Orkuncakilkaya
c7c8e2779c
RFC decision (the split the issue recommended): programmer bugs abort loud and located; recoverable failures become values. This ships the first half. panic(msg) prints `file:line: panic: <msg>` to stderr and aborts the process with exit code 1 — a clear, located error instead of a segfault or a silent wrong result. assert(cond, msg) is the guarded form: it aborts with `file:line: assertion failed: <msg>` only when cond is false, otherwise execution continues. The location is baked in at compile time (the call node carries its source line, g_src_name carries the file); the message is any string. Both lower in emit_call to an fprintf-to-stderr + exit(1) + unreachable tail (assert branches on the condition first). @fprintf and the format constant are declared on demand (g_uses_panic), so a program that never panics is unchanged — and the compiler's own source uses neither, so the C-free bootstrap fixpoint holds. - panic/assert registered as builtins across the vocabulary (ludic_syntax.h, the JetBrains lexer, the TextMate grammar) and documented (docs/language/builtins/) - examples/library/errors.ludic covers the success path (asserts hold, program runs to the end); a panic_case in the suite covers the failure path (non-zero exit + the located stderr message). x test is now 69 checks. Deferred: recoverable failures as `try`/`else` values (needs the tagged-union type system, #1) and a top-level `recover` for the dev game loop. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
1.4 KiB
id: fn-panic name: panic category: builtins kind: builtin tokens: panic sig: panic(msg: string) tip: Abort with a located error message instead of crashing. order: 10
Prints file:line: panic: <msg> to standard error and aborts the process with exit code 1. It turns "something went wrong" into a clear, located message a non-expert can act on — the opposite of a raw segfault or a silent wrong result. Use it for the unrecoverable case: a corrupt asset, a broken invariant, a branch that should be impossible. The source location is baked in at compile time, so the message always points at the exact call. For a guarded check that only aborts when a condition fails, use assert.
Recoverable failures — a missing save, a bad network packet — are a different story: those should be values a game can fall back from rather than a panic. That value-carrying try/else path is sequenced after the type-system work (tagged unions); panic covers the programmer-bug half today.
Parameters:
msg— a message describing what went wrong (a string)
program Demo {
function pick(options: int, n: int) -> int {
if n < 0 { panic("choice index is negative") }
if n >= options { panic("choice index out of range") }
return n
}
entry {
print(pick(3, 1)) # 1
print(pick(3, 9)) # aborts: Demo.ludic:6: panic: choice index out of range
}
}