types - Tool

Postscript file available

Tool for defining types known to the tasking system
include "types.g"

Description

types is the means for defining the user interface (i.e., the functions and arguments) of other AIPS++tools.

An AIPS++tool or function usually takes various types of arguments. Glish itself is type-less and doesn't require that the type of a variable be defined explicitly or fixed, which has advantages and disadvantages. In the tasking system, it is important to impose some typing of variables so that, for example, the toolmanager knows whether a particular argument is a scalar or a measure or a file name. The types tool provides the mechanism for defining the type to be used in the toolmanager's user interface.

This works as follows:

The developer specifies the interface in a meta information file.
In the AIPS++startup, the types tool reads these meta information files, and stores the results in a cached file.
The functions of types may be used to recall information on the interface.
User interfaces for tools and functions are constructed by the toolmanager using the meta information and passed to the autogui or autocli.
The user interface does parsing as appropiate.
If the tool is linked to C++, arguments are passed appropriately.

The net result for the developer is that a user interface for any tool or function may be generated easily merely by provision of a meta information file.

An example of a meta information file follows. This defines the interface for a tool called imager and hence should be located in a file called imager_meta.g.

pragma include once;			# Include once only

include 'types.g';			# Required

#
# Name the include file that defines the tool
types.class('imager').includefile('imager.g');
#
# Constructor names are preceeded by ctor_. Then follows the
# list of arguments.  Each argument is defined with a 
# function call of this form:
#
# type(arg, default=unset, dir='in', checkeval=T)
#
# where type is defined in type.g and is one of:
#
# file|table|string|integer|float|double|record|boolean|vector_string|complex
#
# arg is the name of the argument
# default sets default values (may be an executable string)
# dir sets the direction of the argument
# checkeval=T means that a string value is eval'ed and checked,
# otherwise no such check is done.
#
# The functions may be assigned to groups using the 
# group('mygroup') function. A group() call resets the
# group to the default, which is 'basic'.
#
# Define two constructors, one with just a table name, and the other
# with more arguments
types.method('ctor_imager').table('filename').
    method('ctor_imagertester').string('filename', '3C273XC1.ms').
    integer('size', 256).string('cell', '0.7arcsec').string('stokes', 'IV').
    string('coordinates', 'b1950');

# Methods
# Open with just a table name
types.group('basic').method('open').table('thems');

# Plain close
types.method('close');

# Get the name back
types.method('name').string('return');

# Summary
types.method('summary');

# Set various image parameters. Note the use of the measures
# tool to set the phasecenter.
types.group('setup').method('setimage').integer('nx',128).integer('ny',128).
    string('cellx','1arcsec').string('celly','1arcsec').
    string('stokes', 'I').
    boolean('doshift', F).
    record('phasecenter', 'dm.direction(\'b1950\', \'0d\', \'0d\')',checkeval=F).
    string('shiftx','0arcsec').string('shifty','0arcsec').
    string('mode', 'mfs').integer('nchan', 1).integer('start', 1).
    integer('step', 1).string('mstart', '0km/s').string('mstep', '0km/s').
    integer('spwid', 1).integer('fieldid', 1);

Constructors
Functions

addmeta	Copy meta information to a class
all	Show all classes
antennas	Define a list of antennas
attachhelp	Attach help from the help system
baselines	Define a list of baselines
boolean	Define a boolean
check	Choose one or more from a list of strings
choice	Choose one from a list of strings
class	Define a class or type of tool
classes	Return names of the classes
complex	Define a complex
direction	Define a direction measure
directory	Define a directory
double	Define a double
epoch	Define an epoch measure
exists	Does the class, method, arg exist?
fields	Define a list of field ids
file	Define a file
float	Define a float
getincludefile	Get the include file for a class
group	Define the group name for a function
includefile	Specify the include file for a class
includemeta	Include all meta information files
integer	Define an integer
is_tool	Is this a tool?
list	Define a list of other types
measure	Define a measure
measurecodes	Define the reference code for a measure
meta	Return meta information for a type of tool
method	Define a method or function for a class
msselect	Define a taql string for a MeasurementSet
position	Define a position measure
quantity	Define a quantity
record	Define a record
region	Define a region
spectralwindows	Define a list of spectralwindows
string	Define a string
table	Define a table
taql	Define a Table Query Language string
untyped	Define an untyped variable
vector_boolean	Define a vector of booleans
vector_complex	Define a vector of complexs
vector_double	Define a vector of doubles
vector_float	Define a vector of floats
vector_integer	Define a vector of integer
vector_string	Define a vector of strings

Next: types.exists - Function Up: tasking - Module Previous: logger.brief - Function Contents Index

	Package	utility
	Module	tasking