@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 }"
"@Doc @Text @Begin"
"..."
"@End @Text"
}
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 {
"@IndentedDisplay @CP {"
"#include <stdio.h>"
""
"treeprint(p) /* print tree p recursively */"
"struct tnode *p;"
"{"
" 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(p) /* print tree p recursively */
struct tnode *p;
{
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. When including a program text within a paragraph, use
@Code "@OneCol @CP { ... }" (or @Code "@OneCol @Eiffel { ... }" etc. for
other languages) to prevent it being broken across two lines, if desired.
@PP
In cases where the program text has unbalanced braces, it is necessary to
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 { ... }"
These symbols cause the text between braces to be set verbatim in
a fixed-width font, as explained elsewhere in this guide. This fallback
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
