Topological sort/Extracted top item

From Rosetta Code
Topological sort/Extracted top item is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Given a mapping between items, and items they depend on, a topological sort orders items so that no item precedes an item it depends upon.

The compiling of a design in the VHDL language has the constraint that a file must be compiled after any file containing definitions it depends on. A tool exists that extracts file dependencies.

  • Assume the file names are single words, given without their file extensions.
  • Files mentioned as only dependants, have no dependants of their own, but their order of compiling must be given.
  • Any self dependencies should be ignored.


A top level file is defined as a file that:

  1. Has dependents.
  2. Is not itself the dependent of another file


Task Description

Given the following file dependencies as an example:

FILE    FILE DEPENDENCIES
====    =================
top1    des1 ip1 ip2
top2    des1 ip2 ip3
ip1     extra1 ip1a ipcommon
ip2     ip2a ip2b ip2c ipcommon
des1    des1a des1b des1c
des1a   des1a1 des1a2
des1c   des1c1 extra1

The task is to create a program that given a graph of the dependency:

  1. Determines the top levels from the dependencies and show them.
  2. Extracts a compile order of files to compile any given (usually top level) file.
  3. Give a compile order for file top1.
  4. Give a compile order for file top2.

You may show how to compile multiple top levels as a stretch goal

Note: this task differs from task Topological sort in that the order for compiling any file might not include all files; and that checks for dependency cycles are not mandated.

Cf.



C[edit]

Take code from Topological sort#c and add/change the following:

char input[] =	"top1    des1 ip1 ip2\n"
"top2 des1 ip2 ip3\n"
"ip1 extra1 ip1a ipcommon\n"
"ip2 ip2a ip2b ip2c ipcommon\n"
"des1 des1a des1b des1c\n"
"des1a des1a1 des1a2\n"
"des1c des1c1 extra1\n";
 
...
int find_name(item base, int len, const char *name)
{
int i;
for (i = 0; i < len; i++)
if (!strcmp(base[i].name, name)) return i;
return -1;
}
 
int depends_on(item base, int n1, int n2)
{
int i;
if (n1 == n2) return 1;
for (i = 0; i < base[n1].n_deps; i++)
if (depends_on(base, base[n1].deps[i], n2)) return 1;
return 0;
}
 
void compile_order(item base, int n_items, int *top, int n_top)
{
int i, j, lvl;
int d = 0;
printf("Compile order for:");
for (i = 0; i < n_top; i++) {
printf(" %s", base[top[i]].name);
if (base[top[i]].depth > d)
d = base[top[i]].depth;
}
printf("\n");
 
for (lvl = 1; lvl <= d; lvl ++) {
printf("level %d:", lvl);
for (i = 0; i < n_items; i++) {
if (base[i].depth != lvl) continue;
for (j = 0; j < n_top; j++) {
if (depends_on(base, top[j], i)) {
printf(" %s", base[i].name);
break;
}
}
}
printf("\n");
}
printf("\n");
}
 
int main()
{
int i, n, bad = -1;
item items;
n = parse_input(&items);
 
for (i = 0; i < n; i++)
if (!items[i].depth && get_depth(items, i, bad) < 0) bad--;
 
int top[3];
top[0] = find_name(items, n, "top1");
top[1] = find_name(items, n, "top2");
top[2] = find_name(items, n, "ip1");
 
compile_order(items, n, top, 1);
compile_order(items, n, top + 1, 1);
compile_order(items, n, top, 2);
compile_order(items, n, top + 2, 1);
 
return 0;
}
output (the last item is just to show that it doesn't have to be top level)
Compile order for: top1
level 1: extra1 ip1a ipcommon ip2a ip2b ip2c des1b des1a1 des1a2 des1c1
level 2: ip1 ip2 des1a des1c
level 3: des1
level 4: top1
 
Compile order for: top2
level 1: ip3 extra1 ipcommon ip2a ip2b ip2c des1b des1a1 des1a2 des1c1
level 2: ip2 des1a des1c
level 3: des1
level 4: top2
 
Compile order for: top1 top2
level 1: ip3 extra1 ip1a ipcommon ip2a ip2b ip2c des1b des1a1 des1a2 des1c1
level 2: ip1 ip2 des1a des1c
level 3: des1
level 4: top1 top2
 
