, CLEAR SYN and CLEAR USERSYN are functionally identical: all synonyms of either type will be cleared. Configuration files ------------------- Obviously it would be inconvenient to have to type in all of these commands every time you use your computer. However, you may put any ced command into a special ced configuration file, and have them loaded all at once. The configuration file is simply an ASCII text file (created by your text editor, EDLIN, or word processor in nondocument mode) which contains a series of ced commands. Just leave out the keyword "CED", but include the rest of the command: Rem Remarks are OK if preceded by "REM" Rem Rem Set chain char to '&' Chainch & Rem Set ignore char to '!' Ignorech ! Rem Set a few synonyms Syn d dir Syn e edit Syn cis cd \talk & talk cis & cd \ Usersyn dd d ds:1017 L40 Rem And a few pcall commands 13 === ced 1.0 User's Guide === Pcall e Pcall debug Rem Ignore all DEL, ERASE, and FORMAT commands Ignore erase Ignore format Ignore del To read in your file, use the CED -f command line switch: CED -F<filename> For example, if your configuration file is call CED.CFG, you'd use CED -Fced.cfg If you load new configuration files during one computer session, the PCALL, SYN, USERSYN, and IGNORE commands are added to those already stored, without regard to duplication (see "Multiple definitions" below). Note that if you have several commands that you want to enter into ced (but don't have them in a file), you can use CED -Fcon (which specifies CON: as the configuration file name) and then type a series of ced commands from the keyboard. Type ^Z when you are done. Changing default buffer sizes ----------------------------- Ced maintains six separate internal buffers (regions of memory where data is stored). Each buffer is initially set to a default size. The buffers and their default sizes are: 1. DOS command stack (2048 bytes) 2. Application program command stack (1024) 3. Synonym list (2048) 4. Pcall list (1024) 5. Ignore command list (1024) 6. User command list (described below) (1024) You may make these buffers larger or smaller by including a list of buffer sizes the FIRST time you load ced during a session (i.e., when you turn on the computer, or after a Ctrl-Alt-Del reboot). Use a -B switch as the FIRST ced command: CED -Bn1,n2,n3,n4,n5,n6 14 === ced 1.0 User's Guide === where n1 is the desired size for buffer 1 (DOS command stack), n2 is the size for buffer 2 (App program command stack), etc. You need not specify all sizes, but if you skip one or more sizes (telling ced to use the default) you must include the separating commas. Examples: CED -B1000,2000,3000,4000,5000,6000 (Set all sizes) CED -B1000,,3000 (Set sizes 1 and 3) CED -B,,,,,6000 (Set size 6 only) You cannot set any individual size less than 128 bytes, and the total of all sizes must be not exceed 52K (53248) bytes. Remember that the -B command must be the FIRST command used the FIRST time you run ced during each session. It is not valid any other time. If you wish to set sizes and read a configuration file during autoexec, the syntax would be: CED -Bn1,n2,n3,n4,n5,n6 -F<filename> For your general information, here is what is stored in each of the buffers, and what happens when it fills: 1. DOS Command stack: all non-ignored commands of 3 or more characters entered at the DOS prompt. The command is stored before alias and pcall processing. Each stored command requires one byte more than the length of the command. When the buffer fills, the oldest command is deleted. 2. Application program command stack: same as above, except commands entered at participating program prompts are stored here. 3. Synonym list: the full list of synonyms (both DOS and user synonyms) plus their meanings. Each entry requires the combined length of the synonym and its associated command plus three bytes. When the synonym list fills, no new synonyms will be accepted unless a CLEAR is performed first. 4. Pcall command list: the list of all pcall commands plus the most recent parameter list for each. Each entry requires the combined length of the command and its parameters (including leading separators) plus two bytes. If the buffer is full when a "CED PCALL" command is entered, the new pcall command will not be accepted. If the buffer is full when a pcallable command is entered, its parameters will not be remembered. 5. Ignore command list: the list of all IGNORE commands. Each entry requires the command length plus one byte. If the buffer is full when a new "CED IGNORE" command is entered, the new command will be rejected. 