Dpkg::Substvars(3perl)

NAME
Dpkg::Substvars - handle variable substitution in strings

DESCRIPTION
It provides a class 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), and will not be emitted into the substvars file.

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

$s->set_as_required($key, $value)
    Add/replace a substitution and mark it as required (an error will be produced if it is not used).

$s->set_as_implicit($key, $value)
    Add/replace a substitution and mark it as implicit, where a field will be automatically instantiated if not already present.

$s->get($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.

$s->parse($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.

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

$s->set_version_substvars($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_vendor_substvars()
    Defines vendor variables: ${vendor:Name} and ${vendor:Id}.

    These will never be warned about when unused.

$s->set_desc_substvars()
    Defines source description variables: ${source:Synopsis} and ${source:Extended-Description}.

    These 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.

@substvars = $s->get_implicit_substvars()
    Returns a list of implicit substitution variables to be used by the calling program, by appending them to specific text.

$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(%opts)
    Filter the substitution variables.

    Options:

    remove
        A function returning a boolean, used to decide whether to remove a substitution variable, executed as $opts{remove}->($var).

    keep
        A function returning a boolean, used to decide whether to keep the substitution variable, executed as $opts{keep}->($var).

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

$str = $s->output([$fh])
    Return all substitutions variables except the automatic ones. If $fh is passed print them into the filehandle.

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

CHANGES

  Version 2.04 (dpkg 1.23.0)
New feature: Add support for implicit substitution variables.

New method: $s->set_as_implicit(), $s->get_implicit_substvars().

  Version 2.03 (dpkg 1.22.15)
New methods: $s->set_as_optional(), $s->set_as_required().

  Version 2.02 (dpkg 1.22.7)
New feature: Add support for required substitution variables.

  Version 2.01 (dpkg 1.21.8)
New feature: Add support for optional substitution variables.

  Version 2.00 (dpkg 1.20.0)
Remove method: $s->no_warn().

New method: $s->set_vendor_substvars().

  Version 1.06 (dpkg 1.19.0)
New method: $s->set_desc_substvars().

  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.