Compile order for: ip1
level 1: extra1 ip1a ipcommon
level 2: ip1

Go[edit]

package main
 
import (
"fmt"
"strings"
)
 
var data = `
FILE FILE DEPENDENCIES
==== =================
top1 des1 ip1 ip2
top2 des1 ip2 ip3
ip1 extra1 ip1a ipcommon
ip2 ip2a ip2b ip2c ipcommon
des1 des1a des1b des1c
des1a des1a1 des1a2
des1c des1c1 extra1`

 
func main() {
g, dep, err := parseLibDep(data)
if err != nil {
fmt.Println(err)
return
}
// Task 1: Determine top levels. The input parser returns a list (dep)
// of libraries that are dependants of at least one other library.
// Top levels are then libraries in the graph that are not on this list.
var tops []string
for n := range g {
if !dep[n] {
tops = append(tops, n)
}
}
fmt.Println("Top levels:", tops)
// Task 2 is orderFrom method, below
showOrder(g, "top1") // Task 3
showOrder(g, "top2") // Task 4
showOrder(g, "top1", "top2") // Stretch
 
fmt.Println("Cycle examples:")
// reparse with a cyclic dependency
g, _, err = parseLibDep(data + `
des1a1 des1`
)
if err != nil {
fmt.Println(err)
return
}
showOrder(g, "top1") // runs into cycle
showOrder(g, "ip1", "ip2") // does not involve cycle
}
 
func showOrder(g graph, target ...string) {
order, cyclic := g.orderFrom(target...)
if cyclic == nil {
reverse(order) // compile order is reverse of dependency order
fmt.Println("Target", target, "order:", order)
} else {
fmt.Println("Target", target, "cyclic dependencies:", cyclic)
}
}
 
func reverse(s []string) {
last := len(s) - 1
for i, e := range s[:len(s)/2] {
s[i], s[last-i] = s[last-i], e
}
}
 
type graph map[string][]string // adjacency list representation
type depList map[string]bool
 
// parseLibDep parses the text format of the task and returns a dependency
// graph and a list of nodes that are dependants of at least one other node.
func parseLibDep(data string) (g graph, d depList, err error) {
lines := strings.Split(data, "\n")
if len(lines) < 3 || !strings.HasPrefix(lines[2], "=") {
return nil, nil, fmt.Errorf("data format")
}
lines = lines[3:]
g = graph{}
d = depList{}
for _, line := range lines {
libs := strings.Fields(line)
if len(libs) == 0 {
continue
}
lib := libs[0]
var deps []string
for _, dep := range libs[1:] {
g[dep] = g[dep]
if dep == lib {
continue
}
for i := 0; ; i++ {
if i == len(deps) {
deps = append(deps, dep)
d[dep] = true
break
}
if dep == deps[i] {
break
}
}
}
g[lib] = deps
}
return g, d, nil
}
 
// OrderFrom produces a topological ordering of the subgraph of g reachable
// from a set of start nodes, where the subgraph is a directed acyclic graph.
// If the subgraph contains a cycle, orderFrom returns the first cycle found
// and returns a nil order. Cycles which are in the graph but not in the
// subgraph reachable from start are not detected.
func (g graph) orderFrom(start ...string) (order, cyclic []string) {
L := make([]string, len(g))
i := len(L)
temp := map[string]bool{}
perm := map[string]bool{}
var cycleFound bool
var cycleStart string
var visit func(string)
visit = func(n string) {
switch {
case temp[n]:
cycleFound = true
cycleStart = n
return
case perm[n]:
return
}
temp[n] = true
for _, m := range g[n] {
visit(m)
if cycleFound {
if cycleStart > "" {
cyclic = append(cyclic, n)
if n == cycleStart {
cycleStart = ""
}
}
return
}
}
delete(temp, n)
perm[n] = true
i--
L[i] = n
}
for _, n := range start {
if perm[n] {
continue
}
visit(n)
if cycleFound {
return nil, cyclic
}
}
return L[i:], nil
}
Output:
Top levels: [top1 top2]
Target [top1] order: [des1a1 des1a2 des1a des1b des1c1 extra1 des1c des1 ip1a ipcommon ip1 ip2a ip2b ip2c ip2 top1]
Target [top2] order: [des1a1 des1a2 des1a des1b des1c1 extra1 des1c des1 ip2a ip2b ip2c ipcommon ip2 ip3 top2]
Target [top1 top2] order: [des1a1 des1a2 des1a des1b des1c1 extra1 des1c des1 ip1a ipcommon ip1 ip2a ip2b ip2c ip2 top1 ip3 top2]
Cycle examples:
Target [top1] cyclic dependencies: [des1a1 des1a des1]
Target [ip1 ip2] order: [extra1 ip1a ipcommon ip1 ip2a ip2b ip2c ip2]

