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diff --git a/doc/tools/Translator.tex b/doc/tools/Translator.tex deleted file mode 100644 index 005ca9c0..00000000 --- a/doc/tools/Translator.tex +++ /dev/null @@ -1,898 +0,0 @@ -\ifx\pdfoutput\undefined % si on est pas en pdflatex -\documentclass[11pt,a4paper]{article} -\else -\documentclass[11pt,a4paper,pdftex]{article} -\fi -\usepackage[latin1]{inputenc} -\usepackage[T1]{fontenc} -\usepackage{pslatex} -\usepackage{url} -\usepackage{verbatim} -\usepackage{amsmath} -\usepackage{amssymb} -\usepackage{array} -\usepackage{fullpage} - -\title{Translation from Coq V7 to V8} -\author{The Coq Development Team} - -%% Macros etc. -\catcode`\_=13 -\let\subscr=_ -\def_{\ifmmode\sb\else\subscr\fi} - -\def\NT#1{\langle\textit{#1}\rangle} -\def\NTL#1#2{\langle\textit{#1}\rangle_{#2}} -%\def\TERM#1{\textsf{\bf #1}} -\def\TERM#1{\texttt{#1}} -\newenvironment{transbox} - {\begin{center}\tt\begin{tabular}{l|ll} \hfil\textrm{V7} & \hfil\textrm{V8} \\ \hline} - {\end{tabular}\end{center}} -\def\TRANS#1#2 - {\begin{tabular}[t]{@{}l@{}}#1\end{tabular} & - \begin{tabular}[t]{@{}l@{}}#2\end{tabular} \\} -\def\TRANSCOM#1#2#3 - {\begin{tabular}[t]{@{}l@{}}#1\end{tabular} & - \begin{tabular}[t]{@{}l@{}}#2\end{tabular} & #3 \\} - -%% -%% -%% -\begin{document} -\maketitle - -\section{Introduction} - -Coq version 8.0 is a major version and carries major changes: the -concrete syntax was redesigned almost from scratch, and many notions -of the libraries were renamed for uniformisation purposes. We felt -that these changes could discourage users with large theories from -switching to the new version. - -The goal of this document is to introduce these changes on simple -examples (mainly the syntactic changes), and describe the automated -tools to help moving to V8.0. Essentially, it consists of a translator -that takes as input a Coq source file in old syntax and produces a -file in new syntax and adapted to the new standard library. The main -extra features of this translator is that it keeps comments, even -those within expressions\footnote{The position of those comment might -differ slightly since there is no exact matching of positions between -old and new syntax.}. - -The document is organised as follows: first section describes the new -syntax on simple examples. It is very translation-oriented. This -should give users of older versions the flavour of the new syntax, and -allow them to make translation manually on small -examples. Section~\ref{Translation} explains how the translation -process can be automatised for the most part (the boring one: applying -similar changes over thousands of lines of code). We strongly advise -users to follow these indications, in order to avoid many potential -complications of the translation process. - - -\section{The new syntax on examples} - -The goal of this section is to introduce to the new syntax of Coq on -simple examples, rather than just giving the new grammar. It is -strongly recommended to read first the definition of the new syntax -(in the reference manual), but this document should also be useful for -the eager user who wants to start with the new syntax quickly. - -The toplevel has an option {\tt -translate} which allows to -interactively translate commands. This toplevel translator accepts a -command, prints the translation on standard output (after a % -\verb+New syntax:+ balise), executes the command, and waits for another -command. The only requirements is that they should be syntactically -correct, but they do not have to be well-typed. - -This interactive translator proved to be useful in two main -usages. First as a ``debugger'' of the translation. Before the -translation, it may help in spotting possible conflicts between the -new syntax and user notations. Or when the translation fails for some -reason, it makes it easy to find the exact reason why it failed and -make attempts in fixing the problem. - -The second usage of the translator is when trying to make the first -proofs in new syntax. Well trained users will automatically