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docs/examples/9-from_value.md

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+---
+layout: default
+title: Generate Schema from Example Value
+parent: Examples
+nav_order: 9
+summary: >-
+  Generating a schema for a serializable value.
+nav_exclude: true # schemars 0.8.2 currently unreleased
+---
+
+# Generate Schema from Example Value
+
+If you want a schema for a type that can't/doesn't implement `JsonSchema`, but does implement [`serde::Serialize`](https://docs.serde.rs/serde/trait.Serialize.html), then you can generate a JSON schema from a value of that type. However, this schema will generally be less precise than if the type implemented `JsonSchema` - particularly when it involves enums, since schemars will not make any assumptions about the structure of an enum based on a single variant.
+
+{% include example.md name="from_value" %}
+
+Note that the schema for the enum is not very useful in this case, since schemars doesn't know anything about the second variant.