\section{Mode Control Flags} \label{Mode Control Flags} TECO has flags which control various aspects of its operation. You can find a flag's current setting by executing its command name without an argument; the current setting of the flag is returned as a value. A flag may be set to a specific value by executing its command name preceded by a numerical argument; the flag is set to the value of the argument. The following table describes the commands that set and clear flags; {\tt } represents any of the flags listed below. \begin{table}[h] \caption{\bf{Flag Manipulation Commands}} \label{Flag Manipulation Commands} \end{table} \nopagebreak \begin{list}{}{\labelsep 20pt} \item[{\tt }] Return value of flag. \item[{\tt n}] Set value of flag to {\tt n}. \item[{\tt m,n}] In the flag, turn off those bits specified by {\tt m} and turn on those bits specified by {\tt n}. \item[{\tt 0,n}] Turn on the bits in the flag specified by {\tt n}. \item[{\tt m,0}] Turn off the bits in the flag specified by {\tt m}. \end{list} The flags have the following functions: \begin{list}{ Mode Control Flags}{\labelsep 20pt} \item[{\em COMMAND}] {\em FUNCTION} \item[{\tt ED}] The edit level flag, a bit-encoded word that controls TECO's behavior in various respects. Any combination of the individual bits may be set as the user sees fit. The bits have the following functions: \begin{list}{}{\labelsep 10pt} \item[{\tt ED\&1}] Allow caret (\caret ) in search strings. If this bit is clear, a caret (\caret ) in a search string modifies the immediately following character to become a control character. When this bit is set, a caret in a search string is simply the literal character caret. If you are editing a file that contains many caret characters (e.g., a RUNOFF file with case control), you will want to set this bit. (For control of upper/lower case matching in search strings, see the \caret{\tt X} flag.) \item[{\tt ED\&2}] Allow all {\tt Y} and \_ commands. If this bit is set, the {\tt Y} (Yank) command and \_ (underscore or backarrow) command work unconditionally as described earlier in the manual. If clear, the behavior of the {\tt Y} and \_ commands are modified as follows: If an output file is open and text exists in the text buffer, the {\tt Y} or \_ command will produce an error message and the command will be aborted leaving the text buffer unchanged. Note that if no output file is open the {\tt Y} and \_ commands act normally. Furthermore, if the text buffer is empty the {\tt Y} command can be used to bring in a page of text whether or not an output file is open ({\tt HKY} will always work). The \_ command will succeed in bringing one page of text into an empty text buffer but will fail to bring in successive pages if an output file is open. \item[{\tt ED\&4}] When this bit is clear, TECO will try to expand memory as much as it can in order to try to fit entire pages into memory when requested to do so. If this bit is set, arbitrary memory expansion will not occur. In that case, TECO will expand memory only on the {\tt A} command and not on the {\tt Y}, {\tt P}, or {\tt N} commands. This bit is always set in TECO-10 and has no significance in TECO-8 or in TECO-11 on RT-11. \item[{\tt ED\&8}] Reserved for future use by TECO-8. \ifnotintecoeight \item[{\tt ED\&16}] Allow failing searches to preserve dot. If this bit is set, then whenever a search fails, the original location of the text buffer pointer will be preserved. If this bit is clear, then failing searches (other than bounded searches) leave the text buffer pointer at pointer position 0 after they fail. {\em [not in TECO-8]} \fi % \iftecoeleventrue \iftecoelevenonly \item[{\tt ED\&32}] Enable immediate ESCape-sequence commands. If this bit is set, TECO will recognize an ESCape-sequence key pressed immediately after the prompting asterisk as an immediate command. See section \ref{Immediate ESCAPE-Sequence Commands} for a description of immediate ESCape-sequence commands. If this bit is clear (the default case), TECO will treat an ESCape coming in immediately after the asterisk prompt as a {\tt } That is, TECO will hear a discrete {\tt } character: an ESCape sequence will therefore be treated not as a unified command, but as a sequence of characters. {\em [TECO-11 only]} \item[{\tt ED\&64}] Only move dot by one on multiple occurrence searches. If