J[edit]

Derived from the topological sort implementation:

compileOrder=: dyad define
targets=. ;: x
parsed=. <@;:;._2 y
names=. ~.({.&>parsed),targets,;parsed
depends=. (> =@i.@#) names e.S:1 (#names){.parsed
depends=. (+. +./ .*.~)^:_ depends
b=. +./depends (] , #~) names e. targets
names (</.~ \: ~.@])&(keep&#) +/"1 depends
(b#names) (</.~ /: ~.@]) +/ }.+./ .*.~&(b#"1 b#depends)^:a: 1
)
 
topLevel=: [: ({.&> -. [:;}.&.>) <@;:;._2
 

The changes include:

  1. Added an argument for the target(s) we wish to find dependencies for
  2. Make sure that these targets are included in our dependency structures
  3. Make sure that things we can depend on are included in our dependency structures
  4. Select these targets, and the things they depend on, once we know what depends on what
  5. When ordering names by dependencies:
    1. only consider names and dependencies we want to keep
    2. extract names grouped by their dependency chain length

Example:

dependencies=: noun define
top1 des1 ip1 ip2
top2 des1 ip2 ip3
ip1 extra1 ip1a ipcommon
ip2 ip2a ip2b ip2c ipcommon
des1 des1a des1b des1c
des1a des1a1 des1a2
des1c des1c1 extra1
)
 
>topLevel dependencies
top1
top2
 
 ;:inv@> 'top1' compileOrder dependencies
extra1 ip1a ipcommon ip2a ip2b ip2c des1b des1a1 des1a2 des1c1
ip1 ip2 des1a des1c
des1
top1
 
 ;:inv@> 'top2' compileOrder dependencies
ip3 extra1 ipcommon ip2a ip2b ip2c des1b des1a1 des1a2 des1c1
ip2 des1a des1c
des1
top2
 
 ;:inv@> 'top1 top2' compileOrder dependencies
ip3 extra1 ip1a ipcommon ip2a ip2b ip2c des1b des1a1 des1a2 des1c1
ip1 ip2 des1a des1c
des1
top1 top2
 

Java[edit]

Works with: Java version 8
import java.util.*;
import static java.util.Arrays.asList;
import static java.util.stream.Collectors.toList;
 
public class TopologicalSort2 {
 
public static void main(String[] args) {
String s = "top1,top2,ip1,ip2,ip3,ip1a,ip2a,ip2b,ip2c,ipcommon,des1,"
+ "des1a,des1b,des1c,des1a1,des1a2,des1c1,extra1";
 
Graph g = new Graph(s, new int[][]{
{0, 10}, {0, 2}, {0, 3},
{1, 10}, {1, 3}, {1, 4},
{2, 17}, {2, 5}, {2, 9},
{3, 6}, {3, 7}, {3, 8}, {3, 9},
{10, 11}, {10, 12}, {10, 13},
{11, 14}, {11, 15},
{13, 16}, {13, 17},});
 
System.out.println("Top levels: " + g.toplevels());
String[] files = {"top1", "top2", "ip1"};
for (String f : files)
System.out.printf("Compile order for %s %s%n", f, g.compileOrder(f));
}
}
 
class Graph {
List<String> vertices;
boolean[][] adjacency;
int numVertices;
 
public Graph(String s, int[][] edges) {
vertices = asList(s.split(","));
numVertices = vertices.size();
adjacency = new boolean[numVertices][numVertices];
 
for (int[] edge : edges)
adjacency[edge[0]][edge[1]] = true;
}
 
List<String> toplevels() {
List<String> result = new ArrayList<>();
// look for empty columns
outer:
for (int c = 0; c < numVertices; c++) {
for (int r = 0; r < numVertices; r++) {
if (adjacency[r][c])
continue outer;
}
result.add(vertices.get(c));
}
return result;
}
 
