Error Handling¶

Runtime operations that cannot succeed produce an ABS_ERROR value instead of crashing. You test for it with is_err and inspect the message.

#include "abscom/abs.h"

API¶

Function	Description
`var abs_new_error(const char *msg)`	Build a new error value.
`bool is_err(var obj)`	1 if the object is an error.

Error values carry a message string; printing one shows Error: <msg>, and to_str gives just <msg>.

Checking results¶

abs_init();

var xs = List();
var too_far = get(xs, 5);            /* empty list, index 5 */

if (is_err(too_far)) {
    print(abs_new_str("lookup failed"));
    print(too_far);                  /* Error: Index out of bounds */
}

Common failure points¶

Operation	Fails when
`get` / `slice`	index out of bounds, or object is not a list/set
`split`	object is not a string
`join`	object is not a list
`choice` / `choices`	sequence is empty
`sample`	`k` larger than the list, or non-list
`json_parse`	input is not valid JSON or has trailing garbage
`fopen_safe`, `read_file`	file cannot be opened/read
`http_get`	socket, host, or connect failure
`dget`	object is not a dict

Successful but "missing" results¶

Some lookups return None rather than an error on missing data: - dget on a missing key → None - get_attr on a missing attribute → None - to_int/to_float on an unparseable string → None - add/sub/mul on incompatible types → None

Creating errors¶

You can raise your own errors too:

var val = v(-3);
if (val->val.i < 0) {
    var e = abs_new_error("value must be non-negative");
    print(e);                    /* Error: value must be non-negative */
}

Errors are falsey¶

is_true returns false for ABS_ERROR values, so they work naturally as guard conditions in functional helpers.

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