Changes since Pike 7.2.30

This document outlines the changes between Pike 7.2.30 and 7.4.10.

New/improved functionality

• New Hilfe
  The interactive pike environment you get when running pike without giving a program name, has been thoroughly rewritten. Most notably it now supports more of the common pike constructs, and is more extendable and configurable. Start it and type help for more info.
• Autodoc
  The major parts of Pike now have some sort of documentation on class and function level thanks to the AutoDoc system which has been deployed during the last year. Manual dumps are published on http://pike.ida.liu.se/docs/reference/. Note that the manuals and the manual system are still work in progress.
• pike -x
  When starting pike with the -x parameter, the pike process will run the named script in Tools.Standalone, giving the rest of the arguments as command-line switches. This is a convenient way of running rsif (replace string in file) and pv (the image viewer you may be familiar with from Tools.PV).
• pike -e scope
  When running command line one-liners with pike -e you can now access the number of arguments, the actual arguments and the environment variables through the variables argc, argv and env.
• unbug
  Embryo of a Pike debugger. Neither stable nor finished.
• Unicode 3.2.0
  All tables have been updated to Unicode 3.2.0. This applies both to the Unicode module as well as to Pike-global functionality such as upper_case/lower_case. unicode_to_string() now also has support for surrogate and byteorder mark handling.
• Extended random()
  random() now works on floats, arrays, multisets, mappings and objects in addition to integers.
• delay()/sleep()
  sleep() no longer busywaits, which it previously did for small values. The old behavior is available from the delay() function. (This has change been made in later Pike 7.2 releases too.)
• search(string, int) / has_value(string, int)
  Both of these methods now handle looking for both strings and integers (the unicode number for a single character). Examples: search("hi, ho!", '!'), has_value("Nope.", ' ')
• Extended Charset module
  The character set module now has support for the character sets Shift_JIS, UTF-7.5, EUC, Big5, CP950, UTF-16, UTF-16BE, UTF-16LE. It is now also easier to get the right charset codec since the names are normalized internally.
• sprintf("%O", foo) is more descriptive
  If foo is a program or an object then Pike will try to find the resolved name instead of returning just "program" or "object". However, if an object contains an _sprintf function it will still be called in this case.
• basetype(foo)
  Returns a string with the basic type of foo as opposed to _typeof(foo) which returns the actual type. Also available as sprintf("%t", foo). Note that it is affected by _sprintf() in objects.
• getenv()/putenv()
  The environment variable functions getenv and putenv are both now case-insensitive on Microsoft Windows systems. This should make your programs more portable.
• Return value from catch blocks
  The return value from catch blocks that exit normally has been changed from a normal zero (i.e. zero_type 0) to UNDEFINED (i.e. zero_type 1).
• SSL
  The Pike SSL implementation now supports TLS 1.0. Also the LDAP protocol and the methods in Protocols.HTTP.Query now support secure transport over SSL/TLS.
• Better predefine handling
  It is now possible to change the predefined cpp() macros without forking a new Pike process. Use the master functions add_predefine() and remove_predefine() to add and remove defines.

Language additions

• foreach(X; Y; Z)
  The foreach statement has been extended to allow iterations over mappings, multisets and any object that implements the iterator interface (see below). To make it possible to use this conveniently, a new syntax has been added to get both the index and the value in each iteration:
  

  foreach (something; index-expr; value-expr) ...

  This iterates over something, assigning in turn each index to index-expr and each value to value-expr. The index and value expressions can be declarations or lvalues, and they can also be left out if the index and/or value part isn't interesting.
  
  Note that it depends on the data type whether the iteration order is well defined or not; arrays and multisets are iterated over starting with the first element while mappings are visited in some arbitrary order (each element is still visited only once, though).
• Iterators
  As noted above, an iterator interface has been added that is now used in various places to iterate over different data structures. Not only the built-in data types are supported, but actually any object that fulfills the interface for iterators:
  
  When iterating over an object o, o->_get_iterator() is called to get an iterator object. An iterator object should at least have two functions, index() and value(), to get the index and value at the current position, a function `+=(int steps) to advance the current position the specified number of steps, and a `!() that returns zero if the end of the data set hasn't been reached yet.
  
