NamesOfSideEffectsAreImperative [rule] v0.1.0

The grammar of a method name signals whether it mutates. Mutating methods use imperative verb phrases: array.sort(), set.insert(x), string.append("!"). Their non-mutating counterparts use the past participle (-ed) or present participle (-ing) form: array.sorted(), string.appending("!"). When -ed is awkward, prefer the noun phrase: x.union(y) (non-mutating) vs. x.formUnion(y) (mutating).

Checks

• Mutating methods are imperative verbs (sort, reverse, append, remove).
• Non-mutating versions of the same operation use -ed / -ing (sorted, reversed, appending) or form- prefix on the mutating side (formUnion, formIntersection).
• Side-effect-free methods that return a value read as a noun phrase describing the value (x.distance(to: y), array.lazy).
• Boolean methods read as assertions about the receiver (isEmpty, contains(x), intersects(other)).

Label

Mutating methods read as imperatives; non-mutating versions read as nouns or past participles

NamesOfSideEffectsAreImperative [rule] v0.1.0

The grammar of a method name signals whether it mutates. Mutating methods use imperative verb phrases: array.sort(), set.insert(x), string.append("!"). Their non-mutating counterparts use the past participle (-ed) or present participle (-ing) form: array.sorted(), string.appending("!"). When -ed is awkward, prefer the noun phrase: x.union(y) (non-mutating) vs. x.formUnion(y) (mutating).

Checks

• Mutating methods are imperative verbs (sort, reverse, append, remove).
• Non-mutating versions of the same operation use -ed / -ing (sorted, reversed, appending) or form- prefix on the mutating side (formUnion, formIntersection).
• Side-effect-free methods that return a value read as a noun phrase describing the value (x.distance(to: y), array.lazy).
• Boolean methods read as assertions about the receiver (isEmpty, contains(x), intersects(other)).

Label

Mutating methods read as imperatives; non-mutating versions read as nouns or past participles

Label

Mutating methods read as imperatives; non-mutating versions read as nouns or past participles