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fun/src/vm/len.c

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C

/**
* This file is part of the Fun programming language.
* https://fun-lang.xyz/
*
* Copyright 2025 Johannes Findeisen <you@hanez.org>
* Licensed under the terms of the Apache-2.0 license.
* https://opensource.org/license/apache-2-0
*/
/**
* @file len.c
* @brief Implements the OP_LEN opcode for getting the length of arrays or strings in the VM.
*
* This file handles the OP_LEN instruction, which retrieves the length of an array or string.
* The array or string is popped from the stack, and the length is pushed back.
*
* Behavior:
* - Pops the array or string from the stack.
* - Retrieves the length of the array or string.
* - Pushes the length onto the stack.
*
* Error Handling:
* - Exits with an error if the operand is not an array or string.
*
* Example:
* // Bytecode: OP_LEN
* // Stack before: ["hello"]
* // Stack after: [5]
*
* @author Johannes Findeisen
* @date 2025-09-16
*/
case OP_LEN: {
Value a = pop_value(vm);
int len = 0;
if (a.type == VAL_STRING) {
len = (int)(a.s ? (int)strlen(a.s) : 0);
} else if (a.type == VAL_ARRAY) {
len = array_length(&a);
if (len < 0) len = 0;
} else {
/* Be lenient: for non-array/non-string, treat length as 0 */
push_value(vm, make_int(0));
}
free_value(a);
push_value(vm, make_int(len));
break;
}