;+
; This procedure writes the data in the displayed spectrum to an ASCII
; file.  See the documentation in <a href="../toolbox/dcascii.html">dcascii</a>
; for an explanation of the format of the output.
;
; @param filename {in}{optional}{type=string} The filename can be specified
; using this parameter.  If omitted, the file will be called
; 'gbtidl.ascii' unless /prompt is used.
;
; @keyword brange {in}{optional}{type=integer}{default=0} The beginning
; of the range to be written, in units of the current plotter X-axis.
;
; @keyword erange {in}{optional}{type=integer}{default=0} The end
; of the range to be written, in units of the current plotter X-axis.
;
; @keyword prompt {in}{optional}{type=boolean} When set, a file
; chooser dialogue is used to set the file name, even if filename was
; set as an argument.
;
; @examples
;    write_ascii,'mydata.txt'
;
; @uses <a href="../toolbox/dcascii.html">dcascii</a>
;
; @version $Id$
;-

pro write_ascii,filename,brange=brange,erange=erange,prompt=prompt
	common gbtplot_common,mystate,xarray
	if n_elements(filename) eq 0 then thisfilename='gbtidl.ascii' else thisfilename=filename
	if keyword_set(prompt) then thisfilename = dialog_pickfile(file=thisfilename,/write)
        dcascii,file=thisfilename,brange=brange,erange=erange
end