Hi Juan,

    I see that your new transcript is indeed much faster but is also not
editable.  I wonder if it would be possible to have the best of both worlds
and arrange that, when active, the transcript is editable.  For example,
selecting the TranscriptWIndow could put it into a mode where the
transcript's state was imported into a more conventional editable text
morph, and then when the window was exited, reverted to the standard fast
output mode.  As you can infer I like having an editable transcript.  I can
do without it, because Squeak's slow transcript is indeed a PITA, but I'm
not sure that speed need preclude editability.

On Sat, May 9, 2015 at 10:17 AM, J. Vuletich (mail lists) <
juanlists at jvuletich.org> wrote:

> Hi Folks,
>
> (below)
>
>
> Quoting Ben Coman <btc at openinworld.com>:
>
>  On Sat, May 9, 2015 at 10:35 PM, Eliot Miranda <eliot.miranda at gmail.com>
>> wrote:
>>
>>
>>>
>>> On Sat, May 9, 2015 at 7:09 AM, Ben Coman <btc at openinworld.com> wrote:
>>>
>>>  From my limited experience bug hunting, calling #changed: from a thread
>>>> other than the UI thread is a source of evil.  There are too many
>>>> assumptions throughout the system that the UI is single threaded.  Can
>>>> anyone advise me that is not a proper belief?
>>>>
>>>> Then that implies that a Transcript implementation where #nextPut:
>>>> direct
>>>> calls #changed:
>>>> is not appropriate for use with multi-threaded applications.  In Pharo,
>>>> #changed: is only called from #stepGlobal, which is called from
>>>> doOneCycle:.  (This came about as a last minute bug fix before Pharo 3
>>>> release and maybe could use some cleanup.
>>>>
>>>> Separating the UI from Transcript into its own viewer might be a good
>>>> idea, but actually it would not solve Stef's case since his code would
>>>> still be running in the UI thread -- unless the viewer ran in another
>>>> thread, which would have its own complexities.
>>>>
>>>> I think the point about efficiency is significant. The following
>>>> example...
>>>>      Time millisecondsToRun: [ 1000 timesRepeat:  [ Transcript show: 'x'
>>>> ] ]
>>>> on Squeak 4.5 --> 12749ms
>>>> on Pharo 50029 --> 2ms
>>>>
>>>> This better performance helped me a lot trying to understand the high
>>>> priority timerEventLoop being able to indiscriminately scatter
>>>> Transcript
>>>> tracing through that code.  I believe its also probably beneficial for
>>>> working with externally triggered semaphores and timing sensitive race
>>>> conditions.
>>>>
>>>> So we have two mutually exclusive cases:
>>>> * better interactivity, poorer system performance
>>>> * faster system performance, worse interactivity
>>>>
>>>> Which of these is broken depends on your viewpoint.
>>>>
>>>>
>>> Something that runs fast but is incorrect is still incorrect.  The fact
>>> that the transcript doesn't output until a world step is possible is a
>>> bug.  It forces programs that use the transcript to be rewritten in order
>>> to see transcript output.
>>>
>>>
>> As a point of comparison for correctness, for the following...
>>
>>     Transcript clear.
>>     [   $a asciiValue to: $z asciiValue do: [ :c |
>>   [ 1 to: 9 do: [ :i | Transcript show: c asCharacter printString , i
>> printString , ' ' ] ] forkAt: 40
>> ].
>>     ] forkAt: 41
>>
>> Squeak 4.5 gives...
>> $a1 $a2 $a3 $a4 $a5 $a6 $a7 $a8 $a9 $b1 $b2 $b3 $b4 $b5 $b5 $c1 $c2 $c3
