Usage:
/FOR variable start
end commands
The variable will take on all numeric values between start and end, inclusive. The commands will be executed once for each of the values. If end is less then start, commands will not be executed.
Commands are executed in a new
evaluation scope.
This means, for example, that a /for
called from a macro
must use "%%{...}" and "%%;"
instead of "%{...}" and "%;"
to have the substitutions
perfomred when the /for is
expanded instead of when the
calling macro is
expanded.
Example:
Given the definition
/def countdown = /for i 0 %{1} say $$[%{1} - i]
then the command "/countdown 10"
would cause you to execute the commands "say 10", "say 9", ... "say 0".
Note that the "%{1}" is
substituted when /countdown is
expanded, and the "$$" is replaced
with "$". The resulting "$[10 - i]" is
substituted when
/for is
expanded.
If /countdown used
"$[...]" instead of "$$[...]" in the commands, it would be
substituted when /countdown is
expanded, and you would repeat
"10" 11 times.
If /countdown used
"%%{1}" or "{1}" instead of "%{1}" inside the
expression, it would not be
substituted until
/for was
expanded, so it would have the
value of /for's first argument
(the string "i", which has numeric value 0), and you would end up counting
down from 0 to -10.
See: /while