Process SMIL directives in XML data

Process SMIL directives in XML data 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.

In order to represent evolutions of contents over time, the SMIL standard provides a solution to record the animation of data. Smil animations can be added to any kind of contents formated in XML.

• SMIL on Wikipedia and at W3

The task is to create an utility that given the first Smiled XML file, would return the following ones:

<?xml version="1.0" ?>
<smil>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='2 1 2'>
        <animate attributeName="size" from="2 1 2"
                                        to="1 2 1" begin="0s" dur="10s"/>
      </Box>
      <Appearance>
        <Material diffuseColor='0.0 0.6 1.0'>
          <animate attributeName="diffuseColor" from="0.0 0.6 1.0"
                                                  to="1.0 0.4 0.0" begin="0s" dur="10s"/>
        </Material>
      </Appearance>
    </Shape>
  </Scene>
</X3D>
</smil>

At t = 0 second here is the expected output:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='2 1 2'/>
      <Appearance>
        <Material diffuseColor='0.0 0.6 1.0'/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>

At t = 2 second here is the expected output:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='1.8 1.2 1.8'/>
      <Appearance>
        <Material diffuseColor='0.2 0.56 0.8'/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>

Go

Library: etree

package main

import (
    "fmt"
    "github.com/beevik/etree"
    "log"
    "os"
    "strconv"
    "strings"
)

type animData struct {
    element *etree.Element
    attrib  string
    from    string
    to      string
    begin   float64
    dur     float64
}

func check(err error) {
    if err != nil {
        log.Fatal(err)
    }
}

func (ad *animData) AtTime(t float64) string {
    beg := ad.begin
    end := beg + ad.dur
    if t < beg || t > end {
        log.Fatalf("time must be in interval [%g, %g]", beg, end)
    }
    fromSplit := strings.Fields(ad.from)
    toSplit := strings.Fields(ad.to)
    le := len(fromSplit)
    interSplit := make([]string, le)
    for i := 0; i < le; i++ {
        fromF, err := strconv.ParseFloat(fromSplit[i], 64)
        check(err)
        toF, err := strconv.ParseFloat(toSplit[i], 64)
        check(err)
        interF := (fromF*(end-t) + toF*(t-beg)) / ad.dur
        interSplit[i] = fmt.Sprintf("%.2f", interF)
    }
    return strings.Join(interSplit, " ")
}

func main() {
    doc := etree.NewDocument()
    check(doc.ReadFromFile("smil.xml"))
    smil := doc.SelectElement("smil")
    if smil == nil {
        log.Fatal("'smil' element not found")
    }
    x3d := smil.SelectElement("X3D")
    if x3d == nil {
        log.Fatal("'X3D' element not found")
    }
    doc.SetRoot(x3d) // remove 'smil' element
    var ads []*animData
    for _, a := range doc.FindElements("//animate") {
        attrib := a.SelectAttrValue("attributeName", "?")
        from := a.SelectAttrValue("from", "?")
        to := a.SelectAttrValue("to", "?")
        beginS := a.SelectAttrValue("begin", "?")
        durS := a.SelectAttrValue("dur", "?")
        if attrib == "?" || from == "?" || to == "?" ||
            beginS == "?" || durS == "?" {
            log.Fatal("an animate element has missing attribute(s)")
        }
        begin, err := strconv.ParseFloat(beginS[:len(beginS)-1], 64)
        check(err)
        dur, err := strconv.ParseFloat(durS[:len(durS)-1], 64)
        check(err)
        p := a.Parent()
        if p == nil {
            log.Fatal("an animate element has no parent")
        }
        pattrib := p.SelectAttrValue(attrib, "?")
        if pattrib == "?" {
            log.Fatal("an animate element's parent has missing attribute")
        }
        ads = append(ads, &animData{p, attrib, from, to, begin, dur})
        p.RemoveChild(a) // remove 'animate' element
    }
    ts := []float64{0, 2}
    for _, t := range ts {
        for _, ad := range ads {
            s := ad.AtTime(t)
            ad.element.CreateAttr(ad.attrib, s)
        }
        doc.Indent(2)
        fmt.Printf("At time = %g seconds:\n\n", t)
        doc.WriteTo(os.Stdout)
        fmt.Println()
    }
}

Output:

