Class AssemblySelector

  • public class AssemblySelector
    extends java.lang.Object
    Provides a mechanism for pruning and selecting binary assembled instructions from the results of parsing textual assembly instructions. There are two opportunities: After parsing, but before semantic resolution, and after resolution. In the first opportunity, filtering is optional --- the user may discard any or all parse trees. The second is required, since only one instruction may be placed at the desired address --- the user must select one instruction among the many results, and if a mask is present, decide on a value for the omitted bits. Extensions of this class are also suitable for collecting diagnostic information about attempted assemblies. For example, an implementation may employ the syntax errors in order to produce code completion suggestions in a GUI.
    • Constructor Detail

      • AssemblySelector

        public AssemblySelector()
    • Method Detail

      • filterParse

        public java.util.Collection<AssemblyParseResult> filterParse​(java.util.Collection<AssemblyParseResult> parse)
                                                              throws AssemblySyntaxException
        Filter a collection of parse trees. Generally, the assembly resolver considers every possible parsing of an assembly instruction. If, for some reason, the user wishes to ignore certain trees (perhaps for efficiency, or perhaps because a certain form of instruction is desired), entire parse trees may be pruned here. It's possible that no trees pass the filter. In this case, this method ought to throw an AssemblySyntaxException. Another option is to pass the erroneous result on for semantic analysis, in which case, the error is simply copied into an erroneous semantic result. Depending on preferences, this may simplify the overall filtering and error-handling logic. By default, no filtering is applied. If all the trees produce syntax errors, an exception is thrown.
        parse - the collection of parse results (errors and trees).
        the filtered collection, optionally in-place.
        AssemblySyntaxException - if the selector wishes to forward one or more syntax errors
      • select

        public AssemblyResolvedConstructor select​(AssemblyResolutionResults rr,
                                                  AssemblyPatternBlock ctx)
                                           throws AssemblySemanticException
        Select an instruction from the possible results. Must select precisely one resolved constructor from the results given back by the assembly resolver. Precisely one. That means the mask of the returned result must consist of all 1s. Also, if no selection is suitable, an exception must be thrown. By default, this method selects the shortest instruction that is compatible with the given context and takes 0 for bits that fall outside the mask. If all possible resolutions produce errors, an exception is thrown.
        rr - the collection of resolved constructors
        ctx - the applicable context.
        a single resolved constructor with a full instruction mask.