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Diffstat (limited to 'system/doc/reference_manual')
| -rw-r--r-- | system/doc/reference_manual/typespec.xml | 17 |
1 files changed, 16 insertions, 1 deletions
diff --git a/system/doc/reference_manual/typespec.xml b/system/doc/reference_manual/typespec.xml index e4b9c4f62c..fa751834f6 100644 --- a/system/doc/reference_manual/typespec.xml +++ b/system/doc/reference_manual/typespec.xml @@ -83,17 +83,32 @@ </p> <pre> atom() | integer()</pre> <p> - Because of subtype relations that exist between types, types + Because of subtype relations that exist between types, all types, + except <c>dynamic()</c>, form a lattice where the top-most element, <c>any()</c>, denotes the set of all Erlang terms and the bottom-most element, <c>none()</c>, denotes the empty set of terms. </p> <p> + To facilitate <url href="https://en.wikipedia.org/wiki/Gradual_typing"> + gradual typing</url> of Erlang, the type `dynamic()` is provided. + It is similar to + <url href="https://docs.python.org/3/library/typing.html#the-any-type">Any</url> + in Python, + <url href="https://www.typescriptlang.org/docs/handbook/2/everyday-types.html#any">any</url> + in TypeScript and + <url href="https://docs.hhvm.com/hack/built-in-types/dynamic">dynamic</url> + in Hack. `any()` and `dynamic()` interact with + <url href="https://learnyousomeerlang.com/dialyzer#success-typing">success typing</url> + the same way, so Dialyzer doesn't distinguish between them. + </p> + <p> The set of predefined types and the syntax for types follows: </p> <pre><![CDATA[ Type :: any() %% The top type, the set of all Erlang terms | none() %% The bottom type, contains no terms + | dynamic() | pid() | port() | reference() |