kobold_macros 0.1.0

Macros for the kobold framework
Documentation 
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// The `quote!` macro requires deep recursion.
#![recursion_limit = "196"]
#![warn(clippy::all, clippy::cast_possible_truncation, clippy::unused_self)]

extern crate proc_macro;

use proc_macro::TokenStream;
use proc_macro2::TokenStream as QuoteTokens;
use quote::quote;

mod dom;
mod gen;
mod parser;

use gen::Generator;
use parser::Parser;

#[proc_macro]
pub fn html(body: TokenStream) -> TokenStream {
    let mut parser = Parser::new();

    let dom = match parser.parse(body) {
        Ok(dom) => dom,
        Err(err) => return err.tokenize(),
    };

    // panic!("{:#?}\n\n{:#?}", dom, parser.fields);

    let fields = &parser.fields;

    let generics = fields.iter().map(|field| &field.typ).collect::<Vec<_>>();
    let generics = &generics;

    let field_names = fields.iter().map(|field| &field.name).collect::<Vec<_>>();
    let field_names = &field_names;

    let field_defs = fields
        .iter()
        .map(|field| {
            let typ = &field.typ;
            let name = &field.name;

            quote! {
                #name: #typ,
            }
        })
        .collect::<QuoteTokens>();
    let field_defs = &field_defs;

    let field_declr = fields
        .iter()
        .map(|field| {
            let expr = &field.expr;
            let name = &field.name;

            quote! {
                #name: #expr,
            }
        })
        .collect::<QuoteTokens>();

    let mut generator = Generator::new(fields.iter());

    let root = generator.generate(&dom).unwrap();
    let (js_fn_name, render) = generator.render_js(&root);

    let tokens: TokenStream = (quote! {
        {
            use ::kobold::{Html, Node, JsValue};
            use ::kobold::reexport::wasm_bindgen::{self, prelude::wasm_bindgen};

            #render

            struct TransientHtml<#(#generics),*> {
                #field_defs
            }

            struct TransientBuilt<#(#generics),*> {
                #field_defs
                node: Node,
            }

            impl<#(#generics: Html),*> Html for TransientHtml<#(#generics),*> {
                type Built = TransientBuilt<#(<#generics as Html>::Built),*>;

                fn build(self) -> Self::Built {
                    #(
                        let #field_names = self.#field_names.build();
                    )*
                    let node = #js_fn_name(#(#field_names.js()),*);

                    TransientBuilt {
                        #(#field_names,)*
                        node,
                    }
                }
            }

            impl<#(#generics),*> ::kobold::Mountable for TransientBuilt<#(#generics),*> {
                fn js(&self) -> &JsValue {
                    &self.node
                }
            }

            impl<#(#generics: Html),*> ::kobold::Update<TransientHtml<#(#generics),*>> for TransientBuilt<#(<#generics as Html>::Built),*> {
                fn update(&mut self, new: TransientHtml<#(#generics),*>) {
                    #(
                        self.#field_names.update(new.#field_names);
                    )*
                }
            }

            TransientHtml {
                #field_declr
            }
        }
    }).into();

    // panic!("{}", tokens);

    tokens
}