  Also, if the object lacks a _get_iterator function, it will be assumed to be an iterator itself. This makes it possible to pass an iterator explicitly to e.g. the foreach statement.
  
  The built-in data types also have iterator classes with this interface. They are found as Array.Iterator, Mapping.Iterator, etc and can be used to iterate over these data types in some custom fashion. This is especially useful for mappings and multisets, which cannot be iterated over directly in any other way. For example, to get some arbitrary index in a mapping m:
  

  mixed any_index = Mapping.Iterator(m)->index();

  Other available iterators include the file line iterator, available from Stdio.File through the method line_iterator(), and the split iterator that iterates over the fragments of a split string, available as String.SplitIterator.
• Automap
  To perform per-element operations on arrays, there is now a convenience syntax for map(), that can make code more readable in some situations. Summing up two arrays element by element using automap looks like this:
  

  a[*] + b[*]; // the result has as many elements as the shortest array.

  Multiplying all elements in a by a constant:
  

  a[*] * 4711;

  Make an array of what sprintf("%O", a[n]) returns for all elements in a:
  

  sprintf("%O", a[*]);

• Implicit lambda
  A convenient way to embed code that needs pre- and/or post- initialization. If a statement starts with a function call followed directly by a brace block, then the block is transformed to a lambda function which is passed as the last argument to the function being called.
  
  The following example embeds OpenGL calls that modifies the matrix in an implicit lambda that will save the matrix before execution and restore it afterwards:
  

         void PushPop( function f )
         {
           glPushMatrix();
           mixed err = catch(f());
           glPopMatrix();
           if (err) throw(err);
         }
  
         void do_something()
         {
           PushPop() {
             glTranslate( (1.0-0.08)/2, 0.0, 0.0 );
             draw_stuff();
           };
         }

  
  Note that although useful, this feature has important disadvantages and will probably be obsoleted by a better alternative in the future. The problem is that the inner brace block becomes a completely separate function instead of remaining a block. The difference (apart from being slower) is shown by this example:

         void do_something()
         {
           PushPop() {
             if (glError()) return;
             glTranslate( (1.0-0.08)/2, 0.0, 0.0 );
             draw_stuff();
           };
           draw_more_stuff();
         }

  
  Since the inner block is a separate function, the return statement doesn't exit do_something() as one might expect, causing draw_more_stuff() to be called even when there's a GL error. Another effect is that break and continue can't be associated with statements outside the implicit lambda block.
  
  Another method that overcomes these problems will likely be implemented. The problem is that it can give compatibility problems to change old code that uses implicit lambdas to that one, since e.g. return will work differently without giving any sort of error.
• Access to hidden variables in surrounding scopes
  Include the names of the surrounding classes themselves in the lookup for Foo::, to make it possible to address hidden variables in the scopes of surrounding classes, e.g:
  

         class Foo {
           int i;
           void create (int i) {Foo::i = i;}
         }

• global::
  Added new keyword global to be able to access identifiers on the top level of the compilation unit using global::foo.
• global.
  All top level modules (and other identifiers in that scope) can now be accessed with a "global." prefix. This is useful in cases where local identifiers overshadow the top level, for instance in the Image module, where the Image.Image class can occasionally block your view.
• this
  Added a magic identifier "this" that can be used instead of this_object(). Like this_program, it only exists when there's no other identifier with that name. The primary reason for adding this magic identifier is to make it possible to address the object of a surrounding class with Foo::this.
• The program type can be specialized
  It's possible to specialize a program variable by adding a program identifier, much like an object variable can be specialized. E.g:
  

  program(Stdio.File) fd_prog = Stdio.File;

