As is the case for descriptors, keywords also have a name (max. 8 chars.),
a type and a length (i.e. no. of elements). However, this length is fixed, and
once the keywords are created with a certain size, they cannot be extended.
The possible types for keywords are:
real, integer, character and double precision.
Like for descriptors there are no mixed types possible.
In order to write a value to a keyword, the same format as for descriptors
is used.
WRITE/KEYWORD INPUTC/C/1/8 AKeyword
This command would write the ASCII string AKeyword into the character keyword INPUTC and
WRITE/KEYWORD AZTEC/I/1/2 17,-22
would write the values 17 and -22 into the integer
keyword AZTEC (elements 1 and 2).
Single keyword elements can also be written in a more direct way, via
key = value, e.g. to set the 12th element of keyword INPUTR
to 1.234, use
inputr(12) = 1.234
The value can also be an expression made up of constants and elements
of any MIDAS data structure, see the subsection 
.
Some of the commands dealing with keywords are:
READ/KEYWORD, WRITE/KEYWORD, SHOW/KEYWORD, DELETE/KEYWORD,
COPY/KEYWORD,
COMPUTE/KEYWORD.
Keywords and descriptors can be copied to each other via COPY/KD and
COPY/DK.