At time = 0 seconds:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color="1 1 1" location="0 2 0"/>
    <Shape>
      <Box size="2.00 1.00 2.00"/>
      <Appearance>
        <Material diffuseColor="0.00 0.60 1.00"/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>

At time = 2 seconds:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color="1 1 1" location="0 2 0"/>
    <Shape>
      <Box size="1.80 1.20 1.80"/>
      <Appearance>
        <Material diffuseColor="0.20 0.56 0.80"/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>

Nim

import sequtils, strformat, strtabs, strutils, xmlparser, xmltree

type

  Animation = object
    attrName: string          # Attribute to animate.
    fromValues: seq[float]    # List of "from" values.
    toValues: seq[float]      # List of "to" values.
    begin: float              # Animation starting time.
    duration: float           # Animation duration.


func getAnim(node: XmlNode): Animation =
  ## Build an animation object from an XML node.

  result.attrName = node.attr("attributeName")
  if result.attrName.len == 0:
    raise newException(ValueError, "missing 'attributeName' attribute")
  var str = node.attr("from")
  if str.len == 0:
    raise newException(ValueError, "missing 'from' attribute")
  result.fromValues = str.splitWhitespace().map(parseFloat)
  str = node.attr("to")
  if str.len == 0:
    raise newException(ValueError, "missing 'to' attribute")
  result.toValues = str.splitWhitespace().map(parseFloat)
  if result.fromValues.len != result.toValues.len:
    raise newException(ValueError, "inconsistent number of values")
  str = node.attr("begin")
  if str.len == 0:
    raise newException(ValueError, "missing 'begin' attribute")
  if str[^1] != 's':
    raise newException(ValueError, "missing unit")
  result.begin = parseFloat(str[0..^2])
  str = node.attr("dur")
  if str.len == 0:
    raise newException(ValueError, "missing 'dur' attribute")
  if str[^1] != 's':
    raise newException(ValueError, "missing unit")
  result.duration = parseFloat(str[0..^2])


func buildXml(node: XmlNode; t: float): XmlNode =
  ## Build the XML tree of a SMIL animation at time "t".

  if node.len > 0 and node[0].tag == "animate":
    # Child is an animate node.
    let anim = node[0].getAnim()
    # Check attribute name.
    if node.attr(anim.attrName).len == 0:
      raise newException(ValueError, &"unable to find attribute '{anim.attrName}'")
    # Check time.
    if t notin anim.begin..(anim.begin + anim.duration):
      raise newException(ValueError, "time value out of range")
    # Build attribute value.
    var aVal = newSeq[float](anim.fromValues.len)
    for i in 0..aVal.high:
      aVal[i] = (anim.fromValues[i] * (anim.begin + anim.duration - t) +
                 anim.toValues[i] * (t - anim.begin)) / anim.duration
    # Set attributes.
    let a = node.attrs
    a[anim.attrName] = aVal.mapIt(it.formatFloat(ffDefault, 2)).join(" ")
    result = newElement(node.tag)
    result.attrs = a

  else:
    # Node child (if any) is not an animate node: copy the node and process children.
    result = newElement(node.tag)
    result.attrs = node.attrs
    for child in node:
      result.add child.buildXml(t)


when isMainModule:
  let smil = loadXml("smil.xml")
  if smil.tag != "smil":
    raise newException(ValueError, "not a SMIL file")
  let newRoot = smil[0]
  echo "At time 0 second:\n"
  echo xmlHeader, newRoot.buildXml(0)
  echo "\nAt time 2 seconds:\n"
  echo xmlHeader, newRoot.buildXml(2)

Output:

At time 0 second:

<?xml version="1.0" encoding="UTF-8" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0" />
    <PointLight color="1 1 1" location="0 2 0" />
    <Shape>
      <Box size="2.0 1.0 2.0" />
      <Appearance>
        <Material diffuseColor="0.0 0.60 1.0" />
      </Appearance>
    </Shape>
  </Scene>
</X3D>

At time 2 seconds:

<?xml version="1.0" encoding="UTF-8" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0" />
    <PointLight color="1 1 1" location="0 2 0" />
    <Shape>
      <Box size="1.8 1.2 1.8" />
      <Appearance>
        <Material diffuseColor="0.20 0.56 0.80" />
      </Appearance>
    </Shape>
  </Scene>
</X3D>

