Task 356: .LISP File Format
Task 356: .LISP File Format
File Format Specifications for .LISP
Based on research, .LISP files (often interchangeably .lisp or .lsp) are plain text files used for Lisp programming language source code, particularly in dialects like Common Lisp or AutoLISP. They contain human-readable code in S-expression syntax (parenthesized lists) and have no binary structure, headers, magic numbers, or fixed encoding beyond standard text formats like ASCII or UTF-8. There is no formal binary specification; the "format" is simply text-based scripting.
List of all properties of this file format intrinsic to its file system:
- Encoding: Typically ASCII or UTF-8 (no strict requirement, but common for compatibility).
- MIME type: text/plain or application/x-lisp.
- Magic number/signature: None (as it's not a binary format).
- Structure: Free-form text consisting of S-expressions (balanced parentheses representing lists, atoms, etc.).
- Content: Lisp source code, which may include functions, variables, and expressions.
- File extension: .lisp (case-insensitive, sometimes .lsp).
- No version field or metadata embedded in the file itself.
Note: "Intrinsic to its file system" is interpreted as properties inherent to the format's handling in file systems, such as lack of binary headers leading to treatment as plain text. There are no embedded binary properties to "decode" in the traditional sense.
Two direct download links for files of format .LISP:
Ghost blog embedded HTML JavaScript for drag-and-drop .LISP file dump:
(Assuming "ghost blog" refers to a simple HTML page with embedded JavaScript, like a standalone blog-style snippet. This code creates a basic web page where users can drag and drop a .LISP file, and it displays all the properties listed above by reading the file as text and inferring/dumping them.)
Python class for .LISP file handling:
import os
class LispFileHandler:
def __init__(self, filepath):
self.filepath = filepath
self.content = None
self.properties = {}
def read_and_decode(self):
"""Read and 'decode' (as text) the .LISP file."""
try:
with open(self.filepath, 'r', encoding='utf-8') as f:
self.content = f.read()
self._extract_properties()
return True
except UnicodeDecodeError:
with open(self.filepath, 'r', encoding='ascii') as f:
self.content = f.read()
self._extract_properties()
return True
except Exception as e:
print(f"Error reading file: {e}")
return False
def _extract_properties(self):
"""Extract properties from the text content."""
encoding = 'ASCII' if all(ord(c) < 128 for c in self.content) else 'UTF-8'
mime = 'text/plain or application/x-lisp'
magic = 'None'
structure = 'S-expressions' if '(' in self.content and ')' in self.content else 'Plain text'
file_ext = os.path.splitext(self.filepath)[1].lstrip('.')
self.properties = {
'Encoding': encoding,
'MIME type': mime,
'Magic number/signature': magic,
'Structure': structure,
'Content': self.content,
'File extension': file_ext
}
def print_properties(self):
"""Print all properties to console."""
if not self.properties:
print("No properties extracted. Read the file first.")
return
for key, value in self.properties.items():
print(f"{key}: {value if key != 'Content' else value[:500] + '...' if len(value) > 500 else value}")
def write(self, new_content=None):
"""Write (encode) back to a .LISP file."""
content_to_write = new_content if new_content else self.content
if content_to_write is None:
print("No content to write.")
return False
try:
with open(self.filepath, 'w', encoding='utf-8') as f:
f.write(content_to_write)
print("File written successfully.")
