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TypeConverter

click::types

Trait TypeConverter 

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pub trait TypeConverter:
    Debug
    + Send
    + Sync {
    type Value;

    // Required methods
    fn name(&self) -> &str;
    fn convert(&self, value: &str) -> Result<Self::Value, String>;

    // Provided methods
    fn get_metavar(&self) -> Option<String> { ... }
    fn get_missing_message(&self) -> Option<String> { ... }
    fn split_envvar_value(&self, value: &str) -> Vec<String> { ... }
    fn shell_complete(&self, _incomplete: &str) -> Vec<CompletionItem> { ... }
    fn is_composite(&self) -> bool { ... }
    fn arity(&self) -> usize { ... }
}
Expand description

Trait for parameter types that convert and validate command-line values.

Each type must define how to convert a string value from the command line into the appropriate Rust type.

Required Associated Types§

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type Value

The Rust type that this parameter type converts to.

Required Methods§

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fn name(&self) -> &str

Returns the descriptive name of this type (used in error messages).

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fn convert(&self, value: &str) -> Result<Self::Value, String>

Convert a string value to the target type.

Returns an error message if conversion fails.

Provided Methods§

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fn get_metavar(&self) -> Option<String>

Returns the metavar for this type (used in help text).

For example, INT might return "INTEGER".

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fn get_missing_message(&self) -> Option<String>

Returns an optional message when a required value is missing.

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fn split_envvar_value(&self, value: &str) -> Vec<String>

Split an environment variable value into multiple values.

By default, splits on whitespace. Path-based types override this to split on the platform’s path separator.

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fn shell_complete(&self, _incomplete: &str) -> Vec<CompletionItem>

Returns shell completion items for the given incomplete value.

Most types return an empty list; types like Choice and Path can provide completions.

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fn is_composite(&self) -> bool

Whether this type is a composite type (like Tuple).

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fn arity(&self) -> usize

The arity (number of values consumed) for composite types.

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§