'\" '\" Copyright (c) 1993 The Regents of the University of California. '\" Copyright (c) 1994-1996 Sun Microsystems, Inc. '\" '\" See the file "license.terms" for information on usage and redistribution '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. '\" '\" SCCS: @(#) history.n 1.6 96/03/25 20:16:25 '\" '\" The definitions below are for supplemental macros used in Tcl/Tk '\" manual entries. '\" '\" .AP type name in/out ?indent? '\" Start paragraph describing an argument to a library procedure. '\" type is type of argument (int, etc.), in/out is either "in", "out", '\" or "in/out" to describe whether procedure reads or modifies arg, '\" and indent is equivalent to second arg of .IP (shouldn't ever be '\" needed; use .AS below instead) '\" '\" .AS ?type? ?name? '\" Give maximum sizes of arguments for setting tab stops. Type and '\" name are examples of largest possible arguments that will be passed '\" to .AP later. If args are omitted, default tab stops are used. '\" '\" .BS '\" Start box enclosure. From here until next .BE, everything will be '\" enclosed in one large box. '\" '\" .BE '\" End of box enclosure. '\" '\" .CS '\" Begin code excerpt. '\" '\" .CE '\" End code excerpt. '\" '\" .VS ?br? '\" Begin vertical sidebar, for use in marking newly-changed parts '\" of man pages. If an argument is present, then a line break is '\" forced before starting the sidebar. '\" '\" .VE '\" End of vertical sidebar. '\" '\" .DS '\" Begin an indented unfilled display. '\" '\" .DE '\" End of indented unfilled display. '\" '\" .SO '\" Start of list of standard options for a Tk widget. The '\" options follow on successive lines, in four columns separated '\" by tabs. '\" '\" .SE '\" End of list of standard options for a Tk widget. '\" '\" .OP cmdName dbName dbClass '\" Start of description of a specific option. cmdName gives the '\" option's name as specified in the class command, dbName gives '\" the option's name in the option database, and dbClass gives '\" the option's class in the option database. '\" '\" .UL arg1 arg2 '\" Print arg1 underlined, then print arg2 normally. '\" '\" SCCS: @(#) man.macros 1.8 96/02/15 20:02:24 '\" '\" # Set up traps and other miscellaneous stuff for Tcl/Tk man pages. .if t .wh -1.3i ^B .nr ^l \n(.l .ad b '\" # Start an argument description .de AP .ie !"\\$4"" .TP \\$4 .el \{\ . ie !"\\$2"" .TP \\n()Cu . el .TP 15 .\} .ie !"\\$3"" \{\ .ta \\n()Au \\n()Bu \&\\$1 \\fI\\$2\\fP (\\$3) .\".b .\} .el \{\ .br .ie !"\\$2"" \{\ \&\\$1 \\fI\\$2\\fP .\} .el \{\ \&\\fI\\$1\\fP .\} .\} .. '\" # define tabbing values for .AP .de AS .nr )A 10n .if !"\\$1"" .nr )A \\w'\\$1'u+3n .nr )B \\n()Au+15n .\" .if !"\\$2"" .nr )B \\w'\\$2'u+\\n()Au+3n .nr )C \\n()Bu+\\w'(in/out)'u+2n .. .AS Tcl_Interp Tcl_CreateInterp in/out '\" # BS - start boxed text '\" # ^y = starting y location '\" # ^b = 1 .de BS .br .mk ^y .nr ^b 1u .if n .nf .if n .ti 0 .if n \l'\\n(.lu\(ul' .if n .fi .. '\" # BE - end boxed text (draw box now) .de BE .nf .ti 0 .mk ^t .ie n \l'\\n(^lu\(ul' .el \{\ .\" Draw four-sided box normally, but don't draw top of .\" box if the box started on an earlier page. .ie !\\n(^b-1 \{\ \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .el \}\ \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\l'|0u-1.5n\(ul' .\} .\} .fi .br .nr ^b 0 .. '\" # VS - start vertical sidebar '\" # ^Y = starting y location '\" # ^v = 1 (for troff; for nroff this doesn't matter) .de VS .if !"\\$1"" .br .mk ^Y .ie n 'mc \s12\(br\s0 .el .nr ^v 1u .. '\" # VE - end of vertical sidebar .de VE .ie n 'mc .el \{\ .ev 2 .nf .ti 0 .mk ^t \h'|\\n(^lu+3n'\L'|\\n(^Yu-1v\(bv'\v'\\n(^tu+1v-\\n(^Yu'\h'-|\\n(^lu+3n' .sp -1 .fi .ev .