Slickest REPL console in any language

Question

Many REPL console languages ​​have additional features such as autocomplete and intellisense. For example, iPython, Mathematica, and PyCrust do their best to go beyond the normal eval loop. REPLs are especially useful in languages ​​where interactive intelligence is very important, such as Matlab or R.

I am looking for inspiration. Which application provides slickest REPL? Or what features did you always want to have in your REPL of your choice?

Answer 1

I really like the Javascript Safari Web Inspector console. In particular:

• Complex hierarchies of interactive objects
• sprintf -style logging
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Answer 2

Lisp emacs SLIME. , , , , .

Answer 3

MATLAB 7.8.0 (R2009a) :

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Answer 4

I think PowerShell wins without a doubt.