GO Keyword Types

GO Keywords values can be of several types. These are:

floats

Keywords of the float type can take on any numerical value. Sometimes the range of allowed values is limited. For example, the rest frequency of the observations must be greater than zero.

integers

Keywords of this type can only be integers. Sometimes the range of allowed values is limited.

strings

Must be enclosed in a pair of double quotes. For example,

spacesc.proj_id = ``GBT-01A-075''

boolean

Currently, consists of the two strings ``T'' and ``F''.

enumerated

Some keywords are limited to a few possible values. These keywords are of the enumeration type. The possible values consist of specific string values. For example, the 1 cm receiver beam switching parameter can be either

spacerx18to26.beam_ctrl = ``computer''

or

spacerx18to26.beam_ctrl = ``manual''

sexagecimal

Presently, sexagesimal formats for time, R.A., and Dec. constants are HH:MM:SS.S and sDD:MM:SS.S. No whitespace is allowed in this type.

arrays

Some keywords are actually arrays. For example, there are up to eight IF center frequencies that can be set in the spectral processor, one for each IF channel. As in glish, keyword arrays are subscripted with square brackets, and ranges may be specified. Some possibilities are

Set the second IF channel center frequency to 256.8 MHz.

spacesp.iffrequency[2] = 256.8

Set IF channels 1 through 4 to separate center frequencies.

spacesp.iffrequency[1:4] = [245.0, 255.0, 245.0, 255.0]

Set IF channels 1, 3, and 5 to separate center frequencies.

spacesp.iffrequency[1,3,5] = [245.0, 255.0, 245.0]

Set all IF center frequencies to 250.0 MHz.

spacesp.iffrequency = 250

If there is a mismatch between the number of indices in the keyword index array and the number of values to the right of the equal sign, you will get a warning, but the assignment will be executed anyway. Extra values will be ignored. If there are too few values, the last value will be assigned to all remaining keyword array members specified. More complex glish index syntax, such as [1,2,4:6], or wild cards are not recognized by the table parser. If the keyword is not an array, the index will be ignored.

A keyword array can be an array of any of the above types (floats, integers, strings, boolean or enumerated) except sexagecimal.