Package net.oneandone.mork.semantics

Data types for attribute grammars.

See: Description

Interface Summary

Interface	Description
Compare

Class Summary

Class	Description
Ag	Attribute grammar, supports >=0 synthesized and inherited attributes.
AgBuffer	Attribute grammar, supports >=0 synthesized and inherited attributes.
Alternative
Attribute	An attribute is the type of an attribute instance.
AttributeOccurrence
Attribution	Attribute function call.
AttributionBuffer	Attribution function call buffer.
BuiltIn	Predefined functions usefull for attribution.
Layout	Helper to translate SemanticsBuffer into Semantics TODO: merge this functionality into SemanticsBuffer?
Merger	Stupid data container for CopyBuffer
Node	Node of the syntax tree.
NodeFactory
Oag	Ordered attribute grammar.
OagBuilder	Build visit sequence for ordered attribute grammar.
Occurrence
Partition	Helper class for OagBuilder
Pusher	Attribute grammar, supports >=0 synthesized and inherited attributes.
State	Attribute grammar, supports >=0 synthesized and inherited attributes.
Type	Type of an attribute.
Visits	Build visit sequence for ordered attribute grammar.

Exception Summary

Exception	Description
IllegalLiteral	Thrown by BuiltIn functions.
SemanticError

Package net.oneandone.mork.semantics Description

Data types for attribute grammars.

The semantics package defines the Analyser class that can be considered the main class of Mork. An Analyser reads a streams into objects which includes scanning, parsing and attribution.

TODO
o global attribute optimization
  o 'global' variable for attribute that occur at most once.

o support different threads for scanning, parsing and attribution?
  Attribution might run when scanning blocks on slow input.

o how to get the size of the parsed file
  o would be useful to add statistics to Java examples
  o do I need an explicit EOF?
  o special Variable of the start symbol?
  o position variable for arbitrary symbols?

o optimize computation of scanner attributes
  o compute position in error situations only

o optimizations
  o "parse into abstract syntax"
  o compute attributes as early as possible -- and free memory

o improved semantic errors support
  o recovery
    o compute as may attributes as possible
  o declare exception
    o the user should have to declare checked exception thrown by
      functions
  o declare a replace object (or replace function) instead of throwing
    an exception
  o re-declare unchecked -> checked exception translation,
    e.g. IllegalArgumentException -> xyz

o ordered attribute grammars
  o sufficiently powerfull
  o tests cyclic dependencies at compile-time
  o semantics currently implements a kind of AG buffer that can be modified.
    An OAG would be a reasonable, efficient and powerfull finalization.
  o caveats
    o semantic error recovery:
      o record failed attributes, i.e. attributes whose computation
        failed
      o skip calls, that need failed attribute as arguments
    o second-level AG functions: use a second OAG

o optimization
  o position computation for semantic errors
  o remove local copy rules (as generated by the translation section)

o warn about unused attributes