--- parser3/src/include/pa_pool.h	2001/02/20 18:45:51	1.22
+++ parser3/src/include/pa_pool.h	2001/02/22 11:08:06	1.24
@@ -1,5 +1,5 @@
 /*
-  $Id: pa_pool.h,v 1.22 2001/02/20 18:45:51 paf Exp $
+  $Id: pa_pool.h,v 1.24 2001/02/22 11:08:06 paf Exp $
 */
 
 #ifndef PA_POOL_H
@@ -7,17 +7,18 @@
 
 #include <stddef.h>
 
-class String;
+//class String;
 class Exception;
+class Temp_exception_change;
 
 class Pool {
+	friend Temp_exception_change;
 public:
 
-	// Exception to report pool errors 
-	Pool(Exception& aexception) : fexception(aexception) {}
+	Pool() : fexception(0) {}
 	~Pool() {}
 
-	Exception& exception() { return fexception; }
+	Exception& exception() const { return *fexception; }
 
 	void *malloc(size_t size) {
 		return check(real_malloc(size), size);
@@ -26,17 +27,43 @@ public:
 		return check(real_calloc(size), size);
 	}
 
-protected: // implementation defined
+private: // implementation defined
 
     void *real_malloc(size_t size);
     void *real_calloc(size_t size);
 
-protected:
-
-	Exception& fexception;
+private: 
 
 	// checks whether mem allocated OK. throws exception otherwise
-	void *check(void *ptr, size_t size);
+	void *check(void *ptr, size_t size) {
+		if(ptr)
+			return ptr;
+
+		fail(size);
+
+		// never reached
+		return 0;
+	}
+	// throws proper exception
+	void fail(size_t size) const;
+
+protected: // exception handling
+
+	// exception replacement mechanism is 'protected' from direct usage
+	// Temp_exception_change object enforces paired set/restore
+	Exception *set_exception(Exception *e){
+		Exception *r=fexception;
+		fexception=e;
+		return r;
+	}
+	void restore_exception(Exception *e) {
+		fexception=e;
+	}
+
+private:
+
+	// current request's exception object
+	Exception *fexception;
 
 private: //disabled
 
@@ -45,17 +72,53 @@ private: //disabled
 };
 
 class Pooled {
+	// the pool i'm allocated on
+	Pool& fpool;
 public:
+	
 	static void *operator new(size_t size, Pool& apool) { 
 		return apool.malloc(size);
 	}
 
-	Pooled(Pool& apool) : fpool(apool) {}
+	Pooled(Pool& apool) : fpool(apool) {
+	}
+
 	Pool& pool() const { return fpool; }
 
-protected:
-	// the pool I'm allocated on
-	Pool& fpool;
+	void *malloc(size_t size) const { return fpool.malloc(size); }
+	void *calloc(size_t size) const { return fpool.calloc(size); }
+	Exception& exception() const { return fpool.exception(); }
 };
+#define NEW new(pool())
+
+class Temp_exception_change {
+	Pool pool;
+	Exception *saved_exception;
+public:
+	Temp_exception_change(Pool& apool, Exception& exception) : 
+		pool(apool),
+		saved_exception(apool.set_exception(&exception)) {
+	}
+	~Temp_exception_change() { 
+		pool.restore_exception(saved_exception); 
+	}
+};
+
+#define TRY \
+	{ \
+		Exception temp_exception; \
+		Temp_exception_change le(pool(), temp_exception); \
+		if(setjmp(temp_exception.mark)==0)
+
+#define THROW exception()._throw
+#define CATCH(e) \
+		else{ \
+			Exception& e=temp_exception;
+
+#define END_CATCH \
+		} \
+	}
+// usage:
+//   TRY { ...; if(?) RAISE(?); ...; } CATCH(e) { catch-code e.comment() } END_CATCH
 
 #endif