[TeMPOraL]

I used http://r-fiddle.org to verify what was the intended function, then used built-in Artist Mode (M-x artist-mode) to draw an ellipse for function and square for axes, and finally cut it down in fundamental-mode and added labels. It's basically vanilla Emacs, but I admit to using multiple-cursors.el for some cleanup. It's an excellent addon mode offering a more interactive way to do some things you'd otherwise do via keyboard macros. Check out [0] and [1].

[0] - https://github.com/magnars/multiple-cursors.el

[1] - http://emacsrocks.com/e13.html

[sooheon]

Ah thanks, I was aware of artist-mode, I thought there was some ESS like package that could output ascii graphs of functions :) R-fiddle is new to me though, thanks for that.

[TeMPOraL]

There's also orgtbl-ascii-plot[0], there was a mode for writing out flow diagrams in Emacs that used a web backend to render them (I don't remember the name), and I'm pretty sure you could abuse some graphics-to-ascii or DOT file command line tools to get the required result in Emacs buffer - particularly via org-babel, which lets you invoke external programs to "evaluate" code blocks. I remember using some Java-based local tool to render graphs through org-babel, but again I don't recall the name or URL.

[0] - http://orgmode.org/worg/org-contrib/orgtbl-ascii-plot.html