Tree datastructures
You are encouraged to solve this task according to the task description, using any language you may know.
The following shows a tree of data with nesting denoted by visual levels of indentation:
RosettaCode rocks code comparison wiki mocks trolling
A common datastructure for trees is to define node structures having a name and a, (possibly empty), list of child nodes. The nesting of nodes captures the indentation of the tree. Lets call this the nest form.
# E.g. if child nodes are surrounded by brackets # and separated by commas then: RosettaCode(rocks(code, ...), ...) # But only an _example_
Another datastructure for trees is to construct from the root an ordered list of the nodes level of indentation and the name of that node. The indentation for the root node is zero; node 'rocks is indented by one level from the left, and so on. Lets call this the indent form.
0 RosettaCode 1 rocks 2 code ...
- Task
- Create/use a nest datastructure format and textual representation for arbitrary trees.
- Create/use an indent datastructure format and textual representation for arbitrary trees.
- Create methods/classes/proceedures/routines etc to:
- Change from a nest tree datastructure to an indent one.
- Change from an indent tree datastructure to a nest one
- Use the above to encode the example at the start into the nest format, and show it.
- transform the initial nest format to indent format and show it.
- transform the indent format to final nest format and show it.
- Compare initial and final nest formats which should be the same.
- Note
- It's all about showing aspects of the contrasting datastructures as they hold the tree.
- Comparing nested datastructures is secondary - saving formatted output as a string then a string compare would suffice for this task, if its easier.
Show all output on this page.
C++
<lang cpp>#include <iomanip>
- include <iostream>
- include <list>
- include <string>
- include <vector>
- include <utility>
- include <vector>
class nest_tree;
bool operator==(const nest_tree&, const nest_tree&);
class nest_tree { public:
explicit nest_tree(const std::string& name) : name_(name) {} nest_tree& add_child(const std::string& name) { children_.emplace_back(name); return children_.back(); } void print(std::ostream& out) const { print(out, 0); } const std::string& name() const { return name_; } const std::list<nest_tree>& children() const { return children_; } bool equals(const nest_tree& n) const { return name_ == n.name_ && children_ == n.children_; }
private:
void print(std::ostream& out, int level) const { std::string indent(level * 4, ' '); out << indent << name_ << '\n'; for (const nest_tree& child : children_) child.print(out, level + 1); } std::string name_; std::list<nest_tree> children_;
};
bool operator==(const nest_tree& a, const nest_tree& b) {
return a.equals(b);
}
class indent_tree { public:
explicit indent_tree(const nest_tree& n) { items_.emplace_back(0, n.name()); from_nest(n, 0); } void print(std::ostream& out) const { for (const auto& item : items_) std::cout << item.first << ' ' << item.second << '\n'; } nest_tree to_nest() const { nest_tree n(items_[0].second); to_nest_(n, 1, 0); return n; }
private:
void from_nest(const nest_tree& n, int level) { for (const nest_tree& child : n.children()) { items_.emplace_back(level + 1, child.name()); from_nest(child, level + 1); } } size_t to_nest_(nest_tree& n, size_t pos, int level) const { while (pos < items_.size() && items_[pos].first == level + 1) { nest_tree& child = n.add_child(items_[pos].second); pos = to_nest_(child, pos + 1, level + 1); } return pos; } std::vector<std::pair<int, std::string>> items_;
};
int main() {
nest_tree n("RosettaCode"); auto& child1 = n.add_child("rocks"); auto& child2 = n.add_child("mocks"); child1.add_child("code"); child1.add_child("comparison"); child1.add_child("wiki"); child2.add_child("trolling"); std::cout << "Initial nest format:\n"; n.print(std::cout); indent_tree i(n); std::cout << "\nIndent format:\n"; i.print(std::cout); nest_tree n2(i.to_nest()); std::cout << "\nFinal nest format:\n"; n2.print(std::cout);