think -their scripts in old syntax and might waste much time (and the -intuition of the proof) if they have to search the translation in a -document. Running a translator in the background will allow the user -to instantly have the answer. - -The rest of this section is a description of all the aspects of the -syntax that changed and how they were translated. All the examples -below can be tested by entering the V7 commands in the toplevel -translator. - - -%% - -\subsection{Changes in lexical conventions w.r.t. V7} - -\subsubsection{Identifiers} - -The lexical conventions changed: \TERM{_} is not a regular identifier -anymore. It is used in terms as a placeholder for subterms to be inferred -at type-checking, and in patterns as a non-binding variable. - -Furthermore, only letters (Unicode letters), digits, single quotes and -_ are allowed after the first character. - -\subsubsection{Quoted string} - -Quoted strings are used typically to give a filename (which may not -be a regular identifier). As before they are written between double -quotes ("). Unlike for V7, there is no escape character: characters -are written normally except the double quote which is doubled. - -\begin{transbox} -\TRANS{"abcd$\backslash\backslash$efg"}{"abcd$\backslash$efg"} -\TRANS{"abcd$\backslash$"efg"}{"abcd""efg"} -\end{transbox} - - -\subsection{Main changes in terms w.r.t. V7} - - -\subsubsection{Precedence of application} - -In the new syntax, parentheses are not really part of the syntax of -application. The precedence of application (10) is tighter than all -prefix and infix notations. It makes it possible to remove parentheses -in many contexts. - -\begin{transbox} -\TRANS{(A x)->(f x)=(g y)}{A x -> f x = g y} -\TRANS{(f [x]x)}{f (fun x => x)} -\end{transbox} - - -\subsubsection{Arithmetics and scopes} - -The specialized notation for \TERM{Z} and \TERM{R} (introduced by -symbols \TERM{`} and \TERM{``}) have disappeared. They have been -replaced by the general notion of scope. - -\begin{center} -\begin{tabular}{l|l|l} -type & scope name & delimiter \\ -\hline -types & type_scope & \TERM{type} \\ -\TERM{bool} & bool_scope & \\ -\TERM{nat} & nat_scope & \TERM{nat} \\ -\TERM{Z} & Z_scope & \TERM{Z} \\ -\TERM{R} & R_scope & \TERM{R} \\ -\TERM{positive} & positive_scope & \TERM{P} -\end{tabular} -\end{center} - -In order to use notations of arithmetics on \TERM{Z}, its scope must -be opened with command \verb+Open Scope Z_scope.+ Another possibility -is using the scope change notation (\TERM{\%}). The latter notation is -to be used when notations of several scopes appear in the same -expression. - -In examples below, scope changes are not needed if the appropriate scope -has been opened. Scope \verb|nat_scope| is opened in the initial state of Coq. -\begin{transbox} -\TRANSCOM{`0+x=x+0`}{0+x=x+0}{\textrm{Z_scope}} -\TRANSCOM{``0 + [if b then ``1`` else ``2``]``}{0 + if b then 1 else 2}{\textrm{R_scope}} -\TRANSCOM{(0)}{0}{\textrm{nat_scope}} -\end{transbox} - -Below is a table that tells which notation is available in which -scope. The relative precedences and associativity of operators is the -same as in usual mathematics. See the reference manual for more -details. However, it is important to remember that unlike V7, the type -operators for product and sum are left-associative, in order not to -clash with arithmetic operators. - -\begin{center} -\begin{tabular}{l|l} -scope & notations \\ -\hline -nat_scope & \texttt{+ - * < <= > >=} \\ -Z_scope & \texttt{+ - * / mod < <= > >= ?=} \\ -R_scope & \texttt{+ - * / < <= > >=} \\ -type_scope & \texttt{* +} \\ -bool_scope & \texttt{\&\& || -} \\ -list_scope & \texttt{:: ++} -\end{tabular} -\end{center} - - - -\subsubsection{Notation for implicit arguments} - -The explicitation of arguments is closer to the \emph{bindings} -notation in tactics. Argument positions follow the argument names of -the head constant. The example below assumes \verb+f+ is a function -with two implicit dependent arguments named \verb+x+ and \verb+y+. -\begin{transbox} -\TRANS{f 1!t1 2!t2 t3}{f (x:=t1) (y:=t2) t3} -\TRANS{!f t1 t2}{@f t1 t2} -\end{transbox} - - -\subsubsection{Inferred subterms} - -Subterms that can be automatically inferred by the type-checker is now -written {\tt _} - -\begin{transbox} -\TRANS{?