FS

The fs module allows to access and manipulate the file system

All the given examples assume the following imports:

let fs = import('std/fs');
let io = import('std/io');

And that the following file hierarchy exists in the file system:

- dir1
 |- foo.txt
 |- bar.txt
 |- dir2
    |- hello.txt
    |- world.txt

Functions

• exists
• open
• walkdir

file Member Functions

• lines
• read_blocks
• seek
• each_line
• next

exists

fs.exists(path: string) -> bool

Returns true if the given path exists in the file system and false otherwise

Example:

io.println(fs.exists('dir1/foo.txt'));
io.println(fs.exists('dir2/foo.txt'));

Gives the output:

true
false

open

fs.open(path: string, mode: string = 'r') -> file

Opens the given file path using the (optional) mode. mode can be any of the following:

Note: Appending 'x' to either 'w' or 'w+' will cause the function to fail if the file already exists. This may prevents overwriting existing files.

Example:

let file = fs.open('dir1/foo.txt', 'r');

walkdir

fs.walkdir(dir: string, mode: int = WALK_RECURSE, regex: string = '(.*)') -> vector

Returns a vector of all file paths in path using the (optional) mode and regex. mode can be any combination of the following:

The default regex matches all file names.

Example:

# Recursively finds all files in dir1 ending with o.txt
let files = fs.walkdir('dir1', fs.WALK_FILES + fs.WALK_RECURSE, '(.*o\.txt)');
io.println(files);

Gives the output:

[dir1/foo.txt, dir1/dir2/hello.txt]

lines

file.lines() -> vector

Returns a vector containing all lines in the file

Example:

let file = fs.open('dir1/bar.txt');
io.println(file.lines());

Gives output:

[My, name, is, John]

Given the file dir1/bar.txt:

My
name
is
John

read_blocks

file.read_blocks(begin: string, end: string) -> vector

Returns an iterator pointing to the first line, allowing easy vector iteration

Example:

import('std/vec');

let file = fs.open('dir1/foo.txt');
let quotes = file.read_blocks('"', '"');
io.println("Quotes found:");
for quote in quotes.each() {
    io.println(" - ", quote);
}

Gives output:

Quotes found:
- The greatest glory in living lies not in never falling, but in rising every time we fall.
- The way to get started is to quit talking and begin doing.
- Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma – which is living with the results of other people's thinking.

Given the file dir1/foo.txt:

Top quotes:
"The greatest glory in living lies not in never falling, but in rising every time we fall." -Nelson Mandela
"The way to get started is to quit talking and begin doing." -Walt Disney
"Your time is limited, so don't waste it living someone else's life. Don't be trapped by dogma – which is living with the results of other people's thinking." -Steve Jobs

seek

file.seek(offset: int, origin: int) -> int

Moves the file position indicator to the given offset starting at origin. origin can be any of the following:

Example:

let file = fs.open('dir1/bar.txt');
io.println(file.lines());
file.seek(5, fs.SEEK_SET);
io.println(file.lines());
file.seek(-5, fs.SEEK_END);
io.println(file.lines());

Gives the output:

[My, name, is, John]
[me, is, John]
[John]

Given the file dir1/bar.txt:

My
name
is
John

each_lines

file.each_lines() -> iterator

Returns an iterator pointing to the first line, allowing easy vector iteration

Example:

let file = fs.open('dir1/bar.txt');
for line in file.each_line() {
    io.println(line);
}

Gives output:

[My, name, is, John]

Given the file dir1/bar.txt:

My
name
is
John

next

iterator.next() -> string

Returns the line pointed by the iterator, or nil if out of range, and then advances the iterator to the next line

Example:

let file = fs.open('dir1/bar.txt');
let iter = file.each_line();
while true {
    let line = iter.next();
    if line != nil {
        io.println(line);
    }
    else {
        break;
    }
}

Gives the output:

My
name
is
John

Given the file dir1/bar.txt:

My
name
is
John