# Trait ExtensionLookup

    pub trait ExtensionLookup<'a, T>: FontRead<'a>where
        T: FontRead<'a>,{
        // Required method
        fn extension(&self) -> Result<T, ReadError>;
    }

Expand description

A trait that abstracts the behaviour of an extension subtable

This is necessary because GPOS and GSUB have different concrete types for their extension lookups.

## Required Methods§

#### fn extension(&self) -> Result<T, ReadError>

## Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

## Implementors§