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fun/src/vm/arithmetic/add.c

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C

/**
* 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 Apache-2.0 license.
* https://opensource.org/license/apache-2-0
*/
/**
* @file add.c
* @brief Implements the OP_ADD opcode for arithmetic and string concatenation in the VM.
*
* This file handles the OP_ADD instruction, which performs addition or concatenation
* depending on the types of the operands:
* - Integers: Adds two integers.
* - Strings: Concatenates two strings.
* - Arrays: Concatenates two arrays.
*
* Behavior:
* - Pops two values from the stack.
* - Performs the operation based on the types of the operands.
* - Pushes the result back onto the stack.
*
* Error Handling:
* - Exits with an error if the operands are of incompatible types.
* - Exits with an error if memory allocation fails during string concatenation.
*
* Example:
* // Bytecode: OP_ADD
* // Stack before: [2, 3]
* // Stack after: [5]
*
* @author Johannes Findeisen
* @date 2025-10-16
*/
case OP_ADD: {
Value b = pop_value(vm);
Value a = pop_value(vm);
if (a.type == VAL_INT && b.type == VAL_INT) {
Value res = make_int(a.i + b.i);
free_value(a);
free_value(b);
push_value(vm, res);
} else if (a.type == VAL_STRING && b.type == VAL_STRING) {
const char *sa = a.s ? a.s : "";
const char *sb = b.s ? b.s : "";
size_t la = strlen(sa);
size_t lb = strlen(sb);
char *buf = (char*)malloc(la + lb + 1);
if (!buf) {
fprintf(stderr, "Runtime error: out of memory during string concatenation\n");
exit(1);
}
memcpy(buf, sa, la);
memcpy(buf + la, sb, lb);
buf[la + lb] = '\0';
Value res;
res.type = VAL_STRING;
res.s = buf;
free_value(a);
free_value(b);
push_value(vm, res);
} else if (a.type == VAL_ARRAY && b.type == VAL_ARRAY) {
Value res = array_concat(&a, &b);
free_value(a);
free_value(b);
push_value(vm, res);
} else {
fprintf(stderr, "Runtime type error: ADD expects both ints, both strings, or both arrays, got %s and %s\n",
value_type_name(a.type), value_type_name(b.type));
exit(1);
}
break;
}