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Add 'Scanning the stack with frame_descr' slide
Clarify the stack scanning technique
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-18
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5 files changed

+144
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‎.gitignore

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@@ -11,6 +11,7 @@
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/presentation/src/ocaml/domain_state.h
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/presentation/src/ocaml/domain_state_abbr.h
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/presentation/src/ocaml/domain_state_backtrace.h
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/src/**/*.annot

‎presentation/backtrace.tex

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@@ -134,12 +134,12 @@ \subsection{One advantage of raising with debugging information}
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\mintc[firstline=190,lastline=192,highlightlines={191-192}]{../ocaml/runtime/amd64.S}
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\mintc[firstline=234,lastline=237,highlightlines={235-237}]{../ocaml/runtime/amd64.S}
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}
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\onslide*<1>{\listCamlRaiseExn[highlightlines=705]{}}
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\onslide*<2>{\listCamlRaiseExn[highlightlines={707-708}]{}}
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\onslide*<3>{\listCamlRaiseExn[highlightlines={712-714}]{}}
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\onslide*<4>{\listCamlRaiseExn[highlightlines={715-720}]{}}
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\onslide*<5>{\providecommand\step{1}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<6>{\providecommand\step{2}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<1>{\listCamlRaiseExn[highlightlines=705]{}}%
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\onslide*<2>{\listCamlRaiseExn[highlightlines={707-708}]{}}%
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\onslide*<3>{\listCamlRaiseExn[highlightlines={712-714}]{}}%
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\onslide*<4>{\listCamlRaiseExn[highlightlines={715-720}]{}}%
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\onslide*<5>{\providecommand\step{1}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<6>{\providecommand\step{2}\input{diagrams/backtrace/backtrace.tex}}%
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\end{column}
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\end{columns}
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\end{frame}
@@ -212,6 +212,32 @@ \subsection{One advantage of raising with debugging information}
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\end{columns}
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\end{frame}
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\begin{frame}{Backtraces}{Scanning the stack with \typename{frame\_descr}}
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\begin{columns}[c]
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\begin{column}{0.5\textwidth}
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\begin{itemize}
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\item Given the return address of the code that raises the exception by calling \funcname{caml\_raise\_exn} (\funcarg{pc} argument of \funcname{caml\_stash\_backtrace})
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\item And the position of the stack pointer (\funcarg{sp} argument of \funcname{caml\_stash\_backtrace})
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\item The frame size given by \typename{frame\_descr}.\funcarg{frame\_size}, allows to find the end of the previous frame
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\item And the return address of the caller of this function
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\bigskip
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\onslide<3->{
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\item Note that traps (here the reddish \funcname{ExnA}, \funcname{ExnB} and \funcname{ExnC} blocks) belong to the frame that installed them, and so the frame size changes when traps are removed
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}
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\end{itemize}
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\end{column}
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\begin{column}{0.5\textwidth}
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\raggedleft
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\onslide*<1>{\providecommand\step{2}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<2>{\providecommand\step{1}\input{diagrams/backtrace/scanstack.tex}}%
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\onslide*<3>{\providecommand\step{2}\input{diagrams/backtrace/scanstack.tex}}%
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\onslide*<4>{\providecommand\step{3}\input{diagrams/backtrace/scanstack.tex}}%
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\onslide*<5>{\providecommand\step{4}\input{diagrams/backtrace/scanstack.tex}}%
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\onslide*<6>{\providecommand\step{5}\input{diagrams/backtrace/scanstack.tex}}%
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\end{column}
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\end{columns}
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\end{frame}
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% Duplicate of previous-previous slide
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\begin{frame}{Backtraces}{Continuing on \funcname{caml\_stash\_backtrace}}
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\begin{columns}[c]
@@ -241,8 +267,8 @@ \subsection{One advantage of raising with debugging information}
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\begin{column}{0.5\textwidth}
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\raggedleft
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\onslide*<1>{\listStashBacktrace[highlightlines={114-115}]{}}
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\onslide*<2>{\providecommand\step{3}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<3>{\providecommand\step{4}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<2>{\providecommand\step{3}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<3>{\providecommand\step{4}\input{diagrams/backtrace/backtrace.tex}}%
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\end{column}
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\end{columns}
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\end{frame}
@@ -385,15 +411,15 @@ \subsection{One advantage of raising with debugging information}
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\end{column}
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\begin{column}{0.45\textwidth}
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\raggedleft
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\onslide*<1>{\providecommand\step{6}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<2>{\providecommand\step{6}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<3>{\providecommand\step{7}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<4>{\providecommand\step{8}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<5>{\providecommand\step{9}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<6>{\providecommand\step{10}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<7>{\providecommand\step{11}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<8>{\providecommand\step{12}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<9>{\providecommand\step{13}\input{diagrams/backtrace/backtrace.tex}}
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\onslide*<1>{\providecommand\step{6}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<2>{\providecommand\step{6}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<3>{\providecommand\step{7}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<4>{\providecommand\step{8}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<5>{\providecommand\step{9}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<6>{\providecommand\step{10}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<7>{\providecommand\step{11}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<8>{\providecommand\step{12}\input{diagrams/backtrace/backtrace.tex}}%
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\onslide*<9>{\providecommand\step{13}\input{diagrams/backtrace/backtrace.tex}}%
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\end{column}
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\end{columns}
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\end{frame}

