I tried to solve issues
"13260 inspecting variables in the debugger fails in some cases" and
"14058 Inconsistent information in debugger"
and found some oddities in the way opal (compiler and the debuggermap)
handles tempory variables.
I am not sure if these are bugs.
1. order of temporaries:
Evaluating this method
|a b c|
a:=1.
b:=2.
c:=3.
thisContext tempNames logCr.
["in a block ! " thisContext tempNames logCr . a+b+c ] value.
prints in the transcript
#(#a #b #c)
#(#a #b #c)
- ok, both contexts, the method and block context, use the same
ordering for the tempories
writing on one variable in the block context require an indirection vector
for
the variable
|a b c|
a:=1.
b:=2.
c:=3.
thisContext tempNames logCr.
[b:=1. thisContext tempNames logCr. a+b+c ] value.
here the variable b is written within the block context. This method prints
#(#b #a #c)
#(#a #c #b)
- strange the variable order has changed and is not the same in both
contexts.
2. OCOptimizedBlockScope
Consider a whileTrue: call
["A-Block"] whileTrue:["B-Block"]
or an ifTrue:
("some boolean value") ifTrue:["C-Block"]
stepping into the blocks with the debugger and reading the
values for a tempoariy variable shows that every block has
an OCOpotimizedBlockScope as its scope.
Are all 3 blocks the same kind of "optimized blocks"? because ->
3. Blocks within optimized blocks
This method prints the number of tempories on the Transcript
(the on:do: call is just a dummy for an "block within a block"
but the important part is the usage of the three variables
in the do-block)
|a b c|
a:=1.
b:=2.
c:=3.
(c>0) ifTrue:[
[ a asString ] on:Error do:[:ex | a value:a value:b value:c].
].
thisContext method numTemps logCr.
a
The output on the transcript is "3"
- ok
This method is like the one above, but the nested block
is in the receiver of the whileTrue:[] call (again, an optimized block,
right?)
|a b c|
a:=1.
b:=2.
c:=3.
[
[ a asString ] on:Error do:[:ex | a value:a value:b value:c].
c <0 ] whileTrue:[].
thisContext method numTemps logCr.
a
The output on the Transcript is "1"
And it depends on the number of used variables in the do-Block
The same method but with the do-Block
do:[:ex | a value:a value:b]
would print 2 as number of temporaries.
nicolai
