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- delaying evaluation of arguments... necessary for functions like `<-`. Should this be done with a lookup table, or
should all arguments be unevaluated, passed into the compiling function, and then handled individually?
Well, all arguments are delayed due to lazy evaluation. And then there are the .Primitive() and
.Internal() functions. Let's talk about these tomorrow.
- is positional argument matching ok for now?
Absolutely, it is fine for the moment. However, it is probably quite easy.
We can use match.call() to expand the call and match the arguments.
- I'm a bit unclear on createSExt.
That is a cast operation. What do you need to cast and to what?
- How do we do constant detection? Not necessarily for constant folding...
Do you mean a literal or a constant? I think of a literal as being
a string or number. So a literal is a constant value.
And I think of a constant as a variable that doesn't change, i.e. a const in C.
To identify constants in this sense we have to look through the rest of the code.
I imagine you are talking about literals specifically?
Suppose we have an expression or body of a function such as
{
x = 1 + y
sprintf("0x%f", x)
}
We' see the AST/parse tree and it would be equivalent to
e = quote( { x = 1 + y; sprintf("0x%f", x)})
Now, let's look at the first expression (the x = ...) which is element 2
and specifically the RHS:
sapply(e[[2]][[3]], class)
[1] "name" "numeric" "name"
See that the 1 is of class numeric, whereas the others are of class "name"
referring to variables. So if something is of class
logical, integer, numeric, character, complex
in the parse tree, that is a literal/constant.
- What was the dependency finding system you mentioned?
The CodeDepends package. Should be on the omegahat site.
If not, let me know and I can put it there and/or give you access
to the repository on eeyore.ucdavis.edu