>> $c4
>> $c5 $c6 $c7 $c8 $c9 $d1 $d2 $d3 $d4 $d5 $d6 $d7 $d8 $d9 $d9 $e2 $g2 $h2
>> $h2
>> $i2 $k2 $k2 $l2 $n2 $n2 $o2 $o2 $r2 $s2 $t2 $u2 $u2 $v2 $x2 $y2 $z2 $z2
>> $b7
>> $f3 $e3 $e3 $g3 $j3 $h3 $i3 $k3 $k3 $m3 $n3 $p3 $p3 $q3 $o3 $s3 $t3 $t3
>> $u3
>> $v3 $x3 $y3 $z3 $b8 $f4 $e4 $e4 $g4 $h4 $i4 $k4 $l4 $m4 $m4 $n4 $r4 $q4
>> $o4
>> $o4 $s4 $w4 $u4 $u4 $v4 $y4 $y4 $z4 $z4 $f5 $j5 $j5 $g5 $i5 $k5 $l5 $l5
>> $m5
>> $m5 $n5 $q5 $o5 $s5 $s5 $t5 $u5 $u5 $x5 $y5 $z5 $f6 $f6 $h6 $h6 $g6 $g6
>> $k6
>> $p6 $m6 $r6 $r6 $n6 $o6 $s6 $s6 $w6 $u6 $x6 $x6 $e7 $f7 $j7 $h7 $h7 $i7
>> $l7
>> $l7 $k7 $m7 $m7 $q7 $n7 $n7 $o7 $t7 $w7 $w7 $u7 $v7 $x7 $z7 $z7 $e8 $e8
>> $h8
>> $g8 $i8 $i8 $l8 $k8 $k8 $m8 $q8 $n8 $n8 $s8 $t8 $w8 $y8 $y8 $u8 $x8 $z8
>> $f9
>> $f9 $e9 $h9 $h9 $g9 $p9 $p9 $k9 $r9 $r9 $m9 $n9 $n9 $o9 $t9 $t9 $w9 $v9
>> $u9
>> $u9 $z9 $x9
>>
>> Pharo 50041 gives...
>> $a1 $a2 $a3 $a4 $a5 $a6 $a7 $a8 $a9 $b1 $b2 $b3 $b4 $b5 $b6 $b7 $b8 $b9
>> $c1
>> $c2 $c3 $c4 $c5 $c6 $c7 $c8 $c9 $d1 $d2 $d3 $d4 $d5 $d6 $d7 $d8 $d9 $e1
>> $e2
>> $e3 $e4 $e5 $e6 $e7 $e8 $e9 $f1 $f2 $f3 $f4 $f5 $f6 $f7 $f8 $f9 $g1 $g2
>> $g3
>> $g4 $g5 $g6 $g7 $g8 $g9 $h1 $h2 $h3 $h4 $h5 $h6 $h7 $h8 $h9 $i1 $i2 $i3
>> $i4
>> $i5 $i6 $i7 $i8 $i9 $j1 $j2 $j3 $j4 $j5 $j6 $j7 $j8 $j9 $k1 $k2 $k3 $k4
>> $k5
>> $k6 $k7 $k8 $k9 $l1 $l2 $l3 $l4 $l5 $l6 $l7 $l8 $l9 $m1 $m2 $m3 $m4 $m5
>> $m6
>> $m7 $m8 $m9 $n1 $n2 $n3 $n4 $n5 $n6 $n7 $n8 $n9 $o1 $o2 $o3 $o4 $o5 $o6
>> $o7
>> $o8 $o9 $p1 $p2 $p3 $p4 $p5 $p6 $p7 $p8 $p9 $q1 $q2 $q3 $q4 $q5 $q6 $q7
>> $q8
>> $q9 $r1 $r2 $r3 $r4 $r5 $r6 $r7 $r8 $r9 $s1 $s2 $s3 $s4 $s5 $s6 $s7 $s8
>> $s9
>> $t1 $t2 $t3 $t4 $t5 $t6 $t7 $t8 $t9 $u1 $u2 $u3 $u4 $u5 $u6 $u7 $u8 $u9
>> $v1
>> $v2 $v3 $v4 $v5 $v6 $v7 $v8 $v9 $w1 $w2 $w3 $w4 $w5 $w6 $w7 $w8 $w9 $x1
>> $x2
>> $x3 $x4 $x5 $x6 $x7 $x8 $x9 $y1 $y2 $y3 $y4 $y5 $y6 $y7 $y8 $y9 $z1 $z2
>> $z3
>> $z4 $z5 $z6 $z7 $z8 $z9
>>
>> (start your comparison at $b5)
>>
>> So in one axis Pharo has improved Transcript, but we didn't notice the
>> significance of the use case we lost.
>>
>> cheers -ben
>>
>
> Please take a good look at Cuis' Transcript and consider using it.
>
> By default, the display is updated immediately, but without calling
> Morphic, it can even work with no UI framework at all. It does updates
> faster than Squeak or Visualworks:
>
>         Time millisecondsToRun: [ 1000 timesRepeat:  [ Transcript show:
> 'x' ] ]. 763.
>
> But if you want minimum overhead without immediate feedback:
>
>         Time millisecondsToRun: [ Transcript showOnDisplay: false. 1000
> timesRepeat:  [ Transcript show: 'x' ]. Transcript showOnDisplay: true ]. 1.
>         "As fast as Pharo"
>
> It is also thread safe, and for Ben's example:
>
> Transcript clear.
> [
>         $a asciiValue to: $z asciiValue do: [ :c |
>                 [ 1 to: 9 do: [ :i | Transcript show: c asCharacter
> printString , i printString , ' ' ] ] forkAt: 40
>         ].
> ] forkAt: 41
>
> it gives the same result as Pharo.
>
> The fact that the updates are not bound to Morphic also means that it is
> possible to do #show: deep in Morphic logic, without causing infinite loops
> or recursions, and get immediate feedback. It has proved to be a useful aid
> in debugging Morphic code.
>
> Cheers,
> Juan Vuletich
>
>
>


-- 
best,
Eliot
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