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This directory contains some examples of running recursive algorithms in Nu. It also has the module : tramp which implements the Trampoline pattern to overcome the lack of Tail Call Optimization (TCO) avoiding unlimited stack growth. --------- Co-authored-by: Darren Schroeder <343840+fdncred@users.noreply.github.com>
54 lines
1.3 KiB
Text
54 lines
1.3 KiB
Text
# tree.nu: module for working with trees
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source typeof.nu # Requires Nushell version 0.88 or later
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# A tree is a recursive data structure. In Nu, we take the view that any single atomic value
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# is a leaf. E.g. int, float, string, bool, etc.
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# Any structured data is some kind of a tree. E.g. list, record or table.
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# Applies closure to atomic data.
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def visit-scalar [act: closure] {
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let data = $in
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do $act $data
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}
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# Visit every element of list and apply closure
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def visit-list [act: closure] {
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let l = $in
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$l |each {|x| $x | visit $act }
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}
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# Apply closure to every column and value of record in input. Does a visit on
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# each key and then on each value.
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def visit-record [cl: closure] {
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items {|k, v| $k | visit $cl; $v | visit $cl }
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}
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# Applies closure to every row in table passed to input. Defers to visit-record
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# for each row.
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def visit-table [act: closure] {
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each {|r| $r | visit-record $act }
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}
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# Applies closure to every node in tree passed to input recursively.
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def visit [act: closure] {
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let stream = $in
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match ($stream | typeof) {
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'list' => { do $act 'list'; $stream | visit-list $act },
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'record' => { do $act 'record'; $stream | visit-record $act },
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'table' => { do $act 'table'; $stream | visit-table $act },
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_ => { $stream | visit-scalar $act }
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}
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}
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