Is there a standard/popular parser for ''.ini'' style configuration file parsers?
If not, here is one that I use. It doesn't write config files, but does
read them into arrays named by config file ''section''.

-- [Todd Coram]

 namespace eval cfg {
    variable version 1.0

    variable sections [list DEFAULT]

    variable cursection DEFAULT
    variable DEFAULT;   # DEFAULT section
 }

 proc cfg::sections {} {
    return $cfg::sections
 }

 proc cfg::variables {{section DEFAULT}} {
    return [array names ::cfg::$section]
 }

 proc cfg::add_section {str} {
    variable sections
    variable cursection

    set cursection [string trim $str \[\]]
    if {[lsearch -exact $sections $cursection] == -1} {
 lappend sections $cursection
 variable ::cfg::${cursection}
    }
 }

 proc cfg::setvar {varname value {section DEFAULT}} {
    variable sections
    if {[lsearch -exact $sections $section] == -1} {
 cfg::add_section $section
    }
    set ::cfg::${section}($varname) $value
 }

 proc cfg::getvar {varname {section DEFAULT}} {
    variable sections
    if {[lsearch -exact $sections $section] == -1} {
 error "No such section: $section"
    }
   return [set ::cfg::${section}($varname)]
 }


 proc cfg::parse_file {filename} {
    variable sections
    variable cursection
    set line_no 1
    set fd [open $filename r]
    while {![eof $fd]} {
 set line [string trim [gets $fd] " "]
 switch -regexp -- $line {
     ^#.* { }
     ^\\[.*\\]$ {
  cfg::add_section $line
     }
     .*=.* {
  set pair [split $line =]
  set name [string trim [lindex $pair 0] " "]
  set value [string trim [lindex $pair 1] " "]
  cfg::setvar $name $value $cursection
     }
     default {
  error "Error parsing $filename (line: $line_no): $line"
     }
     incr line_no
 }
    }
    close $fd
 }

-------
Given: (startup.ini)

 # a DEFAULT attribute
 #
 debug=true
 
 [EMAIL]
 from_addr = tcoram@pobox.com
 to_addr = nobody@maplefish.com
 
 [DEFAULT]
 trace_level = 5

Here is how you can use it:

  $cfg::parse_file startup.ini
  set dbg $cfg::DEFAULT(debug)
  set dbg $cfg::getvar debug DEFAULT
  puts "email comes from $cfg::EMAIL(from_addr)