std::cout << "\nAre initial and final nest formats equal? " << std::boolalpha << n.equals(n2) << '\n'; return 0;
}</lang>
- Output:
Initial nest format: RosettaCode rocks code comparison wiki mocks trolling Indent format: 0 RosettaCode 1 rocks 2 code 2 comparison 2 wiki 1 mocks 2 trolling Final nest format: RosettaCode rocks code comparison wiki mocks trolling Are initial and final nest formats equal? true
Go
<lang go>package main
import (
"fmt" "io" "os" "strings"
)
type nNode struct {
name string children []nNode
}
type iNode struct {
level int name string
}
func printNest(n nNode, level int, w io.Writer) {
if level == 0 { fmt.Fprintln(w, "\n==Nest form==\n") } fmt.Fprintf(w, "%s%s\n", strings.Repeat(" ", level), n.name) for _, c := range n.children { fmt.Fprintf(w, "%s", strings.Repeat(" ", level+1)) printNest(c, level+1, w) }
}
func toNest(iNodes []iNode, start, level int, n *nNode) {
if level == 0 { n.name = iNodes[0].name } for i := start + 1; i < len(iNodes); i++ { if iNodes[i].level == level+1 { c := nNode{iNodes[i].name, nil} toNest(iNodes, i, level+1, &c) n.children = append(n.children, c) } else if iNodes[i].level <= level { return } }
}
func printIndent(iNodes []iNode, w io.Writer) {
fmt.Fprintln(w, "\n==Indent form==\n") for _, n := range iNodes { fmt.Fprintf(w, "%d %s\n", n.level, n.name) }
}
func toIndent(n nNode, level int, iNodes *[]iNode) {
*iNodes = append(*iNodes, iNode{level, n.name}) for _, c := range n.children { toIndent(c, level+1, iNodes) }
}
func main() {
n1 := nNode{"RosettaCode", nil} n2 := nNode{"rocks", []nNode{{"code", nil}, {"comparison", nil}, {"wiki", nil}}} n3 := nNode{"mocks", []nNodeTemplate:"trolling", nil} n1.children = append(n1.children, n2, n3)
var sb strings.Builder printNest(n1, 0, &sb) s1 := sb.String() fmt.Print(s1)
var iNodes []iNode toIndent(n1, 0, &iNodes) printIndent(iNodes, os.Stdout)
var n nNode toNest(iNodes, 0, 0, &n) sb.Reset() printNest(n, 0, &sb) s2 := sb.String() fmt.Print(s2)
fmt.Println("\nRound trip test satisfied? ", s1 == s2)
}</lang>
- Output:
==Nest form== RosettaCode rocks code comparison wiki mocks trolling ==Indent form== 0 RosettaCode 1 rocks 2 code 2 comparison 2 wiki 1 mocks 2 trolling ==Nest form== RosettaCode rocks code comparison wiki mocks trolling Round trip test satisfied? true
Haskell
The task is all about the isomorphism between different representations of a nested list structure. Therefore the solution is given in terms of the isomorphisms.
<lang haskell>{-# LANGUAGE FlexibleInstances #-} {-# LANGUAGE MultiParamTypeClasses #-} {-# LANGUAGE UndecidableSuperClasses #-} {-# LANGUAGE TypeApplications #-}
import Data.List (span)
-- A nested tree structure. -- Using `Maybe` allows encoding several zero-level items -- or irregular lists (see test example) data Nest a = Nest (Maybe a) [Nest a]
deriving Eq
instance Show a => Show (Nest a) where
show (Nest (Just a) []) = show a show (Nest (Just a) s) = show a ++ show s show (Nest Nothing []) = "\"\"" show (Nest Nothing s) = "\"\"" ++ show s
-- An indented tree structure. type Indent a = [(Int, a)]
-- class for isomorphic types class Iso b a => Iso a b where
from :: a -> b
-- A bijection from nested form to indent form instance Iso (Nest a) (Indent a) where
from = go (-1) where go n (Nest a t) = case a of Just a -> (n, a) : foldMap (go (n + 1)) t Nothing -> foldMap (go (n + 1)) t
-- A bijection from indent form to nested form instance Iso (Indent a) (Nest a) where
from = revNest . foldl add (Nest Nothing []) where add t (d,x) = go 0 t where go n (Nest a s) = case compare n d of EQ -> Nest a $ Nest (Just x) [] : s LT -> case s of h:t -> Nest a $ go (n+1) h : t [] -> go n $ Nest a [Nest Nothing []] GT -> go (n-1) $ Nest Nothing [Nest a s]