Perl

Translation of: Raku

# 20201101 added Perl programming solution

use 5.014; # for s///r;
use strict;
use warnings;

BEGIN {
   package Animatee;
   use Moo;
   has [qw(todo begin dur from to)] => ( is => 'rw');
   $INC{"Animatee.pm"} = 1;
}

use Animatee;
use XML::Twig;
use List::AllUtils 'pairwise';

my $smil = <<'DATA';
<?xml version="1.0" ?> <smil><X3D><Scene><Viewpoint position="0 0 8" orientation="0 0 1 0" /><PointLight color="1 1 1" location="0 2 0" /><Shape><Box size="2 1 2"><animate attributeName="size" from="2 1 2" to="1 2 1" begin="0s" dur="10s" /></Box><Appearance><Material diffuseColor="0.0 0.6 1.0"><animate attributeName="diffuseColor" from="0.0 0.6 1.0" to="1.0 0.4 0.0" begin="0s" dur="10s" /></Material></Appearance></Shape></Scene></X3D></smil>
DATA

my %Parents;

my $x = XML::Twig->new->parse($smil);

for my $node ($x->findnodes("//animate"))  {

   my $y = $node->parent;
   exists($Parents{$y}) ? (die) : ($Parents{my $k = $y->getName} = Animatee->new);
   for my $animatee ($y->getChildNodes)  {
      my %h = %{$animatee->atts};
      $Parents{$k}->todo($h{attributeName});
      $Parents{$k}->from([ split(/\s+/,$h{from}) ]);
      $Parents{$k}->to([ split(/\s+/,$h{to}) ]);
      $Parents{$k}->begin( $h{begin} =~ m/\d+/g);
      $Parents{$k}->dur  ( $h{dur}   =~ m/\d+/g);
   }
}

my $z =  XML::Twig->new->parse($smil =~ s/\<\/?smil\>//gr) or die;

for my $t ( 0, 2, 4 ) {
   my $clone = $z;
   while ( my( $k,$v ) = each %Parents) {
      my @incre = pairwise { ($a-$b)/$v->dur } @{$v->to}, @{$v->from};
      for my $f ($clone->findnodes("//$k")) {
         my $c = join (' ', pairwise { $a+$b*$t } @{$v->from}, @incre);
         $f->set_att($v->todo,$c);
      }
      for my $f ($clone->findnodes("//animate")) {
         $f->delete
      }
   }
   print "when t = $t\n";
   print $clone->sprint,"\n";
}

Output:

when t = 0
<?xml version="1.0"?>
<X3D><Scene><Viewpoint orientation="0 0 1 0" position="0 0 8"/><PointLight color="1 1 1" location="0 2 0"/><Shape><Box size="2 1 2"></Box><Appearance><Material diffuseColor="0 0.6 1"></Material></Appearance></Shape></Scene></X3D>
when t = 2
<?xml version="1.0"?>
<X3D><Scene><Viewpoint orientation="0 0 1 0" position="0 0 8"/><PointLight color="1 1 1" location="0 2 0"/><Shape><Box size="1.8 1.2 1.8"></Box><Appearance><Material diffuseColor="0.2 0.56 0.8"></Material></Appearance></Shape></Scene></X3D>
when t = 4
<?xml version="1.0"?>
<X3D><Scene><Viewpoint orientation="0 0 1 0" position="0 0 8"/><PointLight color="1 1 1" location="0 2 0"/><Shape><Box size="1.6 1.4 1.6"></Box><Appearance><Material diffuseColor="0.4 0.52 0.6"></Material></Appearance></Shape></Scene></X3D>

Phix

with javascript_semantics
include builtins\xml.e
 
constant xml = """
<?xml version="1.0" ?>
<smil>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='2 1 2'>
        <animate attributeName="size" from="2 1 2"
                                        to="1 2 1" begin="0s" dur="10s"/>
      </Box>
      <Appearance>
        <Material diffuseColor='0.0 0.6 1.0'>
          <animate attributeName="diffuseColor" from="0.0 0.6 1.0"
                                                  to="1.0 0.4 0.0" begin="0s" dur="10s"/>
        </Material>
      </Appearance>
    </Shape>
  </Scene>
</X3D>
</smil>
"""
 
