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Muldis::DB::Engine::Example::Operators - Implementations of all core Muldis D system-defined operators


This document describes Muldis::DB::Engine::Example::Operators version 0.4.0 for Perl 5.


This file is used internally by Muldis::DB::Engine::Example; it is not intended to be used directly in user code.

It provides implementations of all core Muldis D system-defined operators, and their API is designed to exactly match the operator definitions in Language::MuldisD.

Specifically, this file implements the core system-defined operators that all Muldis D implementations must have, which is the selectors for and general purpose functions and update operators for these data types: Bool, Order, Int, Num, Text, Blob, Tuple, Relation, and the Cat.* types.

By contrast, the operators specific to the optional data types are implemented by other files: Muldis::DB::Engine::Example::Operators::Temporal, Muldis::DB::Engine::Example::Operators::Spatial.


The operators declared in this file assume that any user-defined Muldis D code which could be invoking them has already been validated by the Muldis D compiler, in so far as compile time validation can be done, and so the operators in this file only test for invalid input such that couldn't be expected to be caught at compile time. For example, it is usually expected that the compiler will catch attempts to invoke these operators with the wrong number of arguments, or arguments with the wrong names or data types. So if the compiler missed something which the runtime doesn't expect to have to validate, then the Example Engine could have inelegant failures.


Darren Duncan (


This file is part of the Muldis DB framework.

Muldis DB is Copyright © 2002-2007, Darren Duncan.

See the LICENSE AND COPYRIGHT of Muldis::DB for details.

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