revNest (Nest a s) = Nest a (reverse $ revNest <$> s)
-- A bijection from indent form to a string instance Iso (Indent String) String where
from = unlines . map process where process (d, s) = replicate (4*d) ' ' ++ s
-- A bijection from a string to indent form instance Iso String (Indent String) where
from = map process . lines where process s = let (i, a) = span (== ' ') s in (length i `div` 4, a)
-- A bijection from nest form to a string via indent form instance Iso (Nest String) String where
from = from @(Indent String) . from
-- A bijection from a string to nest form via indent form instance Iso String (Nest String) where
from = from @(Indent String) . from</lang>
Testing: <lang haskell>test = unlines
[ "RosettaCode" , " rocks" , " code" , " comparison" , " wiki" , " mocks" , " trolling" , "Some lists" , " may" , " be" , " irregular" ]
itest :: Indent String itest = from test
ttest :: Nest String ttest = from test</lang>
λ> mapM_ print itest (0,"RosettaCode") (1,"rocks") (2,"code") (2,"comparison") (2,"wiki") (1,"mocks") (2,"trolling") (0,"Some lists") (3,"may") (2,"be") (1,"irregular") λ> ttest ""["RosettaCode"["rocks"["code","comparison","wiki"],"mocks"["trolling"]], "Some lists"[""[""["may"],"be"],"irregular"]] λ> putStr $ from (from test :: Indent String) RosettaCode rocks code comparison wiki mocks trolling Some lists may be irregular λ> putStr $ from (from test :: Nest String) RosettaCode rocks code comparison wiki mocks trolling Some lists may be irregular λ> test == from (from test :: Nest String) True λ> test == from (from test :: Indent String) True λ> itest == from (from itest :: String) True λ> itest == from (from itest :: Nest String) True λ> ttest == from (from ttest :: String) True λ> ttest == from (from ttest :: Indent String) True
And less satisfyingly and instructively – just relying a little passively on the existing Data.Tree,
we might also write something like:
<lang haskell>import Data.Bifunctor (bimap, first) import Data.Char (isSpace) import Data.List (find) import Data.Tree (Forest, Tree (..), drawTree)
MAPPINGS BETWEEN INDENTED LINES AND TREES -------
forestFromNestLevels :: [(Int, String)] -> Forest String forestFromNestLevels = go
where go [] = [] go ((n, v) : xs) = uncurry (:) $ bimap (Node v . go) go (span ((n <) . fst) xs)
indentLevelsFromLines :: [String] -> [(Int, String)] indentLevelsFromLines xs =
let pairs = first length . span isSpace <$> xs indentUnit = maybe 1 fst (find ((0 <) . fst) pairs) in first (`div` indentUnit) <$> pairs
outlineFromForest ::
(String -> String -> String) -> String -> Forest String -> String
outlineFromForest showRoot tabString forest =
let go indent node = showRoot indent (rootLabel node) : (subForest node >>= go ((<>) tabString indent)) in unlines $ forest >>= go ""
TESTS -------------------------
main :: IO () main = do
putStrLn "Tree representation parsed directly:\n" putStrLn $ drawTree $ Node "" nativeForest
let levelPairs = indentLevelsFromLines test putStrLn "\n[(Level, Text)] list from lines:\n" mapM_ print levelPairs
putStrLn "\n\nTrees from indented text:\n" let trees = forestFromNestLevels levelPairs putStrLn $ drawTree $ Node "" trees
putStrLn "Indented text from trees:\n" putStrLn $ outlineFromForest (<>) " " trees
test :: [String] test =
[ "RosettaCode", " rocks", " code", " comparison", " wiki", " mocks", " trolling", "Some lists", " may", " be", " irregular" ]
nativeForest :: Forest String nativeForest =
[ Node { rootLabel = "RosettaCode", subForest = [ Node { rootLabel = "rocks", subForest = [ Node { rootLabel = "code", subForest = [] }, Node { rootLabel = "comparison", subForest = [] }, Node { rootLabel = "wiki", subForest = [] } ] }, Node { rootLabel = "mocks", subForest = [ Node { rootLabel = "trolling", subForest = [] } ] } ] }, Node { rootLabel = "Some lists", subForest = [ Node { rootLabel = "may", subForest = [] }, Node {rootLabel = "be", subForest = []}, Node {rootLabel = "irregular", subForest = []} ] } ]</lang>
