Task 017: .AGDA File Format
Task 017: .AGDA File Format
1. Properties of the .AGDA File Format Intrinsic to Its File System
Based on the specifications, the .AGDA file format (associated with Agda source code files, typically using the lowercase extension .agda) is a plain text format encoded in UTF-8. It does not possess binary structures such as magic numbers or headers typical of proprietary binary formats. Instead, its intrinsic properties relate to standard file system metadata, as the format itself is text-based and lacks embedded format-specific attributes beyond content syntax. The following is a comprehensive list of key file system properties, derived from standard POSIX-compliant file systems (e.g., as accessed via stat system calls). These properties are applicable to any file but are listed here as they represent the intrinsic file system characteristics for .AGDA files:
- Device ID (st_dev): The identifier of the device containing the file.
- Inode number (st_ino): The unique inode number assigned to the file.
- Protection mode (st_mode): The file's permission bits and type (e.g., regular file, represented in octal).
- Number of hard links (st_nlink): The count of hard links pointing to the file.
- User ID of owner (st_uid): The numeric user ID of the file's owner.
- Group ID of owner (st_gid): The numeric group ID of the file's owner.
- Device ID for special files (st_rdev): Relevant if the file is a special device file (typically 0 for regular files).
- Total size in bytes (st_size): The size of the file in bytes.
- Block size for filesystem I/O (st_blksize): The optimal block size for I/O operations.
- Number of blocks allocated (st_blocks): The number of 512-byte blocks allocated to the file.
- Time of last access (st_atime): The timestamp of the last access to the file.
- Time of last modification (st_mtime): The timestamp of the last modification to the file's content.
- Time of last status change (st_ctime): The timestamp of the last change to the file's metadata.
These properties are retrieved via system calls and are not encoded within the file content itself.
2. Direct Download Links for .AGDA Files
The following are two direct download links to example .AGDA (.agda) files, sourced from public repositories. These are raw file URLs that allow immediate download without intermediary pages:
- https://raw.githubusercontent.com/agda/agda/master/examples/Introduction/Basics.agda
38
</grok:render] - https://raw.githubusercontent.com/agda/agda/master/examples/SummerSchool07/Lecture/Records.agda
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</grok:render]
3. Ghost Blog Embedded HTML JavaScript for Drag-and-Drop Functionality
The following is a self-contained HTML snippet with embedded JavaScript that can be inserted into a Ghost blog post (or any HTML-compatible platform). It creates a drop zone where a user can drag and drop a .AGDA file. Upon dropping a valid file (checked by extension, case-insensitive), it dumps the available file system-like properties (limited to browser-accessible File object attributes) to the screen. Note that browser security restrictions limit access to full file system metadata; only basic properties are available.
4. Python Class for Handling .AGDA Files
The following Python class opens a .AGDA file, reads and decodes its content (assuming UTF-8 encoding), retrieves the file system properties, prints them to the console, and provides a method to write content back to the file.
import os
import stat as stat_module # For mode interpretation if needed
class AgdaFileHandler:
def __init__(self, filename):
if not filename.lower().endswith('.agda'):
raise ValueError("File must have .AGDA extension.")
self.filename = filename
self.content = None
self.decoded = None
def read_and_decode(self):
with open(self.filename, 'rb') as f:
self.content = f.read()
self.decoded = self.content.decode('utf-8', errors='ignore')
def get_properties(self):
stat_info = os.stat(self.filename)
return {
'device': stat_info.st_dev,
'inode': stat_info.st_ino,
'mode': oct(stat_info.st_mode),
'nlink': stat_info.st_nlink,
'uid': stat_info.st_uid,
'gid': stat_info.st_gid,
'rdev': stat_info.st_rdev,
'size': stat_info.st_size,
'blksize': stat_info.st_blksize,
'blocks': stat_info.st_blocks,
'atime': stat_info.st_atime,
'mtime': stat_info.st_mtime,
'ctime': stat_info.st_ctime
}
def print_properties(self):
properties = self.get_properties()
for key, value in properties.items():
print(f"{key}: {value}")
def write(self, new_content=None):
content_to_write = new_content or self.decoded
with open(self.filename, 'w', encoding='utf-8') as f:
f.write(content_to_write)
5. Java Class for Handling .AGDA Files
The following Java class opens a .AGDA file, reads and decodes its content (using UTF-8), retrieves the file system properties using java.nio.file, prints them to the console, and provides a method to write content back to the file.
