/// <summary>
/// Creates a new macro context in the specified macro session.
/// </summary>
/// <param name = "session">The macro expansion session.</param>
/// <param name = "invocation">The node that is being expanded.</param>
/// <param name = "isJustEffect">Whether the nodes return value will be discarded by the surrounding program.</param>
internal MacroContext(MacroSession session, AstGetSet invocation, bool isJustEffect)
{
if (session == null)
throw new ArgumentNullException("session");
if (invocation == null)
throw new ArgumentNullException("invocation");
_isJustEffect = isJustEffect;
_invocation = invocation;
_session = session;
_block = new AstScopedBlock(invocation.Position, session.CurrentBlock);
_isPartialApplication = _invocation.Arguments.Any(AstPartiallyApplicable.IsPlaceholder);
_sentinelBlock = session.Target.CurrentBlock;
}
/// <summary>
/// Returns the current macro session, or creates one if necessary. Must always be paired with a call to <see
/// cref = "ReleaseMacroSession" />. Do not call <see cref = "MacroSession.Dispose" />.
/// </summary>
/// <returns>The current macro session.</returns>
public MacroSession AcquireMacroSession()
{
_macroSessionReferenceCounter++;
Debug.Assert(_macroSessionReferenceCounter > 0);
return _macroSession ?? (_macroSession = new MacroSession(this));
}
/// <summary>
/// Releases the macro session acquired via <see cref = "AcquireMacroSession" />. Will dispose of the session, if no other release is pending.
/// </summary>
/// <param name = "acquiredSession">A session previously acquired through <see cref = "AcquireMacroSession" />.</param>
// ReSharper disable UnusedParameter.Global
public void ReleaseMacroSession(MacroSession acquiredSession)
// ReSharper restore UnusedParameter.Global
{
if (_macroSession != acquiredSession)
throw new InvalidOperationException(
"Invalid call to CompilerTarget.ReleaseMacroSession. Trying to release macro session that doesn't match.");
_macroSessionReferenceCounter--;
if (_macroSessionReferenceCounter <= 0)
{
_macroSession.Dispose();
_macroSession = null;
}
Debug.Assert(_macroSessionReferenceCounter >= 0);
Debug.Assert(_macroSessionReferenceCounter == 0 || _macroSession != null);
}