NAME
ipp - Include Pre-Processor
SYNOPSIS
ipp [-D name=value] [-S includedir] [-I includedir] [-s includefile]
[-i includefile] [-M options] [-P path] [-m mapfile] [-N nosynclines]
[-o outputfile] [-v] inputfile ...
DESCRIPTION
The ipp program reads all inputfiles and recursively expands all
#include 'file'
#include "file"
#include <file>
directives by substituting the directive with the contents of the file.
The output is send to stdout or to outputfile. The files are searched
according to the following scheme:
#include ’file’
The file is searched in the current working directory only. Use
this to force the loading of a local file.
#include "file"
The file is searched in all directories given by the -I option in
the right-to-left order they are specified on the command line.
Note that a -I . implicit option is automatically appended to
command-line options, then files are first searched in current
directory.
#include <file>
First the file is searched in the system wide "ipp" include
directory specified with the -S option. Second if it was not not
found there it is searched for in all directories given by the -I
option.
And it provides eight additional features:
Using Wildcards
These characters have a special meaning in filenames:
"*" Matches any string, including the null string.
"?" Matches any single character.
"[...]" Like bracketed expressions in regexps, matches any of the
enclosed characters.
If you want to include all your templates, you may write
#include "*.tmpl"
With the following parameters you can control the order and the number
of included files using the #include ’pattern’ directive:
"IPP_SORT=scheme" Specify a sort criterion to include files. There
are actually 3 different criteria : date (files are sorted according to
their last modification time), name (this is the default) and numeric
(filenames are sorted numerically).
"IPP_REVERSE=scheme" As above, but resulting list of filenames is
sorted in reverse order.
"IPP_MAX=nmax" Only nmax files are included.
If you want to include the 5 newest include files of the news directory
with file names like "20000131.inc", you may write:
#include 'news/*.inc' IPP_REVERSE IPP_MAX=5
In the files included with the "#include 'pattern'" directive, the
following variables are set and can be read using "$(name)":
"IPP_THIS" the full name of the included source file including path
and extension
"IPP_PREV" the full name of the previous included file, unset in the
first file
"IPP_NEXT" the full name of the next included file, unset in the last
file
Keep in mind that a directive without wildcards does not set these
variables.
Special ‘Use’ Variant
In analogon to Perl’s "use" statement, ipp provides a special variant
of "#include":
#use type::category::file
This internally is equivalent to the directive
#include <category/file.type>
plus the special semantic that the include file is included (=used)
only once, i.e. multiple inclusion is automatically avoided. In other
words
#include 'file'
#include 'file'
#use 'file'
#use 'file'
results in three inclusions of ’file’. Two from the "#include"’s and
only once from the "#use" directives.
Special ‘Depends’ Variant
You can easily write fragments of Makefiles with the -M flag (see
below) to keep tracks of which files the output file depends on, When
"ipp" is invoked as a piece of "WML", the final output file may depend
on other files. You can tell "ipp" about these hidden dependencies by
using the "#depends" variant , e.g.
#depends 'foo.dat'
#depends "*/*.dat"
#depends <file>
The contents of the file is not inserted, only information about
dependencies are updated.
Input Line Synchronization
All include commands insert some special stuff to help "WML" keeping
track of input line numbers. This feature may be disabled by appending
the string "IPP_NOSYNCLINES" to the "#include" (or its variants)
command. See also the "-N" flag.
Include Variables
You can add
name[=value]
pairs at the end of "#include" (and "#use") directives to let "$(name)"
interpolate to "value" (or 1 if "=value" is missing) in this include
file and all its recursively included files.
There are the following forms of the "$(name)" syntax, similar to the
functionality any Bourne Shell provides:
o "$(name)"
‘Use Only Value’: The standard interpolation.
if (exists(name))
expandto(valueof(name))
else
expandto("")
o "$(name=string)"
‘Assign Value’: Set a variable.
name := string
o "$(name:-string)"
‘Use Default String’: The standard interpolation with a default
value.
if (exists(name))
expandto(valueof(name))
else
expandto(string)
o "$(name:=string)"
‘Use Default String and Assign’: The standard interpolation with a
default value and additional assignment for later use.
if (exists(name))
expandto(valueof(name))
else
expandto(string)
name := string
o "$(name:+string)"
‘Use Alternate String’. The replacement interpolation.
if (exists(name))
expandto(string)
else
expandto("")
o "$(name:*string)"
‘Use Negative Alternate String’. The replacement interpolation with
negated logic.
if (exists(name))
expandto("")
else
expandto(string)
o "$(name:?string)"
‘Indicate Error If Unset’. The error message interpolation. This
can also be used in conjunction with the above variants.
if (exists(name))
expandto(valueof(name))
else
Error(string)
Previous constructs may be nested when variable expansion contains no
parenthesis. You may for instance need these forms:
‘Set a variable if unset’.
