[编程交流] 找不到线的中点

(defun c:test ( / *error* a b c d )
   (setq *error* '(( m ) (vl-bt)))
   (setq a
       (setq b
           (setq c
               (setq d (/ 1.0 0))
           )
       )
   )
)

Command: test Backtrace:
[0.58] (VL-BT)
[1.54] (#<SUBR @000000002c5dc610 -lambda-> "divide by zero")
[2.50] (ill-fun-hk "divide by zero")
[3.45] (((M) (VL-BT)) "divide by zero")
[4.40] (_call-err-hook ((M) (VL-BT)) "divide by zero")
[5.34] (sys-error "divide by zero")
:ERROR-BREAK.29 "divide by zero"
[6.26] (/ 1.0 0)
[7.20] (C:TEST) LAP+28
[8.15] (#<SUBR @000000002c5dc5e8 -rts_top->)
[9.12] (#<SUBR @000000002c598700 veval-str-body> "(C:TEST)" T #<FILE internal>)
:CALLBACK-ENTRY.6 (:CALLBACK-ENTRY)
:ARQ-SUBR-CALLBACK.3 (nil 0)

'(
  ("[code ]"            "[/ code]" )  ;; Container
  ("[color =DARKRED]"   "[/ color]")  ;; Quotes/Dots
 [color=RED] ("[color =RED]"       "[/ color]")  ;; 1st level Brackets
  ("[color =GREEN]"     "[/ color]")  ;; 2nd level Brackets
  ("[color =BLUE]"      "[/ color]")  ;; 3rd level Brackets
  ("[color =CYAN]"      "[/ color]")  ;; 4th level Brackets[/color]
  ("[color =#990099]"   "[/ color]")  ;; Multiline Comments
  ("[color =#990099]"   "[/ color]")  ;; Single Comments
  ("[color =#a52a2a]"   "[/ color]")  ;; Strings
  ("[color =BLUE]"      "[/ color]")  ;; Protected Symbols
  ("[color =#009900]"   "[/ color]")  ;; Integers
  ("[color =#009999]"   "[/ color]")  ;; Reals
)

<PRE><TT><FONT COLOR="FFFFFF">
<FONT COLOR="FFFFFF">   1| </FONT>(</FONT><FONT COLOR="FF9900">defun</FONT> </FONT><FONT COLOR="FFFFFF">c:test </FONT><FONT COLOR="FF00FF">() 
<FONT COLOR="FF00FF">   2| </FONT>  (</FONT><FONT COLOR="FF9900">setq</FONT> </FONT><FONT COLOR="FFFFFF">*error* nil</FONT><FONT COLOR="FF00FF">) 
<FONT COLOR="FF00FF">   3| </FONT>  (</FONT><FONT COLOR="FF9900">setq</FONT> </FONT><FONT COLOR="FFFFFF">a 
<FONT COLOR="0000FF">   4| </FONT>    </FONT><FONT COLOR="0000FF">(</FONT><FONT COLOR="FF9900">setq</FONT> </FONT><FONT COLOR="FFFFFF">b 
<FONT COLOR="00FFFF">   5| </FONT>      </FONT><FONT COLOR="00FFFF">(</FONT><FONT COLOR="FF9900">setq</FONT> </FONT><FONT COLOR="FFFFFF">c 
<FONT COLOR="00FF00">   6| </FONT>        </FONT><FONT COLOR="00FF00">(</FONT><FONT COLOR="FF9900">setq</FONT> </FONT><FONT COLOR="FFFFFF">d </FONT><FONT COLOR="FFFF00">(</FONT><FONT COLOR="FF9900">substr</FONT> </FONT><FONT COLOR="FFFFFF">1 1 1</FONT><FONT COLOR="FFFF00">)</FONT><FONT COLOR="00FF00">)</FONT><FONT COLOR="00FFFF">)</FONT><FONT COLOR="0000FF">)</FONT><FONT COLOR="FF00FF">) 
<FONT COLOR="FF00FF">   7| </FONT>  </FONT><FONT COLOR="FFFFFF">)  
</FONT></PRE></TT>

