private static void AddEmptyMoments(List <Moment> retVal, int time)
{
for (int emptyTime = retVal.Last().Time + 1; emptyTime < time; emptyTime++)
{
retVal.Add(Moment.Empty(emptyTime));
}
}
private static IEnumerable <Moment> ParseSequence(string sequence, out int?timeOffset)
{
var retVal = new List <Moment>();
var time = 0;
var groupTime = 0;
timeOffset = null;
List <string> groupMarbles = null;
List <string> unorderedGroupMarbles = null;
var parsingState = ParsingState.NotInGroup;
var marbleTime = 0;
var marbleBuilder = new StringBuilder();
foreach (var character in sequence.Trim())
{
if (parsingState == ParsingState.NotInGroup)
{
switch (character)
{
case ' ':
case '-':
FlushMarble(marbleBuilder, retVal, marbleTime, time);
retVal.Add(Moment.Empty(time));
break;
case '^':
FlushMarble(marbleBuilder, retVal, marbleTime, time);
if (timeOffset.HasValue)
{
throw new ArgumentException("Only one ^ character allowed", nameof(sequence));
}
timeOffset = -time;
retVal.Add(Moment.Single(time, character.ToString()));
break;
case '(':
FlushMarble(marbleBuilder, retVal, marbleTime, time);
groupTime = time;
parsingState = ParsingState.InOrderedGroup;
groupMarbles = new List <string>();
break;
case '<':
FlushMarble(marbleBuilder, retVal, marbleTime, time);
groupTime = time;
parsingState = ParsingState.InUnorderedGroup;
unorderedGroupMarbles = new List <string>();
break;
case ')':
throw new ArgumentException("Closing parentheses without opening parentheses",
nameof(sequence));
case '>':
throw new ArgumentException("Closing brace without opening brace",
nameof(sequence));
case ',':
throw new ArgumentException("Comma should not occur outside of a group",
nameof(sequence));
default:
GrowMarble(marbleBuilder, ref marbleTime, time, character);
break;
}
}
else if (parsingState == ParsingState.InOrderedGroup)
{
switch (character)
{
case ',':
case ' ':
FlushMarbleToGroup(marbleBuilder, groupMarbles);
break;
case '-':
throw new ArgumentException("Cannot use - within a group", nameof(sequence));
case '^':
if (timeOffset.HasValue)
{
throw new ArgumentException("Only one ^ character allowed", nameof(sequence));
}
FlushMarbleToGroup(marbleBuilder, groupMarbles);
timeOffset = -groupTime;
groupMarbles.Add(character.ToString());
break;
case '(':
throw new ArgumentException("Cannot have nested parentheses", nameof(sequence));
case ')':
FlushMarbleToGroup(marbleBuilder, groupMarbles);
if (groupMarbles.Count <= 1)
{
throw new ArgumentException("Only groups with multiple marbles are allowed", nameof(sequence));
}
retVal.Add(Moment.OrderedGroup(groupTime, groupMarbles.ToArray()));
groupMarbles = null;
parsingState = ParsingState.NotInGroup;
AddEmptyMoments(retVal, time + 1);
break;
default:
GrowMarble(marbleBuilder, ref marbleTime, groupTime, character);
break;
}
}
else if (parsingState == ParsingState.InUnorderedGroup)
{
switch (character)
{
case ',':
case ' ':
FlushMarbleToGroup(marbleBuilder, unorderedGroupMarbles);
break;
case '-':
throw new ArgumentException("Cannot use - within a group", nameof(sequence));
case '^':
if (timeOffset.HasValue)
{
throw new ArgumentException("Only one ^ character allowed", nameof(sequence));
}
FlushMarbleToGroup(marbleBuilder, unorderedGroupMarbles);
timeOffset = -groupTime;
unorderedGroupMarbles.Add(character.ToString());
break;
case '>':
FlushMarbleToGroup(marbleBuilder, unorderedGroupMarbles);
if (unorderedGroupMarbles.Count <= 1)
{
throw new ArgumentException("Only groups with multiple marbles are allowed", nameof(sequence));
}
retVal.Add(Moment.UnorderedGroup(groupTime, unorderedGroupMarbles.ToArray()));
unorderedGroupMarbles = null;
parsingState = ParsingState.NotInGroup;
AddEmptyMoments(retVal, time + 1);
break;
case '<':
throw new ArgumentException("Cannot have braces nested in an unordered group", nameof(sequence));
case '(':
throw new ArgumentException("Cannot have parentheses nested in an unordered group", nameof(sequence));
case ')':
throw new ArgumentException("Cannot have parentheses nested in an unordered group", nameof(sequence));
default:
GrowMarble(marbleBuilder, ref marbleTime, groupTime, character);
break;
}
}
time++;
}
FlushMarble(marbleBuilder, retVal, marbleTime, time);
if (parsingState == ParsingState.InOrderedGroup)
{
throw new ArgumentException("Opening parentheses without closing parentheses", nameof(sequence));
}
if (parsingState == ParsingState.InUnorderedGroup)
{
throw new ArgumentException("Opening brace without closing brace", nameof(sequence));
}
return(retVal);
}