}{_} -\end{transbox} - -\subsubsection{Universal quantification} - -The universal quantification and dependent product types are now -introduced by the \texttt{forall} keyword before the binders and a -comma after the binders. - -The syntax of binders also changed significantly. A binder can simply be -a name when its type can be inferred. In other cases, the name and the type -of the variable are put between parentheses. When several consecutive -variables have the same type, they can be grouped. Finally, if all variables -have the same type, parentheses can be omitted. - -\begin{transbox} -\TRANS{(x:A)B}{forall (x:~A), B ~~\textrm{or}~~ forall x:~A, B} -\TRANS{(x,y:nat)P}{forall (x y :~nat), P ~~\textrm{or}~~ forall x y :~nat, P} -\TRANS{(x,y:nat;z:A)P}{forall (x y :~nat) (z:A), P} -\TRANS{(x,y,z,t:?)P}{forall x y z t, P} -\TRANS{(x,y:nat;z:?)P}{forall (x y :~nat) z, P} -\end{transbox} - -\subsubsection{Abstraction} - -The notation for $\lambda$-abstraction follows that of universal -quantification. The binders are surrounded by keyword \texttt{fun} -and \verb+=>+. - -\begin{transbox} -\TRANS{[x,y:nat; z](f a b c)}{fun (x y:nat) z => f a b c} -\end{transbox} - - -\subsubsection{Pattern-matching} - -Beside the usage of the keyword pair \TERM{match}/\TERM{with} instead of -\TERM{Cases}/\TERM{of}, the main change is the notation for the type of -branches and return type. It is no longer written between \TERM{$<$ $>$} before -the \TERM{Cases} keyword, but interleaved with the destructured objects. - -The idea is that for each destructured object, one may specify a -variable name (after the \TERM{as} keyword) to tell how the branches -types depend on this destructured objects (case of a dependent -elimination), and also how they depend on the value of the arguments -of the inductive type of the destructured objects (after the \TERM{in} -keyword). The type of branches is then given after the keyword -\TERM{return}, unless it can be inferred. - -Moreover, when the destructured object is a variable, one may use this -variable in the return type. - -\begin{transbox} -\TRANS{Cases n of\\~~ O => O \\| (S k) => (1) end}{match n with\\~~ 0 => 0 \\| S k => 1 end} -\TRANS{Cases m n of \\~~0 0 => t \\| ... end}{match m, n with \\~~0, 0 => t \\| ... end} -\TRANS{<[n:nat](P n)>Cases T of ... end}{match T as n return P n with ... end} -\TRANS{<[n:nat][p:(even n)]\~{}(odd n)>Cases p of\\~~ ... \\end}{match p in even n return \~{} odd n with\\~~ ...\\end} -\end{transbox} - -The annotations of the special pattern-matching operators -(\TERM{if}/\TERM{then}/\TERM{else}) and \TERM{let()} also changed. The -only restriction is that the destructuring \TERM{let} does not allow -dependent case analysis. - -\begin{transbox} -\TRANS{ - \begin{tabular}{@{}l} - <[n:nat;x:(I n)](P n x)>if t then t1 \\ - else t2 - \end{tabular}}% -{\begin{tabular}{@{}l} - if t as x in I n return P n x then t1 \\ - else t2 - \end{tabular}} -\TRANS{<[n:nat](P n)>let (p,q) = t1 in t2}% -{let (p,q) in I n return P n := t1 in t2} -\end{transbox} - - -\subsubsection{Fixpoints and cofixpoints} - -An simpler syntax for non-mutual fixpoints is provided, making it very close -to the usual notation for non-recursive functions. The decreasing argument -is now indicated by an annotation between curly braces, regardless of the -binders grouping. The annotation can be omitted if the binders introduce only -one variable. The type of the result can be omitted if inferable. - -\begin{transbox} -\TRANS{Fix plus\{plus [n:nat] : nat -> nat :=\\~~ [m]...\}}{fix plus (n m:nat) \{struct n\}: nat := ...