# history.tcl --
#
# Implementation of the history command.
#
# Copyright (c) 1997 Sun Microsystems, Inc.
#
# See the file "license.terms" for information on usage and redistribution
# of this file, and for a DISCLAIMER OF ALL WARRANTIES.
#
# The tcl::history array holds the history list and
# some additional bookkeeping variables.
#
# nextid the index used for the next history list item.
# keep the max size of the history list
# oldest the index of the oldest item in the history.
namespace eval tcl {
variable history
if {![info exists history]} {
array set history {
nextid 0
keep 20
oldest -20
}
}
}
# history --
#
# This is the main history command. See the man page for its interface.
# This does argument checking and calls helper procedures in the
# history namespace.
proc history {args} {
set len [llength $args]
if {$len == 0} {
return [tcl::HistInfo]
}
set key [lindex $args 0]
set options "add, change, clear, event, info, keep, nextid, or redo"
switch -glob -- $key {
a* { # history add
if {$len > 3} {
return -code error "wrong # args: should be \"history add event ?exec?\""
}
if {![string match $key* add]} {
return -code error "bad option \"$key\": must be $options"
}
if {$len == 3} {
set arg [lindex $args 2]
if {! ([string match e* $arg] && [string match $arg* exec])} {
return -code error "bad argument \"$arg\": should be \"exec\""
}
}
return [tcl::HistAdd [lindex $args 1] [lindex $args 2]]
}
ch* { # history change
if {($len > 3) || ($len < 2)} {
return -code error "wrong # args: should be \"history change newValue ?event?\""
}
if {![string match $key* change]} {
return -code error "bad option \"$key\": must be $options"
}
if {$len == 2} {
set event 0
} else {
set event [lindex $args 2]
}
return [tcl::HistChange [lindex $args 1] $event]
}
cl* { # history clear
if {($len > 1)} {
return -code error "wrong # args: should be \"history clear\""
}
if {![string match $key* clear]} {
return -code error "bad option \"$key\": must be $options"
}
return [tcl::HistClear]
}
e* { # history event
if {$len > 2} {
return -code error "wrong # args: should be \"history event ?event?\""
}
if {![string match $key* event]} {
return -code error "bad option \"$key\": must be $options"
}
if {$len == 1} {
set event -1
} else {
set event [lindex $args 1]
}
return [tcl::HistEvent $event]
}
i* { # history info
if {$len > 2} {
return -code error "wrong # args: should be \"history info ?count?\""
}
if {![string match $key* info]} {
return -code error "bad option \"$key\": must be $options"
}
return [tcl::HistInfo [lindex $args 1]]
}
k* { # history keep
if {$len > 2} {
return -code error "wrong # args: should be \"history keep ?count?\""
}
if {$len == 1} {
return [tcl::HistKeep]
} else {
set limit [lindex $args 1]
if {[catch {expr {~$limit}}] || ($limit < 0)} {
return -code error "illegal keep count \"$limit\""
}
return [tcl::HistKeep $limit]
}
}
n* { # history nextid
if {$len > 1} {
return -code error "wrong # args: should be \"history nextid\""
}
if {![string match $key* nextid]} {
return -code error "bad option \"$key\": must be $options"
}
return [expr {$tcl::history(nextid) + 1}]
}
r* { # history redo
if {$len > 2} {
return -code error "wrong # args: should be \"history redo ?event?\""
}
if {![string match $key* redo]} {
return -code error "bad option \"$key\": must be $options"
}
return [tcl::HistRedo [lindex $args 1]]
}
default {
return -code error "bad option \"$key\": must be $options"
