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ycp.3pm

NAME

ycp - a Perl module for parsing and writing the YaST2 Communication Protocol

SYNOPSIS

"($symbol, @config) = ycp::ParseTerm ('MyAgentConfig ("/etc/file", false, true, $["a":1, "b":2])');"

"($command, $path, $arg) = ycp::ParseCommand ('Write (.magic.path, "abacadabra")');"

"ycp::Return (["arbitrarily", "complex", "data"]);"

DATA

PerlYCPValue

PerlYCPValue is a convention for storing a YCP value in a Perl variable. ``ParseYcp'' parses YCP string representation into PerlYCPValues.

A PerlYCPValue cannot represent a term but only a term is allowed to initialize an agent in a .scr file. Therefore ``ParseTerm'' is provided.

string, integer, boolean

Stored as a scalar.

list

Stored as a reference to a list of PerlYCPValues.

map

Stored as a reference to a map of PerlYCPValues.

path

Stored as a reference to a string (starting with a ``.'' as expected).

nil (void)

Stored as an undef.

PARSING

ParseCommand

ParseComand $line

"($command, $path, $arg) = ParseCommand ('Write (.moria.gate, "mellon")');"

Parse a SCR command of the form Command (.some.path, optional_argument)

Returns a three element list (``Command'', ``.some.path'', $argument) where the argument is a ``PerlYCPValue'' and will be undef if it was not specified. Note that the path is converted to a string.

If there was a parse error, the command or path will be the empty string.

ParseTerm

ParseTerm $line

"($symbol, @config) = ParseTerm ('MyAgentConfig ("/etc/file", false, true, $["a":1, "b":2])');"

Parse a YCP term. Note that there can be no other term inside.

Returns a list whose first element is the term symbol as a string (or "" in case of an error) and the remaining elements are the term arguments (``PerlYCPValue'')

PathComponents

PathComponents $path_ref

 ($cmd, $path) = ParseCommand ('`Read (.foo."%gconf.d"."gernel")'

 @c = PathComponents (\$path);

 if ($c[0] eq '%gconf.d' && $c[1] eq "gernel") {...}

Converts a path (a string reference, ``PerlYCPValue'') to a list of its components. It deals with the nontrivial parts of path syntax. On error it returns undef.

 .                      -> ()

 .foo.bar               -> ('foo', 'bar')

 ."foo"                 -> ('foo')

 ."double\"quote"       -> ('double"quote')

 ."a.dot"               -> ('a.dot')

WRITING

Return

"Return (["arbitrarily", "complex", "data"]);"

Sends a ``PerlYCPValue'' to the partner YCP component.

If there's just one argment, scalars are interpreted this way: ``true'' or ``false'' are sent as booleans, integers or strings of digits are sent as integers, otherwise as strings. If a second argument exists and is true, all scalars are written as strings. If a second argument exists and is false, all scalars are written as byteblocks.

To send a list, call Return(\@list), not Return(@list). Similarly for a map. You can use references to anonymous lists [] and hashes {}.

The difference from ``ycpReturn'' is that Return can return scalars directly, strings are properly escaped if needeed and paths can be returned.

LOGGING

If you are running in the main yast process and thus can afford to import YaST::YCP, it is better to use its logging functions because they use log.conf and logging just works. In such case, you should not need to use ycp.pm at all. Instead, "use YaST::YCP (":LOGGING")".

The log output can now be redirected, which will be useful for test suites. If the first command-line option is ``-l'', the second argument is taken as the log file. A hyphen ``-'' designates standard output.

Otherwise, /var/log/YaST2/y2log and $HOME/.y2log are tried, in that order.

y2debug

y2debug, y2milestone, y2warning, y2error, y2security, y2internal

Logs debug messages to /var/log/YaST2/y2log or $HOME/.y2log

Note a semantic change in y2debug: now the environment variable Y2DEBUG is honored so y2debug will not produce output unless this variable is set. This is for compatibility with the logging system in libycp.

ycpDoVerboseLog

Enables output of y2verbose which is used in some of the obsolete functions.

OBSOLETE FUNCTIONS

ycpArgIsMap

Obsolete. Use (ref($arg) eq ``HASH'') instead.

ycpArgIsList

Obsolete. Use (ref($arg) eq ``ARRAY'') instead.

ycpArgIsInteger

Not really obsolete because the new parser simply treats integers, booleans and strings as scalars. But who cares, nobody used this anyway.

ycpArgIsString

Not really obsolete because the new parser simply treats integers, booleans and strings as scalars. But who cares, nobody used this anyway.

ycpArgIsNil

Obsolete. Use (ref($arg) eq ``SCALAR'' && $$arg eq ``nil'') instead.

ycpArgIsNone

Obsolete. Use (defined ($arg)) instead.

ycpCommandIsDir

Obsolete. Use ($command eq ``Dir'')

ycpCommandIsRead

Obsolete. Use ($command eq ``Read'')

ycpCommandIsWrite

Obsolete. Use ($command eq ``Write'')

ycpCommandIsExecute

Obsolete. Use ($command eq ``Execute'')

ycpCommandIsResult

Obsolete. Use ($command eq ``result''), note the lowercase 'r'.

ycpGetCommand

Obsolete. Use the return value of ``ParseCommand''.

ycpGetPath

Obsolete. Use the return value of ``ParseCommand''.

ycpGetArgType

Obsolete. Use ref on a return value of ``ParseCommand''.

Umm, string/integer/boolean?

ycpGetArgMap

Obsolete. See ``PerlYCPValue''.

ycpGetArgList

Obsolete. See ``PerlYCPValue''.

ycpGetArgString

Obsolete. See ``PerlYCPValue''.

ycpGetArgInteger

Obsolete. See PerlYCPValue.

Umm, string/integer/boolean?

ycpReturnSkalarAsInt

Obsolete. Use ``Return''.

ycpReturnSkalarAsBoolean

Obsolete. Use ``Return''(``true'' or ``false'')

ycpReturnSkalarAsString

Obsolete. Works only on strings not containing backslashes and quotes that would need escaping.

Use ``Return''.

ycpReturnArrayAsList

Obsolete. Works only on list of strings not containing backslashes and quotes that would need escaping.

Use ``Return''.

ycpReturnHashAsMap

Obsolete. Works only on maps of strings not containing backslashes and quotes that would need escaping.

Use ``Return''.

ycpReturn

Obsolete. Use ``Return''

ycpInit

Obsolete. Use ``ParseCommand''.