} -\TRANS{Fix fact\{fact [n:nat]: nat :=\\ -~~Cases n of\\~~~~ O => (1) \\~~| (S k) => (mult n (fact k)) end\}}{fix fact - (n:nat) :=\\ -~~match n with \\~~~~0 => 1 \\~~| (S k) => n * fact k end} -\end{transbox} - -There is a syntactic sugar for single fixpoints (defining one -variable) associated to a local definition: - -\begin{transbox} -\TRANS{let f := Fix f \{f [x:A] : T := M\} in\\(g (f y))}{let fix f (x:A) : T := M in\\g (f x)} -\end{transbox} - -The same applies to cofixpoints, annotations are not allowed in that case. - -\subsubsection{Notation for type cast} - -\begin{transbox} -\TRANS{O :: nat}{0 : nat} -\end{transbox} - -\subsection{Main changes in tactics w.r.t. V7} - -The main change is that all tactic names are lowercase. This also holds for -Ltac keywords. - -\subsubsection{Renaming of induction tactics} - -\begin{transbox} -\TRANS{NewDestruct}{destruct} -\TRANS{NewInduction}{induction} -\TRANS{Induction}{simple induction} -\TRANS{Destruct}{simple destruct} -\end{transbox} - -\subsubsection{Ltac} - -Definitions of macros are introduced by \TERM{Ltac} instead of -\TERM{Tactic Definition}, \TERM{Meta Definition} or \TERM{Recursive -Definition}. They are considered recursive by default. - -\begin{transbox} -\TRANS{Meta Definition my_tac t1 t2 := t1; t2.}% -{Ltac my_tac t1 t2 := t1; t2.} -\end{transbox} - -Rules of a match command are not between square brackets anymore. - -Context (understand a term with a placeholder) instantiation \TERM{inst} -became \TERM{context}. Syntax is unified with subterm matching. - -\begin{transbox} -\TRANS{Match t With [C[x=y]] -> Inst C[y=x]}% -{match t with context C[x=y] => context C[y=x] end} -\end{transbox} - -Arguments of macros use the term syntax. If a general Ltac expression -is to be passed, it must be prefixed with ``{\tt ltac :}''. In other -cases, when a \'{} was necessary, it is replaced by ``{\tt constr :}'' - -\begin{transbox} -\TRANS{my_tac '(S x)}{my_tac (S x)} -\TRANS{my_tac (Let x=tac In x)}{my_tac ltac:(let x:=tac in x)} -\TRANS{Let x = '[x](S (S x)) In Apply x}% -{let x := constr:(fun x => S (S x)) in apply x} -\end{transbox} - -{\tt Match Context With} is now called {\tt match goal with}. Its -argument is an Ltac expression by default. - - -\subsubsection{Named arguments of theorems ({\em bindings})} - -\begin{transbox} -\TRANS{Apply thm with x:=t 1:=u}{apply thm with (x:=t) (1:=u)} -\end{transbox} - - -\subsubsection{Occurrences} - -To avoid ambiguity between a numeric literal and the optional -occurrence numbers of this term, the occurrence numbers are put after -the term itself and after keyword \TERM{as}. -\begin{transbox} -\TRANS{Pattern 1 2 (f x) 3 4 d y z}{pattern f x at 1 2, d at 3 4, y, z} -\end{transbox} - - -\subsubsection{{\tt LetTac} and {\tt Pose}} - -Tactic {\tt LetTac} was renamed into {\tt set}, and tactic {\tt Pose} -was a particular case of {\tt LetTac} where the abbreviation is folded -in the conclusion\footnote{There is a tactic called {\tt pose} in V8, -but its behaviour is not to fold the abbreviation at all.}. - -\begin{transbox} -\TRANS{LetTac x = t in H}{set (x := t) in H} -\TRANS{Pose x := t}{set (x := t)} -\end{transbox} - -{\tt LetTac} could be followed by a specification (called a clause) of -the places where the abbreviation had to be folded (hypothese and/or -conclusion). Clauses are the syntactic notion to denote in which parts -of a goal a given transformation shold occur. Its basic notation is -either \TERM{*} (meaning everywhere), or {\tt\textrm{\em hyps} |- -\textrm{\em concl}} where {\em hyps} is either \TERM{*} (to denote all -the hypotheses), or a comma-separated list of either hypothesis name, -or {\tt (value of $H$)} or {\tt (type of $H$)}. Moreover, occurrences -can be specified after every hypothesis after the {\TERM{at}} -keyword. {\em concl} is either empty or \TERM{*}, and can be followed -by occurences. - -\begin{transbox} -\TRANS{in Goal}{in |- *} -\TRANS{in H H1}{in H1, H2 |-} -\TRANS{in H H1 ...