• ::_indices(), ::_values().
  There are now two "magic" functions ::_indices() and ::_values() that can be used by an object to list all identifiers and their values in itself. They are primarily intended for use when the _indices() and _values() lfuns have been defined, to get the default implementations. This is to complement the "magic" ::`->() and ::`->=() functions that exist in earlier releases.
• UNDEFINED
  To generate a 0 (zero) with a zero_type(var) == 1, you previously had to use constructs like ([])[0]. This is now available as the globally available symbol UNDEFINED.
• _m_delete
  A class can now define a function mixed _m_delete(mixed index) to make the objects work like mappings with respect to m_delete(). (This feature has been added to later 7.2 releases too.)
• Constant objects
  An object can now be constant, allowing for better performance and better dumping. Used for example with Gmp.Bignum, Math.Matrix and Image.Color.
• Increased weakness granularity
  Instead of just declaring a mapping as weak, to avoid its references to be counted during garbage collection, it is now possible to declare only the indices or only the values as weak. To this end set_weak_flag() now takes a second argument to define the kind of weakness its first argument should have; Pike.WEAK, Pike.WEAK_VALUES or Pike.WEAK_INDICES. No second argument implies Pike.WEAK, which is both Pike.WEAK_VALUES and Pike.WEAK_INDICES.

New modules / classes / methods

• ADT.History
  ADT implementation of a "leaking stack". Hilfe example:
  

        > object h=ADT.History(3);
        > for(int i=17; i<22; i++) h->push(i);
        Ok.
        > h->get_first_entry_num();
        (1) Result: 3
        > h[3];
        (2) Result: 19
  

• ADT.Relation.Binary
  Handles binary relations. Hilfe example:
  

        > object r=ADT.Relation.Binary("test");
        > r->add(1,2)->add(2,3)->add(3,5)->add(1,4)->add(4,5);
        (1) Result: ADT.Relation.Binary("test")
        > r->find_shortest_path(1,5);
        (2) Result: ({ /* 3 elements */
                        1,
                        4,
                        5
                    })
        > r->remove(1,4);
        (3) Result: ADT.Relation.Binary("test")
        > r->add(5,1);
        (4) Result: ADT.Relation.Binary("test")
        > r->find_shortest_path(1,5);
        (5) Result: ({ /* 4 elements */
                        1,
                        2,
                        3,
                        5
                    })
  

• Array
  The array module has quite a few new and handy methods. common_prefix() finds the longest common prefix of the arrays in an array of arrays. count() counts the number of occurences of an element in an array. greedy_diff() is a greedy version of the diff() algorithm. oid_sort_func() is an ordering function for sort_array() that sorts SNMP OID values correctly. arrayify() is a simple helper function that makes arrays out of non-arrays. uniq2(), unlike uniq(), works as the UNIX uniq command. Finally sum() sums the elements of an array using +.
• Audio.Codec and Audio.Format
  Contain decoders/encoders and format parsers for audio using Ffmpeg library. Currently WAV and MP3. Note: The API remains marked "unstable".
• Crypto.md4
  Hash used for NT Lanmanager passwords.
• Crypto.crypt_md5
  Convenience function to produce crypted $1$ style crypted passwords (commonly called MD5 passwords).
• Debug
  Many top level debug functions have been moved into the Debug module to keep the amount of top level functions less intimidating to new users and to make the debug functions easier to find.
• Debug.Tracer
  A class that when instantiated will turn on trace, and when destroyed will turn it off again.
• Debug.Subject
  This is a probe subject which you can send in somewhere to get probed (not to be confused with a probe object, which does some active probing). All calls to LFUNs will be printed to stderr.
• DVB
  Access to DVB (digital sat) resources. Controls tuner, MP2 audio and video decoders. Allows extract multiple channels at once. Note: Only old 0.9.4 DVB API is supported.
• Gmp.mpq and Gmp.mpf
  Support for GMP multi-precision fractions and multi-precision floats. Hilfe example:
  

        > Gmp.mpq(5,3);
        (1) Result: 5/3
        > _->invert();
        (2) Result: 3/5
        > (float)_;
        (3) Result: 0.600000
        > Gmp.mpq(5,3)+Gmp.mpq(1,2);
        (4) Result: 13/6
  

• Gz.File
  Pike can now compress and decompress the Gzip file format. This is still a bit experimental but the basic functions should work just fine.
• Image.filled_circle(), Image.filled_circle_layer()\
  Return an Image/Layer object with a filled circle.
• Image.Dims
  Can extract the dimensions of an image with a minimal amount of data loading. Currently handles JPEG, GIF and PNG images. Hilfe example:
  

        > Image.Dims.get(Stdio.File("test.gif"));
        (1) Result: ({ /* 2 elements */
                        1412,
                        1120
                    })
  