15 === ced 1.0 User's Guide === 6. User command list: the list of all user-installed commands. Requires the command length plus six bytes of storage for each. New commands will be rejected if the buffer is full. Ced itself uses ten bytes of this buffer. Status display -------------- You may obtain a partial display of ced status any time CED is active (i.e., at the DOS prompt or in a compatible program awaiting input). Do this by hitting ^T (Ctrl-T). Ced will first display all synonyms (preceded by [S] for SYN or [U] for USERSYN), then a list of all buffers. For each buffer ced will show the total bytes allocated and the number of bytes free. When the display is complete, ced will redisplay any partial input that you typed before ^T, and you may continue data entry. If ^T is not convenient, you can change the status request character by using the ced command CED STATCH <character> as in "CED STATCH ^A" or "CED STATCH %". See the section on command chaining for more information on using control characters in this command. Multiple definitions -------------------- It is possible to duplicate a definition within one of the ced lists (SYN, USERSYN, PCALL, IGNORE). For example, you may create more than one synonym for "d". In the event of multiple definitions, ced will always use the newest. Suppose, for example, that you have "d" defined as a SYN for "dir". If you subsequently issue the command "CED SYN d debug", you will have two synonyms for "d". When you enter "d", ced will use the latest definition: "debug". If you then issue a "CLEAR SYN d", ced will again use the latest definition and clear the "debug" synonym, at which point the "dir" definition again becomes effective. Multiple definitions have no real meaning for PCALL and IGNORE, but they are supported nonetheless. 16 === ced 1.0 User's Guide === User Commands ------------- This section describes how to add new resident commands to DOS using ced. It is an advanced topic, and is intended for programmers only; you don't need to read this section to use ced. Ced provides a means to enqueue new DOS commands, that is, to add internal commands to DOS. Once enqueued, ced will call a routine that you specify whenever the user types the new command (at the DOS prompt, or in a "participating" program). Access to ced service is provided via a bogus DOS function, 0FFH. This function behaves as a normal DOS function; that is, you must set up the registers as needed by the call, place a 0FFH in register AH, and execute an INT 21H. The two subfunctions are described below; the subfunction code is placed in register AL. SUBFUNCTION 0: ENQUEUE This subfunction allows you to enqueue a new command. Input register use is as follows: AH = 0FFH (ced service) AL = 0 (ENQUEUE) BL = MODE This is a bit flag which tells ced when to call your routine. You have the option of being called if your command is typed at the DOS prompt, at a user program prompt, or both. Bit 0, if set, specifies that you are to be called at the DOS prompt; Bit 1, if set, specifies that you are to be called at a user program prompt. DS:SI = command name This is a dword pointer to your command (i.e., you are to be called when the user types this string). The command must be from one to eight characters, terminated by a carriage return. Ced is not case sensitive. ES:DI = command processor entry point This is a dword pointer to the routine which is to be executed when the new command is entered. 17 === ced 1.0 User's Guide === SUBFUNCTION 1: DEQUEUE This subfunction allows you to dequeue a user command; after a command has been dequeued, ced will no longer call you if the user types your command. Input register use is: AH = 0FFH (ced service) AL = 1 (DEQUEUE) DS:SI = command name A dword pointer to the name of the command to be dequeued (i.e., the same DS:SI as was used to enqueue the command). RETURN REGISTERS On return from ced service (DOS function 0FFH), all registers are preserved except AX. The carry flag, if set, indicates that an error occurred; AX has the error code, which will be one of: 1: Invalid function. At present, only subfunctions 0 and 1 are supported. Subfunction 2 is reserved. 2: Command not found (DEQUEUE only). 8: Insufficient memory (ENQUEUE only). 13: Invalid data. (ENQUEUE only; bad MODE flag, or invalid command length). NOTE: In current versions of DOS, AH returns 0FFH if function 0FFH is requested and ced is not installed. You may use the reserved subfunction (2), at your own risk, to test for ced installation. If AH returns any value other than 0FFH, ced is probably installed. COMMAND PROCESSOR Your command processor is entered via a far call from ced. Entry registers are as follows: BL = MODE This is the same bit flag as is used in the ENQUEUE subfunction. You may use it to test "where you are". CL = MAXLEN This is the maximum allowed length of the user input string (i.e., the value of byte 0 of the DOS function 0AH input buffer) less one. 18 === ced 1.0 User's Guide === DS:DX = Command tail pointer This is a dword pointer to the command tail of the user's input. For example, if your command is "hello" and the user types "hello sam", DS:DX will point to the space after "hello". DS:DI = Command pointer This is a dword pointer to the first byte of the actual user input. Note that DS:DI and DS:DX point to buffer space within ced, not to the actual DOS function 0AH input buffer. There are no length attribute bytes preceding the buffer; DS:SI points to the first byte of the buffer, not the third. Ced will copy the final buffer, after all processing, to the actual input buffer. You may manipulate the buffer to your heart's content. It is 255 characters long, but ced will truncate the string if necessary (if the final command is longer than the maximum allowed by the function 0AH request). In particular, note two things about the ced buffer: 1. The string MUST be terminated by a carriage return ASCII 13). 