Operator overloading or alternatives to expression templates

[Martin Nowak via Digitalmars-d]

I find the reasons for turining down my ER a bit moot.

[Issue 14593 – operator overloading can't be used with expression
templates](https://issues.dlang.org/show_bug.cgi?id=14593)

AFAIK expression templates are the primary choice tom implement SIMD and
matrix libraries.
And I still have [this idea](http://dpaste.dzfl.pl/cd375ac594cf) of
implementing a nice query language for ORMs.

D currently doesn't allow to override some operators like < <= > >= &&
|| !=.

At least the comparison operators are really limiting, e.g. it's not
possible to efficiently implement logical indexing.

vec[vec < 15], vec[vec == 15], vec[(vec != 15) & (vec > 10)]

Also opCmp is less efficient to implement than opBinary!"<" for many
types. Generally any good implementation of an algorithm should only
require a less operator, not a full ordering opCmp.

The short circuit operators && and || have a special semantic and can't
be easily, but there is & and | so it's not really required.

Now expression templates make an awful DSL when being used to create a
HTML formatter, but when the original semantic of the operators is
preserved they are really powerful b/c the compiler already handles
typechecking, operator precedence, and captures variables.

Does anyone have a different idea how to make a nice query language?
db.get!Person.where!(p => p.age > 21 && p.name == "Peter")