• Image.DWG
  Decodes the thumbnail images embedded in AutoCAD drawings.
• Image.Fonts
  High level API for font handling. Should be used instead of accessing the FreeType, TTF and Image.Font modules directly.
• Image.Image
  Added two new methods, blur() and grey_blur(), which are hard coded, MMX optimized versions of these common matrix operations.
• Image.JPEG
  Support for lossless transforms, such as rotating and rescaling the image, and handling of metadata.
• Image.PVR
  VQ compression/decompression added.
• Image.SVG
  Support for Structured Vector Graphics through the Gnome SVG library. Requires Gnome 2.
• Local
  All Pike modules and classes found in the directory hierarchies /usr/local/pike_modules, /opt/pike_modules, /opt/share/pike_modules, /usr/local/share/pike_modules, $HOME/pike_modules and $PIKE_LOCAL_PATH (a :-separated list of directories) are available with the prefix "Local.". Local.add_path() and Local.remove_path() respectively adds and removes entries from the list of paths to inspect when resolving Local.* symbols.
• Locale.Language
  Support for time formatting, counting and more for various languages. Currently supported languages are Catalan, Croatian, Czech, Dutch, English, Finnish, French, German, Hungarian, Italian, Japanese, Maori, Norwegian, Polish, Portuguese, Russian, Serbian, Slovenian, Spanish and Swedish.
• Math.Matrix
  Methods sum(), max(), min(), convolve() and dot_product() added.
• Math.Transforms
  Glue for supporting FFT and iFFT via libfftw and librfftw.
• Math
  Added the IEEE float constants inf and nan.
• MIME
  Added method ext_to_media_type which returns the MIME media type for a given extension. The module currently knows of 469 different file extensions. The MIME.Message class has also been extended with a "guess" mode that parses input more forgivingly.
• Oracle
  The Oracle database glue now supports CLOBs and BLOBs.
• Parser
  Added a few methods: get_xml_parser(), which returns a Parser.HTML set up to parse XML, parse_html_entities() and decode_numeric_xml_entity(), which decode XML and HTML entities respectively. Examples:
  

        Parser.decode_numeric_xml_entity("#x7a") => "z"
        Parser.parse_html_entities(">")       => ">"

• Parser.Python
  Splits Python source code into text tokens.
• Parser.RCS
  Extracts data from RCS or CVS repositories.
• Parser.XML.NSTree
  This is an extended version of Parser.XML.Tree that can handle namespaces according to the W3C namespace specification.
• Pike.Backend and Pike.DefaultBackend
  It is now possible to start several backends, and to start the default backend without having to return negative from main(). Example:
  

        while(things_to_do) {
          mixed err;
          if (err = catch{
            while(things_to_do) {
              Pike.DefaultBackend(3600.0);
            } }) {
            master()->handle_error(err);
          }
        }
  

• Pike.Security
  If Pike has been compiled with security support, the security related stuff can now be found in this module.
• Protocols.XMLRPC
  Implements most features of the XML-RPC standard.
• Protocols.HTTP
  All methods in Protocols.HTTP that take a header mapping can now handle array values (signifying multiple headers of that type).
• Protocols.HTTP.Server
  A simple HTTP Server.
• Protocols.SNMP
  Extended to support both SNMP v1 and v2c. A simple SNMP agent with support for Get requests has also been added.
• Protocols.X
  Support for the X11 XTEST extension has been added.
• SDL
  Wrapper for a subset of Simple DirectMedia Layer functionality. Useful for writing games, movie players and other graphically intensive applications.
• Shuffler
  The Shuffler module is what in aspect oriented and component based programming is called a connector. This connector provides an easy way to connect a data source to a file socket and transfer data between them until the data source runs dry, at which point the connection will be closed. The transfer can be throttled according to arbitrarily complex rules. All this with a minimum of attention. Currently the shuffler can use ordinary 8-bit wide strings, System.Memory objects, normal files, network sockets, named pipes, stdin and pike objects adhering to the Stdio.File API as connector sources.
• Standards.CIFF
  Experimental module to read Canon Camera Image File Format data.
• Standards.EXIF
  Support for the EXchangeable Image file Format for digital still cameras version 2.2. Support for maker notes for cameras from Nikon, Canon, Fuji Film, Olympus, Sanyo and Casio.
• Standards.FIPS10_4
  "The Federal Information Processing Standard for Countries, Dependencies, Areas of Special Sovereignty, and their Principal Administrative Divisions" = american standard for countries and country division codes.
• Standards.ID3
  ID3 tag decoder/encoder. Supports versions: 1.0, 1.1, 2.2-2.4. Frequently used in MP3 files for encapsulating metadata.
• Standards.ISO639_2
  This module has been updated with the map_to_639_1() method to convert from ISO 639-2/T to ISO 639-1. With the new methods convert_b_to_t() and convert_t_to_b() it is possible to convert between ISO 639-2/T and ISO 639-2/B.
• Standards.RDF
  Represents an RDF domain and allows you to perform searches in its relations. Currently only serializes/deserializes to N-triple format.
• Stdio
  Two higher order filesystem methods has been added to Stdio, simplify_path() and file_equal(). The first returns a canonic representation of its argument without "/./", "/../", "//" and similar path segments. The second is a speedy way to compare if two files have identical content.
  
