src/vs/editor/common/cursor/cursorWordOperations.ts/WordOperations/moveWordLeft
class WordOperations:	public static moveWordLeft(wordSeparators: WordCharacterClassifier, model: ICursorSimpleModel, position: Position, wordNavigationType: WordNavigationType): Position {
		let lineNumber = position.lineNumber;
		let column = position.column;

		if (column === 1) {
			if (lineNumber > 1) {
				lineNumber = lineNumber - 1;
				column = model.getLineMaxColumn(lineNumber);
			}
		}

		let prevWordOnLine = WordOperations._findPreviousWordOnLine(wordSeparators, model, new Position(lineNumber, column));

		if (wordNavigationType === WordNavigationType.WordStart) {
			return new Position(lineNumber, prevWordOnLine ? prevWordOnLine.start + 1 : 1);
		}

		if (wordNavigationType === WordNavigationType.WordStartFast) {
			if (
				prevWordOnLine
				&& prevWordOnLine.wordType === WordType.Separator
				&& prevWordOnLine.end - prevWordOnLine.start === 1
				&& prevWordOnLine.nextCharClass === WordCharacterClass.Regular
			) {
				// Skip over a word made up of one single separator and followed by a regular character
				prevWordOnLine = WordOperations._findPreviousWordOnLine(wordSeparators, model, new Position(lineNumber, prevWordOnLine.start + 1));
			}

			return new Position(lineNumber, prevWordOnLine ? prevWordOnLine.start + 1 : 1);
		}

		if (wordNavigationType === WordNavigationType.WordAccessibility) {
			while (
				prevWordOnLine
				&& prevWordOnLine.wordType === WordType.Separator
			) {
				// Skip over words made up of only separators
				prevWordOnLine = WordOperations._findPreviousWordOnLine(wordSeparators, model, new Position(lineNumber, prevWordOnLine.start + 1));
			}

			return new Position(lineNumber, prevWordOnLine ? prevWordOnLine.start + 1 : 1);
		}

		// We are stopping at the ending of words

		if (prevWordOnLine && column <= prevWordOnLine.end + 1) {
			prevWordOnLine = WordOperations._findPreviousWordOnLine(wordSeparators, model, new Position(lineNumber, prevWordOnLine.start + 1));
		}

		return new Position(lineNumber, prevWordOnLine ? prevWordOnLine.end + 1 : 1);
	}