1 \documentclass[a4paper,draft]{article}
8 \newcommand{\MATITA}{\ding{46}\textsf{\textbf{Matita}}}
10 \title{Continuationals semantics for \MATITA}
11 \author{Enrico Tassi \qquad Stefano Zacchiroli \\
12 \small Department of Computer Science, University of Bologna \\
13 \small Mura Anteo Zamboni, 7 -- 40127 Bologna, ITALY \\
14 \small \{\texttt{tassi}, \texttt{zacchiro}\}\texttt{@cs.unibo.it}}
16 \newcommand{\DOT}{\mbox{\textbf{.}}}
17 \newcommand{\SEMICOLON}{\mbox{\textbf{;}}}
18 \newcommand{\BRANCH}{\mbox{\textbf{[}}}
19 \newcommand{\SHIFT}{\mbox{\textbf{\textbar}}}
20 \newcommand{\MERGE}{\mbox{\textbf{]}}}
21 \newcommand{\APPLY}[1]{\ensuremath{\mathtt{apply}~\mathit{#1}}}
22 \newcommand{\SKIP}{\ensuremath{\mathtt{skip}}}
23 \newcommand{\TACTICAL}[1]{\ensuremath{\mathtt{tactical}~\mathit{#1}}}
24 \newcommand{\GOTO}[2]{\ensuremath{\mathtt{goal} ~ #1 ~ #2}}
26 \newcommand{\GOAL}{\ensuremath{\mathit{goal}}}
27 \newcommand{\GOALSWITCH}{\ensuremath{\mathit{goal\_switch}}}
28 \newcommand{\LIST}{\ensuremath{\mathtt{list}}}
29 \newcommand{\BOOL}{\ensuremath{\mathtt{bool}}}
30 \newcommand{\STACK}{\ensuremath{\mathtt{stack}}}
31 \newcommand{\OPEN}[1]{\ensuremath{\mathtt{Open}~#1}}
32 \newcommand{\CLOSED}[1]{\ensuremath{\mathtt{Closed}~#1}}
34 \newcommand{\SEMOP}[1]{|[#1|]}
35 \newcommand{\TSEMOP}[1]{{}_t|[#1|]}
36 \newcommand{\SEM}[5]{\SEMOP{#1}_{#2,#3,#4,#5}}
37 \newcommand{\TSEM}[3]{\TSEMOP{#1}_{#2,#3}}
39 \newcommand{\FUN}[2]{\ensuremath{\mathit{#1}(#2)}}
40 \newcommand{\FILTERFUN}[2]{\FUN{filter}{#1,#2}}
41 \newcommand{\MAPFUN}[2]{\FUN{map}{#1,#2}}
42 \newcommand{\DEEPMAPFUN}[2]{\FUN{deep\_map}{#1,#2}}
43 % \newcommand{\ISCLOSEDFUN}{\ensuremath{\mathit{is\_closed}}}
44 \newcommand{\ISOPENFUN}{\ensuremath{\mathit{is\_open}}}
45 % \newcommand{\OPENFUN}{\ensuremath{\mathit{open}}}
46 \newcommand{\CLOSEFUN}{\ensuremath{\mathit{close}}}
47 \newcommand{\GOALOFFUN}{\ensuremath{\mathit{goal\_of}}}
58 C & ::= & & \mbox{(\textbf{continuationals})} \\
59 & & \DOT & \mbox{(dot)} \\
60 & | & C ~ \SEMICOLON ~ C & \mbox{(semicolon)} \\
61 & | & \BRANCH & \mbox{(branch)} \\
62 & | & \SHIFT & \mbox{(shift)} \\
63 & | & \MERGE & \mbox{(merge)} \\
64 & | & \GOTO{n}{C} & \mbox{(goto)} \\
65 & | & \TACTICAL{T} & \mbox{(tactical)} \\[2ex]
67 T & ::= & & \mbox{(\textbf{tacticals})} \\
68 & & \APPLY{tac} & \mbox{(tactic application)} \\
69 & | & \SKIP & \mbox{(closed goal skipping)} \\
77 \mathit{status} & = & \xi\times\Gamma\times\tau\times\kappa & \\
78 \xi & & & \mbox{(metasenv)} \\
79 \Gamma & = & \GOALSWITCH~\LIST~\STACK & \mbox{(context)} \\
80 \GOALSWITCH & = & \OPEN{n} \quad | \quad \CLOSED{n} & \\
81 \tau & = & \GOAL~\LIST~\STACK & \mbox{(todo)} \\
82 \kappa & = & \GOAL~\LIST~\STACK & \mbox{(dot continuations)} \\
86 \subsection{Semantics}
