Syntax for displaying documentation

[warrd]

When working within a technical computing environment (Matlab, Numpy/IPython, R..) it's important to explore code interactively. One very useful feature is being able to quickly bring up the documentation for some function/object.

In IPython, entering obj? at the prompt will output the doc-string for that object.
In Julia it should be possible to use this, or some other syntax, to display the documentation comment (I realise the syntax for this may not yet be decided).

If the underlying implementation is just a function call on the object returning a string, it might also prove useful in non-interactive tasks such as in the automatic generation of documentation for a module.

[StefanKarpinski]

This already exists:

julia> help(cat)
Loading help data...
cat(dim, A...)

   Concatenate the input arrays along the specified dimension

The main issue is that the documentation index is a bit sparse.

[warrd]

That's good to know, thanks..

So at the moment the help strings are generated from the sphinx documentation and stored in a file helpdb.jl.
I don't know if my suggestion (a language mechanism for retrieving inline documentation) is something you may still want to consider at a later date...

[JeffBezanson]

See also #762.