Am 21.10.2011 15:05, schrieb Hans van der Meer:
I cannot find the answer to the following question in Knuth's Metafont book. The following definition with a trailing text argument:
def mydef (expr a, b, c) text modifier = if
:
Have you already tried if modifier = "" :
else: fi enddef;
How can I do the switch on an empty or nonempty modifier argument? It is not a string because calling its length fails with an error. I must do the switch, because "fill modifier" with an empty "modifier" gives horrible results.
Usage would be calls like: mydef(1,2,3) withcolor green; % with modifier text mydef(1,2,3); % without modifier text
Thanks in advance. Hans van der Meer
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