Re: query/ignore and use of Ferret error messages

[Jaison Kurian <jaison@xxxxxxxxxxxxxxxxxx>]

Hi Emilie,
            Make the "go" file as 

     query/ignore $1%portrait|landscape|portrait<USAGE: GO my_file [portrait/landscape]%
     say $1"portrait"
 OR
     query/ignore $1%portrait|landscape|portrait<USAGE: GO my_file [portrait/landscape]%
     define symbol orient = $1"portrait"
     say ($orient)

  In the first case you have to use $1"portrait" wherever you need to
  specify the orientation..like 
  (Please note that "-l" option for Fprint is to specify line : ps/cps.)

          sp Fprint -l cps -p $1"portrait" -o test.ps -R metafile.plt

  In the second case you can use the new symbol "orient" ..like

          sp Fprint -l cps -p ($orient) -o test.ps -R metafile.plt

  For details please refer user manual Ch1 Sec5.3.4. 
  Arguments to GO tools and Ch1 Sec5.3.5.   
  "QUERY/IGNORE" has been explained as : no-op command (has no effect)
 
  For error messages, please refer usermanual Ch7 Sec10. 

 I am not sure wether it is possible to customorize ferret's default
 error messages. But if you know the possible traps for a script then
 desine it with proper error checking steps. Here is a quick example.

  Suppose we need to make vertical profiles, then the data should vary
  only on Z axis. So.....

      set data levitus_climatology
      set reg/x=60

      define symbol shp = "`temp,r=shape`"
      IF `($shp) NE "Z"` THEN 
         say ; say "ERROR : region is not set properly" ; say
         exit
      ENDIF

      plot temp

  This kind of sanity checking can be added to the script for "customorized"
  error/warning messages.

  Suppose if you want to generalize this customorization, then 
    -  put all the required error messages in a text file & read it back 
             (to a variable err_msg)
    -  do the checking 
           - if error occures then assign the respective error
                  message's line number to a "symbol" (say err)
           - if no error then assign 0
           - construct an IF condition... like

               IF `($err) GT 0` THEN  
                     say `err_msg[d=*,i=($err)]`
                     exit
               ENDIF

  Hope This Helps

  With Regards 

  Jaison  
-- 
___________________________________________________

    Jaison Kurian                           
    Centre for Atmospheric and Oceanic Sciences
    Indian Institute of Science
    B A N G A L O R E   560 012
    Ph: +91-80-3942505
        +91-80-3600450
    Fax:+91-80-3600865
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