0.6:      initial release

0.6.1:    made GDL compile with g++ 3.3 (datatypes.hpp)

0.6.2:    fixed bug with # and ## operator (basic_op.cpp)
          added -I.. cpp option (Makefile.am)

0.7:      added graphic support (PLOT, WINDOW, WDELETE, SET_PLOT, WSET)
	  some small bug fixes.

0.7.1:    added 64 bit integer support (LONG64, ULONG64)
	  added python support (PYTHON function and procedure)
	  completed type functions for all types (ULONG, UINT, ...)
	  completed INDGEN and INTARR functions for all types
	  New library routines: SYSTIME, LEGENDRE, MACHAR, FFT, TVLCT,
	  MAX, MIN, TOTAL, ARRAY_EQUAL, CATCH, ON_ERROR
	  Library routines written in GDL (check out *.pro files not
	  starting with test_)
	  several bugfixes: conversion between BYTE and STRING.
	  GOTO within IF statement.
	  Memory leakage concatenating struct arrays.
	  
0.7.2:    Bugfix: dereferenced pointers are now passed by reference

0.8:      added netCDF support.
	  several new library routines.
	  support for .COMPILE command.
	  Improved formatted and unformatted output.
	  Improved configure script.
	  Extended and cleaned up the API for library routines (envt.hpp)
	  Fixed: GOTO,undefined_label made GDL crash. 
	  Several other bugfixes.

0.8.1:    Updated the configuration files (automake).

0.8.2:    added HDF support.
	  added support for several image file formats.
	  changed the code and configuration files to make GDL build 
	  also on Mac OS X.
	  bug fix for TRANSPOSE function.

0.8.3:    now netCDF and HDF can be used together (there were linker
	  errors in 0.8.2).
	  updated some obsolete commands in configure.in
	  more complete HDF support.
	  added DEFSYSV procedure.
	  addef CONJ and IMAGINARY functions.

0.8.4:    introduced _STRICT_EXTRA
	  solved remaining problem of using netCDF and HDF together.
	  HELP now reports variable names correctly.
	  the line continuation operator ($) is now also recognized in
	  interactive mode.
	  Added SORT, UNIQ, SHIFT (1 dim only), STRTOK, FILE_TEST, CD,
	  HISTOGRAM and REFORM function.
	  Added LOADCT, CD and TV procedure.
	  Basic HDF5 support.

0.8.5:    Fixed bug in STRING with PRINT or FORMAT keywords set.
          Fixed bug in STRMID with 3rd parameter undefined or not given.
	  Added MESSAGE procedure.
	  Added FILE_SEARCH, ARG_PRESENT and EOF functions.
	  Fixed bug in AssignAt functions.
	  Fixed subtle bug concerning arrays() and function() which
	  made GDL not recognize library functions when identifier was
	  used before as array.

0.8.6:    Added CONVOL function (very fast).
	  Added EXP function.
	  Added JOURNAL procedure.
          Completed SHIFT for multiple dimensions.
	  HISTOGRAM now supports REVERSE_INDICES keyword.
	  HELP,/LIB sorts now the output.
	  Made # and ## operators IDL conforming for 1 dimensional arrays.
	  N_ELEMENTS now returns LONG (before ULONG)

0.8.7:    Support for GDL_PATH (falls back to IDL_PATH) environment variable.
	  Added EXPAND_PATH, ARRAY_INDICES, REBIN, LEGENDRE, IGAMMA,
	  LNGAMMA, BETA functions.
	  Added OPLOT procedure.
	  Bugfixes for ATAN (with 2 floats), CONVOL (1-dim kernel),
	  MESSAGE (prefix).

0.8.8:    Added OBJ_CLASS, OBJ_ISA, N_TAGS, SWAP_ENDIAN, BYTSCL functions.
	  Added PLOTS, XYOUTS (both 2D only), BYTEORDER procedures.
	  Improved FFT.
	  OMIN,OMAX keyword support for HISTOGRAM.
	  Fixed braced reference argument bug.
	  Changed equality checking to compatibility checking for
	  struct array definitions.
	  Added structure compatibility check for assignment to struct
	  arrays.
	  Fixed offset bug for conversion functions (BYTE, FIX, ...).
	  Fixed libfunction returning parameter bug.
	  Fixed AND, OR operator bug.
	  Fixed TVLCT bug.
	  @file now honors !PATH.
	  Changed configure.in to support python on OS X (fink)
	  Added SETENV, STRUCT_ASSIGN pro.
	  Added GETENV, STREGEX, TAG_NAMES functions.
	  Minor adjustments of default output (no FORMAT keyword).
	  Widen struct tag name rules: "!", "!$" and "!TEXT" are
	  allowed.
	  System variables can be named "!$", or "!$TEXT".
	
