private Range range;

private List<Span> consumedSpans = new ArrayList<>();

public Span(Range range) {

this.range = range;

}

public void reset() {

consumedSpans.clear();

}

// For a span to contain another span, it has to appear first (or equal) in source and end last (or equal).

// TODO: Is it better to compare start and end bytes here? Explore that.

boolean contains(Span span) {

boolean firstInRowStart = range.startRow < span.range.startRow;

boolean equalInRowStart = range.startRow == span.range.startRow;

boolean firstInColStart = range.startCol < span.range.startCol;

boolean equalInColStart = range.startCol == span.range.startCol;

boolean lastInRowEnd = range.endRow > span.range.endRow;

boolean equalInRowEnd = range.endRow == span.range.endRow;

boolean lastInColEnd = range.endCol > span.range.endCol;

boolean equalInColEnd = range.endCol == span.range.endCol;

boolean startOkay = firstInRowStart || (equalInRowStart && (firstInColStart || equalInColStart));

boolean endOkay = lastInRowEnd || (equalInRowEnd && (lastInColEnd || equalInColEnd));

return startOkay && endOkay;

}

private boolean slotIsConsumed(Span span) {

// If a consumed span contains this span, then this span is consumed as well.

for (var consumed : consumedSpans) {

if (consumed.contains(span))

return true;

}

return false;

}

// TODO: Do we have to keep track of consumed spans at all?

public void consume(Span span) {

if (!this.contains(span))

throw new RuntimeException("This span doesn't contain the other span!");

if (slotIsConsumed(span))

throw new RuntimeException("Span slot is consumed!");

consumedSpans.add(span);

}

public int startRow() {

return range.startRow;

}

public int startCol() {

return range.startCol;

}

public int endRow() {

return range.endRow;

}

public int endCol() {

return range.endCol;

}

@Override

public boolean equals(Object o) {

if (!(o instanceof Span other))

return false;

return startRow() == other.startRow() && startCol() == other.startCol() && endRow() == other.endRow() && endCol() == other.endCol();

}