- Output:
Tree representation parsed directly: | +- RosettaCode | | | +- rocks | | | | | +- code | | | | | +- comparison | | | | | `- wiki | | | `- mocks | | | `- trolling | `- Some lists | +- may | +- be | `- irregular [(Level, Text)] list from lines: (0,"RosettaCode") (1,"rocks") (2,"code") (2,"comparison") (2,"wiki") (1,"mocks") (2,"trolling") (0,"Some lists") (3,"may") (2,"be") (1,"irregular") Trees from indented text: | +- RosettaCode | | | +- rocks | | | | | +- code | | | | | +- comparison | | | | | `- wiki | | | `- mocks | | | `- trolling | `- Some lists | +- may | +- be | `- irregular Indented text from trees: RosettaCode rocks code comparison wiki mocks trolling Some lists may be irregular
Julia
<lang julia>const nesttext = """ RosettaCode
rocks code comparison wiki mocks trolling
"""
function nesttoindent(txt)
ret = "" windent = gcd(length.([x.match for x in eachmatch(r"\s+", txt)]) .- 1) for lin in split(txt, "\n") ret *= isempty(lin) ? "\n" : isspace(lin[1]) ? replace(lin, r"\s+" => (s) -> "$(length(s)÷windent) ") * "\n" : "0 " * lin * "\n" end return ret, " "^windent
end
function indenttonest(txt, indenttext)
ret = "" for lin in filter(x -> length(x) > 1, split(txt, "\n")) (num, name) = split(lin, r"\s+", limit=2) indentnum = parse(Int, num) ret *= indentnum == 0 ? name * "\n" : indenttext^indentnum * name * "\n" end return ret
end
indenttext, itext = nesttoindent(nesttext) restorednesttext = indenttonest(indenttext, itext)
println("Original:\n", nesttext, "\n") println("Indent form:\n", indenttext, "\n") println("Back to nest form:\n", restorednesttext, "\n") println("original == restored: ", strip(nesttext) == strip(restorednesttext))
</lang>
- Output:
Original: RosettaCode rocks code comparison wiki mocks trolling Indent form: 0 RosettaCode 1 rocks 2 code 2 comparison 2 wiki 1 mocks 2 trolling Back to nest form: RosettaCode rocks code comparison wiki mocks trolling original == restored: true
Nim
<lang Nim>import strformat, strutils
- Nested representation of trees.
- The tree is simply the first node.
type
NNode*[T] = ref object value*: T children*: seq[NNode[T]]
proc newNNode*[T](value: T; children: varargs[NNode[T]]): NNode[T] =
## Create a node. NNode[T](value: value, children: @children)
proc add*[T](node: NNode[T]; children: varargs[NNode[T]]) =
## Add a list of chlidren to a node. node.children.add children
proc `$`*[T](node: NNode[T]; depth = 0): string =
## Return a string representation of a tree/node. result = repeat(' ', 2 * depth) & $node.value & '\n' for child in node.children: result.add `$`(child, depth + 1)
- Indented representation of trees.
- The tree is described as the list of the nodes.
type
INode*[T] = object value*: T level*: Natural
ITree*[T] = seq[INode[T]]
proc initINode*[T](value: T; level: Natural): INode[T] =
## Return a new node. INode[T](value: value, level: level)
proc initItree*[T](value: T): ITree[T] =
## Return a new tree initialized with the first node (root node). result = @[initINode(value, 0)]
proc add*[T](tree: var ITree[T]; nodes: varargs[INode[T]]) =
## Add a list of nodes to the tree. for node in nodes: if node.level - tree[^1].level > 1: raise newException(ValueError, &"wrong level {node.level} in node {node.value}.") tree.add node
proc `$`*[T](tree: ITree[T]): string =
## Return a string representation of a tree. for node in tree: result.add $node.level & ' ' & $node.value & '\n'
- Conversion between nested form and indented form.
proc toIndented*[T](node: NNode[T]): Itree[T] =
## Convert a tree in nested form to a tree in indented form.
proc addNode[T](tree: var Itree[T]; node: NNode[T]; level: Natural) = ## Add a node to the tree at the given level. tree.add initINode(node.value, level) for child in node.children: tree.addNode(child, level + 1)
result.addNode(node, 0)
