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<P><FONT SIZE="5">3.12 Pragma: Indentation</FONT><BR>
<P>When FunnelWeb expands a macro, it can do so in two
ways. First it can treat the text it is processing as a
one-dimensional stream of text, and merely insert the body
of the macro in place of the macro call. Second, it can
treat the text of the macro as a two dimensional object and
indent each line of the macro body by the amount that the
macro call itself was indented. Consider the following
macros.
<P>
<PRE>
@$@<Loop Structure@>@{@-
i=1;
while (i<=N)
@<Loop body@>
endwhile
@}
@$@<Loop body@>@{@-
a[i]:=0;
i:=i+1;@}
</PRE>
<P>Under the regime of <STRONG>no
indentation</STRONG> the loop structure
macro expands to:
<P>
<PRE>
i=1;
while (i<=N)
a[i]:=0;
i:=i+1;
endwhile
</PRE>
<P>Under the regime of <STRONG>blank
indentation</STRONG> the loop structure
macro expands to:
<P>
<PRE>
i=1;
while (i<=N)
a[i]:=0;
i:=i+1;
endwhile
</PRE>
<P>The <SAMP>indentation</SAMP> pragma determines which of
these two regimes will be used to expand the macros when
constructing the product files. The syntax of the pragma is:
<P>
<PRE>
pragma_ident = ps "indentation" s "=" s
("blank" | "none")
</PRE>
<P>Its two forms look like this:
<P>
<PRE>
@p indentation = blank
@p indentation = none
</PRE>
<P>In the current version of FunnelWeb, the indentation
regime is an attribute that is attached to an entire run of
Tangle; it is not possible to bind it to particular product
files or to particular macros. As a result, it doesn't
matter where indentation pragmas occur in the input file or
how many there are so long as they are all the same. By
default FunnelWeb uses blank indentation.
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