Update documentation
This commit is contained in:
dons
parent
92b8dee308
commit
9ee8796e3e
@ -44,18 +44,18 @@ h2 {font-size: 15pt}
|
||||
\medskip
|
||||
%
|
||||
{\htmlonly \textbf{Download \endhtmlonly
|
||||
\urlh{ftp://ftp.cse.unsw.edu.au/pub/users/dons/hs-plugins/hs-plugins-0.9.10.tar.gz}
|
||||
{version 0.9.10}}
|
||||
\urlh{ftp://ftp.cse.unsw.edu.au/pub/users/dons/hs-plugins/hs-plugins-1.0.tar.gz}
|
||||
{version 1.0}}
|
||||
%
|
||||
\medskip
|
||||
|
||||
\hsplugins{} is a library for loading code written in Haskell into an
|
||||
application at runtime, in the form of plugins. It also provides a
|
||||
mechanism for (re-)compiling Haskell source at runtime. Thirdly, a
|
||||
combination of runtime compilation and dynamic loading provides a set
|
||||
of \code{eval} functions-- a form of runtime metaprogramming. Values
|
||||
combination of runtime compilation and dynamic loading provides a set of
|
||||
\code{eval} functions-- a form of runtime metaprogramming. Values
|
||||
exported by Haskell plugins are transparently available to Haskell host
|
||||
applications, and bindings exist to use Haskell plugins from at least C
|
||||
applications, and bindings exist to use Haskell dynamically in C, Perl
|
||||
and Objective C programs. \hsplugins{} requires GHC 6.4 or later.
|
||||
|
||||
\medskip
|
||||
@ -72,7 +72,7 @@ and Objective C programs. \hsplugins{} requires GHC 6.4 or later.
|
||||
|
||||
\item
|
||||
Download the latest stable release:\\
|
||||
\url{ftp://ftp.cse.unsw.edu.au/pub/users/dons/hs-plugins/hs-plugins-0.9.10.tar.gz}
|
||||
\url{ftp://ftp.cse.unsw.edu.au/pub/users/dons/hs-plugins/hs-plugins-1.0.tar.gz}
|
||||
|
||||
\item
|
||||
Darcs repository of the latest code:\\
|
||||
@ -107,6 +107,14 @@ Windows.
|
||||
\section{History}
|
||||
|
||||
\begin{itemize}
|
||||
\item Jan 2006, v1.0
|
||||
\begin{itemize}
|
||||
\item Cabalised build system
|
||||
\item Behave better on 64 bit platforms
|
||||
\item Haddock documentation of the API.
|
||||
\item A couple of bug fixes
|
||||
\end{itemize}
|
||||
|
||||
\item June 2005, v0.9.10
|
||||
\begin{itemize}
|
||||
\item Support for GHC 6.4, with help from Sean
|
||||
@ -287,10 +295,11 @@ The compilation manager fills this role. It is particularly useful in
|
||||
the implementation of \code{eval}.
|
||||
|
||||
The \emph{evaluator}, \code{eval}, utilizes the loader and compilation
|
||||
manager. When passed a string of Haskell code, it compiles the string to
|
||||
object code, loads the result, and returns a Haskell value representing
|
||||
the compiled string to the caller. It can be considered a Haskell
|
||||
interpreter, implemented as a library.
|
||||
manager. When passed a string containing a Haskell expression, it
|
||||
compiles the string to object code, loads the result, and returns a
|
||||
Haskell value representing the compiled string to the caller. It can be
|
||||
considered a Haskell interpreter, implemented as a library, and can be
|
||||
used to embed Haskell evaluation facilities in an application.
|
||||
|
||||
\section{Dynamic Loader}
|
||||
|
||||
@ -352,8 +361,7 @@ failure, or an abstract representation of the module (for calls to
|
||||
\code{unload} or \code{reload}) with the symbol as a Haskell value. The
|
||||
value returned must be given an explicit type signature, or provided
|
||||
with appropriate type constraints such that GHC can determine the
|
||||
expected type returned by \code{load}, as the return type is notionally
|
||||
polymorphic.
