AIN - Array In Namespace
Directions to find it at Stu
From the distribution, simpleAinTutorial.tcl
# Simple AIN (Array In Namespace) tutorial.
# Cheeses.
# Runnable.
# Results noted with #=>
#
# Stuart Cassoff
# January 2007
#
# Setup
package require ain
#=> 0.2
namespace import ::ain::*
# We want to keep things nice and tidy, so let's create
# a namespace where we'll put our cheeses.
set ns ::cheeses
namespace eval $ns {}
# First we make a 'cheese' ain of __ain_type 'ain'
# -prefix and -namespace are the two most important options,
# they indicate where the ains will be stored and what they
# will be named.
# New 'cheese' ains will be created based on the -struct member
# with the defaults, unless overridden
ainNew ain \
-__ain_type cheese \
-namespace $ns \
-prefix fromage# \
-struct [list name {} country {} hardness firm animal cow]
#=> ::ain::ains::ain#1
# The return value from ainNew is the ain which will be used as
# the template for any future ains of type 'cheese'.
# We don't need this value unless we need to delete
# the 'cheese' ain of __ain_type 'ain'.
# We can see that an ain of __ain_type 'cheese' is now
# available for our use.
# [ainAins] returns a list of available ains.
ainAins
#=> ain cheese
# Note that an ain is also an ain!
# Apologies, I have yet to master statements like:
# "cheese is an ain of type ain which is used to create ains of type cheese"
# "ain is an ain of type ain which is used to create ains of type ain"
# Moving on ...
# Now we can make as much cheese as we want!
set c0 [ainNew cheese]
#=> ::cheeses::fromage#0
# fromage#0 is an array in the namespace ::cheeses
parray $c0
#=> ::cheeses::fromage#0(animal) = cow
#=> ::cheeses::fromage#0(country) =
#=> ::cheeses::fromage#0(hardness) = firm
#=> ::cheeses::fromage#0(name) =
# Let's make another cheese, overriding some of the defaults.
# We'll even add a new element to our newly created 'cheese' ain.
# Notice how elements are given with a leading '-' but are
# stored without it. Order of options is not important.
set c1 [ainNew cheese -animal goat -name feta -country Greece -texture crumbly]
#=> ::cheeses::fromage#1
parray $c1
#=> ::cheeses::fromage#1(animal) = goat
#=> ::cheeses::fromage#1(country) = Greece
#=> ::cheeses::fromage#1(hardness) = firm
#=> ::cheeses::fromage#1(name) = feta
#=> ::cheeses::fromage#1(texture) = crumbly
# Accessing ain elements.
# Since ains are simply arrays,
# one would access them using regular array methods.
# These all give the same result
# The braces in the first statement are needed
# due to the '#' in the ain name
puts ${::cheeses::fromage#1(texture)}
#=> crumbly
puts [set ${c1}(texture)]
#=> crumbly
upvar #0 $c1 arr
puts $arr(texture)
#=> crumbly
# Since ains are fully namespace qualified arrays, they
# can be easily passed around and accessed.
proc fave_cheese {ch} {
upvar 1 $ch cheese
puts -nonewline "My favorite cheese is "
puts -nonewline $cheese(name)
puts -nonewline " because of its "
puts -nonewline $cheese(texture)
puts " texture!"
puts -nonewline [string totitle $cheese(name)]
puts -nonewline " often comes from "
puts -nonewline $cheese(country)
puts "."
}
fave_cheese $c1
#=> My favorite cheese is feta because of its crumbly texture!
#=> Feta often comes from Greece.
# Let's try with another cheese!
set c2 [ainNew cheese -name cheddar -country England -texture smooth]
fave_cheese $c2
#=> My favorite cheese is cheddar because of its smooth texture!
#=> Cheddar often comes from England.
# We've enjoyed our delicious cheeses, now it's time to get rid of them.
# This is essentially the same as [unset -nocomplain]
# Some additional work is performed for more complex
# cases but not in this tutorial.
# Goodbye cheddar, we'll miss you
ainDelete $c2
# Note that the ain extension does not keep track of any ains
# other than __ain_type 'ain'.
# The extension aims to be as lightweight and non-intrusive as possible.
# 'Till we meet again, feta
ainDelete $c1
# Drop this one, too.
ainDelete $c0
# We can clean up completely and remove 'cheese' from the available ains.
# This was created way back in the beginnnig of this tutorial
ainDelete {::ain::ains::ain#1}
# Check
ainAins
#=> ain
# Only 'ain' is left, it can be deleted but that would render the
# ain extension useless!
# EOF