[beamer] proto 0

beamer/beamer.tex

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+\documentclass{beamer}
+\usepackage{tikz}
+%\usepackage{minted}
+
+\usetikzlibrary{positioning}
+\usetheme{Darmstadt}
+
+\begin{document}
+
+\section{Structure of the compiler}
+\begin{frame}{Main ideas}
+	\begin{figure}
+		\begin{tikzpicture}
+			\node (sf) {Source file};
+			\node[right =2cm of sf] (ast) {Typed AST};
+			\node[right =2cm of ast] (C) {C program};
+			\draw
+				(sf) edge[->] node[above] {parser} (ast)
+				(ast) edge[->] node[above] {compiler} (C);
+		\end{tikzpicture}
+		\caption{Structure of the compiler}
+	\end{figure}
+\end{frame}
+
+\begin{frame}{Testing}
+	\begin{block}{Passes}
+		The passes can be split into:
+		\begin{itemize}
+			\item those checking the program validity
+			\item those modifying the AST of the program
+		\end{itemize}
+	\end{block}
+\end{frame}
+
+\section{Typed AST}
+\subsection{First attempt using GADTs}
+\begin{frame}
+	\begin{block}{Main idea}
+		Using GADTs to represent nodes and expressions allows to ensure the
+		well-typedness of a program.
+	\end{block}
+	\begin{figure}
+		\centering
+		\includegraphics[width=.75\textwidth]{imgs/gadt.png}
+	\end{figure}
+%type _ t_var =
+%  | BVar: ident -> bool t_var
+%  | IVar: ident -> int t_var
+%  | RVar: ident -> real t_var
+%
+%type _ t_expression =
+%  | EVar: 'a t_var -> 'a t_expression
+%  | EMonOp: monop * 'a t_expression -> 'a t_expression
+%  | EBinOp: binop * 'a t_expression * 'a t_expression -> 'a t_expression
+%  | ETriOp: triop * bool t_expression * 'a t_expression * 'a t_expression -> 'a t_expression
+%  | EComp:  compop * 'a t_expression * 'a t_expression -> bool t_expression
+%  | EConst: 'a const -> 'a t_expression
+%  | ETuple: 'a t_expression * 'b t_expression -> ('a * 'b) t_expression
+%  | EApp: (('a -> 'b) t_node) * 'a t_expression -> 'b t_expression
+%
+%and _ t_varlist =
+%  | NVar: 'a t_varlist
+%  | CVar: 'a t_var * 'b t_varlist -> ('a * 'b) t_varlist
+%
+%and 'a t_equation = 'a t_varlist * 'a t_expression
+%
+%and _ t_eqlist =
+%  | NEql: unit t_eqlist
+%  | CEql: 'a t_equation * 'b t_eqlist -> ('a * 'b) t_eqlist
+%
+%and _ t_node =
+%  | MakeNode:
+%    ident
+%    * 'i t_varlist * 'o t_varlist
+%    * 'l t_varlist * 'e t_eqlist
+%    -> ('i -> 'o) t_node
+%
+%type _ t_nodelist =
+%  | NNode: unit t_nodelist
+%  | CNode: ('a -> 'b) t_node * 'c t_nodelist -> (('a -> 'b) * 'c) t_nodelist
+%	\end{minted}
+\end{frame}
+\begin{frame}
+	\begin{block}{Pros of using GADTs}
+		\begin{itemize}
+			\item Any term of the GADT represents a well-typed program
+			\item Extending the language to support more types consists of adding
+				constructors to variables and constants
+			\item The types are easy to read and understand
+		\end{itemize}
+	\end {block}
+
+	\begin{block}{Cons of using GADTs}
+		\begin{itemize}
+			\item
+			They cannot be dynamically generated (hence it is impossible to
+			implement a parser that gives back a GADT)
+			\item
+			One should think about the isomorphism between
+			\texttt{a $\ast$ (b $\ast$ c)} and \texttt{(a $\ast$ b) $\ast$ c}.
+		\end{itemize}
+	\end{block}
+\end{frame}
+
+\subsection{Second attempt: using explicit types in the variables, expressions,
+\dots{} constructors}
+\begin{frame}
+	\begin{block}{Idea}
+		Explicitly collect typing information while parsing.
+	\end{block}
+	\begin{figure}
+		\centering
+		\includegraphics[width=.6\textwidth]{imgs/explicit_types.png}
+	\end{figure}
+\end{frame}
+
+\begin{frame}
+	\begin{block}{Pros of using explicit types}
+		\begin{itemize}
+			\item Programs can be built dynamically, hence a parser can be
+			written
+			\item While parsing, the parser has all the required information on
+			the sub-variables/nodes/expressions to check the well-typedness
+		\end{itemize}
+	\end{block}
+	\begin{block}{Cons of these definitions}
+		\begin{itemize}
+			\item The typing information on terms is very redundant.
+			\item The rejection of ill-typed programs depends on the correctness
+			of the parser
+		\end{itemize}
+	\end{block}
+\end{frame}
+
+\section{Passes}
+\begin{frame}{Passes}
+	\begin{block}
+		The passes of our compiler are functions of taking a program and either:
+		\begin{itemize}
+			\item returning a program if the pass succeeded
+			\item returns nothing otherwise
+		\end{itemize}
+
+		We only have one language in our compiler: no intermediary language.
+	\end{block}
+\end{frame}
+
+\subsection{Check}
+\begin{frame}
+	\begin{block}{Passes}
+		The passes can be split into:
+		\begin{itemize}
+			\item those checking the program validity
+			\item those modifying the AST of the program
+		\end{itemize}
+	\end{block}
+\end{frame}
+
+\begin{frame}{Implemented passes}
+	\begin{block}{\texttt{pre}-propagation to leaves}
+	\end{block}
+	\begin{block}{Check: unique initialization for variables}
+	\end{block}
+	\begin{block}{Linearization of the equations}
+	\end{block}
+\end{frame}
+
+\end{document}
+