[b][color=BLACK]([/color][/b]if
[b][color=FUCHSIA]([/color][/b]and [color=#8b4513]; Evaluate arguments from user within the [color=#2f4f4f]"and"[/color] function[/color]
        [b][color=NAVY]([/color][/b]if
                [b][color=MAROON]([/color][/b]not [b][color=GREEN]([/color][/b]Stuff to do #1 [b][color=GREEN])[/color][/b][b][color=MAROON])[/color][/b]
                [b][color=MAROON]([/color][/b]princ [color=#2f4f4f]"\nTheres something wrong in #1 try again!"[/color][b][color=MAROON])[/color][/b]
                [b][color=MAROON]([/color][/b]Stuff to do #1 [b][color=MAROON])[/color][/b]
        [b][color=NAVY])[/color][/b]
        [b][color=NAVY]([/color][/b]if
                [b][color=MAROON]([/color][/b]not [b][color=GREEN]([/color][/b]Stuff to do #2 [b][color=GREEN])[/color][/b][b][color=MAROON])[/color][/b]
                [b][color=MAROON]([/color][/b]princ [color=#2f4f4f]"\nTheres something wrong in #2 try again!"[/color][b][color=MAROON])[/color][/b]
                [b][color=MAROON]([/color][/b]Stuff to do #2 [b][color=MAROON])[/color][/b]
        [b][color=NAVY])[/color][/b]
        [b][color=NAVY]([/color][/b]if
                [b][color=MAROON]([/color][/b]not [b][color=GREEN]([/color][/b]Stuff to do #3 [b][color=GREEN])[/color][/b][b][color=MAROON])[/color][/b]
                [b][color=MAROON]([/color][/b]princ [color=#2f4f4f]"\nTheres something wrong in #3 try again!"[/color][b][color=MAROON])[/color][/b]
                [b][color=MAROON]([/color][/b]Stuff to do #3 [b][color=MAROON])[/color][/b]
        [b][color=NAVY])[/color][/b]
[b][color=FUCHSIA])[/color][/b][color=#8b4513]; All arguments are evaluated, the code proceeds[/color]
[b][color=FUCHSIA]([/color][/b]while somethingisdone [color=#8b4513]; example: a selection was made and the same must be copied or moved within the while loop[/color]
        [b][color=NAVY]([/color][/b]progn
                [b][color=MAROON]([/color][/b]while 
                        [b][color=GREEN]([/color][/b]not [b][color=BLUE]([/color][/b]setq pickline [b][color=RED]([/color][/b]entsel [color=#2f4f4f]"\nPick a line"[/color][b][color=RED])[/color][/b][b][color=BLUE])[/color][/b][b][color=GREEN])[/color][/b]
                        pickline
                        [b][color=GREEN]([/color][/b]cond
                                [b][color=BLUE]([/color][/b]   [b][color=RED]([/color][/b]= 7 [b][color=PURPLE]([/color][/b]getvar 'errno[b][color=PURPLE])[/color][/b][b][color=RED])[/color][/b]
                                        [b][color=RED]([/color][/b]princ [color=#2f4f4f]"\nYou must select a line."[/color][b][color=RED])[/color][/b]
                                [b][color=BLUE])[/color][/b]
                                [b][color=BLUE]([/color][/b]   [b][color=RED]([/color][/b]null pickline[b][color=RED])[/color][/b]
                                        [b][color=RED]([/color][/b]princ [color=#2f4f4f]"\nYou missed, try again."[/color][b][color=RED])[/color][/b]
                                [b][color=BLUE])[/color][/b]
                        [b][color=GREEN])[/color][/b]
                [b][color=MAROON])[/color][/b][color=#8b4513]; to exit this loop and continue a line must be picked[/color]
                [b][color=MAROON]([/color][/b]We got everything we need from Stuff #1, #2 and #3, now the code does its job... [b][color=MAROON])[/color][/b]
        [b][color=NAVY])[/color][/b][color=#8b4513]; the code did its job, exiting with my favourite ESC key, and don't forget the error handling if needed![/color]
[b][color=FUCHSIA])[/color][/b]
[b][color=BLACK])[/color][/b][color=#8b4513];if[/color]