‎presentation/diagrams/backtrace/backtrace.tex

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@@ -153,6 +153,5 @@
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\showRegister{trapsp}{\stashBacktraceArgTrapSPvC}
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}{}
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\end{stackDiagram}
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\end{tikzpicture}

‎presentation/diagrams/backtrace/scanstack.tex

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@@ -0,0 +1,99 @@
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\begin{tikzpicture}[font=\sffamily\tiny]
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\input{../src/backtrace/gdb.out}
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\newcommand\trapExnAEnd{\xinteval{\trapExnABegin - 2 * \wordSize}}
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\newcommand\trapExnBEnd{\xinteval{\trapExnBBegin - 2 * \wordSize}}
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\newcommand\trapExnCEnd{\xinteval{\trapExnCBegin - 2 * \wordSize}}
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\begin{stackDiagram}[yFactor=0.35,showAddress=true]{\frameMainBegin}{\frameDefinitelyEnd}
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\callStack
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\begin{funFrame}[name=main,color=GreenYellow]{\frameMainBegin}{\frameMainEnd}
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\funReturnAddr{\frameMainRetaddr}
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\frameLocal{1}{\frameMainLocalOne}
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\end{funFrame}
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\trapFrame[name=ExnC,handler=\trapExnCHandler,next=\trapExnCNext,color=WildStrawberry]{\trapExnCBegin}
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\coordAtRight{exnCtrap}{\exnHandlerAfterExnCTrap}
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\trapFrame[name=ExnB,handler=\trapExnBHandler,next=\trapExnBNext,color=OrangeRed]{\trapExnBBegin}
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\coordAtRight{exnBtrap}{\exnHandlerAfterExnBTrap}
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\begin{funFrame}[name=maybe,color=YellowGreen]{\frameMaybeBegin}{\frameMaybeEnd}
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\funReturnAddr{\frameMaybeRetaddr}
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\frameLocal{1}{\frameMaybeLocalOne}
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\end{funFrame}
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\begin{funFrame}[name=probably,color=Green]{\frameProbablyBegin}{\frameProbablyEnd}
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\funReturnAddr{\frameProbablyRetaddr}
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\frameLocal{1}{\frameProbablyLocalOne}
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\end{funFrame}
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\trapFrame[name=ExnA,handler=\trapExnAHandler,next=\trapExnANext,color=Red]{\trapExnABegin}
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\coordAtRight{exnAtrap}{\exnHandlerAfterExnATrap}
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\begin{funFrame}[name=definitely,color=JungleGreen]{\frameDefinitelyBegin}{\frameDefinitelyEnd}
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\funReturnAddr{\frameDefinitelyRetaddr}
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\frameLocal{1}{\frameDefinitelyLocalOne}
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\end{funFrame}
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\begin{funFrame}[color=SeaGreen]{\frameCamlRaiseExnBegin}{\frameCamlRaiseExnEnd}
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\funReturnAddr{\frameCamlRaiseExnRetaddr}
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\end{funFrame}
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\coordinate (bottom) at ($(stackBL) + (0,-0.25)$);
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\domainStateBacktrace[pos=(bottom),yFactor=0.03]{\exnHandlerAfterExnATrap}{}{0}
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\newcommand\lineToNextFrame[2]{
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% #1 -> from
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% #2 -> to
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\tikzmath{
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\Ax = 0;
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\Ay = \yOffset{#1}; \Ay = \Ay + 0.5 * \yFactor;
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\Bx = 0;
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\By = \yOffset{#2}; \By = \By + 0.5 * \yFactor;
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\Cx = 0;
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\Cy = \yOffset{#2}; \Cy = \Cy - 0.5 * \yFactor;
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\Lx = -0.08 * \xFactor;
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\Ly = (\Ay + \By) / 2;
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}
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\node (plus) [draw,circle,fill=white,inner sep=0,label={above,rotate=90:framesize}] at (\Lx,\Ly) { + };
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\draw [out=180,in=-90] (\Ax,\Ay) to (plus.south);
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\draw [out=90,in=180] (plus.north) to (\Bx,\By);
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\draw [->,>=stealth,out=180,in=180,looseness=1.5] (\Bx,\By) to (\Cx,\Cy);
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\coordinate (TL) at ($ (0,\Cy+0.5*\yFactor) + (0.06,-0.06) $);
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\coordinate (BR) at ($ (\xFactor,\Cy-0.5*\yFactor) + (-0.4,0.06) $);
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\node [draw,thick,color=red,rounded corners=2,fit=(TL) (BR),inner sep=0] {};
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}
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\ifthenelse{\step<3}{
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\lineToNextFrame{\frameDefinitelyEnd}{\trapExnAEnd}
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}{}
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\ifthenelse{\step=2}{
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\lineToNextFrame{\trapExnAEnd}{\frameMaybeEnd}
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}{}
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\ifthenelse{\step>2}{
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\lineToNextFrame{\frameProbablyEnd}{\frameMaybeEnd}
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}{}
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\ifthenelse{\step>3}{
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\lineToNextFrame{\frameMaybeEnd}{\trapExnBEnd}
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}{}
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\ifthenelse{\step=5}{
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\lineToNextFrame{\trapExnBEnd}{\frameEntryEnd}
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}{}
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\end{stackDiagram}
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\end{tikzpicture}

‎presentation/presentation.tex

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\usetikzlibrary{matrix}
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\usetikzlibrary{positioning}
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\usetikzlibrary{shapes.geometric}
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\usetikzlibrary{fit}
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\usemintedstyle{pastie}

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