antlr3rewritestreams.h

这是一些ANTLR parser generator的grammar文件的例子

#ifndef	ANTLR3REWRITESTREAM_H
#define	ANTLR3REWRITESTREAM_H

#include    <antlr3defs.h>
#include    <antlr3collections.h>
#include    <antlr3commontreeadaptor.h>
#include	<antlr3baserecognizer.h>

#ifdef __cplusplus
extern "C" {
#endif

/// A generic list of elements tracked in an alternative to be used in
/// a -> rewrite rule.  
///
/// In the C implementation, all tree oriented streams return a pointer to 
/// the same type: pANTLR3_BASE_TREE. Anything that has subclassed from this
/// still passes this type, within which there is a super pointer, which points
/// to it's own data and methods. Hence we do not need to implement this as
/// the equivalent of an abstract class, but just fill in the appropriate interface
/// as usual with this model.
///
/// Once you start next()ing, do not try to add more elements.  It will
/// break the cursor tracking I believe.
///
/// 
/// \see #pANTLR3_REWRITE_RULE_NODE_STREAM
/// \see #pANTLR3_REWRITE_RULE_ELEMENT_STREAM
/// \see #pANTLR3_REWRITE_RULE_SUBTREE_STREAM
///
/// TODO: add mechanism to detect/puke on modification after reading from stream
///
typedef struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct
{

    /// Cursor 0..n-1.  If singleElement!=NULL, cursor is 0 until you next(),
    /// which bumps it to 1 meaning no more elements.
    ///
    ANTLR3_UINT32		  cursor;

    /// Track single elements w/o creating a list.  Upon 2nd add, alloc list 
    ///
    void			* singleElement;

    /// The list of tokens or subtrees we are tracking 
    ///
    pANTLR3_VECTOR		  elements;

    /// Indicates whether we should free the vector or it was supplied to us
    ///
    ANTLR3_BOOLEAN		  freeElements;

    /// The element or stream description; usually has name of the token or
    /// rule reference that this list tracks.  Can include rulename too, but
    /// the exception would track that info.
    ///
    void				* elementDescription;

	/// Pointer to the tree adaptor in use for this stream
	///
    pANTLR3_BASE_TREE_ADAPTOR	  adaptor;

	/// Once a node / subtree has been used in a stream, it must be dup'ed
	/// from then on.  Streams are reset after sub rules so that the streams
	/// can be reused in future sub rules.  So, reset must set a dirty bit.
	/// If dirty, then next() always returns a dup.
	///
	ANTLR3_BOOLEAN				dirty;

	// Pointer to the recognizer shared state to which this stream belongs
	//
	pANTLR3_BASE_RECOGNIZER		rec;

    //   Methods 

    /// Reset the condition of this stream so that it appears we have
    ///  not consumed any of its elements.  Elements themselves are untouched.
    ///
    void		(*reset)				(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream); 

    /// Add a new pANTLR3_BASE_TREE to this stream
    ///
    void		(*add)					(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream, void *el, void (ANTLR3_CDECL *freePtr)(void *));

    /// Return the next element in the stream.  If out of elements, throw
    /// an exception unless size()==1.  If size is 1, then return elements[0].
    ///
	void *					(*next)					(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);
    pANTLR3_BASE_TREE		(*nextTree)				(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);
    void *					(*nextToken)			(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);
    void *					(*_next)				(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);

    /// When constructing trees, sometimes we need to dup a token or AST
    ///	subtree.  Dup'ing a token means just creating another AST node
    /// around it.  For trees, you must call the adaptor.dupTree().
    ///
    void *		(*dup)					(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream, void * el);

    /// Ensure stream emits trees; tokens must be converted to AST nodes.
    /// AST nodes can be passed through unmolested.
    ///
    pANTLR3_BASE_TREE	(*toTree)		(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream, void * el);

    /// Returns ANTLR3_TRUE if there is a next element available
    ///
    ANTLR3_BOOLEAN	(*hasNext)			(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);

    /// Treat next element as a single node even if it's a subtree.
    /// This is used instead of next() when the result has to be a
    /// tree root node.  Also prevents us from duplicating recently-added
    /// children; e.g., ^(type ID)+ adds ID to type and then 2nd iteration
    /// must dup the type node, but ID has been added.
    ///
    /// Referencing to a rule result twice is ok; dup entire tree as
    /// we can't be adding trees; e.g., expr expr. 
    ///
    pANTLR3_BASE_TREE	(*nextNode)		(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);

    /// Number of elements available in the stream
    ///
    ANTLR3_UINT32	(*size)				(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);

    /// Returns the description string if there is one available (check for NULL).
    ///
    void *			(*getDescription)	(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);

    void		(*free)					(struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct * stream);

}
    ANTLR3_REWRITE_RULE_ELEMENT_STREAM;

/// This is an implementation of a token stream, which is basically an element
///  stream that deals with tokens only.
///
typedef struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct ANTLR3_REWRITE_RULE_TOKEN_STREAM;

/// This is an implementation of a subtree stream which is a set of trees
///  modelled as an element stream.
///
typedef struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct ANTLR3_REWRITE_RULE_SUBTREE_STREAM;

/// This is an implementation of a node stream, which is basically an element
///  stream that deals with tree nodes only.
///
typedef struct ANTLR3_REWRITE_RULE_ELEMENT_STREAM_struct ANTLR3_REWRITE_RULE_NODE_STREAM;

#ifdef __cplusplus
}
#endif

#endif