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:
UsingWildcards
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 "$(name)":
"IPP_THIS" the full name of the included source file including path and extension
"IPP_PREV" the full name of the previous included file, unset in the first file
"IPP_NEXT" the full name of the next included file, unset in the last file
Keep in mind that a directive without wildcards does not set these variables.
Special`Use'Variant
In analogon to Perl's "use" statement, ipp provides a special variant of "#include":
#use type::category::file
This internally is equivalent to the directive
#include <category/file.type>
plus the special semantic that the include file is included (=used) only once, i.e. multiple inclusion is
automatically avoided. In other words
#include 'file'
#include 'file'
#use 'file'
#use 'file'
results in three inclusions of 'file'. Two from the "#include"'s and only once from the "#use"
directives.
Special`Depends'Variant
You can easily write fragments of Makefiles with the -M flag (see below) to keep tracks of which files
the output file depends on, When "ipp" is invoked as a piece of "WML", the final output file may depend
on other files. You can tell "ipp" about these hidden dependencies by using the "#depends" variant ,
e.g.
#depends 'foo.dat'
#depends "*/*.dat"
#depends <file>
The contents of the file is not inserted, only information about dependencies are updated.
InputLineSynchronization
All include commands insert some special stuff to help "WML" keeping track of input line numbers. This
feature may be disabled by appending the string "IPP_NOSYNCLINES" to the "#include" (or its variants)
command. See also the "-N" flag.
IncludeVariables
You can add
name[=value]
pairs at the end of "#include" (and "#use") directives to let "$(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)
ImplicitIPPVariables
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-FileStopping
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-LineContinuation
It removes all occurrences of the pattern
\<whitespace>*<newline><whitespace>*
Use this to let one or more lines to be concatenated.
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