d87ad9eb7e
The following call sequence is possible: C++ -> Lua -> C++ -> Lua -> C++ The first block of C++ is the Lean main function. The main function invokes the Lua interpreter. The Lua interpreter invokes a C++ Lean API. Then the Lean API invokes a callback implemented in Lua. The Lua callback invokes another Lean API. Now, suppose the Lean API throws an exception. We want the C++ exception to propagate over the mixed C++/Lua call stack. We use the clone/rethrow exception idiom to achieve this goal. Before this commit, the C++ exceptions were converted into strings using the method what(), and then they were propagated over the Lua stack using lua_error. A lua_error was then converted into a lua_exception when going back to C++. This solution was very unsatisfactory, since all C++ exceptions were being converted into a lua_exception, and consequently the structure of the exception was being lost. Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
62 lines
2.1 KiB
C++
62 lines
2.1 KiB
C++
/*
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Copyright (c) 2013 Microsoft Corporation. All rights reserved.
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Released under Apache 2.0 license as described in the file LICENSE.
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Author: Leonardo de Moura
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*/
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#pragma once
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#include "util/lua.h"
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#include <exception>
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#include <string>
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namespace lean {
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class sstream;
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/** \brief Base class for all Lean exceptions */
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class exception : public std::exception {
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protected:
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std::string m_msg;
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exception() {}
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public:
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exception(char const * msg);
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exception(std::string const & msg);
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exception(sstream const & strm);
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virtual ~exception() noexcept;
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virtual char const * what() const noexcept;
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virtual exception * clone() const { return new exception(m_msg); }
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virtual void rethrow() const { throw *this; }
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};
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/** \brief Exception produced by a Lean parser. */
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class parser_exception : public exception {
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protected:
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unsigned m_line;
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unsigned m_pos;
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public:
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parser_exception(char const * msg, unsigned l, unsigned p);
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parser_exception(std::string const & msg, unsigned l, unsigned p);
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parser_exception(sstream const & strm, unsigned l, unsigned p);
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virtual ~parser_exception() noexcept;
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virtual char const * what() const noexcept;
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unsigned get_line() const { return m_line; }
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unsigned get_pos() const { return m_pos; }
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virtual exception * clone() const { return new parser_exception(m_msg, m_line, m_pos); }
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virtual void rethrow() const { throw *this; }
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};
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/** \brief Exception used to sign that a computation was interrupted */
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class interrupted : public exception {
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public:
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interrupted() {}
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virtual ~interrupted() noexcept {}
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virtual char const * what() const noexcept { return "interrupted"; }
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virtual exception * clone() const { return new interrupted(); }
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virtual void rethrow() const { throw *this; }
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};
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/** \brief Throw interrupted exception iff flag is true. */
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inline void check_interrupted(bool flag) {
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if (flag)
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throw interrupted();
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}
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int push_exception(lua_State * L, exception const & e);
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exception const & to_exception(lua_State * L, int i);
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bool is_exception(lua_State * L, int i);
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void open_exception(lua_State * L);
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}
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