}
}
}
# tcl::HistAdd --
#
# Add an item to the history, and optionally eval it at the global scope
#
# Parameters:
# command the command to add
# exec (optional) a substring of "exec" causes the
# command to be evaled.
# Results:
# If executing, then the results of the command are returned
#
# Side Effects:
# Adds to the history list
proc tcl::HistAdd {command {exec {}}} {
variable history
# Do not add empty commands to the history
if {[string trim $command] eq ""} {
return ""
}
set i [incr history(nextid)]
set history($i) $command
set j [incr history(oldest)]
unset -nocomplain history($j)
if {[string match e* $exec]} {
return [uplevel #0 $command]
} else {
return {}
}
}
# tcl::HistKeep --
#
# Set or query the limit on the length of the history list
#
# Parameters:
# limit (optional) the length of the history list
#
# Results:
# If no limit is specified, the current limit is returned
#
# Side Effects:
# Updates history(keep) if a limit is specified
proc tcl::HistKeep {{limit {}}} {
variable history
if {$limit eq ""} {
return $history(keep)
} else {
set oldold $history(oldest)
set history(oldest) [expr {$history(nextid) - $limit}]
for {} {$oldold <= $history(oldest)} {incr oldold} {
unset -nocomplain history($oldold)
}
set history(keep) $limit
}
}
# tcl::HistClear --
#
# Erase the history list
#
# Parameters:
# none
#
# Results:
# none
#
# Side Effects:
# Resets the history array, except for the keep limit
proc tcl::HistClear {} {
variable history
set keep $history(keep)
unset history
array set history [list \
nextid 0 \
keep $keep \
oldest -$keep \
]
}
# tcl::HistInfo --
#
# Return a pretty-printed version of the history list
#
# Parameters:
# num (optional) the length of the history list to return
#
# Results:
# A formatted history list
proc tcl::HistInfo {{num {}}} {
variable history
if {$num eq ""} {
set num [expr {$history(keep) + 1}]
}
set result {}
set newline ""
for {set i [expr {$history(nextid) - $num + 1}]} \
{$i <= $history(nextid)} {incr i} {
if {![info exists history($i)]} {
continue
}
set cmd [string map [list \n \n\t] [string trimright $history($i) \ \n]]
append result $newline[format "%6d %s" $i $cmd]
set newline \n
}
return $result
}
# tcl::HistRedo --
#
# Fetch the previous or specified event, execute it, and then
# replace the current history item with that event.
#
# Parameters:
# event (optional) index of history item to redo. Defaults to -1,
# which means the previous event.
#
# Results:
# Those of the command being redone.
#
# Side Effects:
# Replaces the current history list item with the one being redone.
proc tcl::HistRedo {{event -1}} {
variable history
if {$event eq ""} {
set event -1
}
set i [HistIndex $event]
if {$i == $history(nextid)} {
return -code error "cannot redo the current event"
}
set cmd $history($i)
HistChange $cmd 0
uplevel #0 $cmd
}
# tcl::HistIndex --
#
# Map from an event specifier to an index in the history list.
#
# Parameters:
# event index of history item to redo.
# If this is a positive number, it is used directly.
# If it is a negative number, then it counts back to a previous
# event, where -1 is the most recent event.
# A string can be matched, either by being the prefix of
# a command or by matching a command with string match.
#
# Results:
# The index into history, or an error if the index didn't match.
proc tcl::HistIndex {event} {
variable history
if {[catch {expr {~$event}}]} {
for {set i [expr {$history(nextid)-1}]} {[info exists history($i)]} \
{incr i -1} {
if {[string match $event* $history($i)]} {
return $i;
}
if {[string match $event $history($i)]} {
return $i;
}
}
return -code error "no event matches \"$event\""
} elseif {$event <= 0} {
set i [expr {$history(nextid) + $event}]
} else {
set i $event
}
if {$i <= $history(oldest)} {
return -code error "event \"$event\" is too far in the past"
}
if {$i > $history(nextid)} {
return -code error "event \"$event\" hasn't occured yet"
}
return $i
}
# tcl::HistEvent --
#
# Map from an event specifier to the value in the history list.
#
# Parameters:
# event index of history item to redo. See index for a
# description of possible event patterns.
#
# Results:
# The value from the history list.
proc tcl::HistEvent {event} {
variable history
set i [HistIndex $event]
if {[info exists history($i)]} {
return [string trimright $history($i) \ \n]
} else {
return "";
}
}
# tcl::HistChange --
#
# Replace a value in the history list.
#
# Parameters:
# cmd The new value to put into the history list.
# event (optional) index of history item to redo. See index for a
# description of possible event patterns. This defaults
# to 0, which specifies the current event.
#
# Side Effects:
# Changes the history list.
proc tcl::HistChange {cmd {event 0}} {
variable history
set i [HistIndex $event]
set history($i) $cmd
}
