26 lines
874 B
Forth
26 lines
874 B
Forth
\ Copyright 2023 Bradley D. Nelson
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\
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\ Licensed under the Apache License, Version 2.0 (the "License");
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\ you may not use this file except in compliance with the License.
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\ You may obtain a copy of the License at
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\
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\ http://www.apache.org/licenses/LICENSE-2.0
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\
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\ Unless required by applicable law or agreed to in writing, software
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\ distributed under the License is distributed on an "AS IS" BASIS,
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\ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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\ See the License for the specific language governing permissions and
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\ limitations under the License.
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needs ../oofda.fs
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class Stack
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variable start
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variable sp
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: .construct ( n -- ) here start ! here sp ! cells allot ;
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: .empty? ( -- f ) sp @ start @ = ;
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: .push ( n -- ) sp @ ! cell sp +! ;
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: .pop ( -- n ) this .empty? throw
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cell negate sp +! sp @ @ ;
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end-class
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