proc toNested*[T](tree: Itree[T]): NNode[T] =
## Convert a tree in indented form to a tree in nested form.
var stack: seq[NNode[T]] # Note that stack.len is equal to the current level. var nnode = newNNode(tree[0].value) # Root. for i in 1..tree.high: let inode = tree[i] if inode.level > stack.len: # Child. stack.add nnode elif inode.level == stack.len: # Sibling. stack[^1].children.add nnode else: # Branch terminated. while inode.level < stack.len: stack[^1].children.add nnode nnode = stack.pop() stack[^1].children.add nnode
nnode = newNNode(inode.value)
# Empty the stack. while stack.len > 0: stack[^1].children.add nnode nnode = stack.pop()
result = nnode
- ———————————————————————————————————————————————————————————————————————————————————————————————————
when isMainModule:
echo "Displaying tree built using nested structure:" let nestedTree = newNNode("RosettaCode") let rocks = newNNode("rocks") rocks.add newNNode("code"), newNNode("comparison"), newNNode("wiki") let mocks = newNNode("mocks", newNNode("trolling")) nestedTree.add rocks, mocks echo nestedTree
echo "Displaying tree converted to indented structure:" let indentedTree = nestedTree.toIndented echo indentedTree
echo "Displaying tree converted back to nested structure:" echo indentedTree.toNested
echo "Are they equal? ", if $nestedTree == $indentedTree.toNested: "yes" else: "no"</lang>
- Output:
Displaying tree built using nested structure: RosettaCode rocks code comparison wiki mocks trolling Displaying tree converted to indented structure: 0 RosettaCode 1 rocks 2 code 2 comparison 2 wiki 1 mocks 2 trolling Displaying tree converted back to nested structure: RosettaCode rocks code comparison wiki mocks trolling Are they equal? yes
Perl
<lang perl>use strict; use warnings; use feature 'say'; use JSON; use Data::Printer;
my $trees = <<~END;
RosettaCode encourages code diversity comparison discourages golfing trolling emphasising execution speed code-golf.io encourages golfing discourages comparison END
my $level = ' '; sub nested_to_indent { shift =~ s#^($level*)# ($1 ? length($1)/length $level : 0) . ' ' #egmr } sub indent_to_nested { shift =~ s#^(\d+)\s*# $level x $1 #egmr }
say my $indent = nested_to_indent $trees;
my $nest = indent_to_nested $indent;
use Test::More; is($trees, $nest, 'Round-trip'); done_testing();
- Import outline paragraph into native data structure
sub import {
my($trees) = @_; my $level = ' '; my $forest; my $last = -999;
for my $branch (split /\n/, $trees) { $branch =~ m/(($level*))*/; my $this = $1 ? length($1)/length($level) : 0; $forest .= do { if ($this gt $last) { '[' . trim_and_quote($branch) } elsif ($this lt $last) { ']'x($last-$this).',' . trim_and_quote($branch) } else { trim_and_quote($branch) } }; $last = $this; } sub trim_and_quote { shift =~ s/^\s*(.*\S)\s*$/"$1",/r }
eval $forest . ']' x (1+$last);
}
my $forest = import $trees; say "Native data structure:\n" . np $forest; say "\nJSON:\n" . encode_json($forest);</lang>
- Output:
RosettaCode 1 encourages 2 code 3 diversity 3 comparison 1 discourages 2 golfing 2 trolling 2 emphasising execution speed code-golf.io 1 encourages 2 golfing 1 discourages 2 comparison ok 1 - Round-trip 1..1 Native data structure: \ [ [0] "RosettaCode", [1] [ [0] "encourages", [1] [ [0] "code", [1] [ [0] "diversity", [1] "comparison" ] ], [2] "discourages", [3] [ [0] "golfing", [1] "trolling", [2] "emphasising execution speed" ] ], [2] "code-golf.io", [3] [ [0] "encourages", [1] [ [0] "golfing" ], [2] "discourages", [3] [ [0] "comparison" ] ] ] JSON: ["RosettaCode",["encourages",["code",["diversity","comparison"]],"discourages",["golfing","trolling","emphasising execution speed"]],"code-golf.io",["encourages",["golfing"],"discourages",["comparison"]]]
Phix
The standard Phix sequence is perfect for handling all of these kinds of structures.
