On 29/07/2018 2:59 AM, Robert M. Münch wrote:
Hi, I'm seeking for ideas/comments/experiences how to best implement a
DSL in D.
What I would like to do is something like this:
... my D code ...
my-dsl {
... my multi-line DSL code ...
trade 100 shares(x) when (time < 20:00) and timingisright()
}
... my D code ...
Some things that circle in my head:
* Can the D parser somehow be missued for a DSL? So I can skip all the
generic features for types etc.?
Let's go with no.
* I could use a PEG grammer for parsing the DSL, but this leads to quite
some overhead for a tiny DSL.
* For static DSL code I would like to use CTFE to convert it into D code
* Does this requires a CTFE compatible PEG parser tookit?
Yes.
* Could I somehow call an external program during compilation which
gets the DSL block as input and returns D code?
No. But you can pre-process.
* For dynamic DSL code I think I need to create something like an
interpreter
* How can I reference D variables from DSL code? Is there a lookup
meachnisam or do I have to create a dictonary?
Registration, but like you said, a giant dictionary.
* Is it possible to populate such a dictonary via CTFE?
Sort of, it can be registered, but the actual execution of the
registration occurs at runtime.
But you're slightly over thinking this. Write an interpreter and a
parser. The fact that the parser can work at CTFE is irrelevant and
almost a footnote on the page of details ;).
If you want to be clever you could generate D code and mix it in based
upon what was parsed. But you'd still want that dictionary.