$(var=$(var:-string))
‘Redefine a variable if it is already set.’
$(var=$(var:+string))
Notice that nested expressions are not handled as shells do. In shells
expressions are treated from left to right, whereas "ipp" treat inner
expressions first. With this example below
$(foo=bar)
$(foo:-$(foo=quux))
Bourne shells will show "bar" whereas "ipp" will print "quux".
It is also possible to undefine a variable. To do so, assign an empty
value to this variable, e.g.
$(foo=)
Notice the possibility to do simple If-Then-Else constructs:
$(foo:+string_when_set)$(foo:*string_when_not_set)
This is equivalent to the following pseudo-code:
if (exists(foo))
expandto(string_when_set)
else
expandto(string_when_not_set)
Implicit IPP Variables
The strings "__FILE__" and "__LINE__" are always substituted by the
currently processed include file and the current line number.
Comments
IPP provides support for up-to-end-of-line comments. This type of
comment is like the one found in Bourne-Shell or Perl, i.e. any line
which starts with a sharp symbol (‘"#"’) is entirely (i.e. including
the newline at the end) removed from the input. Additionally these
lines can have whitespaces in front of the sharp symbol. When you
really need a sharp symbol at the start of a line you can use "\#",
i.e. prefix it with an escaping backslash.
End-Of-File Stopping
It stops processing the current include file when a line containing
just
__END__
occurs. Use this to append POD documents to include files for
documentation purposes as in Perl. You can use "__END__" in constructs
like "$(SHORTENING:+__END__)", so that the processing is only stopped
when the variable SHORTENING is set.
End-Of-Line Continuation
It removes all occurences of the pattern
\<whitespace>*<newline><whitespace>*
Use this to let one or more lines to be concatenated.
OPTIONS
-D name=value
Defines a variable the for the initial inputfile the same way you
define ones with the #include for include files. The variable can
be interpolated via "$(name)" in all files.
-S includedir
Adds a system wide include directory. You can use this option more
than once. The files are searched in right-to-left order.
-I includedir
This adds an entry to the include path where include files are
searched for. You can use this option more than once. The files
are searched in right-to-left order. The current working directory
is always appended as the last directory to this list, and so is
searched first.
-s includefile
Pre-load a particular include file, i.e. virtually adds a
#include <includefile>
in front of inputfile. Use this to automatically load default
system include files. You can also use the syntax
"type::category::file" which leads to a virtually added
#include <category/file.type>
-i includefile
Pre-loads a particular include file, i.e. virtually adds a
#include "includefile"
in front of inputfile. Use this to automatically load default user
include files. You can also use the syntax "type::category::file"
which leads to a virtually added
#include "category/file.type"
-M options
Output a rule suitable for ‘make’ describing the dependencies of
each output file, as ‘gcc’ does. It has only sense when the -o
option is used.
The D flag option writes the rule to a dependency file. The name of
this file is obtained by replacing the suffix of the output file by
".d".
The M flag option deletes the system files from the list of
dependencies.
-P path
This sets up one or more prolog program path which are applied to
each single input file just before real processing starts. Use this
to pre-process the data. Each program receives the data to act on
as STDIN and has to produce the filtered data on STDOUT.
-m mapfile
This adds an entry to the list of mapfiles where a mapping between
obsolete include file names and current ones can be found. You can
use this option more than once. The mapfiles can contain the
following lines:
# comment line
<blank line>
<oldname>[,<oldname>] <newname> \[S|W|E: <text>\]
Example:
<std/headfoot.wml>,wml::std::headfoot wml::OBSOLETE::std::headfoot [S]
-N nosynclines
By default, WML inserts some instructions to synchronize line
numbers, which are then interpreted in passes 2 and 3. This option
disables this feature.
-o outputfile
This redirects the output to outputfile. Usually the output will be
send to "stdout" if no such option is specified or outputfile is
""-"".
-v This sets verbose mode where some processing information will be
given on the console.
AUTHORS
Ralf S. Engelschall
rse@engelschall.com
www.engelschall.com
Denis Barbier
barbier@engelschall.com