List<String> compileOrder(String item) {
LinkedList<String> result = new LinkedList<>();
LinkedList<Integer> queue = new LinkedList<>();
 
queue.add(vertices.indexOf(item));
 
while (!queue.isEmpty()) {
int r = queue.poll();
for (int c = 0; c < numVertices; c++) {
if (adjacency[r][c] && !queue.contains(c)) {
queue.add(c);
}
}
result.addFirst(vertices.get(r));
}
return result.stream().distinct().collect(toList());
}
}
Top levels: [top1, top2]
Compile order for top1 [extra1, des1c1, des1a2, des1a1, des1c, des1b, des1a, ip2c, ip2b, ip2a, ipcommon, ip1a, des1, ip2, ip1, top1]
Compile order for top2 [extra1, des1c1, des1a2, des1a1, des1c, des1b, des1a, ipcommon, ip2c, ip2b, ip2a, des1, ip3, ip2, top2]
Compile order for ip1 [extra1, ipcommon, ip1a, ip1]

Perl 6[edit]

sub top_topos ( %deps, *@top ) {
my %ba;
for %deps.kv -> $after, @befores {
for @befores -> $before {
%ba{$after}{$before} = 0 if $before ne $after;
%ba{$before} //= {};
}
}
 
if @top {
my @want = @top;
my %care;
%care{@want} = 1 xx *;
repeat while @want {
my @newwant;
for @want -> $before {
if %ba{$before} {
for %ba{$before}.keys -> $after {
if not %ba{$before}{$after} {
%ba{$before}{$after}++;
push @newwant, $after;
}
}
}
}
@want = @newwant;
%care{@want} = 1 xx *;
}
 
for %ba.keys -> $before {
%ba{$before}:delete unless %care{$before};
}
}
 
my @levels;
while %ba.grep( not *.value )».key -> @befores {
push @levels, ~@befores.sort;
%ba{@befores}:delete;
for %ba.values { .{@befores}:delete }
}
if @top {
say "For top-level-modules: ", @top;
say " $_" for @levels;
}
else {
say "Top levels are: @levels[*-1]";
}
 
say "Cycle found! {%ba.keys.sort}" if %ba;
say '';
}
 
my %deps =
top1 => <des1 ip1 ip2>,
top2 => <des1 ip2 ip3>,
ip1 => <extra1 ip1a ipcommon>,
ip2 => <ip2a ip2b ip2c ipcommon>,
des1 => <des1a des1b des1c>,
des1a => <des1a1 des1a2>,
des1c => <des1c1 extra1>;
 
top_topos(%deps);
top_topos(%deps, 'top1');
top_topos(%deps, 'top2');
top_topos(%deps, 'ip1');
top_topos(%deps, 'top1', 'top2');
Output:
Top levels are: top1 top2

For top-level-modules: top1
  des1a1 des1a2 des1b des1c1 extra1 ip1a ip2a ip2b ip2c ipcommon
  des1a des1c ip1 ip2
  des1
  top1

For top-level-modules: top2
  des1a1 des1a2 des1b des1c1 extra1 ip2a ip2b ip2c ip3 ipcommon
  des1a des1c ip2
  des1
  top2

For top-level-modules: ip1
  extra1 ip1a ipcommon
  ip1

For top-level-modules: top1 top2
  des1a1 des1a2 des1b des1c1 extra1 ip1a ip2a ip2b ip2c ip3 ipcommon
  des1a des1c ip1 ip2
  des1
  top1 top2

Python[edit]

Where the compile order between a subset of files is arbitrary, they are shown on the same line.

