pro dubya,usestop=usestop ;+ ;pro dubya ;Procedure to plot dubya's polularity over time as polled by IAS and ;SRI ;No parameters ;Keywords: setting usestop stops program before the end ;Hugh Pumphrey, Edinburgh (many years ago). Updated: John Marsham, ;Leeds (16/3/05) ;- ; **** Here are the data. **** x = [1, 2, 4, 5, 6.7, 7, 8, 10 ] ; time y = [40, 30, 10, 20, 53, 20, 10, 5] ; popularity (IAS polling) y2 = [30, 28, 8, 19, 50, 22, 12, 6] ; popularity (SRI polling) ; **** make a plot of the first set of data ***** plot,x,y,title='Should he resign?',xtitle='weeks', $ ytitle='Popularity', psym=-2 ; --- Note how we use $ in the above command to continue onto the ; --- next line ; +++++++ Add the second set to the plot +++++++ oplot,x,y2,linestyle=2, psym=-6 ; stop if usestop keyword is set (i.e. > 0) if keyword_set(usestop) then stop ; End of the program - don't forget this! end
The semicolon is a comment
The dollar symbol, $, is a line continuation character
The introduction between the ;+ and ;-. is standard - it's really useful to define all the inputs, outputs, keywords etc here (including units!) You can automatically document all these introductions using
``MK_HTML_HELP''.
Also note the use of ``psym=minus value'' to get a symbol and a line.
It is important that the file name ends in ``.pro'' or IDL may not find it. Also using capitals in the procedure name can cause problems.