b983a6da57
The same plain-backtick "See sample: \`x.good.al\`." form fixed on al-methods-limited-during-write-transactions (PR #161) turned up repo-wide on 15 more of this PR's articles - Knowledge-Retrieval.ps1 requires the markdown-link form to associate a sample with its article. All 16 fixed; the four local validators (frontmatter, knowledge-index, knowledge-retrieval, review-fixtures, skill-index) pass.
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A fixed set of named choices must use Enum, not a raw Integer
Contributions welcome — open a PR to refine or extend this article.
Description
When a variable or field represents a fixed set of named, mutually exclusive states — a difficulty level, a document type, a processing status — it should be typed as Enum (or Option when extending an object that still uses the legacy type). Representing that same state as a plain Integer and tracking the meaning of each value in a comment or in a developer's head is a magic-number anti-pattern: the compiler cannot catch an out-of-range value, and branches read as opaque numbers instead of names. This is about semantics, not member count, matching binary-choice-must-be-boolean.md's own distinction: a domain concept that is genuinely a stable true/false predicate belongs in Boolean even if someone represents it as a two-value Enum, while a domain concept with exactly two current named states is not automatically a Boolean in disguise — it stays an Enum when the states are named alternatives rather than a yes/no flag, or when it needs to implement an interface, preserve an existing contract, or leave room for a future third value.
Best Practice
Declare an Enum with named values and branch on the enum value, not a raw number.
See sample: fixed-choice-set-must-use-enum-not-integer.good.al.
Anti Pattern
Using a plain Integer field with the meaning of each value tracked only in a comment pushes the documentation of the states into something the compiler cannot check and a future maintainer cannot rely on.
See sample: fixed-choice-set-must-use-enum-not-integer.bad.al.