try:
from functools import reduce
except: pass
 
# Python 3.x: def topx(data:'dict', tops:'set'=None) -> 'list':
def topx(data, tops=None):
'Extract the set of top-level(s) in topological order'
for k, v in data.items():
v.discard(k) # Ignore self dependencies
if tops is None:
tops = toplevels(data)
return _topx(data, tops, [], set())
 
def _topx(data, tops, _sofar, _sofar_set):
'Recursive topological extractor'
_sofar += [tops] # Accumulates order in reverse
_sofar_set.union(tops)
depends = reduce(set.union, (data.get(top, set()) for top in tops))
if depends:
_topx(data, depends, _sofar, _sofar_set)
ordered, accum = [], set()
for s in _sofar[::-1]:
ordered += [sorted(s - accum)]
accum |= s
return ordered
 
def printorder(order):
'Prettyprint topological ordering'
if order:
print("First: " + ', '.join(str(s) for s in order[0]))
for o in order[1:]:
print(" Then: " + ', '.join(str(s) for s in o))
 
def toplevels(data):
'''\
Extract all top levels from dependency data
Top levels are never dependents
'''

for k, v in data.items():
v.discard(k) # Ignore self dependencies
dependents = reduce(set.union, data.values())
return set(data.keys()) - dependents
 
if __name__ == '__main__':
data = dict(
top1 = set('ip1 des1 ip2'.split()),
top2 = set('ip2 des1 ip3'.split()),
des1 = set('des1a des1b des1c'.split()),
des1a = set('des1a1 des1a2'.split()),
des1c = set('des1c1 extra1'.split()),
ip2 = set('ip2a ip2b ip2c ipcommon'.split()),
ip1 = set('ip1a ipcommon extra1'.split()),
)
 
tops = toplevels(data)
print("The top levels of the dependency graph are: " + ' '.join(tops))
 
for t in sorted(tops):
print("\nThe compile order for top level: %s is..." % t)
printorder(topx(data, set([t])))
if len(tops) > 1:
print("\nThe compile order for top levels: %s is..."
 % ' and '.join(str(s) for s in sorted(tops)) )
printorder(topx(data, tops))

Sample Output

The top levels of the dependency graph are: top2 top1

The compile order for top level: top1 is...
First: des1a1, des1a2, des1c1, extra1
 Then: des1a, des1b, des1c, ip1a, ip2a, ip2b, ip2c, ipcommon
 Then: des1, ip1, ip2
 Then: top1

The compile order for top level: top2 is...
First: des1a1, des1a2, des1c1, extra1
 Then: des1a, des1b, des1c, ip2a, ip2b, ip2c, ipcommon
 Then: des1, ip2, ip3
 Then: top2

The compile order for top levels: top1 and top2 is...
First: des1a1, des1a2, des1c1, extra1
 Then: des1a, des1b, des1c, ip1a, ip2a, ip2b, ip2c, ipcommon
 Then: des1, ip1, ip2, ip3
 Then: top1, top2

Racket[edit]

#lang racket
(define dep-tree ; go straight for the hash, without parsing strings etc.
#hash((top1 . (des1 ip1 ip2))
(top2 . (des1 ip2 ip3))
(ip1 . (extra1 ip1a ipcommon))
(ip2 . (ip2a ip2b ip2c ipcommon))
(des1 . (des1a des1b des1c))
(des1a . (des1a1 des1a2))
(des1c . (des1c1 extra1))))
 
(define (build-tree Deps Top)
(define (build n b# d)
(hash-set b# n d))
 
(define (inner-b-t node visited built# depth)
(cond
[(hash-ref built# node #f)
built#]
[(member node visited)
(error 'build-tree "circular dependency tree at node: ~a" node)]
[(hash-ref Deps node #f)
=>
(λ (deps)
(define built#+
(for/fold ((built# built#)) ((dependency deps))
(if (equal? dependency node)
built#
(inner-b-t dependency (cons node visited) built# (add1 depth)))))
(build node built#+ depth))]
[else
(build node built# depth)]))
 
(define final-build# (inner-b-t Top null (hash) 1))
 
(define levels# (for/fold ((hsh# (hash))) (([k v] (in-hash final-build#)))
(hash-update hsh# v (curry cons k) null)))
 
(for/list ((lvl (in-list (sort (hash-keys levels#) >))))
(hash-ref levels# lvl)))
 
(define (print-build-order Deps Top)
(define build-order (build-tree Deps Top))
(printf "To build: ~s~%" Top)
(for ((round build-order)) (printf "Build: ~a~%" round))
(newline))
 