  Finally the get_all_active_fd() function has been moved from spider to Stdio in our strive to deprecate the spider module.
• Stdio.FakeFile
  Wraps a string in an object that exports a Stdio.File interface.
• Stdio.File
  This object has received a few additions; With the sync() method the file object can be synchronized with the disk. It is now possible to open UNIX domain sockets with the connect_unix() method. Finally grantpt() can allocate a VTY on systems with /dev/ptmx support. Minimal example:
  

        fd = Stdio.File("/dev/ptmx", "rw" );
        Stdio.File fd2 = Stdio.File( fd->grantpt(), "rw" );
        Process.create_process( ({ "/bin/bash" }), ([
          "stdin":fd2,  "stdout":fd2, "stderr":fd2, "setsid":fd2,
        ]) );
  

• Stdio.FILE.set_charset()
  It is possible to set the charset of a FILE object to get streaming and transparent charset conversion of data to and from the object.
• String
  Added a few new methods: int2char(), int2hex(), int2roman(), int2size(), which convert integers into different string representations, and expand_tabs(), which converts tabs to spaces. Examples:
  

        String.int2char(42)   => "*"
        String.int2hex(42)    => "2a"
        String.int2roman(42)  => "XLII"
        String.int2size(4200) => "4.1 kb"
  

  
  A soundex() method has also been added, which normalizes names according to the soundex algorithm. The algorithm in itself is not very useful, but some databases support it.
• String.Buffer
  A buffer used for building strings very fast.
• String.Elite
  Contains methods that transfer ordinary readable text into leet-speak. A fairly good argument could be laid out for putting this in Crypto as a one way cipher...
• String.HTML
  Contains methods that help in generating HTML.
• System
  The following methods have been added: normalize_path(), which works on NT style paths. get_netinfo_property(), which queries a NetInfo server on MacOS X. gettimeofday(), which uses the system gettimeofday to retrieve the time. nanosleep() and usleep(), which calls the system nanosleep and usleep functions.
• System.Time
  Used to get the current time with sub-second precision.
• System.Timer
  Measures the time between two calls.
• System.Memory
  Handles read/write from mmap'ed or allocated memory.
• Tools.PV
  Convenience tool that sets up a canvas with GTK, presents a picture on it and delivers a number of image inspection and manipulation options. This is a great tool for image work in Hilfe.
  

        > object i=Image.Image(32,32)->random();
        > Tools.PV(i);
  

  
  The Pike Viewer tool is also accessible via "pike -x pv".
• Web.Crawler
  A generic asynchronus web crawler that supports the /robots.txt standard.

Optimizations

Several general optimizations and tuning of algorithms and implementations in Pike have been done since Pike 7.2. Much of the work has been to get a general speed up in the compiler and interpreter, but some targeted work has also been done to make common code constructions execute faster. A comparison between Pike 7.2.440 and Pike 7.4.1 done on an IA32 machine running Red Hat Linux:

              Pike 7.2.440  Pike 7.4.1
   ackermann:         5.98        4.96
        ary3:        10.60        6.53
        fibo:         8.64        6.58
        hash:         5.93        5.13
    heapsort:        10.88        6.65
       lists:         7.12        6.20
    methcall:         8.23        8.45
  nestedloop:        52.75       11.24
     objinst:         6.39        5.27
      random:         7.47        4.64
       sieve:        10.63        6.72
      strcat:         3.22        2.25

These tests use standard tests straight from The Great Computer Language Shootout. If the lists test and the strcat tests are slightly modified to use arrays in the first case and normal strings in the second case, Pike will yield an even better result.

