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Error Handling

Demonstrates Ragul's error model: operations that can fail return a vagy (or) type, -e / -? propagates errors upward automatically, and -hibára / -catch catches them at the boundary.

program-ours-effect
    // -tonum tries to parse a string as a number — it fails on non-numeric strings.
    // -? propagates the error upward; -catch catches it.

    n-into  "not-a-number"-tonum-doing-?.
    n-print-doing.
    -catch
        "Error caught: could not parse string as number"-print-doing.

program-nk-hatás
    // -számmá tries to parse a string as a number — it fails on non-numeric strings.
    // -e propagates the error upward; -hibára catches it.

    n-be  "not-a-number"-számmá-va-e.
    n-képernyőre-va.
    -hibára
        "Error caught: could not parse string as number"-képernyőre-va.

Output:

Error caught: could not parse string as number

How it works

-számmá / -tonum returns vagy-Szám-vagy-Hiba — either a number or an error. The -e / -? suffix after -va / -doing means: "if this produced an error, propagate it upward immediately."

n-be  "not-a-number"-számmá-va-e.
                     │       │  │
                     │       │  └── propagate error if failure
                     │       └── execute the operation
                     └── attempt to parse as number

When the error propagates, execution jumps directly to the -hibára / -catch block, skipping any remaining sentences in the scope.

The -hibára / -catch boundary

-hibára is a sibling block to the scope body — structurally identical to -hanem / -else for conditionals:

program-ours-effect
    // ... sentences that might fail with -? ...
    -catch
        // ... runs only if an error propagated up ...
        hiba-print-doing.     // 'hiba' is bound to the error value

program-nk-hatás
    // ... sentences that might fail with -e ...
    -hibára
        // ... runs only if an error propagated up ...
        hiba-képernyőre-va.   // 'hiba' is bound to the error value

Note

hiba is the built-in name bound to the error value inside a catch block. It is a variable name, not a suffix — it does not have an English alias.

If no -hibára / -catch is present and an error reaches the top of the program, it is fatal — the program terminates with exit code 3.

Error propagation chain

-e / -? can appear anywhere in a chain. Multiple fallible operations in sequence will each propagate to the same -hibára / -catch:

program-ours-effect
    content-into  "data.txt"-readfile-doing-?.  // fails if file missing
    data-into     content-parse-doing-?.         // fails if content invalid
    data-print-doing.
    -catch
        "Pipeline failed: "-hiba-concat-doing  print-doing.

program-nk-hatás
    tartalom-be  "adat.txt"-fájlolvasó-va-e.  // fails if file missing
    adat-be      tartalom-elemző-va-e.          // fails if content invalid
    adat-képernyőre-va.
    -hibára
        "Pipeline failed: "-hiba-összefűz-va  képernyőre-va.

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