Added tons of opcode documentation, changed license to ISC and a lot of file refactoring.

src/vm/io/read_file.c

@@ -1,3 +1,36 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the ISC license.
+ * https://opensource.org/license/isc-license-txt
+ */
+
+/**
+* @file read_file.c
+ * @brief Implements the OP_READ_FILE opcode for reading file contents in the VM.
+ *
+ * This file handles the OP_READ_FILE instruction, which reads the contents of a file
+ * and pushes the result as a string onto the stack.
+ *
+ * Behavior:
+ * - Pops the file path from the stack.
+ * - Reads the file contents.
+ * - Pushes the contents as a string onto the stack.
+ *
+ * Error Handling:
+ * - Exits with an error if the file path is invalid or the file cannot be read.
+ *
+ * Example:
+ * // Bytecode: OP_READ_FILE
+ * // Stack before: ["file.txt"]
+ * // Stack after: ["file contents"]
+ *
+ * @author Johannes Findeisen
+ * @date 2025-10-16
+ */
+
 case OP_READ_FILE: {
     Value path = pop_value(vm);
     if (path.type != VAL_STRING) { fprintf(stderr, "READ_FILE expects string\n"); exit(1); }

src/vm/io/write_file.c

@@ -1,3 +1,36 @@
+/**
+ * This file is part of the Fun programming language.
+ * https://hanez.org/project/fun/
+ *
+ * Copyright 2025 Johannes Findeisen <you@hanez.org>
+ * Licensed under the terms of the ISC license.
+ * https://opensource.org/license/isc-license-txt
+ */
+
+/**
+* @file write_file.c
+ * @brief Implements the OP_WRITE_FILE opcode for writing to a file in the VM.
+ *
+ * This file handles the OP_WRITE_FILE instruction, which writes data to a file.
+ * The file path and data are popped from the stack, and a success/failure flag is pushed back.
+ *
+ * Behavior:
+ * - Pops the file path and data from the stack.
+ * - Writes the data to the file.
+ * - Pushes 1 (success) or 0 (failure) onto the stack.
+ *
+ * Error Handling:
+ * - Exits with an error if the file path is invalid or the file cannot be written.
+ *
+ * Example:
+ * // Bytecode: OP_WRITE_FILE
+ * // Stack before: ["file.txt", "data"]
+ * // Stack after: [1]
+ *
+ * @author Johannes Findeisen
+ * @date 2025-10-16
+ */
+
 case OP_WRITE_FILE: {
     Value data = pop_value(vm);
     Value path = pop_value(vm);