Description:

Gri is a language for scientific graphics programming. It is a
command-driven application, as opposed to a click/point application.
It is analogous to latex, and shares the property that extensive power
is the reward for tolerating a modest learning curve. Gri output is
in industry-standard PostScript, suitable for incorporation in
documents prepared by various text processors.

Gri can make x-y graphs, contour-graphs, and image graphs. In
addition to high-level capabilities, it has enough low-level
capabilities to allow users to achieve a high degree of customization.
Precise control is extended to all aspects of drawing, including
line-widths, colors, and fonts. Text includes a subset of the tex
language, so that it is easy to incorporate Greek letters and
mathematical symbols in labels.

The following is a terse yet working Gri program. If it is stored in
a file called 'example.gri', and executed with the unix command 'gri
example', it will create a postscript file called 'example.ps' with
a linegraph connecting data points in the file called `file.dat'.

open file.dat # open a file with columnar data
read columns x * y # read first column as x and third as y
draw curve # draw line through data (autoscaled axes)