(print-build-order dep-tree 'top1)
(print-build-order dep-tree 'top2)
(with-handlers [(exn? (λ (x) (displayln (exn-message x) (current-error-port))))]
(build-tree #hash((top . (des1 ip1)) (ip1 . (net netip)) (netip . (mac ip1))) 'top))
Output:
To build: top1
Build: (extra1 des1c1 des1a2 des1a1)
Build: (ip2c ip2b ip2a ipcommon ip1a des1b des1c des1a)
Build: (des1 ip2 ip1)
Build: (top1)

To build: top2
Build: (extra1 des1c1 des1a2 des1a1)
Build: (ip2c ip2b ip2a ipcommon des1b des1c des1a)
Build: (ip3 des1 ip2)
Build: (top2)

build-tree: circular dependency tree at node: ip1

REXX[edit]

Where the compile order between a subset of files is arbitrary, they are shown on the same line.
This REXX version can handle multiple top levels.

/*REXX program  display s the  compile  order of jobs  (indicating the dependencies).   */
parse arg job /*obtain optional argument from the CL.*/
jobL. =; stage.=; #.=0; @.=; JL= /*define some handy-dandy variables. */
tree. =
tree.1= ' top1 des1 ip1 ip2 '
tree.2= ' top2 des1 ip2 ip3 '
tree.3= ' ip1 extra1 ip1a ipcommon '
tree.4= ' ip2 ip2a ip2b ip2c ipcommon '
tree.5= ' des1 des1a des1b des1c '
tree.6= ' des1a des1a1 des1a2 '
tree.7= ' des1c des1c1 extra1 '
$=
do j=1 while tree.j\=='' /*build job tree.*/
parse var tree.j x deps; @.x=space(deps) /*extract jobs. */
if wordpos(x,$)==0 then $=$ x /*Unique? Add it.*/
do k=1 for words(@.x); _=word(@.x,k)
if wordpos(_,$)==0 then $=space($ _)
end /*k*/
end /*j*/
!.=;  !!.=
do j=1 for words($); x=word($,j);  !.x.0=words(@.x)
do k=1 for !.x.0;  !.x.k=word(@.x,k);  !!.x.k=!.x.k
end /*k*/ /* [↑] build arrays of job departments*/
end /*j*/
 
do words($) /*process all the jobs specified. */
do j=1 for words($); x=word($,j); z=words(@.x); allN=1; m=0
if z==0 then do; #.x=1; iterate; end /*if no dependents, then skip this one.*/
do k=1 for z; y=!.x.k /*examine all the stage numbers. */
if datatype(y,'W') then m=max(m,y) /*find the highest stage number. */
else do; allN=0 /*at least one entry isn't numeric. */
if #.y\==0 then !.x.k=#.y
end /* [↑] replace with a number. */
end /*k*/
if allN & m\==0 then #.x=max(#.x,m+1) /*replace with the stage number max. */
end /*j*/ /* [↑] maybe set the stage number. */
end /*words($)*/
 
jobL.1=job /*define the bottom level jobList. */
s=1 /*define the stage level for jobList. */
do j=1; yyy=jobL.j
do r=1 for words(yyy) /*verify that there are no duplicates. */
do c=1 while c<words(yyy); z=word(yyy,c)
p=wordpos(z,yyy,c+1); if p\==0 then yyy=delword(yyy,p,1)
end /*c*/ /* [↑] Dup? Then delete it. */
end /*r*/
jobL.j=yyy
if yyy='' then leave /*if null, then we're done with jobList*/
z=words(yyy) /*number of jobs in the jobList. */
s=s+1 /*bump the stage number. */
do k=1 for z; _=word(yyy,k) /*obtain a stage number for the job. */
jobL.s=jobL.s @._ /*add a job to a stage. */
end /*k*/
end /*j*/
 
do k=1 for s; JL=JL jobL.k; end /*build a complete jobList (JL). */
 
do s=1 for words(JL) /*process each job in the jobList. */
_=word(JL,s); level=#._ /*get the proper level for the job. */
stage.level=stage.level _ /*assign a level to job stage number. */
end /*s*/ /* [↑] construct various job stages. */
 
