MODULE logging

  ! see also logging.h
  ! macro LOGBUF accumulates log output into logging_buffer
  ! flush_plugin points to a procedure pointer that typically prints all lines in the buffer and prepends tags
  ! This module provides a default implementation of flush_plugin but the top-level driver is welcome to override it.

  IMPLICIT NONE
  SAVE
  PRIVATE

  INTERFACE 
     SUBROUTINE plugin(lev, tag, buf)
       INTEGER, INTENT(IN) :: lev
       CHARACTER(*), INTENT(IN) :: tag, buf(:)
     END SUBROUTINE plugin
  END INTERFACE

  PROCEDURE(plugin), POINTER :: flush_plugin => default_flush_plugin

  INTEGER, PARAMETER :: bufsize=10000
  CHARACTER(bufsize) :: logging_buf(100)

  INTEGER :: logging_lineno=0

  INTEGER, PARAMETER, PUBLIC :: log_level_dbg=0, log_level_info=1

  PUBLIC :: logging_buf, logging_lineno, flush_log, flush_plugin

CONTAINS

  SUBROUTINE flush_log(lev,tag)
    INTEGER, INTENT(IN) :: lev
    CHARACTER(*), INTENT(IN) :: tag
    CALL flush_plugin(lev, TRIM(tag), logging_buf(1:logging_lineno))
    logging_lineno=0
  END SUBROUTINE flush_log

  SUBROUTINE default_flush_plugin(lev, tag, buf)
    INTEGER, INTENT(IN) :: lev
    CHARACTER(*), INTENT(IN) :: tag, buf(:)
    INTEGER :: i
    DO i=1, SIZE(buf)
       PRINT *, '[INFO ',tag,']', TRIM(buf(i))
    END DO
  END SUBROUTINE default_flush_plugin
  
END MODULE logging