3e1fd06903
After this commit, a value of type 'expr' cannot be a reference to nullptr. This commit also fixes several bugs due to the use of 'null' expressions. TODO: do the same for kernel objects, sexprs, etc. Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
60 lines
1.9 KiB
C++
60 lines
1.9 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 "kernel/context.h"
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namespace lean {
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/**
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\brief Given the context (n_1 : T_1 [:= V_1]) ... (n_k : T_k [:= V_k]) and expression e into,
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return the "meaningless" lambda expression:
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(lambda (n_1 : (fake T_1 V_1)) ... (lambda (n_k : (fake T_k V_k)) e))
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The constant "fake" is irrelevant, it is just used as a marker.
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It is used to "glue" T_i and V_i.
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This little hack allows us to use the machinery for instantiating
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lambdas with contexts.
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\remark If a context entry (n_i : T_i [:= V_i]) does not have a
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value V_i, then we just use (fake T_i).
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*/
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expr context_to_lambda(context const & c, expr const & e);
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/**
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\brief Return true if \c e is a fake context created using
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context_to_lambda.
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(lambda (n_1 : (fake T_1 V_1)) ... (lambda (n_k : (fake T_k V_k)) e))
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*/
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bool is_fake_context(expr const & e);
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/**
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\brief Return the name n_1 of the head of the (fake) context
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(lambda (n_1 : (fake T_1 V_1)) ... (lambda (n_k : (fake T_k V_k)) e))
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\pre is_fake_context(e)
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*/
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name const & fake_context_name(expr const & e);
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/**
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\brief Return the domain T_1 of the head of the (fake) context
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(lambda (n_1 : (fake T_1 V_1)) ... (lambda (n_k : (fake T_k V_k)) e))
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\pre is_fake_context(e)
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*/
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optional<expr> fake_context_domain(expr const & e);
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/**
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\brief Return (if available) the value V_1 of the head of the (fake) context
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(lambda (n_1 : (fake T_1 V_1)) ... (lambda (n_k : (fake T_k V_k)) e))
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\pre is_fake_context(e)
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*/
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optional<expr> fake_context_value(expr const & e);
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/**
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\brief Return the rest (lambda (n_2 : (fake T_2 V_2)) ... (lambda (n_k : (fake T_k V_k)) e)) of the fake context
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(lambda (n_1 : (fake T_1 V_1)) ... (lambda (n_k : (fake T_k V_k)) e))
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\pre is_fake_context(e)
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*/
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expr const & fake_context_rest(expr const & e);
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}
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