src/simulation.ml

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+open Ast
+
+type sim_var =
+  | SIVar of ident * (int option)
+  | SBVar of ident * (bool option)
+  | SRVar of ident * (real option)
+
+type sim_node_st =
+  {
+    node_outputs: sim_var list;
+    node_loc_vars: sim_var list;
+    node_inner_nodes: sim_node list;
+  }
+and sim_node_step_fn =
+  sim_node_st -> sim_var list -> (sim_var list * sim_node_st)
+and sim_node = sim_node_st * sim_node_step_fn
+
+let pp_sim fmt ((sn, _): sim_node) =
+  let rec aux fmt vars =
+    match vars with
+    | [] -> ()
+    | SIVar (s, None) :: t ->
+        Format.fprintf fmt "\t<%s : int> uninitialized yet.\n%a" s aux t
+    | SBVar (s, None) :: t ->
+        Format.fprintf fmt "\t<%s : bool> uninitialized yet.\n%a" s aux t
+    | SRVar (s, None) :: t ->
+        Format.fprintf fmt "\t<%s : real> uninitialized yet.\n%a" s aux t
+    | SIVar (s, Some i) :: t ->
+        Format.fprintf fmt "\t<%s : real> = %d\n%a" s i aux t
+    | SBVar (s, Some b) :: t ->
+        Format.fprintf fmt "\t<%s : real> = %s\n%a" s (Bool.to_string b) aux t
+    | SRVar (s, Some r) :: t ->
+        Format.fprintf fmt "\t<%s : real> = %f\n%a" s r aux t
+  in
+  if sn.node_loc_vars <> []
+    then
+      Format.fprintf fmt "State of the simulated node:\n\
+                          \tOutput variables:\n%a
+                          \tLocal variables:\n%a"
+        aux sn.node_outputs
+        aux sn.node_loc_vars
+    else
+      Format.fprintf fmt "State of the simulated node:\n\
+                          \tOutput variables:\n%a
+                          \tThere are no local variables:\n"
+        aux sn.node_outputs
+
+
+exception MySimulationException of string
+
+let fetch_node (p: t_nodelist) (s: ident) : t_node =
+  match List.filter (fun n -> n.n_name = s) p with
+  | [e] -> e
+  | _ -> raise (MySimulationException (Format.asprintf "Node %s undefined." s))
+
+let fetch_var (l: sim_var list) (s: ident) =
+  match List.filter
+    (function
+      | SBVar (v, _) | SRVar (v, _) | SIVar (v, _) -> v = s) l with
+  | [v] -> v
+  | _ -> raise (MySimulationException
+                (Format.asprintf "Variable %s undefined." s))
+
+(** TODO! *)
+let make_sim (main_fn: ident) (p: t_nodelist): sim_node =
+  let main_n = fetch_node p main_fn in
+  let node_outputs =
+    List.map
+      (function
+        | IVar s -> SIVar (s, None)
+        | BVar s -> SBVar (s, None)
+        | RVar s -> SRVar (s, None))
+      (snd main_n.n_outputs) in
+  let node_loc_vars: sim_var list =
+    List.map
+      (function
+        | IVar s -> SIVar (s, None)
+        | BVar s -> SBVar (s, None)
+        | RVar s -> SRVar (s, None))
+      (snd main_n.n_local_vars) in
+  let node_inner_nodes = (* TODO! *) [] in
+  ({node_outputs = node_outputs;
+    node_loc_vars = node_loc_vars;
+    node_inner_nodes = node_inner_nodes; },
+    (fun s l -> (s.node_outputs, s)))
+
+
+
+let simulate main_fn ast =
+  let sim_ast = make_sim main_fn ast in
+  Format.printf "Initial state:\n%a" pp_sim sim_ast
+