In the Premise language function rules are very simple. A function name
follows a left parenthesis.However the name can be fully qualified
<namespace>.<function> or unqualified <function> .
When the name is unqualified we have to resolve the name, qualifiy it in order
to select the appropriate function to execute. Each namespace has a set of
imported namespaces which may contain the correctfunction definition. We only
need the first namespace that has the correct function definition, we don't
care if it is multiply defined.
Suppose we're in the namespace User and want to access the sum function defined
in the Math namespace.We have a situation like this:
(using User) .: User
(dependencies User) ; return the namespaces this namespace requires.:
{Premise System}
(namespace Math (function sum ?args (apply + ?args))).: Math
(dependencies User) .: {Premise System}
(Math.sum 1 2 3) ; fully qualified function call.: 6
(sum 1 2 3) ; unqualified function call Math namespace is
not known to User.: [Exception :Text 'The function sum is unknown']
(require Math) ; make Math known to user.: Math
(dependencies User) .: {Premise System Math}
(sum 1 2 3) ; resolves sum to Math.sum.: 6
The resolution takes time. Albeit a small fraction of time. But it is
cumulative.
This is the specific problem.
~PM
Date: Thu, 1 Jan 2015 20:39:02 -0500
Subject: Re: [agi] Namespace search optimization
From: [email protected]
To: [email protected]
Are you referring to a problem which involves taking runtime data and searches
for an appropriate function given the dynamic value? The search for the type of
object that is defined in runtime is not part of the problem is it? Because a
simple call where the type of the variable is given or directly implied (by
uniqueness for example) should not take too much time even during runtime. I
can think of two search problems that might occur in something like that. If
the establishment of the appropriate set function requires some trial and error
data-fitting (or function fitting) that could turn out to be inefficient. Or if
the search involves a proverbial tree search then that might take some time as
well. I don't see a straightforward run-time function call (to something that
is like a template) as being that time consuming.Jim Bromer
On Thu, Jan 1, 2015 at 8:11 PM, Piaget Modeler via AGI <[email protected]> wrote:
It basically boils down to a basic speed versus extensibility tradeoff.
From: [email protected]
To: [email protected]
Subject: RE: [agi] Namespace search optimization
Date: Thu, 1 Jan 2015 08:55:44 -0800
Given 200-250 base functions in 10 packages (namespaces), if the functions are
defined as language intrinsics (like if or for) then there is no need for
pakckage lookup, no need to resolve the name with the namespace, so no
overheard is incurred. If the functions are defined as qualified identifiers
(prefixed by package name) then we need to look up any unqualified identifiers
first, thereby resolving the identifier with the package, before proceeding
with the evaluation.
For Example, the set function in the System.KB package (namespace) sets a slot
in a prototype instance to a value.
The programmer can fully qualify the function call
(System.KB.set ?identifier ?slot ?value)
Or the programmer can reference the package and use an unqualified call
(require System.KB) (set ?identifier ?slot ?value)
When set is encountered we need to search the required namespaces to
determinewhich set function is implied, hence we find System.KB.set and
replace set withthe fully qualified name. We do this during form evaluation in
the REPL,whetherthe REPL is just-in-time compiled or interpreted.
If we defined set as an intrinsic then there would be no package issue, but
also no modularity. We just encounter set and call the set intrinsic. So there
is no overheadincurred by attempting to resolve the function name with a
namespace.
So, my question is, are there any known optimizations to this problem of
resolving function names with packages?
~PM
From: [email protected]
To: [email protected]
Subject: RE: [agi] Namespace search optimization
Date: Thu, 1 Jan 2015 09:03:05 +0000
Dictionary lookups (on the first part of the name if the full list is big
compared to RAM)?
From: Piaget Modeler via AGI [[email protected]]
Sent: 01 January 2015 05:53
To: AGI
Subject: [agi] Namespace search optimization
Are there any optimizations that can be done to look up identifiers in
namespaces
for either just in time compilers or interpreters
?
I'm writing a REPL and namespace resolution of function identifiers takes too
much
time away from overall evaluation.
Any ideas or thoughts?
~PM
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