I/O

I/O mk Tue, 03/30/2010 - 16:26

8.11 Input/Output module

The IO module provides simple ascii-io rendering options. It is modeled after the tuple formats, but does not attempt to outline the results. Instead, it is geared at speed, which also means that some functionality regarding the built-in types is duplicated from the atoms definitions.

A functional limited form of formatted printf is also provided. It accepts at most one variable. A more complete approach is the tablet module.

The commands to load and save a BAT from/to an ASCII dump are efficient, but work only for binary tables.

module io;
pattern stdin():bstream
address io_stdin comment "return the input stream to the database client";
pattern stderr():streams
address io_stderr comment "return the error stream for the database console";
pattern stdout():streams
address io_stdout comment "return the output stream for the database client";
pattern print(val:any_1,lst:any...):void
address IOprint_val comment "Print a MAL value tuple .";
pattern print(b1:bat[:any_1,:any]...):void
address IOtable comment "BATs are printed with '#' for legend lines, and the BUNs on seperate lines between brackets, containing each to comma separated values (head and tail). If multiple BATs are passed for printing, print() performs an implicit natural join, producing a multi attribute table.";
pattern ftable( filep:streams, b1:bat[:any_1,:any], b:bat[:any_1,:any]... ):void
address IOftable comment "Print an n-ary table to a file.";
pattern print(order:int,b:bat[:any_1,:any], b2:bat[:any_1,:any]...):void
address IOotable comment "The same as normal table print, but enforces to use the order of BAT number [1..argc] to do the printing.";
pattern table(b1:bat[:any_1,:any], b2:bat[:any_1,:any]...):void
address IOttable comment "Print an n-ary table. Like print, but does not print oid column";
pattern table(order:int, b1:bat[:any_1,:any], b2:bat[:any_1,:any]...):void
address IOtotable comment "Print an n-ary table.";
pattern ftable(fp:streams, order:int, b1:bat[:any_1,:any], b:bat[:any_1,:any]...):void
address IOfotable comment "Print an n-ary table to a file.";
pattern print(val:any_1):void
address IOprint_val comment "Print a MAL value tuple .";
pattern print(val:bat[:any_1,:any_2]):void
address IOprint_val comment "Print a MAL value tuple .";
pattern prompt(val:any_1):void
address IOprompt_val comment "Print a MAL value without brackets.";
pattern printf(fmt:str,val:any...):void
address IOprintf comment "Select default format ";
pattern printf(fmt:str):void
address IOprintf comment "Select default format ";
pattern printf(filep:streams,fmt:str,val:any...):void
address IOprintfStream comment "Select default format ";
pattern printf(filep:streams,fmt:str):void
address IOprintfStream comment "Select default format ";
command data(fname:str):str
address IOdatafile comment "Signals receipt of tuples in a file fname. It returns the name of the file, if it still exists.";
command export(b:bat[:any_1,:any_2], filepath:str):bit
address IOexport comment "Export a BAT as ASCII to a file. If the 'filepath' is not absolute, it is put into the .../dbfarm/$DB directory. Success of failure is indicated.";
command import(b:bat[:any_1,:any_2], filepath:str) :bat[:any_1,:any_2]
address IOimport comment "Import a BAT from an ASCII dump. The new tuples are *inserted* into the parameter BAT. You have to create it! Its signature must match the dump, else parsing errors will occur and FALSE is returned.";