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

src/vm/strings/find.c

@@ -1,3 +1,37 @@
+/**
+ * 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 find.c
+ * @brief Implements the OP_FIND opcode for finding substrings in the VM.
+ *
+ * This file handles the OP_FIND instruction, which finds the index of a substring
+ * within a string. The substring and string are popped from the stack, and the index
+ * (or -1) is pushed back.
+ *
+ * Behavior:
+ * - Pops the substring and string from the stack.
+ * - Finds the index of the substring within the string.
+ * - Pushes the index (or -1 if not found) onto the stack.
+ *
+ * Error Handling:
+ * - Exits with an error if the operands are not strings.
+ *
+ * Example:
+ * // Bytecode: OP_FIND
+ * // Stack before: ["world", "hello world"]
+ * // Stack after: [6]
+ *
+ * @author Johannes Findeisen
+ * @date 2025-10-16
+ */
+
 case OP_FIND: {
     Value needle = pop_value(vm);
     Value hay = pop_value(vm);

src/vm/strings/split.c

@@ -1,3 +1,37 @@
+/**
+ * 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 split.c
+ * @brief Implements the OP_SPLIT opcode for splitting strings in the VM.
+ *
+ * This file handles the OP_SPLIT instruction, which splits a string into an array
+ * of substrings using a separator. The separator and string are popped from the stack,
+ * and the resulting array is pushed back.
+ *
+ * Behavior:
+ * - Pops the separator and string from the stack.
+ * - Splits the string into an array of substrings using the separator.
+ * - Pushes the resulting array onto the stack.
+ *
+ * Error Handling:
+ * - Exits with an error if the operands are not strings.
+ *
+ * Example:
+ * // Bytecode: OP_SPLIT
+ * // Stack before: [", ", "a, b, c"]
+ * // Stack after: [["a", "b", "c"]]
+ *
+ * @author Johannes Findeisen
+ * @date 2025-10-16
+ */
+
 case OP_SPLIT: {
     Value sep = pop_value(vm);
     Value str = pop_value(vm);

src/vm/strings/substr.c

@@ -1,3 +1,38 @@
+/**
+ * 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 substr.c
+ * @brief Implements the OP_SUBSTR opcode for extracting substrings in the VM.
+ *
+ * This file handles the OP_SUBSTR instruction, which extracts a substring from a string
+ * using a start index and length. The length, start index, and string are popped from the stack,
+ * and the resulting substring is pushed back.
+ *
+ * Behavior:
+ * - Pops the length, start index, and string from the stack.
+ * - Extracts the substring from the string.
+ * - Pushes the resulting substring onto the stack.
+ *
+ * Error Handling:
+ * - Exits with an error if the operands are not integers or strings.
+ * - Exits with an error if the start index or length is out of bounds.
+ *
+ * Example:
+ * // Bytecode: OP_SUBSTR
+ * // Stack before: [5, 6, "hello world"]
+ * // Stack after: ["world"]
+ *
+ * @author Johannes Findeisen
+ * @date 2025-10-16
+ */
+
 case OP_SUBSTR: {
     Value lenv = pop_value(vm);
     Value startv = pop_value(vm);