In Harlowe, macros are called by writing the name, a colon, and some data values to provide it, all in parentheses. For instance, you call the (print:)
macro like so:
(print: 54). In this example,
54 is the value.
The name of the macro is case-insensitive, dash-insensitive and underscore-insensitive. This means that
any combination of case, dashes and underscores in the name will be ignored. You can, for instance, write
any other combination or variation.
You can provide any type of data values to a macro call - numbers, strings, booleans, and so forth. These
can be in any form, as well -
"Red" + "belly" is an expression that produces a single string, “Redbelly”,
and can be used anywhere that the joined string can be used. Variables, too, can be used with macros, if
their contents matches what the macro expects. So, if
$var contains the string “Redbelly”, then
(print: "Redbelly") and
(print: "Red" + "belly") are exactly the same.
Furthermore, each macro call produces a value itself - (num:), for instance, produces a number, (a:) an array - so
they too can be nested inside other macro calls.
(if: (num:"5") > 2) nests the (num:) macro inside the (if:) macro.
If a macro can or should be given multiple values, separate them with commas. You can give the
three numbers like so:
(a: 2, 3, 4). The final value may have a comma after it, or it may not -
(a: 2, 3, 4,)
is equally valid. Also, if you have a data value that's an array, string or dataset, you can “spread out” all
of its values into the macro call by using the
(either: ...$array) will act as if every value in
$array was placed in the (either:) macro call separately.