2 \documentclass[12pt]{article}
4 \usetikzlibrary{shapes}
5 \usetikzlibrary{arrows}
10 \setlength{\fboxrule}{0.01pt}
11 \setlength{\fboxsep}{4pt}
13 \fcolorbox{white}{white}{
15 \newcommand{\sys}[1]{\emph{#1}}
17 \begin{tikzpicture}[x = 4cm, y = 1cm]
18 \tikzstyle positive=[color = black, fill = white];
19 \tikzstyle negative=[color = white, fill = black];
20 \tikzstyle entity=[rounded corners, draw, thick];
21 \tikzstyle process=[ellipse, draw, thick];
22 \tikzstyle arrow=[-stealth, semithick];
23 \node (spec) at (0, 3) [entity, positive] {specification tools};
24 \node (user) at (1, 3) [entity, positive] {user proofs};
25 \node (spec_user_join) at (0.5, 3) [shape=coordinate] {};
26 \node (raw) at (0.5, 4) [entity, positive] {raw code equations};
27 \node (pre) at (1.5, 4) [process, positive] {preprocessing};
28 \node (eqn) at (2.5, 4) [entity, positive] {code equations};
29 \node (iml) at (0.5, 0) [entity, positive] {intermediate program};
30 \node (seri) at (1.5, 0) [process, positive] {serialisation};
31 \node (SML) at (2.5, 3) [entity, positive] {\sys{SML}};
32 \node (OCaml) at (2.5, 2) [entity, positive] {\sys{OCaml}};
33 \node (further) at (2.5, 1) [entity, positive] {(\ldots)};
34 \node (Haskell) at (2.5, 0) [entity, positive] {\sys{Haskell}};
35 \draw [semithick] (spec) -- (spec_user_join);
36 \draw [semithick] (user) -- (spec_user_join);
37 \draw [-diamond, semithick] (spec_user_join) -- (raw);
38 \draw [arrow] (raw) -- (pre);
39 \draw [arrow] (pre) -- (eqn);
40 \draw [arrow] (eqn) -- node (transl) [process, positive] {translation} (iml);
41 \draw [arrow] (iml) -- (seri);
42 \draw [arrow] (seri) -- (SML);
43 \draw [arrow] (seri) -- (OCaml);
44 \draw [arrow, dashed] (seri) -- (further);
45 \draw [arrow] (seri) -- (Haskell);