Stratego Release 064

Stratego -- Strategies for Program Transformation
Stratego 0.6.4 is now available from

The release fixes a "fikse bug in Stratego!!" in the translation of Strategy Rules (rules of the form

  L :: s1 --> s2 where s3
</verbatim>). Thanks to Hedzer for letting me know. See 


for more about these rules. Since it is not widely advertised feature, it
doesn't probably affect your specifications and it will be safe to wait until
the next release, which will have some new goodies again.

-- Main.EelcoVisser - 03 Jan 2002 <br />


Version 0.6.4

 released: January 3, 2002


 (with respect to release 0.6)

 * Term wrap syntax generalizes split
 * Term project syntax generalizes projection
 * New library strategies
 * Tracing of evaluation
 * CGEN package adapted to grammar identifiers
 * New version of gpp
 * Several bug repairs
 * Anonymous CVS checkout is possible again
 * Website runs new twiki


 * Bug reports by Otto Skrove Bagge, Robert Feldt (configuration),
   Merijn de Jonge (strings & #), Hedzer Westra
 * Bug repairs by Merijn de Jonge (strings & #)
 * Library contributions by Otto Skrove Bagge (insert), 
   Martin Bravenboer
 * CVS support by Henk van Lingen
 * Web hosting by Henk Penning


 * Term patterns can contain strategy applications <s>. 

 * Term wrap patterns simplify wrapping some complex constructor pattern
   around a term. For instance, split(f,g) can now be written as
   !(<f>,<g>), and this generalizes to arbitrary build patterns.

 * Term project patterns simplify projection of sub-terms. A strategy
   application <s> inside a match pattern selects the corresponding sub-term
   and applies s to it. For example, instead of writing 
   \ Typed(Var(x),_) -> x \ it is now possible to write ?Typed(Var(<id>),_)
   This feature can also be used to perform tests on subterm in a
   match pattern, e.g., the pattern ?[x | <not([])>] binds the head of a list
   to x, checks that the tail is not empty and produces the tail as


 * Improved efficiency of needed
   definition extraction by using dynamic rules instead of a list of
   definitions to look up definitions in. The effect of this change
   is that the order of evaluation of definitions for the same label
   is reversed.  This is fine since the order of evaluation of
   rules/definitions with the same name is undefined, but it might
   break some specifications. It might be a good idea to change the
   evaluation order with every distribution in order to force
   programmers to use left choice when the order is relevant.

 * Added compile time option to generate code to trace strategies
   - --trace-all: trace all strategies
   - -t f: trace strategy f
   - Note: -t option does not work properly yet.

 * Optimization is set to O2 by default (used to be O4). The higher
   optimization level (which comes down to inlining functions in addition
   to the O2 optimizations) seems to produce faulty code on some
   machine/compiler combinations. Optimization can be increased by
   passing the option -CI "O3" to SC. However, it seems appropriate to
   leave inlining decisions to SC.

 * Repair in implementation of dynamic rules; added rule stamp in order
   to record to which rule the information belongs.

 * Repair of compilation of overlays

 * New version of GPP in GPP-BOOT

 * CGEN now supports GB grammar identifiers

 * Repaired bug in compilation of :: --> rules (Hedzer Westra)


 * Repair of term explosion for strings (Merijn de Jonge). Quoted
   identifiers (strings) can now be used as constructor symbols.
   Not yet supported in signatures.
 * Type annotations added to strategy operators with higher-order
 * Numerous small refactorings, including
    - memo in terms of dynamic rules
 * Some new tests
 * New
    - occurrences(s): all occurrence for which s succeeds
    - om-occurrences(s): outermost occurrences only
    - collect-all(s): collect all occurrences
    - collect-om(s): collect outermost occurrences only
    - innermost-memo(s): memoization of intermediate results
    - restore(s,r): always perform restoration r after doing s,
      even when s fails
 * Obsolete: 
    - collect-kids/1 -> crush/3


 * The Stratego CVS repository is accessible again. To check out the contents
   of the repository type:

      cvs -d checkout Stratego

   Thanks to Henk van Lingen for setting up the cvs server.

 * If you would like to get involved in development of the compiler or library,
   it is also possible to obtain write access to the repository. Contact me
   if you're interested.


 * The twiki running the website has moved from losser to the production server
   of the Utrecht University CS department. Thanks to Henk Penning for making 
   this possible. Individual pages are now bookmarkable under the URL. Access control has been improved. Users need to 
   re-register to enter a password.
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