}{in * |-} -\TRANS{in H H1 Goal}{in H1, H2 |- *} -\TRANS{in H H1 H2 ... Goal}{in *} -\TRANS{in 1 2 H 3 4 H0 1 3 Goal}{in H at 1 2, H0 at 3 4 |- * at 1 3} -\end{transbox} - -\subsection{Main changes in vernacular commands w.r.t. V7} - - -\subsubsection{Require} - -The default behaviour of {\tt Require} is not to open the loaded -module. - -\begin{transbox} -\TRANS{Require Arith}{Require Import Arith} -\end{transbox} - -\subsubsection{Binders} - -The binders of vernacular commands changed in the same way as those of -fixpoints. This also holds for parameters of inductive definitions. - - -\begin{transbox} -\TRANS{Definition x [a:A] : T := M}{Definition x (a:A) : T := M} -\TRANS{Inductive and [A,B:Prop]: Prop := \\~~conj : A->B->(and A B)}% - {Inductive and (A B:Prop): Prop := \\~~conj : A -> B -> and A B} -\end{transbox} - -\subsubsection{Hints} - -Both {\tt Hints} and {\tt Hint} commands are beginning with {\tt Hint}. - -Command {\tt HintDestruct} has disappeared. - - -The syntax of \emph{Extern} hints changed: the pattern and the tactic -to be applied are separated by a {\tt =>}. -\begin{transbox} -\TRANS{Hint name := Resolve (f ? x)}% -{Hint Resolve (f _ x)} -\TRANS{Hint name := Extern 4 (toto ?) Apply lemma}% -{Hint Extern 4 (toto _) => apply lemma} -\TRANS{Hints Resolve x y z}{Hint Resolve x y z} -\TRANS{Hints Resolve f : db1 db2}{Hint Resolve f : db1 db2} -\TRANS{Hints Immediate x y z}{Hint Immediate x y z} -\TRANS{Hints Unfold x y z}{Hint Unfold x y z} -%% \TRANS{\begin{tabular}{@{}l} -%% HintDestruct Local Conclusion \\ -%% ~~name (f ? ?) 3 [Apply thm] -%% \end{tabular}}% -%% {\begin{tabular}{@{}l} -%% Hint Local Destuct name := \\ -%% ~~3 Conclusion (f _ _) => apply thm -%% \end{tabular}} -\end{transbox} - - -\subsubsection{Implicit arguments} - - -{\tt Set Implicit Arguments} changed its meaning in V8: the default is -to turn implicit only the arguments that are {\em strictly} implicit -(or rigid), i.e. that remains inferable whatever the other arguments -are. For instance {\tt x} inferable from {\tt P x} is not strictly -inferable since it can disappears if {\tt P} is instanciated by a term -which erases {\tt x}. - -\begin{transbox} -\TRANS{Set Implicit Arguments}% -{\begin{tabular}{l} - Set Implicit Arguments. \\ - Unset Strict Implicits. - \end{tabular}} -\end{transbox} - -However, you may wish to adopt the new semantics of {\tt Set Implicit -Arguments} (for instance because you think that the choice of -arguments it sets implicit is more ``natural'' for you). - - -\subsection{Changes in standard library} - -Many lemmas had their named changed to improve uniformity. The user -generally do not have to care since the translators performs the -renaming. - - Type {\tt entier} from fast_integer.v is renamed into {\tt N} by the -translator. As a consequence, user-defined objects of same name {\tt N} -are systematically qualified even tough it may not be necessary. The -following table lists the main names with which the same problem -arises: -\begin{transbox} -\TRANS{IF}{IF_then_else} -\TRANS{ZERO}{Z0} -\TRANS{POS}{Zpos} -\TRANS{NEG}{Zneg} -\TRANS{SUPERIEUR}{Gt} -\TRANS{EGAL}{Eq} -\TRANS{INFERIEUR}{Lt} -\TRANS{add}{Pplus} -\TRANS{true_sub}{Pminus} -\TRANS{entier}{N} -\TRANS{Un_suivi_de}{Ndouble_plus_one} -\TRANS{Zero_suivi_de}{Ndouble} -\TRANS{Nul}{N0} -\TRANS{Pos}{Npos} -\end{transbox} - - -\subsubsection{Implicit arguments} - -%% Hugo: -Main definitions of standard library have now implicit -arguments. These arguments are dropped in the translated files. This -can exceptionally be a source of incompatibilities which has to be -solved by hand (it typically happens for polymorphic functions applied -to {\tt nil} or {\tt None}). -%% preciser: avant ou apres trad ? - -\subsubsection{Logic about {\tt Type}} - -Many notations that applied to {\tt Set} have been extended to {\tt -Type}, so several definitions in {\tt Type} are superseded by them. - -\begin{transbox} -\TRANS{x==y}{x=y} -\TRANS{(EXT x:Prop | Q)}{exists x:Prop, Q} -\TRANS{identityT}{identity} -\end{transbox} - - - -%% Doc of the translator -\section{A guide to translation} -\label{Translation} - -%%\subsection{Overview of the translation process} - -Here is a short description of the tools involved in the translation process: -\begin{description} -\item{\tt coqc -translate} -is the automatic translator. It is a parser/pretty-printer. This means -that the translation is made by parsing every command using a parser -of old syntax, which