\} .nr ^v 0 .. '\" # Special macro to handle page bottom: finish off current '\" # box/sidebar if in box/sidebar mode, then invoked standard '\" # page bottom macro. .de ^B .ev 2 'ti 0 'nf .mk ^t .if \\n(^b \{\ .\" Draw three-sided box if this is the box's first page, .\" draw two sides but no top otherwise. .ie !\\n(^b-1 \h'-1.5n'\L'|\\n(^yu-1v'\l'\\n(^lu+3n\(ul'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .el \h'-1.5n'\L'|\\n(^yu-1v'\h'\\n(^lu+3n'\L'\\n(^tu+1v-\\n(^yu'\h'|0u'\c .\} .if \\n(^v \{\ .nr ^x \\n(^tu+1v-\\n(^Yu \kx\h'-\\nxu'\h'|\\n(^lu+3n'\ky\L'-\\n(^xu'\v'\\n(^xu'\h'|0u'\c .\} .bp 'fi .ev .if \\n(^b \{\ .mk ^y .nr ^b 2 .\} .if \\n(^v \{\ .mk ^Y .\} .. '\" # DS - begin display .de DS .RS .nf .sp .. '\" # DE - end display .de DE .fi .RE .sp .. '\" # SO - start of list of standard options .de SO .SH "STANDARD OPTIONS" .LP .nf .ta 4c 8c 12c .ft B .. '\" # SE - end of list of standard options .de SE .fi .ft R .LP See the \\fBoptions\\fR manual entry for details on the standard options. .. '\" # OP - start of full description for a single option .de OP .LP .nf .ta 4c Command-Line Name: \\fB\\$1\\fR Database Name: \\fB\\$2\\fR Database Class: \\fB\\$3\\fR .fi .IP .. '\" # CS - begin code excerpt .de CS .RS .nf .ta .25i .5i .75i 1i .. '\" # CE - end code excerpt .de CE .fi .RE .. .de UL \\$1\l'|0\(ul'\\$2 .. .TH history n "" Tcl "Tcl Built-In Commands" .BS '\" Note: do not modify the .SH NAME line immediately below! .SH NAME history \- Manipulate the history list .SH SYNOPSIS \fBhistory \fR?\fIoption\fR? ?\fIarg arg ...\fR? .BE .SH DESCRIPTION .PP The \fBhistory\fR command performs one of several operations related to recently-executed commands recorded in a history list. Each of these recorded commands is referred to as an ``event''. When specifying an event to the \fBhistory\fR command, the following forms may be used: .IP [1] A number: if positive, it refers to the event with that number (all events are numbered starting at 1). If the number is negative, it selects an event relative to the current event (\fB\-1\fR refers to the previous event, \fB\-2\fR to the one before that, and so on). .IP [2] A string: selects the most recent event that matches the string. An event is considered to match the string either if the string is the same as the first characters of the event, or if the string matches the event in the sense of the \fBstring match\fR command. .PP The \fBhistory\fR command can take any of the following forms: .TP \fBhistory\fR Same as \fBhistory info\fR, described below. .TP \fBhistory add\fI command \fR?\fBexec\fR? Adds the \fIcommand\fR argument to the history list as a new event. If \fBexec\fR is specified (or abbreviated) then the command is also executed and its result is returned. If \fBexec\fR isn't specified then an empty string is returned as result. .TP \fBhistory change\fI newValue\fR ?\fIevent\fR? Replaces the value recorded for an event with \fInewValue\fR. \fIEvent\fR specifies the event to replace, and defaults to the \fIcurrent\fR event (not event \fB\-1\fR). This command is intended for use in commands that implement new forms of history substitution and wish to replace the current event (which invokes the substitution) with the command created through substitution. The return value is an empty string. .TP \fBhistory event\fR ?\fIevent\fR? Returns the value of the event given by \fIevent\fR. \fIEvent\fR defaults to \fB\-1\fR. This command causes history revision to occur: see below for details. .TP \fBhistory info \fR?