Ceylon: dealing with files

As we saw earlier Ceylon is modularized. So the API to deal with files is not part of the core language. Check Modularity for how to specify a dependency on Ceylon file.

	import ceylon.file { ... }
	/**
	the parsePath function returns a Path. A path's resource either refers to an ExistingResource or Nil.
	An ExistingResource is one of File|Directory|Link.
	**/
	void readFile() {
	Path demoFilePath = parsePath("c:/tmp/demo.txt");
	if (is File file = demoFilePath.resource) {
	//below we define a resource expression. We don't need to take care of opening and
	//closing the resource ourselves.
	try (reader = file.Reader()) {
	//readLine returns a String?, null if there is no more line so we
	//conveniently print lines while the end of file has not been reached
	while (is String line = reader.readLine()) {
	print(line);
	}
	}
	}
	}

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	import ceylon.file { ... }
	/**
	In this little exercise we will write all words from a text to
	a newline starting with a line number to a file:
	0:I
	1:like
	2:programming
	**/
	void writeFile() {
	String text = "I like programming";
	Path filePath = parsePath("c:/tmp/words.txt");
	//now we need to make sure the file does not already exist
	if (is Nil resource = filePath.resource) {
	File file = resource.createFile();
	try (writer = file.Overwriter()) {
	for (index -> word in entries(text.split())) {
	writer.writeLine("``index``:``word``");
	}
	}
	}
	}

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	/**
	Let's say we want to move the following folder
	c:/tmp/map1 and its content
	to
	c:/tmp/movedmap
	**/
	void moveFolder() {
	Path sourcePath = parsePath("c:/tmp/map1");
	Path targetPath = sourcePath.siblingPath("movedmap");
	if (is Directory sourceDir = sourcePath.resource) {
	if (is Nil targetDir = targetPath.resource) {
	sourceDir.move(targetDir);
	}
	}
	}

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