function animate_contents(sequence doc, atom t)
    doc = deep_copy(doc)
    sequence a = xml_get_nodes(doc,"animate")
    if a={} then
        for i=1 to length(doc[XML_CONTENTS]) do
            doc[XML_CONTENTS][i] = animate_contents(doc[XML_CONTENTS][i],t)
        end for
    else
        for i=1 to length(doc[XML_CONTENTS]) do
            if doc[XML_CONTENTS][i][XML_TAGNAME]="animate" then
                string name = xml_get_attribute(doc[XML_CONTENTS][i],"attributeName"),
                       vfrm = xml_get_attribute(doc[XML_CONTENTS][i],"from"),
                       v_to = xml_get_attribute(doc[XML_CONTENTS][i],"to"),
                       sbeg = xml_get_attribute(doc[XML_CONTENTS][i],"begin"),
                       sdur = xml_get_attribute(doc[XML_CONTENTS][i],"dur")
                sequence from = apply(split(vfrm),to_number),
                         to_s = apply(split(v_to),to_number)
                atom begin = to_number(trim_tail(sbeg,"s")),
                     durat = to_number(trim_tail(sdur,"s")),
                     fj = begin+durat-t,
                     tj = t-begin
                -- plenty more error handling possible here...
                if tj<0 or fj<0 or length(from)!=length(to_s) then ?9/0 end if
                for j=1 to length(from) do
                    from[j] = sprintf("%.2f",(from[j]*fj+to_s[j]*tj)/durat)
                end for
                doc = xml_set_attribute(doc,name,join(from," "))
                doc[XML_CONTENTS][i..i] = "" -- remove 'animate'
                exit
            end if
        end for
    end if
    return doc
end function
 
function animate(sequence doc, atom t)
    doc = deep_copy(doc)
    doc[XML_CONTENTS] = doc[XML_CONTENTS][XML_CONTENTS][1]  -- remove smil
    doc[XML_CONTENTS] = animate_contents(doc[XML_CONTENTS],t)
    return doc
end function
 
sequence doc = xml_parse(xml)
if doc[XML_DOCUMENT]!="document"
or doc[XML_CONTENTS][XML_TAGNAME]!="smil"
or length(doc[XML_CONTENTS][XML_CONTENTS])!=1
or doc[XML_CONTENTS][XML_CONTENTS][1][XML_TAGNAME]!="X3D" then
    ?9/0
end if
printf(1,"At time = 0:\n\n")
puts(1,xml_sprint(animate(doc,0)))
printf(1,"\nAt time = 2:\n\n")
puts(1,xml_sprint(animate(doc,2)))

Output:

At time = 0:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0" />
    <PointLight color="1 1 1" location="0 2 0" />
    <Shape>
      <Box size="2.00 1.00 2.00" />
      <Appearance>
        <Material diffuseColor="0.00 0.60 1.00" />
      </Appearance>
    </Shape>
  </Scene>
</X3D>

At time = 2:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0" />
    <PointLight color="1 1 1" location="0 2 0" />
    <Shape>
      <Box size="1.80 1.20 1.80" />
      <Appearance>
        <Material diffuseColor="0.20 0.56 0.80" />
      </Appearance>
    </Shape>
  </Scene>
</X3D>

Raku

(formerly Perl 6) A crude attempt that only works with task data.

use XML::XPath;

my $smil = q:to<DATA>; # cramped verison, modified from task data
<?xml version="1.0" ?> <smil><X3D><Scene><Viewpoint position="0 0 8" orientation="0 0 1 0" /><PointLight color="1 1 1" location="0 2 0" /><Shape><Box size="2 1 2"><animate attributeName="size" from="2 1 2" to="1 2 1" begin="0s" dur="10s" /></Box><Appearance><Material diffuseColor="0.0 0.6 1.0"><animate attributeName="diffuseColor" from="0.0 0.6 1.0" to="1.0 0.4 0.0" begin="0s" dur="10s" /></Material></Appearance></Shape></Scene></X3D></smil>
DATA

class Animatee { has ($.todo, @.from, @.to, $.begin, $.dur) is rw };

my %Parents; # keys store the parent tags that got <animate> child

my $x = XML::XPath.new(xml => $smil) or die;

for @($x.find("//animate")) { # strangely need .List or @ coercion to work
   my $y = .parent.name;
   %Parents{$y}:exists ?? die() !! %Parents{$y} = Animatee.new; # unique only
   for .parent.elements {
      %Parents{$y}.todo  = .attribs<attributeName>;
      %Parents{$y}.from  = .attribs<from>.split(/\s+/);
      %Parents{$y}.to    = .attribs<to>.split(/\s+/);
      %Parents{$y}.begin = .attribs<begin>.match(/\d+/);
      %Parents{$y}.dur   = .attribs<dur>.match(/\d+/);
   }
}