|
||||
expected type returned by \code{load}.
|
||||
|
||||
\code{load\_} is provided for the common situation where no user-defined
|
||||
package.conf files are required.
|
||||
@ -383,7 +391,6 @@ do mv <- dynload "Plugin.o" ["api"] ["plugins.conf.inplace"] "resource"
|
||||
\code{dynload} is a safer form of \code{load}. It uses dynamic types
|
||||
to perform a check on the value returned by \code{load} at runtime, to
|
||||
ensure that it has the type the application expects it to have.
|
||||
\code{pdynload} is on average 7\% slower than an unchecked load.
|
||||
|
||||
In order to use \code{dynload}, the symbol the plugin exports must be
|
||||
of type \code{AltData.Dynamic:Dynamic}. (See the \code{AltData} library
|
||||
@ -409,8 +416,8 @@ wrapped inside a rank-N type to hide the polymorphism from the
|
||||
typechecker. This is a bit cumbersome. An alternative typesafe
|
||||
\code{load} is available via the \code{pdynload} interface, which is
|
||||
able to enforce the type of the plugin using GHC's type inference
|
||||
mechanism, and is not restricted in its expressiveness (at the cost of greater load
|
||||
times):
|
||||
mechanism, and is not restricted in its expressiveness (at the cost of
|
||||
greater load times):
|
||||
|
||||
\begin{quote}
|
||||
\scm{
|
||||
@ -554,7 +561,7 @@ Examples:
|
||||
\begin{quote}
|
||||
\scm{
|
||||
do loadPackageWith "yi" ["yi.conf"]
|
||||
unloadPackage "yi"
|
||||
unloadPackage "yi-0.1"
|
||||
}
|
||||
\end{quote}
|
||||
|
||||
@ -895,64 +902,59 @@ mkHsValues :: (Show a) => Data.Map String a -> String
|
||||
}
|
||||
\end{quote}
|
||||
\end{itemize}
|
||||
\subsection{Foreign Eval}
|
||||
|
||||
A preliminary binding to \code{eval} has been implemented to allow C
|
||||
(and Objective C) programs access to the evaluator. Foreign bindings
|
||||
to the compilation manager and dynamic loader are yet to be
|
||||
implemented, but shouldn't be too hard. An foreign binding to a
|
||||
Haskell module that wraps up calls to \code{make} and \code{load}
|
||||
would be fairly trivial.
|
||||
|
||||
At the moment we have an ad-hoc binding to \code{eval}, so that C
|
||||
programmers who know the type of value that will be returned by
|
||||
Haskell can call the appropriate hook into the evaluator. If they get
|
||||
the type wrong, a nullPtr will be returned (so calling Haskell is
|
||||
still typesafe). The foreign bindings to \code{eval} all return
|
||||
\code{NULL} if an error occurred, otherwise a pointer to the value is
|
||||
returned.
|
||||
|
||||
\begin{quote}
|
||||
\scm{
|
||||
foreign export ccall hs_eval_b :: CString -> IO (Ptr CInt)
|
||||
|
||||
foreign export ccall hs_eval_c :: CString -> IO (Ptr CChar)
|
||||
|
||||
foreign export ccall hs_eval_i :: CString -> IO (Ptr CInt)
|
||||
|
||||
foreign export ccall hs_eval_s :: CString -> IO CString
|
||||
}
|
||||
\end{quote}
|
||||
|
||||
An example C program for compiling and evaluating Haskell code at
|
||||
runtime follows. This program calculates a fibonacci number, returning
|
||||
it as a \code{CString} to the C program:
|
||||
% \subsection{Foreign Eval}
|
||||
%
|
||||
% A preliminary binding to \code{eval} has been implemented to allow C
|
||||
% (and Objective C) programs access to the evaluator. Foreign bindings
|
||||
% to the compilation manager and dynamic loader are yet to be
|
||||
% implemented, but shouldn't be too hard. An foreign binding to a
|
||||
% Haskell module that wraps up calls to \code{make} and \code{load}
|
||||
% would be fairly trivial.