• Machine code generation
  On systems with IA32, SPARC or PPC32 processors Pike can use native machine code as byte code. This byte code can then be executed directly outside the virtual machine and give a ~30% performance boost compared to the old byte code.
• Improved module dumping
  More modules than ever can now be dumped successfully into object files, making the Pike startup time less than ever.
• Deferred backtraces
  Most of the information in backtraces is now calculated on demand for the backtrace information and not when the backtrace is generated. This improves the performance of catched errors.

Compatibility changes

The following changes are known to break compatibility. The old behavior is emulated in the compatibility layer that is activated by adding the preprocessor directive "#pike 7.2" to your program or by giving the argument "-V7.2" to the pike executable.

• "global" has become a reserved keyword.
  
• Changed lookup rule for ::
  Previously the identifier in front of :: was only looked up among the preceding inherits. Now the lookup additionally includes the names of the surrounding classes. The inherits inside a class still take precedence over the name of the class, though.
• Using local:: on variables is an error
  Previously the construct local::foo could be used to access the identifier "foo" in the class scope if it had been overridden by an argument or function variable. That is however only a side-effect of the real use for local::, namely to bind the identifier statically at that point only, to avoid getting an overridden version. In the case of variables this leads to questionable semantics, which is the reason it's been made an error in this version. Pike 7.2 didn't implement it correctly; there local:: on variables had only the effect to access the class scope. Now a proper way to access shadowed identifiers has been added, so all such uses of local:: should be replaced with this_program::.
• Identifier lookup
  The search algorithm for finding identifiers from inherited classes has been changed to look for the most recent definition in the most recent inherit. In Pike 7.2 and prior, it looked up the last definition regardless of inherit depth, unless there was a definition in the current program. (This actually changed more than once during 7.3 - between 7.3.23 and 7.3.32, it looked up the most recent definition with the least inherit depth.) This example shows what the lookup strategies would find:
  

      class A {
        int foo() {}
      }
  
      class B {
        int foo() {}
        inherit A;
      }
  
      class C {
        inherit B;
      }
  
      class D {
        inherit B;
        inherit C;
      }

  
  Lookup of identifier "foo" in D():
  

      D-+-B-+-foo          (Pike 7.3.23 --- Pike 7.3.32)
        |   |
        |   +-A---foo
        |
        +-C---B-+-foo      Pike 7.3.33 --- (present day)
                |
                +-A---foo              --- Pike 7.3.22

  
  Lookup of identifier "foo" in C():
  

      C---B-+-foo          Pike 7.3.23 --- (present day)
            |
            +-A---foo                  --- Pike 7.3.22

  
  Lookup of identifier "foo" in B():
  

      B-+-foo              All versions of Pike
        |
        +-A---foo

• Individual parent object pointers are now only kept when needed
  In Pike 7.0 and 7.2 all objects kept a pointer to the surrounding object. This led to an excess of circular datastructures, which ment that the garbage collector had to kick in more often. In Pike 7.4 parent object pointers are only kept if the object actually refers to identifiers in the parent. This change however affects the behaviour of object_program() and function_object(). Examples:
  

        >  class A {
        >>   int q;
        >>   class B {
        >>     int inq(){return q++;}
        >>   }
        >>   class C {
        >>     int q;
        >>     int inq(){return q++;}
        >>   }
        >> }
        > indices(A);
        (1) Result: ({ /* 1 element */
                        "C"
                    })
  

  
  C doesn't refer to variables in surrounding classes, and is thus constant.
  

