75 lines
1.7 KiB
Text
75 lines
1.7 KiB
Text
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#lang scribble/manual
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@(require (for-label racket))
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@title{Key Value Pairs}
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An interface for translating between three common data structures: Dictionaries, Arrays of Associations and of Pairs@section{categories}
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Collections, Interfaces
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@section{related}
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Classes/IdentityDictionary, Classes/Array, Classes/Association
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@section{SECTION}
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Motivation
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There are three very similar ways to represent maps between keys and values, each of which have a specific purpose:
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@section{TABLE}
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## key value pairs || common representation of arguments ||
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@racketblock[[\freq, 452, \amp, 0.2]::
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## collections of associations || ordering, array and collection methods || ]
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@racketblock[[0 -> [1, 2, 3], 1 -> [2, 1]]::
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## dictionaries: fast lookup || event compatibility || ]
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@racketblock[(instrument: \sine, freq: 561)::
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::
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To make it easy to translate between these purposes and representations, there is a uniform set of methods:
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]
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@section{TABLE}
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##
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@racketblock[asPairs:: || returns an array of key value pairs
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##]
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@racketblock[asAssociations:: || returns an array of associations
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##]
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@racketblock[asDict:: || returns an IdentityDictionary
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::
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]
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@section{EXAMPLES}
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@racketblock[
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// the following all return [\freq, 452, \amp, 0.2]
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[\freq, 452, \amp, 0.2].asPairs
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[\freq -> 452, \amp -> 0.2].asPairs
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(freq: 452, amp: 0.2).asPairs
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// the following all return [\freq -> 452, \amp -> 0.2]
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[\freq, 452, \amp, 0.2].asAssociations
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[\freq -> 452, \amp -> 0.2].asAssociations
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(freq: 452, amp: 0.2).asAssociations
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// the following all return (freq: 452, amp: 0.2) or the equivalent IdentityDictionary
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[\freq, 452, \amp, 0.2].asDict
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[\freq -> 452, \amp -> 0.2].asDict
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(freq: 452, amp: 0.2).asDict
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::
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]
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