f97c260b0b
The environment object is a "smart-pointer".
Before this commit, the use of "const &" for environment objects was broken.
For example, suppose we have a function f that should not modify the input environment.
Before this commit, its signature would be
void f(environment const & env)
This is broken, f's implementation can easilty convert it to a read-write pointer by using
the copy constructor.
environment rw_env(env);
Now, f can use rw_env to update env.
To fix this issue, we now have ro_environment. It is a shared *const* pointer.
We can convert an environment into a ro_environment, but not the other way around.
ro_environment can also be seen as a form of documentation.
For example, now it is clear that type_inferer is not updating the environment, since its constructor takes a ro_environment.
Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
71 lines
2.6 KiB
C++
71 lines
2.6 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 <utility>
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#include <vector>
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#include "util/lua.h"
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#include "util/list.h"
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#include "util/name.h"
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#include "kernel/formatter.h"
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#include "kernel/expr.h"
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#include "kernel/context.h"
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#include "kernel/environment.h"
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namespace lean {
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typedef std::pair<name, expr> hypothesis;
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typedef list<hypothesis> hypotheses;
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class goal {
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hypotheses m_hypotheses;
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expr m_conclusion;
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public:
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goal() {}
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goal(hypotheses const & hs, expr const & c);
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hypotheses const & get_hypotheses() const { return m_hypotheses; }
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expr const & get_conclusion() const { return m_conclusion; }
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format pp(formatter const & fmt, options const & opts) const;
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name mk_unique_hypothesis_name(name const & suggestion) const;
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};
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inline goal update(goal const & g, expr const & c) { return goal(g.get_hypotheses(), c); }
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inline goal update(goal const & g, hypotheses const & hs) { return goal(hs, g.get_conclusion()); }
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inline goal update(goal const & g, buffer<hypothesis> const & hs) { return goal(to_list(hs.begin(), hs.end()), g.get_conclusion()); }
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inline hypotheses add_hypothesis(name const & h_name, expr const & h, hypotheses const & hs) {
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return cons(mk_pair(h_name, h), hs);
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}
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inline hypotheses add_hypothesis(hypothesis const & h, hypotheses const & hs) {
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return cons(h, hs);
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}
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/**
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\brief Functor for converting a proof for a goal \c g produced using <tt>to_goal(env, ctx, T)</tt>
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into a term of type \c t.
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That is, the goal was created to synthesize a proof term for a proposition/type \c T in a
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context \c ctx. This functor allows us to convert a proof for \c g into a term/expression \c p
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s.t. <tt>ctx |- p : T</t>
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*/
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class goal_proof_fn {
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friend std::pair<goal, goal_proof_fn> to_goal(ro_environment const & env, context const & ctx, expr const & t);
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std::vector<expr> m_constants;
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goal_proof_fn(std::vector<expr> && constants);
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public:
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expr operator()(expr const & pr) const;
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};
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/**
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\brief Convert the synthesis problem <tt>ctx |- ?p : T</tt> into a goal,
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where \c T is a proposition (i.e., has type Boolean), and \c ?p is a proof we want to synthesize.
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We can use tactics for solving the resultant goal, and the functor \c goal_proof_fn
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to convert the proof for the goal into the proof term \c ?p.
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*/
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std::pair<goal, goal_proof_fn> to_goal(ro_environment const & env, context const & ctx, expr const & t);
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UDATA_DEFS_CORE(hypotheses)
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UDATA_DEFS(goal)
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void open_goal(lua_State * L);
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}
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