# use regex to strip SMIL tag and create a master template; sub-optimal approach
my $z = XML::XPath.new(xml => $smil.subst(/\<\/?smil\>/,'',:g:ii:ss)) or die;

for 0, 2, 4 -> $t { # task requires 0 & 2 only
   my $clone = $z.clone; # work on a copy
   for %Parents.kv -> $k,$v {
      my @incre = ($v.to »-« $v.from) »/» $v.dur; # increment list
      with $clone.find("//$k") { # moving attribute = @from + @increment*$t
         .attribs{%Parents{$_.name}.todo} = $v.from »+« @incre »*» $t;
         .removeChild($_); #  ditch <animate> and friends
      }
   }
   say "when t = ", $t;
   say $clone.find("/");
}

Output:

when t = 0
<?xml version="1.0"?><X3D><Scene><Viewpoint position="0 0 8" orientation="0 0 1 0"/><PointLight location="0 2 0" color="1 1 1"/><Shape><Box size="2 1 2"/><Appearance><Material diffuseColor="0 0.6 1"/></Appearance></Shape></Scene></X3D>
when t = 2
<?xml version="1.0"?><X3D><Scene><Viewpoint position="0 0 8" orientation="0 0 1 0"/><PointLight location="0 2 0" color="1 1 1"/><Shape><Box size="1.8 1.2 1.8"/><Appearance><Material diffuseColor="0.2 0.56 0.8"/></Appearance></Shape></Scene></X3D>
when t = 4
<?xml version="1.0"?><X3D><Scene><Viewpoint position="0 0 8" orientation="0 0 1 0"/><PointLight location="0 2 0" color="1 1 1"/><Shape><Box size="1.6 1.4 1.6"/><Appearance><Material diffuseColor="0.4 0.52 0.6"/></Appearance></Shape></Scene></X3D>

Tcl

Works with: Tcl version 8.6

Library: tDOM

package require Tcl 8.6
package require tdom

# Applies a time-based interpolation to generate a space-separated list
proc interpolate {time info} {
    dict with info {
	scan $begin "%fs" begin
	scan $dur "%fs" dur
    }
    if {$time < $begin} {
	return $from
    } elseif {$time > $begin+$dur} {
	return $to
    }
    set delta [expr {($time - $begin) / $dur}]
    return [lmap f $from t $to {expr {$f + ($t-$f)*$delta}}]
}

# Applies SMIL <transform> elements to their container
proc applySMILtransform {sourceDocument time} {
    set doc [dom parse [$sourceDocument asXML]]
    foreach smil [$doc selectNodes //smil] {
	foreach context [$smil selectNodes {//*[animate]}] {
	    set animator [$context selectNodes animate]
	    set animated [$context selectNodes @[$animator @attributeName]]
	    $context removeChild $animator
	    $context setAttribute [$animator @attributeName] \
		[interpolate $time [lindex [$animator asList] 1]]
	}
	if {[$smil parentNode] eq ""} {
	    set reparent 1
	} else {
	    [$smil parentNode] replaceChild $smil [$smil firstChild]
	}
    }
    if {[info exist reparent]} {
	set doc [dom parse [[$smil firstChild] asXML]]
    }
    return $doc
}

set t [expr {[lindex $argv 0] + 0.0}]
set result [applySMILtransform [dom parse [read stdin]] $t]
puts {<?xml version="1.0" ?>}
puts -nonewline [$result asXML -indent 2]

Demonstration:

Note that input.smil contains the source document from the task description.

