if { [info commands lassign] == "" } {
      proc lassign {L args} {
        uplevel 1 [list foreach $args [linsert $L end {}] break]
        lrange $L [llength $args] end
      }
    }
    
    interp alias {} nosubst {} subst -nobackslashes -nocommands -novariables
    
    proc template {name vars body} {
        set outvar [lindex $vars 0]
        lset vars 0 ${outvar}_var
        proc $name $vars [concat upvar 1 \$${outvar}_var $outvar \; [genrender $body $outvar]]
    }
    
    proc render {args} { uplevel 1 [eval {genrender} $args] }
    
    proc genrender {template {var OUT} {sub subst}} {
      set a "append $var \[$sub {"
      set b "}]\n\\1\n"
      set c [regsub -all -line {$\s*%\s(.*)} $template $b$a ]
      return $a$c\}\]
    }
    
    set v 3
    set mjd "Mark J. Dominus"
    set mjdweb "http://perl.plover.com/"
    set L [split "ABCD" ""]
    
    template example {OUTPUT v L} {
    % global env
    You can access variables: $v
    or environment variables: $env(HOME)
    
    You can call functions and evaluate code inline.
    The list [join $L ", "] has [llength $L] elements.
        [string repeat = [llength $L]]
        [join $L ""]
        [string repeat = [llength $L]]
    
    Loop
    % for {set i 0} { $i < [llength $L] } {incr i} {
        elem  L\[$i\] = [lindex $L $i]
    % }
    
    Append to output
    
    % for {set i 0} { $i < [llength $L] } {incr i} {
    %   append OUTPUT "  L\[$i\] = " ' [lindex $L $i] '
    % }
    % global mjd mjdweb
    
    This example is from $mjd at ${mjdweb}
    
    % set len [llength $L]
    The Lord High Chamberlain has gotten $len things for me this year.
    % set diff [expr { $len - 5 }]
    % set more "more"
    % if { $diff == 0 } {
    %   set more "no"
    % } elseif { $diff < 0 } {
    %   set diff [expr {-$diff}]
    %   set more "fewer"
    % }
    That is $diff $more than he gave me last year.
    }
    
    set OUT "For example"
    puts [example OUT $v $L]
    
    
    array set structs {
        a long
        c float
    }
    
    template render_struct {out n t} {
        struct $n {
            struct $n *next;
            $t data;
        };
    }
    
    foreach {n t} [array get structs] {
        render_struct output $n $t
    }
    puts $output

    For example
    You can access variables: 3
    or environment variables: /home/pshook
    
    You can call functions and evaluate code inline.
    The list A, B, C, D has 4 elements.
        ====
        ABCD
        ====
    
    Loop
        elem  L[0] = A
        elem  L[1] = B
        elem  L[2] = C
        elem  L[3] = D
    
    Append to output  L[0] = 'A'  L[1] = 'B'  L[2] = 'C'  L[3] = 'D'
    
    This example is from Mark J. Dominus at http://perl.plover.com/
    The Lord High Chamberlain has gotten 4 things for me this year.
    That is 1 fewer than he gave me last year.