return True
except Exception as e:
print(f"Error writing file: {e}")
return False
# Example usage:
# handler = LispFileHandler('example.lisp')
# handler.read_and_decode()
# handler.print_properties()
# handler.write('(defun example () (print "Hello"))')
Java class for .LISP file handling:
import java.io.*;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Paths;
public class LispFileHandler {
private String filepath;
private String content;
private java.util.Map<String, String> properties;
public LispFileHandler(String filepath) {
this.filepath = filepath;
this.content = null;
this.properties = new java.util.HashMap<>();
}
public boolean readAndDecode() {
try {
byte[] bytes = Files.readAllBytes(Paths.get(filepath));
this.content = new String(bytes, StandardCharsets.UTF_8);
extractProperties();
return true;
} catch (IOException e) {
try {
this.content = new String(Files.readAllBytes(Paths.get(filepath)), StandardCharsets.US_ASCII);
extractProperties();
return true;
} catch (IOException ex) {
System.out.println("Error reading file: " + ex.getMessage());
return false;
}
}
}
private void extractProperties() {
String encoding = isAscii(content) ? "ASCII" : "UTF-8";
String mime = "text/plain or application/x-lisp";
String magic = "None";
String structure = (content.contains("(") && content.contains(")")) ? "S-expressions" : "Plain text";
String fileExt = filepath.substring(filepath.lastIndexOf('.') + 1);
properties.put("Encoding", encoding);
properties.put("MIME type", mime);
properties.put("Magic number/signature", magic);
properties.put("Structure", structure);
properties.put("Content", content);
properties.put("File extension", fileExt);
}
private boolean isAscii(String str) {
for (char c : str.toCharArray()) {
if (c >= 128) return false;
}
return true;
}
public void printProperties() {
if (properties.isEmpty()) {
System.out.println("No properties extracted. Read the file first.");
return;
}
for (java.util.Map.Entry<String, String> entry : properties.entrySet()) {
String value = entry.getValue();
if (entry.getKey().equals("Content")) {
value = value.length() > 500 ? value.substring(0, 500) + "..." : value;
}
System.out.println(entry.getKey() + ": " + value);
}
}
public boolean write(String newContent) {
String contentToWrite = (newContent != null) ? newContent : this.content;
if (contentToWrite == null) {
System.out.println("No content to write.");
return false;
}
try (BufferedWriter writer = new BufferedWriter(new FileWriter(filepath))) {
writer.write(contentToWrite);
System.out.println("File written successfully.");
return true;
} catch (IOException e) {
System.out.println("Error writing file: " + e.getMessage());
return false;
}
}
// Example usage:
// public static void main(String[] args) {
// LispFileHandler handler = new LispFileHandler("example.lisp");
// handler.readAndDecode();
// handler.printProperties();
// handler.write("(defun example () (print \"Hello\"))");
// }
}
JavaScript class for .LISP file handling:
(Note: JavaScript runs in Node.js for file I/O; use fs module.)
const fs = require('fs');
class LispFileHandler {
constructor(filepath) {
this.filepath = filepath;
this.content = null;
this.properties = {};
}
readAndDecode(callback) {
fs.readFile(this.filepath, 'utf8', (err, data) => {
if (err) {
fs.readFile(this.filepath, 'ascii', (errAscii, dataAscii) => {
if (errAscii) {
console.error(`Error reading file: ${errAscii}`);
callback(false);
} else {
this.content = dataAscii;
this.extractProperties();
callback(true);
}
});
} else {
this.content = data;
this.extractProperties();
callback(true);
}
});
}
extractProperties() {
const encoding = /[^\x00-\x7F]/.test(this.content) ? 'UTF-8' : 'ASCII';
const mime = 'text/plain or application/x-lisp';
const magic = 'None';
const structure = this.content.includes('(') && this.content.includes(')') ? 'S-expressions' : 'Plain text';
const fileExt = this.filepath.split('.').pop();
this.properties = {
'Encoding': encoding,
'MIME type': mime,
'Magic number/signature': magic,
'Structure': structure,
'Content': this.content,
'File extension': fileExt
};
}
printProperties() {
if (Object.keys(this.properties).length === 0) {
console.log('No properties extracted. Read the file first.');
return;
}
for (const [key, value] of Object.entries(this.properties)) {
const displayValue = key === 'Content' ? (value.length > 500 ? value.substring(0, 500) + '...' : value) : value;
console.log(`${key}: ${displayValue}`);
}
}
write(newContent, callback) {
const contentToWrite = newContent || this.content;
if (!contentToWrite) {
console.log('No content to write.');
callback(false);
return;
}
fs.writeFile(this.filepath, contentToWrite, 'utf8', (err) => {
if (err) {
console.error(`Error writing file: ${err}`);
callback(false);
} else {
console.log('File written successfully.');
callback(true);
}
});
}
}
// Example usage:
// const handler = new LispFileHandler('example.lisp');
// handler.readAndDecode((success) => {
// if (success) handler.printProperties();
// handler.write('(defun example () (print "Hello"))', (writeSuccess) => {});
// });
C class (using struct for class-like behavior) for .LISP file handling:
(C doesn't have classes, so using a struct with functions. Assumes standard C with no extra libs.)