90 \SEMOP{\cdot} & : & C -> \mathit{status} -> \mathit{status} &
91 \mbox{(continuationals semantics)} \\
92 \TSEMOP{\cdot} & : & T -> \xi -> \GOALSWITCH ->
93 \xi\times\GOAL~\LIST\times\GOAL~\LIST & \mbox{(tacticals semantics)} \\
99 \mathit{apply\_tac} & : & \mathit{tac} -> \xi -> \GOAL ->
100 \xi\times\GOAL~\LIST\times\GOAL~\LIST \\[1ex]
101 \mathit{filter} & : & (\alpha->\BOOL)->\alpha~\LIST->\alpha~\LIST \\
102 \mathit{map} & : & (\alpha->\beta)->\alpha~\LIST->\beta~\LIST \\
103 \mathit{deep\_map} & :
104 & (\alpha->\beta)->\alpha~\LIST~\STACK->\beta~\LIST~\STACK \\[1ex]
105 % \ISCLOSEDFUN & : & \GOALSWITCH -> \BOOL \\
106 \ISOPENFUN & : & \GOALSWITCH -> \BOOL \\
107 \CLOSEFUN & : & \GOALSWITCH -> \GOALSWITCH \\[1ex]
108 % \OPENFUN & : & \GOAL -> \GOALSWITCH \\[1ex]
109 \GOALOFFUN & : & \GOALSWITCH -> \GOAL \\
115 \TSEM{\APPLY{tac}}{\xi}{\OPEN{n}} & =
116 & \mathit{apply\_tac}(\mathit{tac},\xi,n) & \\
117 \TSEM{\SKIP}{\xi}{\CLOSED{n}} & = & \langle \xi, [], [n]\rangle & \\
123 \SEM{\TACTICAL{T}}{\xi}{[g_1;\dots;g_n]::\Gamma}{\tau}{\kappa}
126 \MAPFUN{\mathtt{Open}}{G^O_n}::\DEEPMAPFUN{\CLOSEFUN}{G^C_n,\Gamma},
127 \tau\setminus G^C_n,\kappa\setminus G^O_n\rangle
130 \multicolumn{3}{l}{\hspace{2em}\mathit{where} ~
133 \langle\xi_0, G^O_0, G^C_0\rangle & = & \langle\xi, [], []\rangle \\
134 \langle\xi_{i+1}, G^O_{i+1}, G^C_{i+1}\rangle
136 & \langle\xi_i, G^O_i, G^C_i\rangle
137 & g_{i+1}\in G^C_i \\
138 \langle\xi_{i+1}, G^O_{i+1}, G^C_{i+1}\rangle
140 & \langle\xi, (G^O_i\setminus G^C)\cup G^O, G^C_i\cup G^C\rangle
141 & g_{i+1}\not\in G^C_i \\
142 & & \mathit{where} ~ \langle\xi,G^O,G^C\rangle=\TSEM{T}{\xi_i}{g_{i+1}}
149 \SEM{C_1 ~ \SEMICOLON ~ C_2}{\xi}{\Gamma}{\tau}{\kappa}
151 & \SEM{C_2}{\xi'}{\Gamma'}{\tau'}{\kappa'}
155 \langle\xi',\Gamma',\tau',\kappa',\rangle =
156 \SEM{C_1}{\xi}{\Gamma}{\tau}{\kappa}
159 \SEM{~\DOT~}{\xi}{(g::G)::\Gamma}{\tau}{K::\kappa}
161 & \langle\xi, [g]::\Gamma, \tau,
162 (\MAPFUN{\mathtt{Open}}{\FILTERFUN{\ISOPENFUN}{G}}\cup K)::\kappa\rangle
165 \SEM{~\DOT~}{\xi}{[]::\Gamma}{\tau}{(n::N)::\kappa}
167 & \langle\xi, [\OPEN{n}]::\Gamma, \tau, N::\kappa\rangle
170 \SEM{~\BRANCH~}{\xi}{[g_1;\dots;g_n]::\Gamma}{\tau}{\kappa}
172 & \langle\xi, [g_1]::[g_2;\dots;g_n]::\Gamma, []::\tau, []::\kappa\rangle
175 \SEM{~\SHIFT~}{\xi}{G::[g_i;\dots;g_n]::\Gamma}{T::\tau}{K::\kappa}
178 [g_i]::[g_{i+1};\dots;g_n]::\Gamma,
179 (T\cup\MAPFUN{\GOALOFFUN}{\FILTERFUN{\ISOPENFUN}{G}}\cup K)::\tau,
183 \SEM{~\MERGE~}{\xi}{G::[g_i;\dots;g_n]::\Gamma}{T::\tau}{K::\kappa}
187 \cup\FILTERFUN{\ISOPENFUN}{G}
189 \cup\MAPFUN{\mathtt{Open}}{K})::\Gamma,
194 \SEM{\GOTO{n}{C}}{\xi}{\Gamma}{\tau}{\kappa}
196 & \langle \xi',\Gamma',\tau',\kappa' \rangle
200 \langle \xi', []::\Gamma', []::\tau', []::\kappa' \rangle
201 = \SEM{C}{\xi}{[\OPEN{n}]::\Gamma}{[]::\tau}{[]::\kappa}