This C program requires the names of one or more files as arguments,
and will copy each of them in turn to standard output, eg
catex file1 file2 >tempfile
The single file ("tempfile" in this case) will contain the contents of
"file1" and "file2". In the process of copying the files,
certain special text strings are scanned for and processed
without copying verbatim.
If the string
%include name%
is found,
the name is interpreted as a file name;
reading of the original file is suspended, and the new file is
inserted in the output stream.
A file being included will itself be checked in the same way as the
original file for occurrences of instructions such as
%include newname%
and such new files will be inserted appropriately. Calls to include
files can be nested to any depth.
A file-name is interpreted relative to the file from which it was called, and simple names are interpreted as being in the same directory. Names beginning with '..' are interpreted as being in a higher level directory.
A string %DATE% within a file will be
replaced by the current local date.
Macros can be defined using the form
%DM,name:string:%
and such strings
will not be copied to the output. These set up text substitutions
that will apply to the remainder of the document.
Such macros can be invoked with %M,name%, so
that this text will be
replaced by the string in the definition. Invocation is recursive,
by which I mean that the replacement text is not simply copied directly
to standard output, but instead is processed as the input stream.
Within this replacement text may be other macro invocations
(%M,othername%), new macro definitions, or
%include.. directives.
(A macro cannot be redefined within its own body; our simple syntax
will not allow colons to appear in the 'string' part of a definition).
A situation where macros might be useful is if we wanted to use
two paragraph styles within the one document. Paragraphs have
four attributes, the body alignment, the first line indentation,
the inter-paragraph gap, and the minimum distance from the bottom
of the page for the start of a new paragraph. If we needed to use
the style of paragraph with indented first line for most of the
document, but in some areas to switch to a hanging first line style
for numbered points, we could define two macros for each style:
%DM,Num:%P,15,-10,-.5%:%
%DM,Par:%P,0,5,0%:%
Then to commence a normal paragraph, we would use %M,Par%,
and commence a numbered paragraph, %M,Num%. The parameters
of the two styles would be defined once, and we could switch between
the two styles as needed without needing to remember to reset the
parameters of the original style at the end of a section.
Similar styles can be set up for section titles, where a little
extra space before the title, a change in font size and paragraph
style, and the use of bold will be used systematically for all
headings throughout the document.
%DM,Head:%L%%SZ,16%%PH,0,0,0%%BD%:%
%DM,Body:%SZ,11%%P,0,0,0%%LT%:%
A file is provided (macros.qs) which contains a set of macro definitions that are useful for structured documents, with lists possibly containing sub-lists. In this way, a layout style can be established in the one place, so that measurements of offsets or indentations do not need to be actually used within the document.