function text_to_indent(string plain_text) sequence lines = split(plain_text,"\n",no_empty:=true), parents = {} for i=1 to length(lines) do string line = trim_tail(lines[i]), text = trim_head(line) integer indent = length(line)-length(text) -- remove any completed parents while length(parents) and indent<=parents[$] do parents = parents[1..$-1] end while -- append potential new parent parents &= indent integer depth = length(parents) lines[i] = {depth,text} end for return lines end function function indent_to_nested(sequence indent, integer idx=1, level=1) sequence res = {} while idx<=length(indent) do {integer lvl, string text} = indent[idx] if lvl<level then exit end if {sequence children,idx} = indent_to_nested(indent,idx+1,level+1) res = append(res,{text,children}) end while return {res,idx} end function function nested_to_indent(sequence nested, integer level=1) sequence res = {} for i=1 to length(nested) do {string text, sequence children} = nested[i] res = append(res,{level,text}) res &= nested_to_indent(children,level+1) end for return res end function constant text = """ RosettaCode encourages code diversity comparison discourages emphasising execution speed code-golf.io encourages golfing discourages comparison""" sequence indent = text_to_indent(text), nested = indent_to_nested(indent)[1], n2ichk = nested_to_indent(nested) puts(1,"Indent form:\n") pp(indent,{pp_Nest,1}) puts(1,"\nNested form:\n") pp(nested,{pp_Nest,8}) printf(1,"\nNested to indent:%s\n",{iff(n2ichk==indent?"same":"***ERROR***")})
- Output:
Indent form: {{1, `RosettaCode`}, {2, `encourages`}, {3, `code`}, {4, `diversity`}, {4, `comparison`}, {2, `discourages`}, {3, `emphasising execution speed`}, {1, `code-golf.io`}, {2, `encourages`}, {3, `golfing`}, {2, `discourages`}, {3, `comparison`}} Nested form: {{`RosettaCode`, {{`encourages`, {{`code`, {{`diversity`, {}}, {`comparison`, {}}}}}}, {`discourages`, {{`emphasising execution speed`, {}}}}}}, {`code-golf.io`, {{`encourages`, {{`golfing`, {}}}}, {`discourages`, {{`comparison`, {}}}}}}} Nested to indent:same
You can also strictly enforce these structures, which is obviously useful for debugging.
Admittedly this is somewhat more tedious, but at the same time infinitely more flexible and powerful than a "plain old struct".
type indent_struct(object o) if sequence(o) then for i=1 to length(o) do object oi = o[i] if not sequence(oi) or length(oi)!=2 or not integer(oi[1]) or not string(oi[2]) then return false end if end for return true end if return false end type type nested_struct(object o) if sequence(o) then for i=1 to length(o) do object oi = o[i] if not sequence(oi) or length(oi)!=2 or not string(oi[1]) or not nested_struct(oi[2]) then return false end if end for return true end if return false end type -- and as above except: function indent_to_nested(indent_struct indent, integer idx=1, level=1) function nested_to_indent(nested_struct nested, integer level=1) -- also make the output sequences better typed: indent_struct indent = text_to_indent(text) nested_struct nested = indent_to_nested(indent)[1] indent_struct r2ichk = nested_to_indent(nested)
Python
Just arranges the standard lists and tuples for the datastructures allowing pprint to show the different arrangement of storage.
<lang python>from pprint import pprint as pp
def to_indent(node, depth=0, flat=None):
if flat is None: flat = [] if node: flat.append((depth, node[0])) for child in node[1]: to_indent(child, depth + 1, flat) return flat
def to_nest(lst, depth=0, level=None):
if level is None: level = [] while lst: d, name = lst[0] if d == depth: children = [] level.append((name, children)) lst.pop(0) elif d > depth: # down to_nest(lst, d, children) elif d < depth: # up return return level[0] if level else None
if __name__ == '__main__':
print('Start Nest format:') nest = ('RosettaCode', [('rocks', [('code', []), ('comparison', []), ('wiki', [])]), ('mocks', [('trolling', [])])]) pp(nest, width=25)
print('\n... To Indent format:') as_ind = to_indent(nest) pp(as_ind, width=25)
print('\n... To Nest format:') as_nest = to_nest(as_ind) pp(as_nest, width=25)
if nest != as_nest: print("Whoops round-trip issues")</lang>
- Output:
Start Nest format: ('RosettaCode', [('rocks', [('code', []), ('comparison', []), ('wiki', [])]), ('mocks', [('trolling', [])])]) ... To Indent format: [(0, 'RosettaCode'), (1, 'rocks'), (2, 'code'), (2, 'comparison'), (2, 'wiki'), (1, 'mocks'), (2, 'trolling')] ... To Nest format: ('RosettaCode', [('rocks', [('code', []), ('comparison', []), ('wiki', [])]), ('mocks', [('trolling', [])])])
Raku
(formerly Perl 6)
Code golf is a entertaining passtime, even if it isn't appropriate for this site. To a large extent, I agree with Hout, I am not really on board with mocking anybody, especially espousing it as an official RosettaCode position. So, feel free to mark this incorrect.
