Class Macros

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

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

Version:
JFlex 1.9.1

  • Field Details

    • macros

      private final Map<String,RegExp> macros
      Maps names of macros to their definition

    • used

      private final Map<String,Boolean> used
      Maps names of macros to their "used" flag

  • Constructor Details

    • Macros

      public Macros()
      Creates a new macro expander.

  • Method Details

    • insert

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

    • getDefinition

      public RegExp getDefinition(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

      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(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