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#define MAX_CONTENT_SIZE 1048576 // 1MB max for simplicity
typedef struct {
char *filepath;
char *content;
char *properties[6][2]; // Key-value pairs
} LispFileHandler;
void init_handler(LispFileHandler *handler, const char *filepath) {
handler->filepath = strdup(filepath);
handler->content = NULL;
for (int i = 0; i < 6; i++) {
handler->properties[i][0] = NULL;
handler->properties[i][1] = NULL;
}
}
int read_and_decode(LispFileHandler *handler) {
FILE *file = fopen(handler->filepath, "r");
if (!file) {
printf("Error opening file.\n");
return 0;
}
handler->content = malloc(MAX_CONTENT_SIZE);
size_t len = fread(handler->content, 1, MAX_CONTENT_SIZE - 1, file);
handler->content[len] = '\0';
fclose(file);
// Extract properties
int is_ascii = 1;
for (size_t i = 0; i < len; i++) {
if ((unsigned char)handler->content[i] >= 128) {
is_ascii = 0;
break;
}
}
handler->properties[0][0] = strdup("Encoding");
handler->properties[0][1] = strdup(is_ascii ? "ASCII" : "UTF-8");
handler->properties[1][0] = strdup("MIME type");
handler->properties[1][1] = strdup("text/plain or application/x-lisp");
handler->properties[2][0] = strdup("Magic number/signature");
handler->properties[2][1] = strdup("None");
int has_sexpr = (strchr(handler->content, '(') && strchr(handler->content, ')'));
handler->properties[3][0] = strdup("Structure");
handler->properties[3][1] = strdup(has_sexpr ? "S-expressions" : "Plain text");
handler->properties[4][0] = strdup("Content");
handler->properties[4][1] = strdup(handler->content);
const char *ext = strrchr(handler->filepath, '.');
handler->properties[5][0] = strdup("File extension");
handler->properties[5][1] = strdup(ext ? ext + 1 : "none");
return 1;
}
void print_properties(LispFileHandler *handler) {
for (int i = 0; i < 6; i++) {
if (handler->properties[i][0]) {
char *value = handler->properties[i][1];
if (strcmp(handler->properties[i][0], "Content") == 0) {
size_t val_len = strlen(value);
if (val_len > 500) {
char truncated[504];
strncpy(truncated, value, 500);
truncated[500] = '.'; truncated[501] = '.'; truncated[502] = '.'; truncated[503] = '\0';
printf("%s: %s\n", handler->properties[i][0], truncated);
} else {
printf("%s: %s\n", handler->properties[i][0], value);
}
} else {
printf("%s: %s\n", handler->properties[i][0], value);
}
}
}
}
int write_file(LispFileHandler *handler, const char *new_content) {
const char *content_to_write = new_content ? new_content : handler->content;
if (!content_to_write) {
printf("No content to write.\n");
return 0;
}
FILE *file = fopen(handler->filepath, "w");
if (!file) {
printf("Error opening file for write.\n");
return 0;
}
fprintf(file, "%s", content_to_write);
fclose(file);
printf("File written successfully.\n");
return 1;
}
void free_handler(LispFileHandler *handler) {
free(handler->filepath);
free(handler->content);
for (int i = 0; i < 6; i++) {
free(handler->properties[i][0]);
free(handler->properties[i][1]);
}
}
// Example usage:
// int main() {
// LispFileHandler handler;
// init_handler(&handler, "example.lisp");
// if (read_and_decode(&handler)) {
// print_properties(&handler);
// write_file(&handler, "(defun example () (print \"Hello\"))");
// }
// free_handler(&handler);
// return 0;
// }