this bit is clear, TECO treats {\tt nStext}\escape exactly as {\tt n<1Stext} \escape. That is, skip over the whole matched search string when proceeding to the $n$th search match. For example, if the text buffer contains only {\tt A}'s, the command {\tt 5SAA}\escape will complete with {\em dot} equal to ten ({\em 10}). If this bit is set, TECO increments {\em dot} by one each search match. In the example above, {\em dot} would become five ({\em 5}). {\em[TECO-11 only]} \item[{\tt ED\&128}] Automatic refresh inhibit. If scroll mode is enabled (that is, if {\tt 7:W} is non-zero), TECO normally refreshes the text buffer display just before printing its {\tt *} prompt. Setting the 128 bit in {\tt ED} inhibits this automatic refresh. (Inhibiting the automatic refresh may be useful when running over a slow terminal line; see also the \caret {\tt W} immediate command.) {\em [TECO-11 only]} \item[{\tt ED\&128}] Automatic refresh inhibit. If scroll mode is enabled (that is, if {\tt 7:W} is non-zero), TECO normally refreshes the text buffer display just before printing its {\tt *} prompt. Setting the {\em 128} bit in {\tt ED} inhibits this automatic refresh. (Inhibiting the automatic refresh may be useful when running over a slow terminal line; see also the \caret {\tt W} immediate command.) {\em [TECO-11 only]} \fi The initial value of {tt ED\&1} is system dependent (See appendices). The initial value of the other bits in the {\tt ED} flag is 0. \end{list} % \ifrstsetrue \item[{\tt EE}] This flag is initially zero, and (unless the 8192 {\tt ET} bit is set) TECO recognizes only the ESCape as its {\tt } character from the console. If it is desired to use another character as an ESCape surrogate (as when working from a terminal lacking an ESCape key), the ASCII value of that other character may be set in the {\tt EE} flag. Note that when an ESCape surrogate is set, the designated character (when typed at the console) is received by TECO as an ESCape -- that character is no longer directly available at the keyboard. When an ESCape surrogate is active, an ESCape received by TECO echos as accent grave; when none is active, an ESCape received by TECO echos as dollar sign. This feature is provided for the benefit of newer terminals which lack an ESCape key. ({\tt 8192ET} and {\tt 96EE} both set \escape as ESCape surrogate. {\tt EE}, however, can be used to designate a character other than accent grave.) {\em [RSTS/E only]} % \fi \item[{\tt EH}] The help level flag, which controls the printing of error messages and failed commands. (See also the {\tt /} command.) \begin{list}{}{\labelsep 20pt} \item[{\tt EH\&3}] The low two bits of {\tt EH} (value range 0 through 3) control the printing of TECO error messages as follows (assuming the low two bits have value {\tt m}): If {\tt m} is equal to 1, error messages are output in abbreviated form ({\tt ?XXX}). If m is equal to 2, error messages are output in normal form ({\tt ?XXX Message}). If {\tt m} is equal to 3, error messages are output in long or {\em War and Peace} form, that is, a paragraph of informative material is typed following the normal form of the error message. In TECO-11, {\tt m}=3 is implemented only on VAX/VMS. (See section \ref{VMS Help} for a description of HELP facilities available on VAX/VMS.) In other TECO-11's, case {\tt m}=3 is equivalent to {\tt m}=2. \item[{\tt EH\&4}] If this bit of {\tt EH} is set, the failing command is also output up to and including the failing character in the command followed by a question mark. (Just like TECO's response to the typing of a question mark immediately after an error.) This bit is not supported by TECO-10. \end{list} The initial value of the EH flag is 0 which is equivalent to a value of 2. \iftecotenonly \item[{\tt EO}] Setting the value of the {\tt EO} flag to {\tt n} allows features that were peculiar to that version of TECO to work. {\em [TECO-10 only]} \fi \ifnotintecoeight \item[{\tt ES}] The search verification flag, which controls the text typed out after searches. If {\tt n} is equal to 0, nothing is typed out after searches. If {\tt n} is -1, the current line is typed out when a successful search at top level is completed (i.e., a {\tt V} command is done automatically). If {\tt n} is between 1 and 31, the current line is typed out with a line feed immediately following the position of the pointer to identify its position. If {\tt n} is between 32 and 126, the current line is typed out with the ASCII character corresponding to the value of {\tt n} immediately following the position of the pointer to identify its position. If you want to see more than one line of type out, use the form {\em m*256+n}. The {\tt n} is the same as above. The {\tt m} is the number of lines of view. For example, {\tt 3*256+^^!