$ tclsh8.6 applySmil.tcl 0 < input.smil
<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color="1 1 1" location="0 2 0"/>
    <Shape>
      <Box size="2.0 1.0 2.0"/>
      <Appearance>
        <Material diffuseColor="0.0 0.6 1.0"/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>
$ tclsh8.6 applySmil.tcl 2 < input.smil
<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color="1 1 1" location="0 2 0"/>
    <Shape>
      <Box size="1.8 1.2 1.8"/>
      <Appearance>
        <Material diffuseColor="0.2 0.5599999999999999 0.8"/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>

Wren

Library: Wren-pattern

As Wren lacks any kind of XML support (let alone SMIL), I've had to resort to string parsing to complete this task.

import "./pattern" for Pattern

var xml = """
<?xml version="1.0" ?>
<smil>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='2 1 2'>
        <animate attributeName="size" from="2 1 2"
                                        to="1 2 1" begin="0s" dur="10s"/>
      </Box>
      <Appearance>
        <Material diffuseColor='0.0 0.6 1.0'>
          <animate attributeName="diffuseColor" from="0.0 0.6 1.0"
                                                  to="1.0 0.4 0.0" begin="0s" dur="10s"/>
        </Material>
      </Appearance>
    </Shape>
  </Scene>
</X3D>
</smil>
"""

var extractValue = Fn.new { |s| s.replace("\"", "").split("=")[1] }

var interpolate = Fn.new { |from, to, begin, dur, t|
    if (begin >= t) return from
    if (begin + t >= dur) return to
    var mid = List.filled(3, 0)
    for (i in 0..2) {
        mid[i] = (from[i] * (dur - t) + to[i] * (t - begin)) / (dur - begin)
    }
    return mid
}

var smil = xml.indexOf("smil") > -1
if (!smil) {
    System.print(xml)
    return
}
xml = xml.replace("<smil>\n", "").replace("\n</smil>", "")
var animate = Pattern.new("<animate +1^///>")
var matches = animate.findAll(xml)
var mcount = matches.count
if (mcount == 0) {
    System.print(xml)
    return
}

var elem  = List.filled(mcount, null)
var attr  = List.filled(mcount, null)
var from  = List.filled(mcount, null)
var to    = List.filled(mcount, null)
var begin = List.filled(mcount, 0)
var dur   = List.filled(mcount, 0)
for (i in 0...mcount) {
    var match = matches[i]
    xml = xml.replace(match.text + "\n", "")
    var p = Pattern.new("+1/s")
    var items = p.splitAll(match.text[1..-3])
    attr[i] = extractValue.call(items[1])
    from[i] = [0] * 3
    from[i][0] = Num.fromString(items[2].replace("from=\"", ""))
    from[i][1] = Num.fromString(items[3])
    from[i][2] = Num.fromString(items[4].replace("\"", ""))
    to[i] = [0] * 3
    to[i][0] = Num.fromString(items[5].replace("to=\"", ""))
    to[i][1] = Num.fromString(items[6])
    to[i][2] = Num.fromString(items[7].replace("\"", ""))
    begin[i] = Num.fromString(extractValue.call(items[8]).replace("s", ""))
    dur[i]   = Num.fromString(extractValue.call(items[9]).replace("s", ""))
    p = Pattern.new("<[+1/w] %(attr[i])/='[+1^']'>")
    var matches2 = p.find(xml)
    elem[i] = matches2.capsText[0]
    p = Pattern.new(">\n+1/s<//%(elem[i])>")
    xml = p.replaceAll(xml, "/>")
}

for (t in [0, 2]) {
    var xml2 = xml
    for (i in 0...mcount) {
        var p = Pattern.new("<%(elem[i]) %(attr[i])/='[+1^']'//>")
        var sfrom = p.find(xml2).capsText[0]
        var mid = interpolate.call(from[i], to[i], begin[i], dur[i], t)
        var smid = mid.map { |n| n.toString }.join(" ")
        xml2 = xml2.replace("<%(elem[i]) %(attr[i])='%(sfrom)'/>", "<%(elem[i]) %(attr[i])='%(smid)'/>")
    }
    System.print("At t = %(t) seconds:\n")
    System.print(xml2)
    System.print()
}

Output:

At t = 0 seconds:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='2 1 2'/>
      <Appearance>
        <Material diffuseColor='0 0.6 1'/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>

At t = 2 seconds:

<?xml version="1.0" ?>
<X3D>
  <Scene>
    <Viewpoint position="0 0 8" orientation="0 0 1 0"/>
    <PointLight color='1 1 1' location='0 2 0'/>
    <Shape>
      <Box size='1.8 1.2 1.8'/>
      <Appearance>
        <Material diffuseColor='0.2 0.56 0.8'/>
      </Appearance>
    </Shape>
  </Scene>
</X3D>