82 lines
2.4 KiB
C++
82 lines
2.4 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/list.h"
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#include "util/optional.h"
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#include "kernel/expr.h"
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#include "frontends/lean/parser_types.h"
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namespace lean {
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class parser_imp;
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class operator_info;
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/**
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\brief Information for a operator available in the
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calculational proof module. It must have at least two arguments.
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It may have implicit ones. We assume the implicit arguments
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occur in the beginning.
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*/
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struct op_data {
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expr m_fn;
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unsigned m_num_args;
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op_data(expr const & f, unsigned n): m_fn(f), m_num_args(n) {}
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};
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/**
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\brief Information about a transitivity-like proof step.
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The m_fn function must have at least 5 arguments.
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We assume the implicit ones occur in the beginning.
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The last five are a, b, c and a proof for 'a op1 b' and 'b op2 c'.
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The function m_fn produces a proof for 'a rop b'.
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The resultant operator must be in the list of supported operators.
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*/
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struct trans_data {
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expr m_fn;
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unsigned m_num_args; // number of arguments of m_fn .
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expr m_rop; // resultant operator
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trans_data(expr const & f, unsigned n, expr const & rop):
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m_fn (f), m_num_args(n), m_rop(rop) {
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}
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};
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/**
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\brief Calculational proof support in the Lean parser.
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It parses expression of the form:
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calc expr op expr : proof1
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... op expr : proof2
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... op expr : proofn
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*/
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class calc_proof_parser {
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/**
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\brief List of supported operators in calculational proofs.
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*/
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list<op_data> m_supported_operators;
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/**
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\brief Maps to operators to the corresponding transitivity operator.
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For example, the pair (=, =>) maps to
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Theorem EqImpTrans {a b c : Bool} (H1 : a == b) (H2 : b ⇒ c) : a ⇒ c
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:= assume Ha, MP H2 (EqMP H1 Ha).
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*/
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list<std::tuple<expr, expr, trans_data>> m_trans_ops;
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optional<trans_data> find_trans_data(expr const & op1, expr const & op2) const;
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optional<expr> find_op(operator_info const & op, pos_info const & p) const;
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expr parse_op(parser_imp & imp) const;
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public:
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calc_proof_parser();
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bool supports(expr const & op1) const;
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void add_supported_operator(op_data const & op);
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void add_trans_step(expr const & op1, expr const & op2, trans_data const & d);
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expr parse(parser_imp & p) const;
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};
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}
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