如果Tcl找不到命令,[它執行unknown
](以原始命令作爲參數),並使用該命令的結果作爲缺少命令的結果。
如果TCL在交互模式(tcl_interactive
爲1,則該命令是在0級執行,沒有當前的腳本執行),它會嘗試一些其他步驟找到的東西,可能會執行運行:
if {([info level] == 1) && ([info script] eq "") && [info exists tcl_interactive] && $tcl_interactive} {
if {![info exists auto_noexec]} {
set new [auto_execok $name]
if {$new ne ""} {
set redir ""
if {[namespace which -command console] eq ""} {
set redir ">&@stdout <@stdin"
}
uplevel 1 [list ::catch [concat exec $redir $new [lrange $args 1 end]] ::tcl::UnknownResult ::tcl::UnknownOptions]
dict incr ::tcl::UnknownOptions -level
return -options $::tcl::UnknownOptions $::tcl::UnknownResult
}
}
if {$name eq "!!"} {
set newcmd [history event]
} elseif {[regexp {^!(.+)$} $name -> event]} {
set newcmd [history event $event]
} elseif {[regexp {^\^([^^]*)\^([^^]*)\^?$} $name -> old new]} {
set newcmd [history event -1]
catch {regsub -all -- $old $newcmd $new newcmd}
}
if {[info exists newcmd]} {
tclLog $newcmd
history change $newcmd 0
uplevel 1 [list ::catch $newcmd ::tcl::UnknownResult ::tcl::UnknownOptions]
dict incr ::tcl::UnknownOptions -level
return -options $::tcl::UnknownOptions $::tcl::UnknownResult
}
set ret [catch {set candidates [info commands $name*]} msg]
if {$name eq "::"} {
set name ""
}
if {$ret != 0} {
dict append opts -errorinfo "\n (expanding command prefix \"$name\" in unknown)"
return -options $opts $msg
}
# Filter out bogus matches when $name contained
# a glob-special char [Bug 946952]
if {$name eq ""} {
# Handle empty $name separately due to strangeness
# in [string first] (See RFE 1243354)
set cmds $candidates
} else {
set cmds [list]
foreach x $candidates {
if {[string first $name $x] == 0} {
lappend cmds $x
}
}
}
if {[llength $cmds] == 1} {
uplevel 1 [list ::catch [lreplace $args 0 0 [lindex $cmds 0]] ::tcl::UnknownResult ::tcl::UnknownOptions]
dict incr ::tcl::UnknownOptions -level
return -options $::tcl::UnknownOptions $::tcl::UnknownResult
}
if {[llength $cmds]} {
return -code error "ambiguous command name \"$name\": [lsort $cmds]"
}
}
首先檢查是否有任何可以執行的名稱的命令。
然後它檢查是否有任何歷史替換。 最後,它會檢查此命令是否有唯一的前綴。
啊,'unknown'。 –