42 lines
1.1 KiB
C++
42 lines
1.1 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 "expr.h"
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namespace lean {
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/**
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\brief Return true iff the given expression has free variables.
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*/
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bool has_free_vars(expr const & a);
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/**
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\brief Return true iff the given expression does not have free variables.
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*/
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inline bool closed(expr const & a) { return !has_free_vars(a); }
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/**
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\brief Return true iff \c e contains the free variable <tt>(var i)</tt>.
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*/
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bool has_free_var(expr const & e, unsigned i);
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/**
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\brief Return true iff \c e constains a free variable <tt>(var i)</tt> s.t. \c i in <tt>[low, high)</tt>.
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\pre low < high
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*/
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bool has_free_var(expr const & e, unsigned low, unsigned high);
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/**
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\brief Lower the free variables in \c e by d. That is, a free variable <tt>(var i)</tt> is mapped into <tt>(var i-d)</tt>.
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\pre d > 0
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\pre !has_free_var(e, 0, d)
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*/
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expr lower_free_vars(expr const & e, unsigned d);
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/**
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\brief Lift free variables in \c e by d.
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*/
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expr lift_free_vars(expr const & e, unsigned d);
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}
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