Contribution by Patrick Fradin <patrick.fradin@planar.com>contrib_patrick_fradin_code_cleanup

Quoting his mail:

<pre>
==========================================================
Hi Jeff,

I spent some of my time to contribute to the TclTk community ! I'm in
late for Christmas gift but like we said in French : "Mieux vaut tard
que jamais". ;-)

I've use TclDevKit 5.3.0 tclchecker to analyse TclTk code in Tcl and
Tk library directories (library, tools and tests) to correct a lot of
warnings and few errors. (encapsulate some expr, use 'chan xxx'
instead of fconfigure, fileevent...)

I've made some improvements too :

Examples :

- Use 'lassign' instead of many 'lindex' of 'foreach/break' loop.

- Use 'in' or 'ni' operators instead of 'lsearch -exact' or to
  factorise some eq/ne && / || tests.

- Use 'eq' or 'ne' to tests strings instead of '==' or '!='.

- Use 'unset -nocomplain' to avoid 'catch {unset...}'.

- Remove some useless catch around 'destroy' calls.

- Use expand {*} instead of 'eval'. Don't touch a lot of code because
  I don't know all structs and lists. I think it could be a greater
  improvement to reduce 'eval' calls.

Due to previous experience, I dot not change any indentation ! ;-)
==========================================================
</pre>

1 files changed, 12 insertions, 11 deletions

diff --git a/library/demos/plot.tcl b/library/demos/plot.tcl
index e7f0361..b1b87bd 100644
--- a/library/demos/plot.tcl
+++ b/library/demos/plot.tcl
@@ -10,7 +10,7 @@ if {![info exists widgetDemo]} {
 package require Tk
 
 set w .plot
-catch {destroy $w}
+destroy $w
 toplevel $w
 wm title $w "Plot Demonstration"
 wm iconname $w "Plot"
@@ -27,30 +27,31 @@ pack $btns -side bottom -fill x
 canvas $c -relief raised -width 450 -height 300
 pack $w.c -side top -fill x
 
-set plotFont {Helvetica 18}
+set plotFont "Helvetica 18"
 
 $c create line 100 250 400 250 -width 2
 $c create line 100 250 100 50 -width 2
 $c create text 225 20 -text "A Simple Plot" -font $plotFont -fill brown
 
 for {set i 0} {$i <= 10} {incr i} {
-    set x [expr {100 + ($i*30)}]
+    set x [expr {100 + ($i * 30)}]
     $c create line $x 250 $x 245 -width 2
-    $c create text $x 254 -text [expr {10*$i}] -anchor n -font $plotFont
+    $c create text $x 254 -text [expr {10 * $i}] -anchor n -font $plotFont
 }
 for {set i 0} {$i <= 5} {incr i} {
-    set y [expr {250 - ($i*40)}]
+    set y [expr {250 - ($i * 40)}]
     $c create line 100 $y 105 $y -width 2
-    $c create text 96 $y -text [expr {$i*50}].0 -anchor e -font $plotFont
+    $c create text 96 $y -text [expr {$i * 50}].0 -anchor e -font $plotFont
 }
 
 foreach point {
     {12 56} {20 94} {33 98} {32 120} {61 180} {75 160} {98 223}
 } {
-    set x [expr {100 + (3*[lindex $point 0])}]
-    set y [expr {250 - (4*[lindex $point 1])/5}]
-    set item [$c create oval [expr {$x-6}] [expr {$y-6}] \
-	    [expr {$x+6}] [expr {$y+6}] -width 1 -outline black \
+    lassign $point p_x p_y
+    set x [expr {100 + (3 * $p_x)}]
+    set y [expr {250 - ((4 * $p_y) / 5)}]
+    set item [$c create oval [expr {$x - 6}] [expr {$y - 6}] \
+	    [expr {$x + 6}] [expr {$y + 6}] -width 1 -outline black \
 	    -fill SkyBlue2]
     $c addtag point withtag $item
 }
@@ -91,7 +92,7 @@ proc plotDown {w x y} {
 
 proc plotMove {w x y} {
     global plot
-    $w move selected [expr {$x-$plot(lastX)}] [expr {$y-$plot(lastY)}]
+    $w move selected [expr {$x - $plot(lastX)}] [expr {$y - $plot(lastY)}]
     set plot(lastX) $x
     set plot(lastY) $y
 }