} would give two lines on either side of the found line, and the found line with the character {\tt !} at the pointer's position. The {\tt ES} flag does not apply to searches executed inside iterations or macros; lines found inside iterations or macros are never typed out. {\em [Not in TECO-8]} \fi The initial value of ES is 0. \item[{\tt ET}] The {\tt ET} flag is a bit-encoded word controlling TECO's treatment of the console terminal. Any combination of the individual bits may be set. The bits provide the following functions, when set: \begin{list}{}{\labelsep 10pt} \item[{\tt ET\&1 }] Type out in image mode. Setting this bit inhibits all of TECO's type out conversions. All characters are output to the terminal exactly as they appear in the buffer or \caret{\tt A} command. For example, the changing of control characters into the {\tt caret/character} form, and the conversion of {\tt } to \escape (accent grave) or to {\tt \$} (dollar sign) are suppressed. This mode is useful for driving displays. It should be used with caution, especially if you are talking to TECO over a dial-up line. \item[{\tt ET\&2 }] Process {\tt }s and {\tt }s in ``scope'' mode. Scope mode processing uses the cursor control features of CRT type terminals to handle character deletion by actually erasing characters from the screen. \item[{\tt ET\&4 }] Read lower case. TECO normally converts all lower case alphabetics to upper case on input. Setting this bit causes lower case alphabetics to be input as lower case. TECO commands and file specifiers may be typed in either upper or lower case. For the purpose of searches, however, upper and lower case may be treated as different characters. (See \caret{\tt X} flag). \item[{\tt ET\&8 }] Read without echo for \caret{\tt T} commands. This allows data to be read by the \caret{\tt T} command without having the characters echo at the terminal. Normal command input to TECO will echo. \item[{\tt ET\&16 }] Cancel {\tt } on type out. Setting this bit will cancel any outstanding {\tt } when the next type out occurs. After TECO has canceled the {\tt }, it will automatically clear the bit. \item[{\tt ET\&32 }] Read with no wait. This enables the \caret{\tt T} command to test if a character is available at the user terminal. If a character has been typed, \caret{\tt T} returns the value of the character as always. If no character has been typed, \caret{\tt T} immediately returns a value of -1 and execution continues without waiting for a character. \item[{\tt ET\&64 }] Detach flag (See appendices). \item[{\tt ET\&128 }] {\em Abort-on-error} bit. Initially set, when TECO starts up; cleared each time TECO issues its asterisk prompt. When this bit is set: 1) all informational messages are supressed, 2) any {\tt } causes the immediate termination of TECO, and 3) any error causes the termination of TECO after the error message is printed. \item[{\tt ET\&256 }] If this bit is set, all lines output to the terminal are truncated to the terminal's width if needed. (RSTS/E, RSX-11, and VAX/VMS only. On VAX/VMS, this bit reflects and can change the state of the terminal characteristic WRAP/NOWRAP; TECO restores the terminal characteristic to its original state upon exit.) \item[{\tt ET\&512 }] If this bit is set, the scope {\em WATCH} feature of TECO is present and your terminal is a scope type terminal. This bit is a read-only bit; its state cannot be altered. (See Section \ref{Scope Commands}.) \item[{\tt ET\&1024 }] If this bit is set, the refresh scope {\em WATCH} feature of TECO is present and a refresh scope is available. This bit is a read-only bit; its state cannot be altered. (See Section \ref{Scope Commands}.) \item[{\tt ET\&4096 }] This bit reflects and can change the state of the terminal characteristic (maintained by the operating system) recording whether the terminal is capable of handling eight-bit character codes. Upon entry