63 lines
3.1 KiB
C++
63 lines
3.1 KiB
C++
/*
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Copyright (c) 2014 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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#include "util/sstream.h"
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#include "library/explicit.h"
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#include "library/kernel_bindings.h"
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namespace lean {
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static name g_explicit_name("@");
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static name g_implicit_name("@^-1");
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static name g_as_is_name("as_is");
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[[ noreturn ]] static void throw_ex(name const & n) { throw exception(sstream() << "unexpected occurrence of '" << n << "' expression"); }
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// We encode the 'explicit' expression mark '@' using a macro.
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// This is a trick to avoid creating a new kind of expression.
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// 'Explicit' expressions are temporary objects used by the elaborator,
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// and have no semantic significance.
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class explicit_macro_cell : public macro_definition_cell {
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public:
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virtual bool operator==(macro_definition_cell const & other) const { return this == &other; }
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virtual name get_name() const { return g_explicit_name; }
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virtual expr get_type(expr const &, expr const *, extension_context &) const { throw_ex(get_name()); }
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virtual optional<expr> expand(expr const &, extension_context &) const { throw_ex(get_name()); }
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virtual void write(serializer &) const { throw_ex(get_name()); }
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};
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struct as_is_macro_cell : public explicit_macro_cell { virtual name get_name() const { return g_as_is_name; } };
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struct implicit_macro_cell : public explicit_macro_cell { virtual name get_name() const { return g_implicit_name; } };
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static macro_definition g_explicit(new explicit_macro_cell());
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static macro_definition g_as_is(new as_is_macro_cell());
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static macro_definition g_implicit(new implicit_macro_cell());
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expr mk_explicit(expr const & e) { return mk_macro(g_explicit, 1, &e); }
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bool is_explicit(expr const & e) { return is_macro(e) && macro_def(e) == g_explicit; }
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expr mk_as_is(expr const & e) { return mk_macro(g_as_is, 1, &e); }
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bool is_as_is(expr const & e) { return is_macro(e) && macro_def(e) == g_as_is; }
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expr mk_implicit(expr const & e) { return mk_macro(g_implicit, 1, &e); }
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bool is_implicit(expr const & e) { return is_macro(e) && macro_def(e) == g_implicit; }
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expr const & get_explicit_arg(expr const & e) { lean_assert(is_explicit(e)); return macro_arg(e, 0); }
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expr const & get_as_is_arg(expr const & e) { lean_assert(is_as_is(e)); return macro_arg(e, 0); }
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expr const & get_implicit_arg(expr const & e) { lean_assert(is_implicit(e)); return macro_arg(e, 0); }
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static int mk_explicit(lua_State * L) { return push_expr(L, mk_explicit(to_expr(L, 1))); }
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static int is_explicit(lua_State * L) { return push_boolean(L, is_explicit(to_expr(L, 1))); }
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static void check_explicit(lua_State * L, int idx) {
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if (!is_explicit(to_expr(L, idx)))
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throw exception(sstream() << "arg #" << idx << " is not a '@'-expression");
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}
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static int get_explicit_arg(lua_State * L) {
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check_explicit(L, 1);
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return push_expr(L, get_explicit_arg(to_expr(L, 1)));
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}
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void open_explicit(lua_State * L) {
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SET_GLOBAL_FUN(mk_explicit, "mk_explicit");
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SET_GLOBAL_FUN(is_explicit, "is_explicit");
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SET_GLOBAL_FUN(get_explicit_arg, "get_explicit_arg");
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}
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}
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