2. If you null out the buffer (by putting a carriage return in relative byte 0) ced will return a null string to DOS or the user program. This is probably what you will want to do. There are few restrictions on what you can do within your service routine. You may request other DOS service (but you may NOT request more buffered input via function 0AH!!), and you need not preserve any registers except SS:SP. The stack in effect on entry will have about 200 bytes free; switch to a larger internal stack if necessary. Return to ced via a far RET. Appendix D contains a sample MASM program to enqueue a trivial command. Problem reporting ----------------- If you find any problems with ced, please report them to me, preferably at CompuServe ID 76703,2002. Before reporting problems, however, please take the following steps: 1. Reread the documentation! 19 === ced 1.0 User's Guide === 2. Install ced in a "clean" environment, i.e., without any other resident utilities. Temporarily rename your AUTOEXEC.BAT and CONFIG.SYS files to other names; reboot, reinstall ced, and test. If it works correctly, there is a conflict with some other program. Isolate the conflict by reinstalling your other programs one by one and by varying the load order. If you locate the conflict, let me know about it. I cannot guarantee that the conflict will be resolved, but I will make an attempt when time permits. It would not be necessary to rename CONFIG.SYS if it only contains FILE, BUFFER, COUNTRY, FCBS, and ANSI.SYS statements. If the problem persists, please report the problem as accurately and completely as possible. Include the ced version number (obtained by the command CED VER), and a listing of your CONFIG.SYS and AUTOEXEC.BAT files if you think that might have some bearing. Copyright and Disclaimer ------------------------ Ced is hereby placed in the public domain. Both ced and this documentation are, however, copyrighted by the author. Ced is intended for your private, noncommercial use only. You may make copies of the ced program and documentation files for your own use, and you may copy the files for others. You may not, however, charge for such copies, or in any other way sell the program or otherwise attempt to make money from it or any modified version of it. However, recognized user's groups are hereby authorized to charge an amount not more than $6.00 for materials, postage, etc. I do not warrant that the documentation is accurate, or that the program operates as designed. I will not be liable for any damages of any kind sustained through the use of the program. By using the program, you agree to this. IBM is a registered trademark of International Business Machines Corporation. MS-DOS is a trademark of Microsoft Corporation. Both ced and this document are: Copyright (c) 1985 by Christopher J. Dunford 10057-2 Windstream Drive Columbia, Maryland 21044 CompuServe ID 76703,2002 20 === ced 1.0 User's Guide === Appendix A: Command summary --------------------------- The following is a complete summary of all ced commands. These commands may be included in a ced configuration file (with the exception of -F and -B), or they may be typed in directly by prefixing them with "CED ". -Bn1,n2,n3,n4,n5,n6 Sets the sizes of the six internal buffers. Valid ONLY as first command when installing ced after boot or reboot. -F<Filename> Loads a ced configuration file. Not a valid command within a config file. SYN <synonym> <command> Defines a synonym. The first word is the synonym, all remaining words are substituted for the synonym. USERSYN <synonym> <command> Defines a user synonym. Identical to SYN, except that the synonym is available within user programs rather than at the DOS prompt. PCALL <command> Defines a command subject to pcall processing. IGNORE <command> Defines a command to be ignored--ced will not perform any processing on this command at all. CHAINCH <char> Defines the command chaining character, which is the character used to separate commands in a multi-command synonym. IGNORECH <char> Defines the keyboard-ignore character; when this character is typed as the first character of keyboard input, ced will perform no further processing on it. STATCH <char> Defines the status request character. When you type this character while ced is active, ced will display its status. CLEAR <function> [[FROM] <name>] Clears all or part of a list of ced objects. <function> is one of SYN, USERSYN, PCALL, or IGNORE. Without arguments, clears all of the specified list. With a <name>, clears that item only. With a FROM <name>, 21 === ced 1.0 User's Guide === clears that item and all subsequent items. VER Display ced version number and copyright notice. Commands may be abbreviated as follows: USERSYN USYN PCALL PC IGNORE IG CHAINCH CC IGNORECH IC STATCH SC CLEAR CL Note, however, that the arguments to CLEAR may NOT be abbreviated; CLEAR USYN or CLEAR PC are not valid. 