So FoldingRange.type can be a FoldingRangeType or a string. What is the string supposed to be?

If it's a FoldingRangeType what makes each type special? Are they displayed differently or does it serve a different purpose?

• If it is supposed to be categorized by source element (presumably so an editor can determine if a region should be collapsed by default or something), can we get more?
  Ex: Collapsing a declaration, heredoc string (like in PHP), or automatically implemented property with a getter/setter (like in C#; which could be collapsed by default).

If the client sends a textDocument/foldingRanges request with maxRanges set to 10 and the returned JSON { ranges: [ ... ] } has ten items in ranges, what should happen? Are clients expected to just send another request, increasing the value of maxRanges and see what happens? Or should the server instead be sending something like { ranges: [ ... ], isIncomplete: true } back to the client similar to returning an incomplete CompletionList for a textDocument/completion request?

The Markdown file defines the following:

/**
 * Represents a folding range.
 */
export interface FoldingRange {

	/**
	 * The start line number of the folding range. The first line will stay visible, all folloing lines, including the end line will be folded.
	 */
	startLine: number;

	/**
	 * The end line number. The last line will be hidden.
	 */
	endLine: number;

	/**
	 * The type of folding range.
	 */
	type?: FoldingRangeType | string;
}

The TypeScript file defines the following:

/**
 * Represents a folding range.
 */
export interface FoldingRange {

	/**
	 * The start line number of the folding range.
	 */
	startLine: number;

	/**
	 * The start column of the folding range. If not set, this defaults to the length of the start line.
	 */
	startColumn?: number;

	/**
	 * The end line number. The last line will be hidden.
	 */
	endLine: number;

	/**
	 * The start column of the folding range. If not set, this defaults to the length of the end line.
	 */
	endColumn?: number;

	/**
	 * The type of folding range.
	 */
	type?: FoldingRangeType | string;
}

I'm assuming that the TypeScript one is correct with startColumn and endColumn?

Are "lines" and "columns" zero-based or one-based?

What is a "column"? Is it the space between two characters (similar to the LSP Position)? If it's zero-based and has a value of 0 then it is the beginning of the line? In Windows' Notepad, columns are one-based and a value of 1 puts it at the beginning of the line.

Or is a "column" the actual space that is taken up by a character?

The protocol currently states the following:

export interface FoldingRangeRequestParam {
	/**
	 * The text document.
	 */
	textDocument: TextDocumentIdentifier;

	/**
	 * The maximum number of ranges to provide
	 */
	maxRanges?: number;
}

How can a client specify that the server should return "all" possible ranges in the document? Should Number.MAX_SAFE_INTEGER be used? Should a negative number be used? Or should a negative number in maxRanges cause the server to throw an error back to the client?