<lang perl6>#`( Sort of vague as to what we are trying to accomplish here. If we are just trying to transform from one format to another, probably easiest to just perform string manipulations. )
my $level = ' ';
my $trees = q:to/END/;
RosettaCode encourages code diversity comparison discourages golfing trolling emphasising execution speed code-golf.io encourages golfing discourages comparison END
sub nested-to-indent { $^str.subst: / ^^ ($($level))* /, -> $/ { "{+$0} " }, :g } sub indent-to-nested { $^str.subst: / ^^ (\d+) \s* /, -> $/ { "{$level x +$0}" }, :g }
say $trees; say my $indent = $trees.&nested-to-indent; say my $nest = $indent.&indent-to-nested;
use Test; is($trees, $nest, 'Round-trip equals original');
- `(
If, on the other hand, we want perform more complex transformations; better to load it into a native data structure which will then allow us to manipulate it however we like. )
- Import outline paragraph into native data structure
sub import (Str $trees, $level = ' ') {
my $forest; my $last = -Inf;
for $trees.lines -> $branch { $branch ~~ / ($($level))* /; my $this = +$0; $forest ~= do { given $this cmp $last { when More { "\['{esc $branch.trim}', " } when Same { "'{esc $branch.trim}', " } when Less { "{']' x $last - $this}, '{esc $branch.trim}', " } } } $last = $this; }
sub esc { $^s.subst( /(<['\\]>)/, -> $/ { "\\$0" }, :g) }
$forest ~= ']' x 1 + $last; $forest.EVAL;
}
my $forest = import $trees;
say "\nNative data structure:\n", $forest.raku;
{
use JSON::Fast; say "\nJSON:\n", $forest.&to-json;
}
{
use YAML; say "\nYAML:\n", $forest.&dump;
}</lang>
- Output:
RosettaCode encourages code diversity comparison discourages golfing trolling emphasising execution speed code-golf.io encourages golfing discourages comparison 0 RosettaCode 1 encourages 2 code 3 diversity 3 comparison 1 discourages 2 golfing 2 trolling 2 emphasising execution speed 0 code-golf.io 1 encourages 2 golfing 1 discourages 2 comparison RosettaCode encourages code diversity comparison discourages golfing trolling emphasising execution speed code-golf.io encourages golfing discourages comparison ok 1 - Round-trip equals original Native data structure: $["RosettaCode", ["encourages", ["code", ["diversity", "comparison"]], "discourages", ["golfing", "trolling", "emphasising execution speed"]], "code-golf.io", ["encourages", ["golfing"], "discourages", ["comparison"]]] JSON: [ "RosettaCode", [ "encourages", [ "code", [ "diversity", "comparison" ] ], "discourages", [ "golfing", "trolling", "emphasising execution speed" ] ], "code-golf.io", [ "encourages", [ "golfing" ], "discourages", [ "comparison" ] ] ] YAML: --- - RosettaCode - - encourages - - code - - diversity - comparison - discourages - - golfing - trolling - emphasising execution speed - code-golf.io - - encourages - - golfing - discourages - - comparison ...
Wren
<lang ecmascript>import "/dynamic" for Struct import "/fmt" for Fmt
var NNode = Struct.create("NNode", ["name", "children"]) var INode = Struct.create("INode", ["level", "name"])
var sw = ""
var printNest // recursive printNest = Fn.new { |n, level|
if (level == 0) sw = sw + "\n==Nest form==\n\n" sw = sw + Fmt.swrite("$0s$s\n", " " * level, n.name) for (c in n.children) { sw = sw + (" " * (level + 1)) printNest.call(c, level+1) }
}
var toNest // recursive toNest = Fn.new { |iNodes, start, level, n|
if (level == 0) n.name = iNodes[0].name var i = start + 1 while (i < iNodes.count) { if (iNodes[i].level == level + 1) { var c = NNode.new(iNodes[i].name, []) toNest.call(iNodes, i, level+1, c) n.children.add(c) } else if (iNodes[i].level <= level) return i = i + 1 }
}
var printIndent = Fn.new { |iNodes|
sw = sw + "\n==Indent form==\n\n" for (n in iNodes) sw = sw + Fmt.swrite("$d $s\n", n.level, n.name)
}
var toIndent // recursive toIndent = Fn.new { |n, level, iNodes|
