cc: [email protected]
Subject: Re: [ast-developers] typeset -T ksh crash
--------
> it seems easy to fix, but I've never used it and even don't know
> what typeset -T should do?
>
> I've tried
> typeset -T abc=hello; typeset -T
> which outputs
> typeset -T abc
> typeset -T abc=hell)
>
> and that did not help to understand it, especially missing last
> letter and extra parenthesis. So I don't know if it should print
> both "typeset -T abc" and "typeset -T abc=" or just first one.
>
> Michal
>
typeset -T is used to create user defined types or to list the current
types and their definitions.
A type is defined with
typeset -T name=(...)
Note the assignment typeset -T abc is not valid and it should have
produced an error (which it now does).
typeset -T abc
is legal and should list all variables of type T
typeset -T should list all type definitions.
Here is an example of a type definition:
typeset -T Pt_t=(
float x=1
float y=0
len(){
print $(( sqrt(_.x**2+_.y**2)))
}
)
This creates a builtin named Pt_t which is a constructor for this type.
Pt_t p q=(x=3 y=4)
This creates two instance of type Pt_t.
The function len is a discipline function and _ will be a reference to
the instance that invoked it. Each instance can redefine their own
version of these functions.
p.len
outputs 1 and
q.len
outputs 5.
David Korn
[email protected]
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