Prompted parameters

When a prompt occurs, it consists of the parameter name, a prompt string, and possibly a prompt default. Normally the user responds with the value for the parameter. But other responses are possible:

   PARNAME - Prompt text /Default/ >
   PARNAME - Prompt text /Default/ > \
   PARNAME - Prompt text /Default/ > 123.45
   PARNAME - Prompt text /Default/ > a_file
   PARNAME - Prompt text /Default/ > '1st_file'
   PARNAME - Prompt text /Default/ > @1st_object
   PARNAME - Prompt text /Default/ > min
   PARNAME - Prompt text /Default/ > max
   PARNAME - Prompt text /Default/ > !
   PARNAME - Prompt text /Default/ > !!
   PARNAME - Prompt text /Default/ > ?

By entering nothing and just hitting return, the prompt default is accepted as the proper value. Entering the backslash ($\backslash$) accepts the default for this parameter and the respective defaults for all parameters that would subsequently be prompted for; no further prompting will occur. Sometimes it is necessary to make clear that a value is not a number. When a file name begins with a digit then in may have to be given with single quotes or with an `at' (@).

Numeric parameters have a permitted range. The user can ask for either of the extreme values to be used by entering `min' or `max'. In most circumstances the permitted range of `xstart' etc. is the extent of the data in question. The `splot' command is an exception: The permitted range is close to the floating point range of the machine and grossly exceeds the extent of any reasonable spectrum. This is necessary so that you can have a plot that is wider than the data reach. `splot' has the logical parameter `whole' to adjust the plotted range to the data range itself.

Entering an exclamation mark should assign the null value to the parameter, i.e. make the value undefined. In Figaro this has no meaning and the application should abort. A double exclamation mark is the proper signal for the application to abort. The question mark can be used to get `run-time' help, i.e. help on the parameter currently prompted for.