Dpkg::Substvars(3)

NAME
Dpkg::Substvars - handle variable substitution in strings

DESCRIPTION
It provides some an object which is able to substitute variables in strings.

METHODS

$s = Dpkg::Substvars->new($file)
    Create a new object that can do substitutions. By default it contains generic substitutions like ${Newline}, ${Space}, ${Tab}, ${dpkg:Version} and ${dpkg:Upstream-Version}.

    Additional substitutions will be read from the $file passed as parameter.

    It keeps track of which substitutions were actually used (only counting substvars(), not get()), and warns about unused substvars when asked to. The substitutions that are always present are not included in these warnings.

$s->set($key, $value)
    Add/replace a substitution.

$s->set_as_used($key, $value)
    Add/replace a substitution and mark it as used (no warnings will be produced even if unused).

$s->set_as_auto($key, $value)
    Add/replace a substitution and mark it as used and automatic (no warnings will be produced even if unused).

$s->get($key)
    Get the value of a given substitution.

$s->delete($key)
    Remove a given substitution.

$s->mark_as_used($key)
    Prevents warnings about a unused substitution, for example if it is provided by default.

$s->no_warn($key)
    Obsolete function, use mark_as_used() instead.

$s->load($file)
    Add new substitutions read from $file.

$s->parse($fh, $desc)
    Add new substitutions read from the filehandle. $desc is used to identify the filehandle in error messages.

    Returns the number of substitutions that have been parsed with success.

$s->set_version_substvars($sourceversion, $binaryversion)
    Defines ${binary:Version}, ${source:Version} and ${source:Upstream-Version} based on the given version strings.

    These will never be warned about when unused.

$s->set_arch_substvars()
    Defines architecture variables: ${Arch}.

    This will never be warned about when unused.

$s->set_field_substvars($ctrl, $prefix)
    Defines field variables from a Dpkg::Control object, with each variable having the form "${$prefix:$field}".

    They will never be warned about when unused.

$newstring = $s->substvars($string)
    Substitutes variables in $string and return the result in $newstring.

$s->warn_about_unused()
    Issues warning about any variables that were set, but not used.

$s->set_msg_prefix($prefix)
    Define a prefix displayed before all warnings/error messages output by the module.

$s->filter(remove => $rmfunc)
$s->filter(keep => $keepfun)
    Filter the substitution variables, either removing or keeping all those that return true when $rmfunc->($key) or $keepfunc->($key) is called.

$s->save($file)
    Store all substitutions variables except the automatic ones in the indicated file.

"$s"
    Return a string representation of all substitutions variables except the automatic ones.

$str = $s->output($fh)
    Print all substitutions variables except the automatic ones in the filehandle and return the content written.

CHANGES

  Version 1.05 (dpkg 1.18.11)
Obsolete substvar: Emit an error on Source-Version substvar usage.

New return: $s->parse() now returns the number of parsed substvars.

New method: $s->set_field_substvars().

  Version 1.04 (dpkg 1.18.0)
New method: $s->filter().

  Version 1.03 (dpkg 1.17.11)
New method: $s->set_as_auto().

  Version 1.02 (dpkg 1.16.5)
New argument: Accept a $binaryversion in $s->set_version_substvars(), passing a single argument is still supported.

New method: $s->mark_as_used().

Deprecated method: $s->no_warn(), use $s->mark_as_used() instead.

  Version 1.01 (dpkg 1.16.4)
New method: $s->set_as_used().

  Version 1.00 (dpkg 1.15.6)
Mark the module as public.