\fIcount\fR? Returns a formatted string (intended for humans to read) giving the event number and contents for each of the events in the history list except the current event. If \fIcount\fR is specified then only the most recent \fIcount\fR events are returned. .TP \fBhistory keep \fIcount\fR This command may be used to change the size of the history list to \fIcount\fR events. Initially, 20 events are retained in the history list. This command returns an empty string. .TP \fBhistory nextid\fR Returns the number of the next event to be recorded in the history list. It is useful for things like printing the event number in command-line prompts. .TP \fBhistory redo \fR?\fIevent\fR? Re-executes the command indicated by \fIevent\fR and return its result. \fIEvent\fR defaults to \fB\-1\fR. This command results in history revision: see below for details. .TP \fBhistory substitute \fIold new \fR?\fIevent\fR? Retrieves the command given by \fIevent\fR (\fB\-1\fR by default), replace any occurrences of \fIold\fR by \fInew\fR in the command (only simple character equality is supported; no wild cards), execute the resulting command, and return the result of that execution. This command results in history revision: see below for details. .TP \fBhistory words \fIselector\fR ?\fIevent\fR? Retrieves from the command given by \fIevent\fR (\fB\-1\fR by default) the words given by \fIselector\fR, and return those words in a string separated by spaces. The \fBselector\fR argument has three forms. If it is a single number then it selects the word given by that number (\fB0\fR for the command name, \fB1\fR for its first argument, and so on). If it consists of two numbers separated by a dash, then it selects all the arguments between those two. Otherwise \fBselector\fR is treated as a pattern; all words matching that pattern (in the sense of \fBstring match\fR) are returned. In the numeric forms \fB$\fR may be used to select the last word of a command. For example, suppose the most recent command in the history list is .RS .CS \fBformat {%s is %d years old} Alice [expr $ageInMonths/12]\fR .CE Below are some history commands and the results they would produce: .DS .ta 4c .fi .UL Command " " .UL Result .nf \fBhistory words $ [expr $ageInMonths/12]\fR \fBhistory words 1-2 {%s is %d years old} Alice\fR \fBhistory words *a*o* {%s is %d years old} [expr $ageInMonths/12]\fR .DE \fBHistory words\fR results in history revision: see below for details. .RE .SH "HISTORY REVISION" .PP The history options \fBevent\fR, \fBredo\fR, \fBsubstitute\fR, and \fBwords\fR result in ``history revision''. When one of these options is invoked then the current event is modified to eliminate the history command and replace it with the result of the history command. For example, suppose that the most recent command in the history list is .CS \fBset a [expr $b+2]\fR .CE and suppose that the next command invoked is one of the ones on the left side of the table below. The command actually recorded in the history event will be the corresponding one on the right side of the table. .ne 1.5c .DS .ta 4c .fi .UL "Command Typed" " " .UL "Command Recorded" .nf \fBhistory redo set a [expr $b+2]\fR \fBhistory s a b set b [expr $b+2]\fR \fBset c [history w 2] set c [expr $b+2]\fR .DE History revision is needed because event specifiers like \fB\-1\fR are only valid at a particular time: once more events have been added to the history list a different event specifier would be needed. History revision occurs even when \fBhistory\fR is invoked indirectly from the current event (e.g. a user types a command that invokes a Tcl procedure that invokes \fBhistory\fR): the top-level command whose execution eventually resulted in a \fBhistory\fR command is replaced. If you wish to invoke commands like \fBhistory words\fR without history revision, you can use \fBhistory event\fR to save the current history event and then use \fBhistory change\fR to restore it later. .SH KEYWORDS event, history, record, revision