is printed using the new syntax. Many efforts -were made to preserve as much as possible of the quality of the -presentation: it avoids expansion of syntax extensions, comments are -not discarded and placed at the same place. -\item{\tt translate-v8} (in the translation package) is a small -shell-script that will help translate developments that compile with a -Makefile with minimum requirements. -\end{description} - -\subsection{Preparation to translation} - -This step is very important because most of work shall be done before -translation. If a problem occurs during translation, it often means -that you will have to modify the original source and restart the -translation process. This also means that it is recommended not to -edit the output of the translator since it would be overwritten if -the translation has to be restarted. - -\subsubsection{Compilation with {\tt coqc -v7}} - -First of all, it is mandatory that files compile with the current -version of Coq (8.0) with option {\tt -v7}. Translation is a -complicated task that involves the full compilation of the -development. If your development was compiled with older versions, -first upgrade to Coq V8.0 with option {\tt -v7}. If you use a Makefile -similar to those produced by {\tt coq\_makefile}, you probably just -have to do - -{\tt make OPT="-opt -v7"} ~~~or~~~ {\tt make OPT="-byte -v7"} - -When the development compiles successfully, there are several changes -that might be necessary for the translation. Essentially, this is -about syntax extensions (see section below dedicated to porting syntax -extensions). If you do not use such features, then you are ready to -try and make the translation. - -\subsection{Translation} - -\subsubsection{The general case} - -The preferred way is to use script {\tt translate-v8} if your development -is compiled by a Makefile with the following constraints: -\begin{itemize} -\item compilation is achieved by invoking make without specifying a target -\item options are passed to Coq with make variable COQFLAGS that - includes variables OPT, COQLIBS, OTHERFLAGS and COQ_XML. -\end{itemize} -These constraints are met by the makefiles produced by {\tt coq\_makefile} - -Otherwise, modify your build program so as to pass option {\tt --translate} to program {\tt coqc}. The effect of this option is to -ouptut the translated source of any {\tt .v} file in a file with -extension {\tt .v8} located in the same directory than the original -file. - -\subsubsection{What may happen during the translation} - -This section describes events that may happen during the -translation and measures to adopt. - -These are the warnings that may arise during the translation, but they -generally do not require any modification for the user: -Warnings: -\begin{itemize} -\item {\tt Unable to detect if $id$ denotes a local definition}\\ -This is due to a semantic change in clauses. In a command such as {\tt -simpl in H}, the old semantics were to perform simplification in the -type of {\tt H}, or in its body if it is defined. With the new -semantics, it is performed both in the type and the body (if any). It -might lead to incompatibilities - -\item {\tt Forgetting obsolete module}\\ -Some modules have disappeared in V8.0 (new syntax). The user does not -need to worry about it, since the translator deals with it. - -\item {\tt Replacing obsolete module}\\ -Same as before but with the module that were renamed. Here again, the -translator deals with it. -\end{itemize} - -\subsection{Verification of the translation} - -The shell-script {\tt translate-v8} also renames {\tt .v8} files into -{\tt .v} files (older {\tt .v} files are put in a subdirectory called -{\tt v7}) and tries to recompile them. To do so it invokes {\tt make} -without option (which should cause the compilation using {\tt coqc} -without particular option). - -If compilation fails at this stage, you should refrain from repairing -errors manually on the new syntax, but rather modify the old syntax -script and restart the translation. We insist on that because the -problem encountered can