Tcl 的初始化脚本文件"init.tcl"

Tcl运行环境在启动时会通过tclInit函数按如下顺序加载第一个找到的文件"init.tcl"。

如果没有找到，则提示错误并退出。

"init.tcl"文件的定位

根据proc tclInit源码整理如下：

#------#
 1. $tcl_library

 2. $env(TCL_LIBRARY)
 3.   $env(TCL_LIBRARY)/../tcl8.5    ;# require TCL_LIBRARY ~= /tcl(.*)$

 4. $tclDefaultLibrary || ::tcl::pkgconfig get scriptdir,runtime

 5. $tcl_dir/lib/tcl8.5         ;# tcldir = [file dir [file dir $argv0] ] 
 6. $tcl_dir/../lib/tcl8.5      ;# argv0 = tclsh = $tcl_dir/bin/tclsh
 7. $tcl_dir/library
 8. $tcl_dir/../library
 9. $tcl_dir/../tcl8.5.9/library  ;# info patchlevel
10. $tcl_dir/../../tcl8.5.9/library

11. {*}$tcl_libPath
#------#
# Note: 
tcl8.5   = tcl[info tclversion]
tcl8.5.9 = tcl[info patchlevel]

综上来看，可以考虑在两个位置安装"init.tcl"文件：

• $TCL_LIBRARY：设置为"/some/path/tcl" 或者 "/some/path/tcl8.5"
• $0/../lib/tcl8.5，比如 "/some/path/to/tcl/lib/tcl8.5"

proc tclInit

if {[namespace which -command tclInit] eq ""} {
  proc tclInit {} {
    global tcl_libPath tcl_library env tclDefaultLibrary
    rename tclInit {}
    if {[info exists tcl_library]} {
 set scripts {{set tcl_library}}
    } else {
 set scripts {}
 if {[info exists env(TCL_LIBRARY)] && ($env(TCL_LIBRARY) ne {})} {
     lappend scripts {set env(TCL_LIBRARY)}
     lappend scripts {
if {[regexp ^tcl(.*)$ [file tail $env(TCL_LIBRARY)] -> tail] == 0} continue
if {$tail eq [info tclversion]} continue
file join [file dirname $env(TCL_LIBRARY)] tcl[info tclversion]}
 }
 if {[info exists tclDefaultLibrary]} {
     lappend scripts {set tclDefaultLibrary}
 } else {
     lappend scripts {::tcl::pkgconfig get scriptdir,runtime}
 }
 lappend scripts {
set parentDir [file dirname [file dirname [info nameofexecutable]]]
set grandParentDir [file dirname $parentDir]
file join $parentDir lib tcl[info tclversion]} \
 {file join $grandParentDir lib tcl[info tclversion]} \
 {file join $parentDir library} \
 {file join $grandParentDir library} \
 {file join $grandParentDir tcl[info patchlevel] library} \
 {
file join [file dirname $grandParentDir] tcl[info patchlevel] library}
 if {[info exists tcl_libPath]
  && [catch {llength $tcl_libPath} len] == 0} {
     for {set i 0} {$i < $len} {incr i} {
  lappend scripts [list lindex \$tcl_libPath $i]
     }
 }
    }
    set dirs {}
    set errors {}
    foreach script $scripts {
 lappend dirs [eval $script]
 set tcl_library [lindex $dirs end]
 set tclfile [file join $tcl_library init.tcl]
 if {[file exists $tclfile]} {
     if {[catch {uplevel #0 [list source $tclfile]} msg opts]} {
  append errors "$tclfile: $msg
"
  append errors "[dict get $opts -errorinfo]
"
  continue
     }
     unset -nocomplain tclDefaultLibrary
     return
 }
    }
    unset -nocomplain tclDefaultLibrary
    set msg "Can't find a usable init.tcl in the following directories: 
"
    append msg " $dirs

"
    append msg "$errors

"
    append msg "This probably means that Tcl wasn't installed properly.
"
    error $msg
  }
}