You're right that my post's algo does not handle this case (it's more of a toy to explain the basic cases).
> When I read Allan and Kennedy my impression was that vectorising arbitrary imperative code is a much harder problem than designing a language that only allows for vectorisable constructs to be expressed in the first place.
Yeah, I buy this.
> In my example that would produce different code, requiring a multiplication:
lambda i: table[(phase0 + i*inc) % TABLE_LEN]
I think some compilers may lower this without the multiplication.. (e.g. turning it back into an induction variable) but with floats they may not be allowed to, since repeated addition and "phase0 + i*inc" are not strictly equal.
Author here, and yeah, I agree. I skipped writing a parser altogether and just split on whitespace and `|` so that I could get to the interesting bits.
For side-projects, I have to ask myself if I'm writing a parser, or if I'm building something else; e.g. for a toy programming language, it's way more fun to start with an AST and play around, and come back to the parser if you really fall in love with it.
The Lisp variant that the compiler supports at the moment only handles f64 numbers so I don't think this kind of issue is possible.
However, this is a very relevant point. If the goal is just shorter code (as opposed to a mix of shorter code and less run-time operations), then you need to check that folding strings (and similar types) actually makes the expression shorter to represent.
> When I read Allan and Kennedy my impression was that vectorising arbitrary imperative code is a much harder problem than designing a language that only allows for vectorisable constructs to be expressed in the first place.
Yeah, I buy this.
> In my example that would produce different code, requiring a multiplication:
I think some compilers may lower this without the multiplication.. (e.g. turning it back into an induction variable) but with floats they may not be allowed to, since repeated addition and "phase0 + i*inc" are not strictly equal.