Curry Partial Evaluator  (v1.3)

This is a purely declarative partial evaluator for the multi-paradigm language Curry. It has been implemented in Curry itself by Elvira Albert, Germán Vidal (UPV), and Michael Hanus (CAU Kiel). The partial evaluator is able to deal with programs containing local declarations, external functions, constraints, higher-order functions, conditional equations, and several built-in functions.

The partial evaluator considers an intermediate language, FlatCurry, and translates programs to FlatCurry in order to specialize them. This is essential to express the above language features at an appropriate level of abstraction. In this way, the resulting partial evaluator can be used to specialize "real" Curry programs, even a meta-interpreter for Curry.

A complete description of the partial evaluator can be found in [AHV00, AHV01, AHV02].

The partial evaluation tool has been integrated into the PAKCS compiler for Curry. It is integrated in PAKCS as follows:

• After loading some program into PAKCS/curry2prolog, this program can be partially evaluated by the command ":peval".
  
  
• The expressions to be partially evaluated must be marked in the program by (PEVAL ...) where PEVAL is the identity function (defined in the standard prelude).
  
  
• The marked expressions are partially evaluated and replaced by their partially evaluated versions. This modified program is stored in "_pe.fcy" provided that is the name of the source program.
  
  
• The partially evaluated program "_pe.fcy" is automatically loaded into PAKCS. Although there is no Curry source file for this program, the (decompiled) source can be viewed by the command ":show" (if you are interested to see the result of the partial evaluation).
  

If you want to play with the partial evaluator, you can use the (annotated) examples contained in PevalExamples.tar.gz.

The latest version (v1.3) of the partial evaluator can be found here (it contains peval.curry and a modified file of the PAKCS library, Flat.curry, which should be in the same directory as peval.curry). Once the file peval.curry is loaded in PAKCS, you can partially evaluate programs by using the command mainauto "filename". The current version requires PAKCS 1.6.0. If you have an older version of PAKCS, you can try this.

The partial evaluator does not work yet in the Münster Curry Compiler. The reason is that the partial evaluator requires the meta-programming facilities of PAKCS.

Please report any bug or comment to gvidal@dsic.upv.es.

• [AHV00]: E. Albert, M. Hanus, G. Vidal. Using an Abstract Representation to Specialize Functional Logic Programs. Proc. of the 7th International Conference on Logic for Programming and Automated Reasoning (LPAR'2000), Reunion Island, France, 2000.
  © Springer-Verlag
  Available: Abstract / PS / BibTeX entry
  
  
• [AHV01]: E. Albert, M. Hanus, G. Vidal. A Practical Partial Evaluator for Multi-Paradigm Declarative Programs. Proc. of the 5th International Symposium on Functional and Logic Programming, FLOPS'2001, Tokyo (Japan).
  © Springer-Verlag
  Available: Abstract / PS / BibTeX entry
  
  
• [AHV02]: E. Albert, M. Hanus, and G. Vidal. A Practical Partial Evaluation Scheme for Multi-Paradigm Declarative Languages. Journal of Functional and Logic Programming 2002(1):1-34, March 2002
  © EAPLS
  
  

Last update June 2004 # gvidal (at) dsic (dot) upv (dot) es