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Error Code Examples

Each file in examples/error-codes/ contains a minimal program that triggers one specific compiler diagnostic. Run any of them with ragul check to see the exact error output.

E001 — Root Guard Failure

Fires when a suffix is applied to a root whose type does not satisfy the suffix's type contract.

ragul check examples/error-codes/E001_root_guard.ragul

program-ours-effect
    // ERROR — "hello" is a String; -above requires a Number
    result-into  "hello"-5-above-it.
    result-print-doing.

Output:

ERROR  E001  Suffix -felett (-above) expects Number (Szám), but root is String (Szöveg).
WARN   W001  Suffix chain crosses type boundary from String (Szöveg) to Number (Szám) without a bridge suffix.

Fix: Use a Number root directly (42-5-above-it.) or convert first with -tonum ("42"-tonum-5-above-it.).

E003 — Parallel Write Conflict

Fires when two independent sentences in a pure (non-effect) scope both write to the same root.

ragul check examples/error-codes/E003_parallel_write.ragul

// ERROR — x is written twice in the same pure scope
x-into  3-it.
x-into  5-it.

Output:

ERROR  E003  Root 'x' is written by two independent sentences — parallel write conflict.

Fix: Give each write a distinct name, or use an effect scope (-ours-effect) for sequential reassignment.

E004 — Effectful Call from Pure Scope

Fires when an I/O or side-effect suffix is used outside a -ours-effect (-nk-hatás) scope.

ragul check examples/error-codes/E004_effect_pure_scope.ragul

// ERROR — -print is an effect suffix; the top-level scope is pure
x-into  42-it.
x-print-doing.

Output:

ERROR  E004  Effectful suffix -képernyőre (-print) called from the top-level scope.

Fix: Wrap the program in an effect scope:

program-ours-effect
    x-into  42-it.
    x-print-doing.

E005 — Unhandled Fallible (vagy) Type

Fires when a vagy (fallible) result is used without first handling the error case.

ragul check examples/error-codes/E005_unhandled_fallible.ragul

program-ours-effect
    // -tonum returns Number|Error — using the result without handling the error fires E005
    n-into  "abc"-tonum-doing.
    n-print-doing.

Output:

ERROR  E005  Root '"abc"' is Number|Error — both cases must be handled.
ERROR  E005  Root 'n' is Number|Error — both cases must be handled.

Fix — propagate with -doing-?:

program-ours-effect
    n-into  "abc"-tonum-doing-?.
    n-print-doing.

Fix — catch the error:

program-ours-effect
    n-into  "abc"-tonum-doing-?.
    n-print-doing.
    -catch
        "Could not parse as number"-print-doing.

E006 — Scope Leak

Fires when a root defined inside a child scope is referenced in an outer scope where it does not exist.

ragul check examples/error-codes/E006_scope_leak.ragul

calculator-ours-effect
    result-into  6-7-mul-it.   // 'result' lives inside 'calculator'
    result-print-doing.

program-ours-effect
    // ERROR — 'result' is defined inside 'calculator', not here
    summary-into  result-it.
    summary-print-doing.

Output:

ERROR  E006  Root 'result' is referenced outside its defining scope (scope 'calculator').

Fix: Either reference result from inside calculator, or define a scope that returns the value and bind the result in the outer scope.

E007 — Module Not Found

Fires when a -from (-ból) import cannot be resolved to a .ragul file on the module search path.

ragul check examples/error-codes/E007_module_not_found.ragul

program-ours-effect
    // ERROR — no geometry.ragul exists on the search path
    geometry-from.
    area-into  10-5-area-calc-it.
    area-print-doing.

Output:

ERROR  E007  Module 'geometry' cannot be resolved.
             Searched: 'examples/error-codes/geometry.ragul'

Fix: Create geometry.ragul in the same directory as your script, or add its directory to modulok.utvonalak in ragul.config.

E009 — Field Mutation Outside Effect Scope

Planned for v0.3.0. The diagnostic is implemented; OOP / record-update syntax is not yet in the parser. Until then, the equivalent enforcement is E003 (parallel write conflict in a pure scope).

Fires when a field on a data record is mutated from inside a pure scope.

Intended pattern (v0.3.0):

// ERROR — field mutation outside an effect scope
person-name-into  "Bob"-it.

Output (v0.3.0):

ERROR  E009  Field 'name' is mutated outside a -hatás scope (in the top-level scope).

Fix: Move the mutation inside a -ours-effect scope, or return a new record with the updated field.

W001 — Type Harmony Warning

Fires when a suffix changes the element type (e.g. String → List) without an explicit bridge suffix. This is a warning, not an error — the program still runs.

ragul check examples/error-codes/W001_harmony.ragul

program-ours-effect
    sentence-into  "hello world"-it.
    // W001 — -split converts String → List without an explicit bridge
    words-into  sentence-split-" "-it.
    words-print-doing.

Output:

WARN  W001  Suffix chain crosses type boundary from String (Szöveg) to List[String (Szöveg)] without a bridge suffix.

Suppressing W001: Set harmonia = "off" in ragul.config to disable harmony checks, or "strict" to promote them to errors.

Running All Examples

for f in examples/error-codes/*.ragul; do
    echo "=== $f ==="
    ragul check "$f"
done

See the full error code reference in the Tooling guide.