0.8.9:    Added SPAWN, WAIT procedure.
	  Added FINITE, ROUTINE_INFO, TEMPORARY functions.	
	  Added DIST function and TVSCL procedure (as .pro files).
	  !EXCEPT system variable.
	  Changed common block compilation.	  
	  Allow RETURN as jump label (remove it from reserved words)
	  Allow library functions to return their own parameters if used
	  in a return statement.
	  Allow library functions as l-functions.
	  Fixed assignment to indexed array at one position (insert at) for
	  indices which are 0.
	  Cleaned up Compiler/Interpreter.
	  Added NAN keywords to BYTSCL, MIN, MAX.
	  Added SUBSCRIPT_MIN/MAX keywords to MAX/MIN.
	  Added NTOHL, NTOHS, HTONL, HTONS keywords to BYTEORDER.
	  Added z-buffer device
	  Fixed MOD division by zero for integers.
	  Support for files with main programs.
	  Fixed COMMON and GOTO for interactive use.	
	  Added .RUN command
	  True color support for TV (X-device).
	  
0.8.10:   Optimization (~10%): Arrayindexing, non-copy constants, 
	  Complex (pow, abs).
	  Optimization (>200%): Dedicated ProgNodes for compiled programs
	  Fixed RETURN statement in FOR loops.
	  Made GDL buildable as a python module.
	  .RUN handle files without subroutines.
	  GCC 4.0 compilance.
	  INTERPOLATE function.
	  Fixed eof detection on input.
	  Implemented strided index support.
	  Improved raise to power (^ operator) for integer types.

0.8.11:   Added CONTOUR procedure.
          Added CREATE_STRUCT, RADON, LAGUERRE, STRCMP, GAUSS_PDF, GAUSS_CVF
	  functions.
 	  Added STRUCTURES keyword to HELP.
	  Added NAN keyword to TOTAL.
	  Sub-millisecond resolution for SYSTIME function
	  Added !DIR system variable
          Much faster array indexing.
	  Much faster operators (+-/*^...)
	  Faster FFT (requires FFTW library: http://www.fftw.org/download.html)

0.9:      Added HEAP_GC, PRODUCT, FILEPATH, MEDIAN (no filtering), READ_ASCII,
	  PUSHD, POPD, PRINTD, PRIMES, NORM, T_PDF, POLY_2D routines.
	  Support for SAVE and RESTORE through Craig Markwardt's CMSVLIB library.
	  Added SMOOTH and DERIV as external functions.
	  Full support of ON_IOERROR
	  Full support of F77_UNFORMATTED.
	  Support for XDR I/O.
          Fixed positional index (value and dimension) returned by STREGEX.
	  HELP without parameters and keywords puts out a list of all local
	  variables as well as compiled procedures and functions.
	  Add support for PROCEDURES & FUNCTIONS keywords in HELP
	  Made GDL compile under x86_64 linux.
	  Fixed incompatibility with # operator and one-dim vectors.
	  Speedup for ^ operator for integer types.
	  Speedup (>100x!) for REVERSE_INDICES of HISTOGRAM.
	  Implement INPUT keyword in HISTOGRAM.
	  Support for non-rectangular (x,y 2d arrays) calls to SURFACE and CONTOUR.
	  Support for DICOM files (GDLffDICOM object).
	  INTEGER keyword for TOTAL.
	  Add support for variable-length VMS files.	  
	  Add support for CHANNEL keyword in TV/TVSCL.
	  Add support for TRUE/CHANNEL keywords in TVRD (X only)
	  Add support for DIMENSION keyword in FFT.
	  Add REGEX keyword support to STRTOK.
	  Add preliminary support for MPI.
	  Add initial support for SOCKET.
	  Preliminary support for map projections. (requires libproj4 from
	  (http://members.verizon.net/~vze2hc4d/proj4/lbp4_050319S.tar.gz)
          Add initial support for BESELI, BESELJ, BESELK and BESELY but only for
	  integer order due to limitations of GSL Bessel functions
	  Added Erf() [and Errorf() for compatibility], Erfc(), Expint(), Gaussint().
	  Fixed I/O of Gamma(), Igamma(), LnGamma() and Beta().
	  Added Erf() [and Errorf() for compatibility], Erfc(), Expint(), Gaussint()
	  Fixed I/O of Gamma(), Igamma(), LnGamma() and Beta()
	  +-Inf now managed in MIN and MAX (if called with /Nan)
	  NaN and +-Inf now properly managed in PLOT, OPLOT, PLOTS
	  Speedup in PLOT, OPLOT, PLOTS for large data sets (see test_plot_benchmark.pro)
	  Add 6 linestyles (via !p.linestyle or keyword) for PLOT, OPLOT, PLOTS
	  Improved memory management.
	  Improved new implementation of struct arrays.