show up in many instances (especially if the -problem comes from a syntactic extension), and fixing the original -sources (for instance the {\tt V8only} parts of notations) once will -solve all occurrences of the problem. - -%%\subsubsection{Errors occurring after translation} -%%Equality in {\tt Z} or {\tt R}... - -\subsection{Particular cases} - -\subsubsection{Lexical conventions} - -The definition of identifiers changed. Most of those changes are -handled by the translator. They include: -\begin{itemize} -\item {\tt \_} is not an identifier anymore: it is tranlated to {\tt -x\_} -\item avoid clash with new keywords by adding a trailing {\tt \_} -\end{itemize} - -If the choices made by translation is not satisfactory -or in the following cases: -\begin{itemize} -\item use of latin letters -\item use of iso-latin characters in notations -\end{itemize} -the user should change his development prior to translation. - -\subsubsection{{\tt Case} and {\tt Match}} - -These very low-level case analysis are no longer supported. The -translator tries hard to translate them into a user-friendly one, but -it might lack type information to do so\footnote{The translator tries -to typecheck terms before printing them, but it is not always possible -to determine the context in which terms appearing in tactics -live.}. If this happens, it is preferable to transform it manually -before translation. - -\subsubsection{Syntax extensions with {\tt Grammar} and {\tt Syntax}} - - -{\tt Grammar} and {\tt Syntax} are no longer supported. They -should be replaced by an equivalent {\tt Notation} command and be -processed as described above. Before attempting translation, users -should verify that compilation with option {\tt -v7} succeeds. - -In the cases where {\tt Grammar} and {\tt Syntax} cannot be emulated -by {\tt Notation}, users have to change manually they development as -they wish to avoid the use of {\tt Grammar}. If this is not done, the -translator will simply expand the notations and the output of the -translator will use the regular Coq syntax. - -\subsubsection{Syntax extensions with {\tt Notation} and {\tt Infix}} - -These commands do not necessarily need to be changed. - -Some work will have to be done manually if the notation conflicts with -the new syntax (for instance, using keywords like {\tt fun} or {\tt -exists}, overloading of symbols of the old syntax, etc.) or if the -precedences are not right. - - Precedence levels are now from 0 to 200. In V8, the precedence and -associativity of an operator cannot be redefined. Typical level are -(refer to the chapter on notations in the Reference Manual for the -full list): - -\begin{center} -\begin{tabular}{|cll|} -\hline -Notation & Precedence & Associativity \\ -\hline -\verb!_ <-> _! & 95 & no \\ -\verb!_ \/ _! & 85 & right \\ -\verb!_ /\ _! & 80 & right \\ -\verb!~ _! & 75 & right \\ -\verb!_ = _!, \verb!_ <> _!, \verb!_ < _!, \verb!_ > _!, - \verb!_ <= _!, \verb!_ >= _! & 70 & no \\ -\verb!_ + _!, \verb!_ - _! & 50 & left \\ -\verb!_ * _!, \verb!_ / _! & 40 & left \\ -\verb!- _! & 35 & right \\ -\verb!_ ^ _! & 30 & left \\ -\hline -\end{tabular} -\end{center} - - - By default, the translator keeps the associativity given in V7 while -the levels are mapped according to the following table: - -\begin{center} -\begin{tabular}{l|l|l} -V7 level & mapped to & associativity \\ -\hline -0 & 0 & no \\ -1 & 20 & left \\ -2 & 30 & right \\ -3 & 40 & left \\ -4 & 50 & left \\ -5 & 70 & no \\ -6 & 80 & right \\ -7 & 85 & right \\ -8 & 90 & right \\ -9 & 95 & no \\ -10 & 100 & left -\end{tabular} -\end{center} - -If this is OK, just simply apply the translator. - - -\paragraph{Associativity conflict} - - Since the associativity of the levels obtained by translating a V7 -level (as shown on table above) cannot be changed, you have to choose -another level with a compatible associativity. - - You can choose any level between 0 and 200, knowing that the -standard operators are already set at the levels shown on the list -above. - -Assume you have a notation -\begin{verbatim} -Infix NONA 