to TECO, this bit reflects the characteristic as recorded with the operating system at that time. If you change this bit, the operating system is directed to change its recording of the characteristic to match. Because the data manipulated (edited) by TECO can consist of all 256 possible byte codes, the way data characters are displayed (typed out) at the console varies depending upon the setting of the 4096 {\tt ET} bit. If the bit is clear (meaning that TECO understands your terminal to be 7-bit), valid DEC multi-national codes are typed out as {\tt } (where {\tt xy} is the corresponding LK201 keyboard compose sequence). If the bit is set (meaning that TECO understands your terminal to be 8-bit), valid DEC multi-national codes are typed out as themselves. In either case, unprintable or illegal codes in the 128 to 255 range are typed out as {\tt [ab]} (where {\tt ab} is the corresponding hexadecimal code). The scope watch feature (screen buffer display, controlled by the W commands) always uses the {\tt } and {\tt [ab]} notations. \iftecoelevenonly \item[{\tt ET\&8192 }] Accent grave as ESCape surrogate. If this bit is set, TECO recognizes the \escape (accent grave) character as an ESCAPE surrogate. That is, an \escape character typed at the console will be recognized as a command {\tt } character, and passed to TECO as an ESCape. (This interpretation applies only to {\tt }s typed at the console; ESCape characters must still be used in macros and indirect files.) When an ESCape surrogate is set, an ESCape received by TECO echos as accent grave; when none is set, an ESCape received by TECO echos as dollar sign. This feature is provided for the benefit of certain newer terminals which lack an ESCape key. (See also the Introduction, and the EE flag.) {\em [TECO-11 only]} \fi \item[{\tt ET\&32768 }] If this bit is set and a {\tt } is typed, the bit is turned off, but execution of the current command string is allowed to continue. This allows a TECO macro to detect typed {\tt }s. In TECO-8, this bit is the 2048's bit rather than the 32768's bit. \end{list} The initial setting of {\tt ET} is operating system dependent (See appendices). In addition, some of the {\tt ET} bits are automatically turned off by certain error conditions. \item[{\tt EU}] The upper/lower case flag. If {\tt n} is -1, no case flagging of any type is performed on type out, lower case characters are output as lower case characters. If {\tt n} is 0, lower case characters are flagged by outputting a ' (quote) before the lower case character and the lower case character is output in upper case; upper case characters are unchanged. If {\tt n} is +1, upper case characters are flagged by outputting a ' (quote) before each one and then the upper case character is output; lower case characters are output as their upper case equivalents. The initial value of the {\tt EU} flag is -1 if TECO can tell from the operating system that the user's terminal supports display of lower case characters; otherwise te initial value is 0. Consult the appendices for more details. \iftecoelevenonly \item[{\tt EV}] The edit verify flag is decoded just like the {\tt ES} flag. Just before TECO prints its prompting {\tt *}, the {\tt EV} flag is checked. If it is non-zero the lines to be viewed are printed on the terminal. The initial value of the {\tt EV} flag is 0. {\em [TECO-11 only]} \fi \ifnotintecoeight \item[\caret {\tt X}] The search mode flag. {\em [Not in TECO-8]} If \caret{\tt X} is 0, the text argument in a search command will match text in the text buffer independent of case in either the search argument or the text buffer. The lower case alphabetics match the upper case alphabetics, and \escape , {\tt \{},{\tt \}}, \squiggle , match {\tt @}, {\tt [}, {\tt \bs }, {\tt ]}, \caret respectively. In addition, DEC multinational characters having diacritical marks are regarded as matching the corresponding characters without diacritical marks. If \caret{\tt X} is -1, the search will succeed only if the text argument is identical to text in the text buffer. (This means that lower case does NOT match upper case, nor does a character having a diacritical mark match one without). The initial value of the \caret{\tt X} flag is 0. (For control of caret or uparrow treatment in search strings, see the {\tt ED\&1} bit above.) \fi \end{list}