-- -- DOCUMENT_HANDLER by Richard Conn, TI Ada Technology Branch -- 27 Feb 85 -- with Text_Io, Machine_Dependencies, Token_Definition; package Document_Handler is -------------------------------------------------------------------------- -- Abstract : DOCUMENT_HANDLER provides input from a document, which -- is specified to OPEN_SOURCE by a pathname/filename. -- It returns a WORD from this document each time the routine -- GET_WORD is called. When there are no more WORDs in the -- document, the exception NO_MORE_WORDS is raised. -- -- DOCUMENT_HANDLER can also create a second document, the -- destination, or output, document. This facility is -- enabled when the routine OPEN_DESTINATION is called, -- where the pathname/filename of the new document is the -- passed parameter. The destination document is a mirror -- of the source document, except that selected words can -- be replaced with other words via the RESTORE_WORD routine. -- RESTORE_WORD replaces the last word returned by GET_WORD -- with a new word. -- -- The context, or lines surrounding the last word returned -- by GET_WORD, can be obtained from the CONTEXT_OF_LAST_ -- GET_WORD routine. This routine returns LINES, which is -- an array of strings, and an INDEX, which is the offset -- to the first character of the last word returned by -- GET_WORD, and LENGTH, which is the number of characters -- in this word. The constant, TARGET_LINE_IN_CONTEXT, -- is the index of the line of the context which contains -- the indicated word. -- -------------------------------------------------------------------------- subtype Token is Token_Definition.Token_Type; Max_Line : constant Positive := Machine_Dependencies.File_Line_Length; Number_Of_Lines_In_Context : constant Natural := 3; Target_Line_In_Context : constant Natural := 2; type Context_Element is record Line : String (1 .. Max_Line); Last : Natural; end record; type Context is array (1 .. Number_Of_Lines_In_Context) of Context_Element; -- Note: Exceptions from TEXT_IO may also be raised Restore_Failed : exception; No_More_Words : exception; Source_Not_Open : exception; procedure Open_Source (File_Name : String); -------------------------------------------------------------------------- -- Abstract : The source document from which future words are to be -- returned is opened for input. GET_WORD returns these -- words. -------------------------------------------------------------------------- -- Parameters : FILE_NAME - Pathname/Filename of file containing -- document -------------------------------------------------------------------------- procedure Open_Destination (File_Name : String); -------------------------------------------------------------------------- -- Abstract : The destination document which is built of words from the -- source document and new, correctly-spelled words provided -- through RESTORE_WORD -------------------------------------------------------------------------- -- Parameters : FILE_NAME - Pathname/Filename of file to contain -- the destination document -------------------------------------------------------------------------- procedure Close_Source_And_Destination; -------------------------------------------------------------------------- -- Abstract : Close both the source document and destination document -- files -------------------------------------------------------------------------- -- Parameters : None -------------------------------------------------------------------------- procedure Get_Word (Word : out Token; Word_In_Bounds : out Boolean); -------------------------------------------------------------------------- -- Abstract : Return the next word from the Source Document -------------------------------------------------------------------------- -- Parameters : WORD - the next word from the source document; -- this structure includes the word itself -- (as a string) and the word length -- WORD_IN_BOUNDS - TRUE if WORD is small enough to fit in -- a TOKEN; FALSE if WORD is larger than -- the maximum size of a TOKEN; if FALSE, -- the full word can be obtained from -- the procedure CONTEXT -------------------------------------------------------------------------- procedure Restore_Word (Word : String); -------------------------------------------------------------------------- -- Abstract : Replace the last word obtained from GET_WORD with the -- passed string (WORD); the replacement is done in the -- destination document only (the source document is not -- affected) -------------------------------------------------------------------------- -- Parameters : WORD - the string containing the new word -------------------------------------------------------------------------- procedure Context_Of_Last_Get_Word (Lines : out Context; Index : out Natural; Length : out Natural); -------------------------------------------------------------------------- -- Abstract : Return the lines surrounding and including the last word -- returned by GET_WORD; also return the INDEX and LENGTH -- of the last word returned by GET_WORD which indicate -- its position in the TARGET_LINE_IN_CONTEXT -------------------------------------------------------------------------- -- Parameters : LINES - the context (lines) surrounding the last -- word -- INDEX - the offset to the first character of the -- last word in TARGET_LINE_IN_CONTEXT -- LENGTH - number of characters in the last word -- in TARGET_LINE_IN_CONTEXT -------------------------------------------------------------------------- end Document_Handler;