2 "=_S" my_setoid_eq. -\end{verbatim} -By default, the translator moves it to level 30 which is right -associative, hence a conflict with the expected no associativity. - -To solve the problem, just add the "V8only" modifier to reset the -level and enforce the associativity as follows: -\begin{verbatim} -Infix NONA 2 "=_S" my_setoid_eq V8only (at level 70, no associativity). -\end{verbatim} -The translator now knows that it has to translate "=_S" at level 70 -with no associativity. - -Remark: 70 is the "natural" level for relations, hence the choice of 70 -here, but any other level accepting a no-associativity would have been -OK. - -Second example: assume you have a notation -\begin{verbatim} -Infix RIGHTA 1 "o" my_comp. -\end{verbatim} -By default, the translator moves it to level 20 which is left -associative, hence a conflict with the expected right associativity. - -To solve the problem, just add the "V8only" modifier to reset the -level and enforce the associativity as follows: -\begin{verbatim} -Infix RIGHTA 1 "o" my_comp V8only (at level 20, right associativity). -\end{verbatim} -The translator now knows that it has to translate "o" at level 20 -which has the correct "right associativity". - -Remark: we assumed here that the user wants a strong precedence for -composition, in such a way, say, that "f o g + h" is parsed as -"(f o g) + h". To get "o" binding less than the arithmetical operators, -an appropriated level would have been close of 70, and below, e.g. 65. - - -\paragraph{Conflict: notation hides another notation} - -Remark: use {\tt Print Grammar constr} in V8 to diagnose the overlap -and see the section on factorization in the chapter on notations of -the Reference Manual for hints on how to factorize. - -Example: -\begin{verbatim} -Notation "{ x }" := (my_embedding x) (at level 1). -\end{verbatim} -overlaps in V8 with notation \verb#{ x : A & P }# at level 0 and with -x at level 99. The conflicts can be solved by left-factorizing the -notation as follows: -\begin{verbatim} -Notation "{ x }" := (my_embedding x) (at level 1) - V8only (at level 0, x at level 99). -\end{verbatim} - -\paragraph{Conflict: a notation conflicts with the V8 grammar} - -Again, use the {\tt V8only} modifier to tell the translator to -automatically take in charge the new syntax. - -Example: -\begin{verbatim} -Infix 3 "@" app. -\end{verbatim} -Since {\tt @} is used in the new syntax for deactivating the implicit -arguments, another symbol has to be used, e.g. {\tt @@}. This is done via -the {\tt V8only} option as follows: -\begin{verbatim} -Infix 3 "@" app V8only "@@" (at level 40, left associativity). -\end{verbatim} -or, alternatively by -\begin{verbatim} -Notation "x @ y" := (app x y) (at level 3, left associativity) - V8only "x @@ y" (at level 40, left associativity). -\end{verbatim} - -\paragraph{Conflict: my notation is already defined at another level - (or with another associativity)} - -In V8, the level and associativity of a given notation can no longer -be changed. Then, either you adopt the standard reserved levels and -associativity for this notation (as given on the list above) or you -change your notation. -\begin{itemize} -\item To change the notation, follow the directions in the previous -paragraph -\item To adopt the standard level, just use {\tt V8only} without any -argument. -\end{itemize} - -Example: -\begin{verbatim} -Infix 6 "*" my_mult. -\end{verbatim} -is not accepted as such in V8. Write -\begin{verbatim} -Infix 6 "*" my_mult V8only. -\end{verbatim} -to tell the translator to use {\tt *} at the reserved level (i.e. 40 -with left associativity). Even better, use interpretation scopes (look -at the Reference Manual). - - -\subsubsection{Strict implicit arguments} - -In the case you want to adopt the new semantics of {\tt Set Implicit - Arguments} (only setting rigid arguments as implicit), add the option -{\tt -strict-implicit} to the translator. - -Warning: changing the number of implicit arguments can break the -notations. Then use the {\tt V8only} modifier of {\tt Notation}. - -\end{document} |