Package jflex.core

Class Macros

  • public final class Macros
extends java.lang.Object
    Symbol table and expander for macros.

    Maps macros to their (expanded) definitions, detects cycles and unused macros.

    Version:
    JFlex 1.9.1

    • Field Summary

      Fields 
      Modifier and Type Field Description
      private java.util.Map<java.lang.String,​RegExp> macros
      Maps names of macros to their definition
      private java.util.Map<java.lang.String,​java.lang.Boolean> used
      Maps names of macros to their "used" flag

    • Constructor Summary

      Constructors 
      Constructor Description
      Macros()
      Creates a new macro expander.

    • Method Summary

      All Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      void expand()
      Expands all stored macros, so that getDefinition always returns a definition that doesn't contain any macro usages.
      private RegExp expandMacro​(java.lang.String name, RegExp definition)
      Expands the specified macro by replacing each macro usage with the stored definition.
      RegExp getDefinition​(java.lang.String name)
      Fetches the definition of the macro with the specified name,
      boolean insert​(java.lang.String name, RegExp definition)
      Stores a new macro and its definition.
      boolean isUsed​(java.lang.String name)
      Tests if a macro has been used.
      boolean markUsed​(java.lang.String name)
      Marks a macro as used.
      java.util.List<java.lang.String> unused()
      Returns all unused macros.

      • Methods inherited from class java.lang.Object

        clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

    • Field Detail

      • macros

        private final java.util.Map<java.lang.String,​RegExp> macros
        Maps names of macros to their definition

      • used

        private final java.util.Map<java.lang.String,​java.lang.Boolean> used
        Maps names of macros to their "used" flag

    • Constructor Detail

      • Macros

        public Macros()
        Creates a new macro expander.

    • Method Detail

      • insert

        public boolean insert​(java.lang.String name,
                      RegExp definition)
        Stores a new macro and its definition.
        Parameters:
        name - the name of the new macro
        definition - the definition of the new macro
        Returns:
        true, iff the macro name has not been stored before.

      • markUsed

        public boolean markUsed​(java.lang.String name)
        Marks a macro as used.
        Parameters:
        name - a String object.
        Returns:
        true, iff the macro name has been stored before.

      • isUsed

        public boolean isUsed​(java.lang.String name)
        Tests if a macro has been used.
        Parameters:
        name - a String object.
        Returns:
        true, iff the macro has been used in a regular expression.

      • unused

        public java.util.List<java.lang.String> unused()
        Returns all unused macros.
        Returns:
        the macro names that have not been used.

      • getDefinition

        public RegExp getDefinition​(java.lang.String name)
        Fetches the definition of the macro with the specified name,

        The definition will either be the same as stored (expand() not called), or an equivalent one, that doesn't contain any macro usages (expand() called before).

        Parameters:
        name - the name of the macro
        Returns:
        the definition of the macro, null if no macro with the specified name has been stored.
        See Also:
        expand()

      • expand

        public void expand()
            throws MacroException
        Expands all stored macros, so that getDefinition always returns a definition that doesn't contain any macro usages.
        Throws:
        MacroException - if there is a cycle in the macro usage graph.

      • expandMacro

        private RegExp expandMacro​(java.lang.String name,
                           RegExp definition)
                    throws MacroException
        Expands the specified macro by replacing each macro usage with the stored definition.
        Parameters:
        name - the name of the macro to expand (for detecting cycles)
        definition - the definition of the macro to expand
        Returns:
        the expanded definition of the macro.
        Throws:
        MacroException - when an error (such as a cyclic definition) occurs during expansion