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Feature #12931

Updated by nobu (Nobuyoshi Nakada) over 2 years ago

Many people would probably like to use `binding.instance_eval` binding.instance_eval when executing templates. The reason for this is because `binding.eval` binding.eval is slow.

The use case is template rendering, e.g. systems like ERB.

In my template renderer, I did have

```ruby


if Binding === scope
# Slow code path, evaluate the code string in the given binding (scope).
scope.eval(code, @buffer.path)
else
# Faster code path, use instance_eval on a compiled Proc.
scope.instance_eval(&to_proc)
end
```


The binding path is several orders of magnitude slower because the code is a string and must be parsed, compiled, etc. But, `to_proc` to_proc path can be cached.

In terms of duck typing, it would be nice if binding implemented `#instance_eval` #instance_eval and would allow passing a block.

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