- GNU Data Language is a high level language for numerical computations and data visualization similar to IDL (Interactive Data Language from Research Systems Inc.).

A free IDL (Interactive Data Language) compatible incremental compiler (ie. runs IDL programs). IDL is a registered trademark of ITT Visual Information Solutions.

Full syntax compatibility with IDL 6.0

ALL IDL language elements are supported, including:

• Objects,
• Pointers,
• Structs,
• Arrays,
• System variables,
• Common blocks,
• Assoc variables,
• All operators,
• All datatypes,
• _EXTRA, _STRICT_EXTRA and _REF_EXTRA keywords...

The file input output system is fully implemented
(Exception: For formatted I/O the C() sub-codes are not supported yet)

netCDF files are fully supported.

HDF files are partially supported.

Basic support for HDF5 files.

Overall more than 330 library routines are implemented. For a sorted list enter HELP,/LIB at the command prompt and look for library routines written in GDL in the src/pro subdirectory.

Alain Coulais maintains a list of subroutines available in GDL.

SAVE and RESTORE are supported through Craig Markwardt's CMSVLIB library.

Graphical output is partially implemented. The PLOT, OPLOT, PLOTS, XYOUTS, SURFACE, TVRD and TV commands (along with WINDOW, WDELETE, SET_PLOT, WSET, TVLCT) work (important keywords, some !P system variable tags and multi-plots are supported) for X windows, z-buffer and postscript output.

GDL has an interface to python (python routines can be called from GDL).

GDL can be build as a pyhton module (GDL subroutines can be called from python).

No GUI support (widgets) is implemented so far.

GDL is free software licensed under the GPL.