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.nio.file.*;
import java.nio.file.attribute.*;
import java.time.Instant;
public class AgdaFileHandler {
private final Path path;
private String decodedContent;
public AgdaFileHandler(String filename) throws IOException {
this.path = Paths.get(filename);
if (!filename.toLowerCase().endsWith(".agda")) {
throw new IllegalArgumentException("File must have .AGDA extension.");
}
}
public void readAndDecode() throws IOException {
byte[] content = Files.readAllBytes(path);
decodedContent = new String(content, StandardCharsets.UTF_8);
}
public BasicFileAttributes getProperties() throws IOException {
return Files.readAttributes(path, BasicFileAttributes.class);
}
public void printProperties() throws IOException {
BasicFileAttributes attrs = getProperties();
PosixFileAttributes posixAttrs = Files.readAttributes(path, PosixFileAttributes.class); // Assuming POSIX system
System.out.println("creationTime: " + attrs.creationTime());
System.out.println("lastAccessTime: " + attrs.lastAccessTime());
System.out.println("lastModifiedTime: " + attrs.lastModifiedTime());
System.out.println("isDirectory: " + attrs.isDirectory());
System.out.println("isOther: " + attrs.isOther());
System.out.println("isRegularFile: " + attrs.isRegularFile());
System.out.println("isSymbolicLink: " + attrs.isSymbolicLink());
System.out.println("size: " + attrs.size());
System.out.println("fileKey: " + attrs.fileKey());
System.out.println("owner: " + posixAttrs.owner());
System.out.println("group: " + posixAttrs.group());
System.out.println("permissions: " + posixAttrs.permissions());
}
public void write(String newContent) throws IOException {
String contentToWrite = (newContent != null) ? newContent : decodedContent;
Files.writeString(path, contentToWrite, StandardCharsets.UTF_8);
}
}
6. JavaScript Class for Handling .AGDA Files
The following JavaScript class (intended for Node.js, as browser JavaScript lacks direct file system access) opens a .AGDA file, reads and decodes its content (UTF-8), retrieves the file system properties using fs.stat, prints them to the console, and provides a method to write content back to the file.
const fs = require('fs');
class AgdaFileHandler {
constructor(filename) {
if (!filename.toLowerCase().endsWith('.agda')) {
throw new Error('File must have .AGDA extension.');
}
this.filename = filename;
this.decoded = null;
}
readAndDecode() {
const content = fs.readFileSync(this.filename);
this.decoded = content.toString('utf-8');
}
getProperties() {
return fs.statSync(this.filename);
}
printProperties() {
const stats = this.getProperties();
console.log('dev:', stats.dev);
console.log('ino:', stats.ino);
console.log('mode:', stats.mode.toString(8)); // Octal
console.log('nlink:', stats.nlink);
console.log('uid:', stats.uid);
console.log('gid:', stats.gid);
console.log('rdev:', stats.rdev);
console.log('size:', stats.size);
console.log('blksize:', stats.blksize);
console.log('blocks:', stats.blocks);
console.log('atime:', stats.atime);
console.log('mtime:', stats.mtime);
console.log('ctime:', stats.ctime);
}
write(newContent = null) {
const contentToWrite = newContent || this.decoded;
fs.writeFileSync(this.filename, contentToWrite, 'utf-8');
}
}
7. C Implementation for Handling .AGDA Files
C does not have built-in classes, so the following implementation uses a struct with associated functions to achieve similar functionality. It opens a .AGDA file, reads and decodes its content (treating it as UTF-8 text), retrieves the file system properties using stat, prints them to the console, and provides a function to write content back to the file. Compile with a standard C compiler (e.g., gcc file.c -o program).
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <time.h>
#include <unistd.h>
#include <fcntl.h>
struct AgdaFileHandler {
char *filename;
char *content; // Raw bytes
char *decoded; // Assuming UTF-8, same as content for simplicity
size_t size;
};
struct AgdaFileHandler* create_handler(const char *filename) {
size_t len = strlen(filename);
if (len < 5 || strcasecmp(filename + len - 5, ".agda") != 0) {
fprintf(stderr, "File must have .AGDA extension.\n");
exit(1);
}
struct AgdaFileHandler *handler = malloc(sizeof(struct AgdaFileHandler));
handler->filename = strdup(filename);
handler->content = NULL;
handler->decoded = NULL;
handler->size = 0;
return handler;
}
void read_and_decode(struct AgdaFileHandler *handler) {
int fd = open(handler->filename, O_RDONLY);
if (fd == -1) {
perror("open");
exit(1);
}
struct stat st;
fstat(fd, &st);
handler->size = st.st_size;
handler->content = malloc(handler->size + 1);
read(fd, handler->content, handler->size);
handler->content[handler->size] = '\0';
handler->decoded = handler->content; // UTF-8 decoding not needed for printing
close(fd);
}
void print_properties(struct AgdaFileHandler *handler) {
struct stat st;
if (stat(handler->filename, &st) == -1) {
perror("stat");
exit(1);
}
printf("dev: %ld\n", (long)st.st_dev);
printf("ino: %ld\n", (long)st.st_ino);
printf("mode: %o\n", (unsigned int)st.st_mode);
printf("nlink: %ld\n", (long)st.st_nlink);
printf("uid: %ld\n", (long)st.st_uid);
printf("gid: %ld\n", (long)st.st_gid);
printf("rdev: %ld\n", (long)st.st_rdev);
printf("size: %ld\n", (long)st.st_size);
printf("blksize: %ld\n", (long)st.st_blksize);
printf("blocks: %ld\n", (long)st.st_blocks);
printf("atime: %ld\n", (long)st.st_atime);
printf("mtime: %ld\n", (long)st.st_mtime);
printf("ctime: %ld\n", (long)st.st_ctime);
}
void write_file(struct AgdaFileHandler *handler, const char *new_content) {
FILE *f = fopen(handler->filename, "w");
if (f == NULL) {
perror("fopen");
exit(1);
}
const char *content_to_write = new_content ? new_content : handler->decoded;
fprintf(f, "%s", content_to_write);
fclose(f);
}
void destroy_handler(struct AgdaFileHandler *handler) {
free(handler->filename);
free(handler->content);
free(handler);
}