|
||||
%
|
||||
% At the moment we have an ad-hoc binding to \code{eval}, so that C
|
||||
% programmers who know the type of value that will be returned by
|
||||
% Haskell can call the appropriate hook into the evaluator. If they get
|
||||
% the type wrong, a nullPtr will be returned (so calling Haskell is
|
||||
% still typesafe). The foreign bindings to \code{eval} all return
|
||||
% \code{NULL} if an error occurred, otherwise a pointer to the value is
|
||||
% returned.
|
||||
%
|
||||
% \begin{quote}
|
||||
% \scm{
|
||||
% foreign export ccall hs_eval_b :: CString -> IO (Ptr CInt)
|
||||
%
|
||||
% foreign export ccall hs_eval_c :: CString -> IO (Ptr CChar)
|
||||
%
|
||||
% foreign export ccall hs_eval_i :: CString -> IO (Ptr CInt)
|
||||
%
|
||||
% foreign export ccall hs_eval_s :: CString -> IO CString
|
||||
% }
|
||||
% \end{quote}
|
||||
%
|
||||
% An example C program for compiling and evaluating Haskell code at
|
||||
% runtime follows. This program calculates a fibonacci number, returning
|
||||
% it as a \code{CString} to the C program:
|
||||
% %
|
||||
% \begin{quote}
|
||||
% \begin{verbatim}
|
||||
% #include "EvalHaskell.h"
|
||||
% #include <stdio.h>
|
||||
%
|
||||
% int main(int argc, char *argv[])
|
||||
% {
|
||||
% char *p;
|
||||
% hs_init(&argc, &argv);
|
||||
% p = hs_eval_s("show $ let fibs = 1:1:zipWith (+) fibs (tail fibs) in fibs !! 20");
|
||||
% if (p != NULL)
|
||||
% printf("%s\n",p);
|
||||
% else
|
||||
% printf("error in code\n");
|
||||
% hs_exit();
|
||||
% return 0;
|
||||
% }
|
||||
% \end{verbatim}
|
||||
% \end{quote}
|
||||
%
|
||||
\begin{quote}
|
||||
\begin{verbatim}
|
||||
#include "EvalHaskell.h"
|
||||
#include <stdio.h>
|
||||
|
||||
int main(int argc, char *argv[])
|
||||
{
|
||||
char *p;
|
||||
hs_init(&argc, &argv);
|
||||
p = hs_eval_s("show $ let fibs = 1:1:zipWith (+) fibs (tail fibs) in fibs !! 20");
|
||||
if (p != NULL)
|
||||
printf("%s\n",p);
|
||||
else
|
||||
printf("error in code\n");
|
||||
hs_exit();
|
||||
return 0;
|
||||
}
|
||||
\end{verbatim}
|
||||
\end{quote}
|
||||
|
||||
\subsection{Notes}
|
||||
|
||||
Be careful if you're calling eval from a forked thread. This can
|
||||
introduce races between the thread and the forked process used by eval
|
||||
to compile its code.
|
||||
|
||||
\section{RTS Binding}
|
||||
|
||||
@ -1657,7 +1659,7 @@ This library is distributed under the terms of the LGPL:
|
||||
|
||||
\begin{quote}
|
||||
|
||||
Copyright 2004, Don Stewart - \url{http://www.cse.unsw.edu.au/~dons}
|
||||
Copyright 2003-5, Don Stewart - \url{http://www.cse.unsw.edu.au/~dons}
|
||||
|
||||
This library is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU Lesser General Public
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user