iNodes.add(INode.new(level, n.name)) for (c in n.children) toIndent.call(c, level+1, iNodes)
}
var n1 = NNode.new("RosettaCode", []) var n2 = NNode.new("rocks", [NNode.new("code", []), NNode.new("comparison", []), NNode.new("wiki", [])]) var n3 = NNode.new("mocks", [NNode.new("trolling", [])]) n1.children.add(n2) n1.children.add(n3)
printNest.call(n1, 0) var s1 = sw System.print(s1)
var iNodes = [] toIndent.call(n1, 0, iNodes) sw = "" printIndent.call(iNodes) System.print(sw)
var n = NNode.new("", []) toNest.call(iNodes, 0, 0, n) sw = "" printNest.call(n, 0) var s2 = sw System.print(s2)
System.print("\nRound trip test satisfied? %(s1 == s2)")</lang>
- Output:
==Nest form== RosettaCode rocks code comparison wiki mocks trolling ==Indent form== 0 RosettaCode 1 rocks 2 code 2 comparison 2 wiki 1 mocks 2 trolling ==Nest form== RosettaCode rocks code comparison wiki mocks trolling Round trip test satisfied? true
zkl
<lang zkl>fcn nestToIndent(nestTree){
fcn(out,node,level){ out.append(List(level,node[0])); // (n,name) or ("..",name) if(node.len()>1){ // (name children), (name, (tree))
level+=1; foreach child in (node[1,*]){ if(String.isType(child)) out.append(List(level,child)); else self.fcn(out,child,level) }
} out }(List(),nestTree,0)
} fcn nestToString(nestTree,dot="."){
fcn(out,dot,node,level){ out.writeln(dot*level,node[0]); // (name) if(node.len()>1){ // (name children), (name, (tree))
level+=1; foreach child in (node[1,*]){ if(String.isType(child)) out.writeln(dot*level,child); else self.fcn(out,dot,child,level) }
} out }(Data(),dot,nestTree,0).text
}
fcn indentToNest(iTree,depth=0,nTree=List()){
while(iTree){ // (n,name) d, name := iTree[0]; if(d==depth){ nTree.append(name);
iTree.pop(0);
} else if(d>depth){ // assume can't skip levels down
if(nTree.len()>1 and not List.isType((nm:=nTree[-1]))){ nTree[-1]=(children:=List(nm)); indentToNest(iTree,d,children); }else{ nTree.append(children:=List(name)); iTree.pop(0); indentToNest(iTree,d+1,children); }
} else break; // d<depth } return(nTree)
} fcn indentToString(indentTree){ indentTree.apply("concat"," ").concat("\n") }</lang> <lang zkl>tree:=L("RosettaCode",
L("rocks","code","comparison","wiki"),
L("mocks","golfing") );
println("Nest tree internal format:\n",tree.toString(*,*)); println("Formated:\n",nestToString(tree));
indentTree:=nestToIndent(tree); println("To indent format:\n",indentToString(indentTree));
nestTree:=indentToNest(indentTree); println("\nIndent to nested format:\n",nestTree); println("Is this tree the same as what we started with? ",nestTree==tree);</lang>
- Output:
Nest tree internal format: L("RosettaCode",L("rocks","code","comparison","wiki"),L("mocks","golfing")) Formated: RosettaCode .rocks ..code ..comparison ..wiki .mocks ..golfing To indent format: 0 RosettaCode 1 rocks 2 code 2 comparison 2 wiki 1 mocks 2 golfing Indent to nested format: L("RosettaCode",L("rocks","code","comparison","wiki"),L("mocks","golfing")) Is this tree the same as what we started with? True
I'm choosing to only allow one root per tree/forest so the Raku example is coded differently: <lang zkl>rakutrees:=L(
L("RosettaCode", L("encourages", L("code",
"diversity","comparison")),
L("discourages", "golfing","trolling","emphasising execution speed"), ), L("code-golf.io", L("encourages","golfing"), L("discourages","comparison"), )
); println(rakutrees.apply(nestToString).concat()); iTrees := rakutrees.apply(nestToIndent); println(iTrees.apply(indentToString).concat("\n")); (iTrees.apply(indentToNest)==rakutrees).println();</lang>
- Output:
RosettaCode encourages code diversity comparison discourages golfing trolling emphasising execution speed code-golf.io encourages golfing discourages comparison 0 RosettaCode 1 encourages 2 code 3 diversity 3 comparison 1 discourages 2 golfing 2 trolling 2 emphasising execution speed 0 code-golf.io 1 encourages 2 golfing 1 discourages 2 comparison True