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@Section
@Title { Typesetting computer programs as part of a larger document }
@Tag { embedded }
@Begin
@PP
When the program texts are to be part of a larger Lout document,
the procedure is somewhat different. You need to include the setup file
appropriate to your language, like this:
@ID @OneRow @Code {
"@SysInclude { cprint }"
"@SysInclude { doc }"
}
The @Code cprint setup file includes everything needed to set up for C
program formatting; for the other languages, consult the second column
of the table at the start of this chapter.
@PP
The program texts within the Lout document are enclosed in braces
preceded by the Lout symbol from the third column of the table, like
this for the C language:
@ID @OneRow @Code @Verbatim {
@IndentedDisplay @CP {
#include <stdio.h>
treeprint(struct tnode *p) /* print tree p recursively */
{
if (p != NULL) {
treeprint(p->left);
printf(\%4d %s\\n\, p->count, p->word);
treeprint(p->right);
}
}
}
}
Although computer programs violate the rules of legal Lout input in many ways,
these rules are suspended by the {@Code "@CP"}, {@Code "@Eiffel"} etc. symbols,
allowing the program text to be incorporated with absolutely no
modifications. The result is
@ID @OneRow @CP {
#include <stdio.h>
treeprint(struct tnode *p) /* print tree p recursively */
{
if (p != NULL) {
treeprint(p->left);
printf("%4d %s\n", p->count, p->word);
treeprint(p->right);
}
}
}
We have chosen to use the @Code "@IndentedDisplay" symbol from Section
{@NumberOf displays} to obtain an indented display, but in fact
{@Code "@CP"}, {@Code "@Eiffel"} and the rest may appear anywhere at
all: the result is an object in the usual way, which may go
anywhere.
@PP
It is quite normal to include fragments of programs, particularly
identifiers, within paragraphs; this is done in the obvious way:
@ID @OneRow @Code @Verbatim {
Calling @CP { remove_cooling_rods() } without checking @CP { temp } first
is not recommended since it may cause the reactor to melt down.
}
Use @Code "@OneCol @CP { ... }" (or @Code "@OneCol @Eiffel { ... }" etc. for
other languages) to prevent the program text being broken across two lines,
if desired. Hyphenation is on by default in computer programs; however,
the current language is changed from @Code English or whatever to
{@Code Programming}, whose hyhenation rules permit hyphenation after
an underscore character or between a preceding lower-case letter
and a following upper-case letter, but not elsewhere.
@PP
In cases where the program text has unbalanced braces, it is necessary to
programs. @RawIndex { programs }
programs.braces @SubIndex { braces in }
braces. @RawIndex { braces }
braces.in.program @SubIndex { in program formatting }
use the alternative form @Code "@CP @Begin ... @End @CP" (or the
equivalent for other languages), so that Lout does not confuse program
braces with Lout braces. In that case the program text must not
contain {@Code "@End"}; and in either case the program text must not
include @Code "@Include" or @Code "@SysInclude" unless you are really
including a file at that point (Section {@NumberOf pipes}).
@PP
If your Lout document contains program texts in several languages,
simply add one @Code "@SysInclude" line for each of them and proceed
as before. If your programming language is not currently supported,
a viable alternative is
@ID @Code "@F @Verbatim { ... }"
This causes the text between braces to be set verbatim in
a fixed-width font, as explained elsewhere in this guide. This
method will not handle tab and formfeed characters very well. Again,
use @Code "@Verbatim @Begin ... @End @Verbatim" if your program text
contains unbalanced braces.
@End @Section
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