Overlays and templates

The transfer of information from one side of the equal sign to the other can involve combining several variables or values. This transfer is called an overlay. When you perform overlays, there are certain guidelines to remember.

When two values (or a keyphrase and a value) are on one side of an equal sign and separated by a plus sign (+), only nonblank characters in the value on the right overlay corresponding positions in the value on the left. For example:

CLIST statements

ISREDIT LINE .ZCSR = LINE + '//'
ISREDIT MASKLINE = MASKLINE + <40 '&STR(/*)' 70 '&STR(*/)'>

REXX statements

ADDRESS ISPEXEC
"ISREDIT LINE .ZCSR = LINE + '//'"
"ISREDIT MASKLINE = MASKLINE + <40 '/*' 70 '*/'>"

The first example causes two slashes to replace the first two column positions of the current line (the line containing the cursor). The remainder of the line is unchanged. The second example uses a template to cause columns 40-41 of the current mask line to be replaced with /* and columns 70-71 to be replaced with */. Again, remember that the template replaces the corresponding positions on the left only if those left positions are blank. The template shown in the preceding example has the form:

<col1 literal1 col2 literal2 ... >

It can be designed with col1 and col2 indicating a starting column position, and literal1 and literal2 indicating the data to start in that column. The entire template is delimited with less-than (<) and greater-than (>) signs. A template can be designed by using variable names (enclosed in parentheses) for either col1, col2, literal1, literal2, or for all four. All of these forms are valid:

<(colvar1) (datavar1) (colvar2) (datavar2) ... >
<(colvar1,datavar1)   (colvar2,datavar2)   ... >
<(colvar1)  literal1   col2     (datavar2) ... >