        > object a = A();
        > object b = a->B();
        > object c = a->C();
        > function_object(object_program(b));
        (2) Result: HilfeInput()->A()
        > function_object(object_program(c));
        (3) Result: HilfeInput()->A
        > function_object(object_program(b)) == a;
        (4) Result: 1
        > function_object(object_program(c)) == A;
        (5) Result: 1
  

  
  The b object has an intact parent object pointer, while the c object only has a parent program pointer.
• __pragma_save_parent__
  To change the default parent object pointer behaviour to the Pike 7.0/7.2 default it is possible to add_constant("__pragma_save_parent__", 1).
• #pragma save_parent
  To get the Pike 7.0/7.2 parent object pointer behaviour for a single compilation unit use the #pragma save_parent.
• #pragma dont_save_parent
  To restore the default Pike 7.4 parent object pointer behaviour from #pragma save_parent or __pragma_save_parent__ for a single compilation unit use the #pragma dont_save_parent.
• Thread.Condition()->wait()
  This function takes a mutex lock to unlock while it waits on the condition. That argument was previously optional, but not any more. The reason is that any code that leaves it out will always contain a race; it doesn't work to e.g. rely on the internal interpreter lock in this case.
• Protocols.LDAP.client()
  The return code from all methods has been changed to follow Pike's logic better. 0 is now a failure. The old behavior is emulated in a compatibility layer.
• dirname()
  Now correctly returns a directory instead of just stripping the part after the nearest directory separator.
• default_yp_domain()
  The EFUN default_yp_domain() is now only available as Yp.default_domain().
• clone()/new()
  The functions clone() and new() have been removed. Instead of doing clone(x) or new(x), now do x() if x is a program and ((program)x)() if x is a string.
• LR
  The LR module has been moved to Parser.LR and the API has been changed slightly to conform to current API practices, e.g. regarding casing of symbols.
• wmml documentation removed
  Use the documentation in the refdoc directory instead.
• .build_lobotomize_crypto removed
  Use the Makefile target lobotomize_crypto to lobotomize Pike. Should preferably be executed in an unused tree straight from CVS.

Compatibility changes without backward compatibility

The following changes were considered bugfixes and have no backwards compatibility layer.

• enum and typedef have implicit local binding
  Symbols defined by enum and typedef now always have static binding. In 7.2 they could sometimes be dynamically bound.
• Image.Layer modes modified
  Alpha channel handling for modes add, subtract, multiply, divide, modulo, invsubtract, invdivide, invmodulo, difference, max, min, bitwise_and, bitwise_or, bitwise_xor, screen and overlay modified so that the source layer alpha channel copied to the destination layer alpha channel rather then mixed with the current layer alpha channel:
  

      aD=aS

  
  rather then the behavior before:
  

      aD=(aL+(1-aL)*aS)

  (which is the behavior of the 'normal' mode.)

C level/development changes

• Some global symbols have been renamed to avoid name clashes
  

      sp           -> Pike_sp
      fp           -> Pike_fp
      fatal        -> Pike_fatal
      empty_string -> empty_pike_string

• C-module symbols not available from other modules
  To avoid clashes between modules the symbols of dynamically loaded modules are now no longer available to each other. Modules that used this relied on a predefined load order of dynamic modules to work, so any such module could have failed to load unpredictedly.
• Pike valgrinded
  Pike has been the subject to some Valgrind scrutiny. Some specific Valgrind enhancements have been made to Pike to improve markup of forbidden memory areas. While all Valgrind issues are not yet resolved, partially due to Valgrind breakage, our confidence in the quality of Pike has been reassured.
• Some gdb helpers.
  If Pike is compiled with --with-rtldebug there's a function gdb_backtraces that can be called from gdb (using the "call" command) to print all Pike thread backtraces. It doesn't do any destructive changes of the memory structures (besides the stack) and it tries to be tolerant wrt inconsistencies.
  
  --with-rtldebug also makes a dummy function _gdb_breakpoint available in Pike. It doesn't do anything and is intended to be used by setting a gdb breakpoint on the C level counterpart pike_gdb_breakpoint and then use _gdb_breakpoint at the appropriate place in the Pike code to enter gdb at that point.

Bugs fixed

To browse all bug tickets, visit http://pike.ida.liu.se/development/bugs/.

• Reworked trampolines to cause less circular references.
• It is now possible to inherit Pike programs from C programs.
• Now supports Autoconf 2.50 & Autoconf 2.52.
• Modules with the constant dont_dump_mode will not be dumped, as a workaround for modules that can not yet be dumped.