Orkuncakilkaya
0d1b09e4f0
A fallible function returns a `result` value, built with ok(payload) on success
or err(message) on failure. The caller recovers a value with `try EXPR else {
… }`: on ok the whole expression is the payload; on err the else block runs —
with the failure message bound to `error` — and its trailing expression supplies
the fallback. It is a plain branch on the result's tag: no exceptions, no hidden
control flow, nothing unwinds. is_ok(r) / is_err(r) classify without unwrapping.
Payloads are any i32-width scalar (int/fixed/bool/entity). The feature is
additive and only kicks in when ok/err/try are used, so untouched programs
compile byte-identically (verified) and the C-free bootstrap fixpoint holds.
Complements panic/assert from #8 (the unrecoverable half). The optional
top-level frame `recover` stays deferred (needs a frame-abort mechanism); the
full tagged-union/any generalization is tracked in #1.
Adds the `try` keyword and ok/err/is_ok/is_err builtins across the compiler,
the vocabulary header, JetBrains + TextMate/VSCode grammars, the docs inventory
and pages, examples/library/recover.ludic, and a regression case.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
30 lines
1.2 KiB
Markdown
30 lines
1.2 KiB
Markdown
---
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id: fn-ok
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name: ok
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category: builtins
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kind: builtin
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tokens: ok
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sig: ok(v) -> result
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tip: Wrap a success payload in a result — the happy half of try/else.
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order: 12
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---
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Wraps a success value in a <code>result</code> — the value type a fallible function returns. A <code>result</code> carries either a success payload (this) or a failure message (from <a href="fn-err"><code>err</code></a>), and a caller recovers it with <a href="kw-try"><code>try</code></a>/<code>else</code> or classifies it with <a href="fn-is_ok"><code>is_ok</code></a> / <a href="fn-is_err"><code>is_err</code></a>. A function that can fail declares <code>-> result</code> and returns <code>ok(value)</code> on the happy path.
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The payload is any <code>i32</code>-width scalar — <code>int</code>, <code>fixed</code>, <code>bool</code>, or <code>entity</code>.
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Parameters:
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- `v` — the success payload
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```ludic
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program Parse {
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function to_digit(c: int) -> result {
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if c >= 48 and c <= 57 { return ok(c - 48) } # '0'..'9'
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return err("not a digit")
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}
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test "ok carries the parsed value" {
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let d = try to_digit(55) else { 0 } # '7' -> 7
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expect_eq(d, 7)
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}
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}
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```
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