22 === ced 1.0 User's Guide === Appendix B: Order of Processing ------------------------------- Ced performs its basic processing in the following order: 1. Obtain input. If there is a chained command pending, obtain input from the chain; otherwise from keyboard. 2. Check for "ignore". If command is an "ignore" command or if the first character of input is the ignore character, suspend all further processing. 3. Stack the command (if longer than two characters) in the appropriate command stack. 4. Perform pcall (parameter recall) processing and store the result for pcall processing next time the same command is entered. 5. Perform synonym processing and parameter substitution. If the synonym contains chained commands, set up for chaining of subsequent input requests. 6. Examine the resulting command and see if it's a user-installed command or a CED command. If so, call CED or user command processor. 23 === ced 1.0 User's Guide === Appendix C: Limitations ----------------------- There is a limit of 255 characters on any input line from a ced configuration file. DOS will limit you to 127 characters at the DOS prompt. For PCALL, SYN, USERSYN, and IGNORE to be effective, their commands must begin in the first column of input and must be separated from any parameters by one of the following characters: ; , < > | = + [ ] / <Tab> <Space> Thus, if you have "cd" defined for pcall processing, "cd\" will not work correctly. However, "cd \" will be OK. Similarly, if you have a synonym "d" for "debug", the command "c:\util\d" will not work, nor will " d" (note leading space). Programs which allow you to execute DOS commands or other programs as subtasks generally do not use DOS function 0AH to input the name of the subtask or command; thus, ced is not active, and synonyms are usually not effective. 24 === ced 1.0 User's Guide === Appendix D: User Command Demo ----------------------------- Comment * userdemo.com - demo of ced user command enqueuing Assembly: (M)ASM userdemo; LINK userdemo; (ignore NO STACK message) EXE2BIN userdemo userdemo.com Use: Just type 'userdemo'. You now have a new DOS command, "hello" Author: CJDunford 05/28/85 * CED equ 0FFH ; Special "DOS" fn for CED service ENQUEUE equ 0 ; Subfunction: enqueue DEQUEUE equ 1 ; Subfunction: dequeue DOS equ 1 ; Cmd to be active at DOS prompt USER equ 2 ; Cmd to be active at user prompt CR equ 13 LF equ 10 code segment assume cs:code,ds:code org 100H main proc far jmp Install ; Go to installation ; ----------------------------------------------------- ; This is the command processor. It will be called ; whenever the user types "hello" at the DOS prompt. ; The routine simply prints the string "Hi there, ace". ; ; On entry: ; BL: mode flag ; 1 = at DOS prompt ; 2 = at user program prompt ; CL: max length of input ; DS:SI => user command ; DS:DX => user command tail ; ; Remember to null out the user string so that ; it is not passed on to DOS, then exit via a far 25 === ced 1.0 User's Guide === ; return to ced. Not necessary to preserve any ; registers. ; ------------------------------------------------------ Hello proc far ; Must be a far procedure mov byte ptr [si],CR ; Null out the user's input mov ax,cs ; Set up local addressing mov ds,ax mov dx,offset HiThere$ ; Display our message mov ah,9 int 21H ret ; No need to restore any regs Hello endp HiThere$ db 'Hi there, ace',CR,LF,'$' ; Message to be displayed ; ----------------------------------------------- ; This is the installation routine. It sets up ; the regs for a call to the ced command enqueing ; service, enqueues the command, and terminates, ; leaving the command service routine resident ; ------------------------------------------------ Install: mov ah,CED ; CED service request mov al,ENQUEUE ; Enqueue a new command mov bl,DOS ; To be active at DOS prompt mov si,offset Hello$ ; DS:SI => command ("Hello") mov di,offset Hello ; ES:DI => service routine int 21H ; Enqueue new command jnc OK ; No carry, no error mov dx,offset Error$ ; Only 1 error possible here mov ah,9 ; Print string int 21H int 20H ; Return to DOS OK: mov dx,offset Install ; OK: terminate/resident int 27H main endp Hello$ db 'hello',CR ; New command Error$ db 'ced user command list full',CR,LF,'$' code ends end main