say '─────── The compile order for job: ' job; say
/* [↓] display the stages for the job.*/
do show=1 for s; if stage.show\=='' then say show stage.show; end
/*stick a fork in it, we're all done. */

output   when using the input of:   top1

─────── The compile order for job:  top1 

1  des1b extra1 ip1a ipcommon ip2a ip2b ip2c des1a1 des1a2 des1c1 extra1
2  ip1 ip2 des1a des1c
3  des1
4  top1

output   when using the input of:   top2

─────── The compile order for job:  top2

1  ip3 des1b ip2a ip2b ip2c ipcommon des1a1 des1a2 des1c1 extra1
2  ip2 des1a des1c
3  des1
4  top2

output   when using the input of:   top1 top2

─────── The compile order for job:  top1 top2

1  ip3 des1b extra1 ip1a ipcommon ip2a ip2b ip2c des1a1 des1a2 des1c1 extra1
2  ip1 ip2 des1a des1c
3  des1
4  top1 top2

Tcl[edit]

The topsort proc is taken from Topological sort#Tcl with {*} removed from the line commented so that results are returned by level:

package require Tcl 8.5
proc topsort {data} {
# Clean the data
dict for {node depends} $data {
if {[set i [lsearch -exact $depends $node]] >= 0} {
set depends [lreplace $depends $i $i]
dict set data $node $depends
}
foreach node $depends {dict lappend data $node}
}
# Do the sort
set sorted {}
while 1 {
# Find available nodes
set avail [dict keys [dict filter $data value {}]]
if {![llength $avail]} {
if {[dict size $data]} {
error "graph is cyclic, possibly involving nodes \"[dict keys $data]\""
}
return $sorted
}
lappend sorted $avail ;# change here: [[Topological sort]] had {*}$avail
# Remove from working copy of graph
dict for {node depends} $data {
foreach n $avail {
if {[set i [lsearch -exact $depends $n]] >= 0} {
set depends [lreplace $depends $i $i]
dict set data $node $depends
}
}
}
foreach node $avail {
dict unset data $node
}
}
}
 
# The changes to $data in this proc offer an interesting reflection on value semantics.
# Consider the value of $data seen by [dict for], by each invocation of [dict keys]
# and [dict unset] and how that affects the soundness of the loops.
proc tops {data} {
dict for {k v} $data {
foreach t [dict keys $data] {
if {$t in $v} {
dict unset data $t
}
}
}
dict keys $data
}
 
proc withdeps {dict tops {res {}}} {
foreach top $tops {
if {[dict exists $dict $top]} {
set deps [dict get $dict $top]
set res [dict merge $res [dict create $top $deps] [withdeps $dict $deps]]
}
}
return $res
}
 
proc parsetop {t} {
set top {}
foreach l [split $t \n] {
catch {dict lappend top {*}$l}
}
return $top
}
 
set inputData {
top1 des1 ip1 ip2
top2 des1 ip2 ip3
ip1 extra1 ip1a ipcommon
ip2 ip2a ip2b ip2c ipcommon
des1 des1a des1b des1c
des1a des1a1 des1a2
des1c des1c1 extra1
}
 
set d [parsetop $inputData]
pdict $d
set tops [tops $d]
 
puts "Tops: $tops\n"
 
set targets [list $tops {*}$tops]
foreach target $targets {
puts "Target: $target"
set i 0
foreach deps [topsort [withdeps $d $target]] {
puts "\tround [incr i]:\t$deps"
}
}
Output:
Tops: top1 top2

Target: top1 top2
        round 1:        des1b des1a1 des1a2 des1c1 extra1 ip1a ipcommon ip2a ip2b ip2c ip3
        round 2:        des1a des1c ip1 ip2
        round 3:        des1
        round 4:        top1 top2
Target: top1
        round 1:        des1b des1a1 des1a2 des1c1 extra1 ip1a ipcommon ip2a ip2b ip2c
        round 2:        des1a des1c ip1 ip2
        round 3:        des1
        round 4:        top1
Target: top2
        round 1:        ip3 des1b des1a1 des1a2 des1c1 extra1 ip2a ip2b ip2c ipcommon
        round 2:        des1a des1c ip2
        round 3:        des1
        round 4:        top2