lean2/src/library/tactic/expr_to_tactic.cpp

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/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include <unordered_map>
#include <string>
#include "kernel/instantiate.h"
#include "kernel/type_checker.h"
#include "library/string.h"
#include "library/tactic/expr_to_tactic.h"
#include "library/tactic/apply_tactic.h"
namespace lean {
typedef std::unordered_map<name, expr_to_tactic_fn, name_hash, name_eq> expr_to_tactic_map;
expr_to_tactic_map & get_expr_to_tactic_map() {
static expr_to_tactic_map g_map;
return g_map;
}
void register_expr_to_tactic(name const & n, expr_to_tactic_fn const & fn) {
get_expr_to_tactic_map().insert(mk_pair(n, fn));
}
tactic expr_to_tactic(type_checker & tc, expr const & e, pos_info_provider const * p) {
expr f = get_app_fn(tc.whnf(e));
if (is_constant(f)) {
auto const & map = get_expr_to_tactic_map();
auto it = map.find(const_name(f));
if (it != map.end()) {
return it->second(tc, e, p);
} else if (auto it = tc.env().find(const_name(f))) {
if (it->is_definition()) {
buffer<expr> locals;
get_app_rev_args(e, locals);
expr v = it->get_value();
v = instantiate_univ_params(v, it->get_univ_params(), const_levels(f));
v = apply_beta(v, locals.size(), locals.data());
return expr_to_tactic(tc, v, p);
}
}
throw expr_to_tactic_exception(e, "failed to convert expression into tactic");
} else {
throw expr_to_tactic_exception(e, "failed to convert expression into tactic");
}
}
tactic expr_to_tactic(environment const & env, expr const & e, pos_info_provider const * p) {
type_checker tc(env);
return expr_to_tactic(tc, e, p);
}
register_simple_tac::register_simple_tac(name const & n, std::function<tactic()> f) {
register_expr_to_tactic(n, [=](type_checker &, expr const & e, pos_info_provider const *) {
if (!is_constant(e))
throw expr_to_tactic_exception(e, "invalid constant tactic");
return f();
});
}
register_bin_tac::register_bin_tac(name const & n, std::function<tactic(tactic const &, tactic const &)> f) {
register_expr_to_tactic(n, [=](type_checker & tc, expr const & e, pos_info_provider const * p) {
buffer<expr> args;
get_app_args(e, args);
if (args.size() != 2)
throw expr_to_tactic_exception(e, "invalid binary tactic, it must have two arguments");
return f(expr_to_tactic(tc, args[0], p),
expr_to_tactic(tc, args[1], p));
});
}
register_unary_tac::register_unary_tac(name const & n, std::function<tactic(tactic const &)> f) {
register_expr_to_tactic(n, [=](type_checker & tc, expr const & e, pos_info_provider const * p) {
buffer<expr> args;
get_app_args(e, args);
if (args.size() != 1)
throw expr_to_tactic_exception(e, "invalid unary tactic, it must have one argument");
return f(expr_to_tactic(tc, args[0], p));
});
}
static name g_tac("tactic"), g_tac_name(g_tac, "tactic"), g_exact_tac_name(g_tac, "exact"), g_and_then_tac_name(g_tac, "and_then");
static name g_or_else_tac_name(g_tac, "or_else"), g_repeat_tac_name(g_tac, "repeat");
static expr g_exact_tac_fn(Const(g_exact_tac_name)), g_and_then_tac_fn(Const(g_and_then_tac_name));
static expr g_or_else_tac_fn(Const(g_or_else_tac_name)), g_repeat_tac_fn(Const(g_repeat_tac_name));
static expr g_tac_type(Const(g_tac_name));
expr const & get_exact_tac_fn() { return g_exact_tac_fn; }
expr const & get_and_then_tac_fn() { return g_and_then_tac_fn; }
expr const & get_or_else_tac_fn() { return g_or_else_tac_fn; }
expr const & get_repeat_tac_fn() { return g_repeat_tac_fn; }
expr const & get_tactic_type() { return g_tac_type; }
static register_simple_tac reg_id(name(g_tac, "id"), []() { return id_tactic(); });
static register_simple_tac reg_now(name(g_tac, "now"), []() { return now_tactic(); });
static register_simple_tac reg_assumption(name(g_tac, "assumption"), []() { return assumption_tactic(); });
static register_simple_tac reg_fail(name(g_tac, "fail"), []() { return fail_tactic(); });
static register_simple_tac reg_beta(name(g_tac, "beta"), []() { return beta_tactic(); });
static register_bin_tac reg_then(g_and_then_tac_name, [](tactic const & t1, tactic const & t2) { return then(t1, t2); });
static register_bin_tac reg_orelse(g_or_else_tac_name, [](tactic const & t1, tactic const & t2) { return orelse(t1, t2); });
static register_unary_tac reg_repeat(g_repeat_tac_name, [](tactic const & t1) { return repeat(t1); });
static register_tac reg_state(name(g_tac, "state"), [](type_checker &, expr const & e, pos_info_provider const * p) {
if (p)
return trace_state_tactic(std::string(p->get_file_name()), p->get_pos_info(e));
else
return trace_state_tactic("unknown", mk_pair(0, 0));
});
static register_tac reg_trace(name(g_tac, "trace"), [](type_checker & tc, expr const & e, pos_info_provider const *) {
buffer<expr> args;
get_app_args(e, args);
if (args.size() != 1)
throw expr_to_tactic_exception(e, "invalid trace tactic, argument expected");
if (auto str = to_string(args[0]))
return trace_tactic(*str);
else if (auto str = to_string(tc.whnf(args[0])))
return trace_tactic(*str);
else
throw expr_to_tactic_exception(e, "invalid trace tactic, string value expected");
});
static register_tac reg_apply(name(g_tac, "apply"), [](type_checker &, expr const & e, pos_info_provider const *) {
return apply_tactic(app_arg(e));
});
static register_tac reg_exact(g_exact_tac_name, [](type_checker &, expr const & e, pos_info_provider const *) {
return exact_tactic(app_arg(e));
});
static register_tac reg_unfold(name(g_tac, "unfold"), [](type_checker &, expr const & e, pos_info_provider const *) {
expr id = get_app_fn(app_arg(e));
if (!is_constant(id))
return fail_tactic();
else
return unfold_tactic(const_name(id));
});
// We encode the 'by' expression that is used to trigger tactic execution.
// This is a trick to avoid creating a new kind of expression.
// 'by' macros are temporary objects used by the elaborator,
// and have no semantic significance.
[[ noreturn ]] static void throw_ex() { throw exception("unexpected occurrence of 'by' expression"); }
static name g_by_name("by");
class by_macro_cell : public macro_definition_cell {
public:
virtual name get_name() const { return g_by_name; }
virtual expr get_type(expr const &, expr const *, extension_context &) const { throw_ex(); }
virtual optional<expr> expand(expr const &, extension_context &) const { throw_ex(); }
virtual void write(serializer &) const { throw_ex(); }
};
static macro_definition g_by(new by_macro_cell());
expr mk_by(expr const & e) {
return mk_macro(g_by, 1, &e);
}
bool is_by(expr const & e) {
return is_macro(e) && macro_def(e) == g_by;
}
expr const & get_by_arg(expr const & e) {
lean_assert(is_by(e));
return macro_arg(e, 0);
}
}