* Add proc_macro2 and quote dependencies
* Completly switch over to proc_macro2 where possible
* Remove unessesary ::from casts
* Remove pendantic cast that i missed
* Make Builder::push_tokens accept TokenStream
* Remove stray commented out code
* Reword unclear comment on `Span` to a todo item
* Move comment closer to its intended line
* Use into instead of explicit conversion
Instead of a `kind` field containting a `TokenNode` variant, a
TokenTree is now an enum with variants of different types (Literal, Op,
Term, etc). Note that a TokenTree could be a sequence of TokenTrees if it is a
Group variant.
Other notes:
I'm unsure about the set_span call in Builder::emit_if, but I did not want to
throw away the passed in Span.
Parsing relies on destructuring references to the values associated with
TokenTree enum variants
It doesn't seem as easy to compose/chain TokenStreams as it is to
collect a Vec<TokenTree> into a TokenStream. There is probably some
iterator API I could use instead. See `match_arms` and build.rs
Refs #121
After fiddling around with zero-allocation solutions, I concluded that
all non-allocating approaches are too annoying to work with in realistic
code. Using closures leads to yak-shaving with lifetimes; and because
Iron needs to take ownership of the response body we often end up
cloning the input data anyway.
Removing this constraint has let me simplify the entire system, removing
a net 300 lines from the library. The `html!` macro no longer takes a
writer, and instead returns a `PreEscaped<String>`. This means that the
result of an `html!` can be spliced directly into another `html!`,
removing the need for the `impl Template` rigmarole.
To rub it in, benchmarks show the new code is in fact *faster* than it
was before. How lovely.
