51 lines
2.0 KiB
Plaintext
51 lines
2.0 KiB
Plaintext
-- Copyright (c) 2003-2007 ETH Zurich, Switzerland
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-- 2016 The University of Sheffield, UK
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--
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-- All rights reserved.
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--
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-- Redistribution and use in source and binary forms, with or without
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-- modification, are permitted provided that the following conditions are met:
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--
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-- * Redistributions of source code must retain the above copyright notice, this
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-- list of conditions and the following disclaimer.
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--
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-- * Redistributions in binary form must reproduce the above copyright notice,
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-- this list of conditions and the following disclaimer in the documentation
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-- and/or other materials provided with the distribution.
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--
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-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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-- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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-- SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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-- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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-- OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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-- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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--
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-- SPDX-License-Identifier: BSD-2-Clause
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--
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package Stack
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context Stack::pop(): Stack
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pre notEmpty: isEmpty() = false
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post topElementRemoved: top() <> self.top@pre()
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post: elements = elements@pre->subSequence(2,self@pre->size())
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post: elements->size() = elements@pre->size() -1
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context Stack::top(): ElemType
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pre notEmpty: isEmpty() = false
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post: result = elements->first()
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context Stack::push(e: ElemType): Stack
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post pushedElemTypeIsOnTop: top() = e
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post: elements = elements@pre->prepend(e)
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post: result = self
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context Stack::isEmpty(): Boolean
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post: result = (elements->size() <> 0)
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endpackage
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