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Cut down wrapping in ast macro parser

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David Tolnay 2019-08-03 13:50:57 -07:00
parent 11c68a39f5
commit dfe0fe7198
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GPG Key ID: F9BA143B95FF6D82
1 changed files with 62 additions and 75 deletions
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137
codegen/src/parse.rs
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@ -256,7 +256,7 @@ mod parsing {
use proc_macro2::{TokenStream, TokenTree};
use quote::quote;
use syn;
use syn::parse::{Parse, ParseStream, Result};
use syn::parse::{ParseStream, Result};
use syn::*;
use syn_codegen as types;
@ -304,16 +304,12 @@ mod parsing {
})
}
// ast_struct! parsing
pub struct AstStruct(pub(super) Vec<AstItem>);
impl Parse for AstStruct {
fn parse(input: ParseStream) -> Result<Self> {
input.call(Attribute::parse_outer)?;
input.parse::<Token![pub]>()?;
input.parse::<Token![struct]>()?;
let res = input.call(ast_struct_inner)?;
Ok(AstStruct(vec![res]))
}
pub fn ast_struct(input: ParseStream) -> Result<AstItem> {
input.call(Attribute::parse_outer)?;
input.parse::<Token![pub]>()?;
input.parse::<Token![struct]>()?;
let res = input.call(ast_struct_inner)?;
Ok(res)
}
fn no_visit(input: ParseStream) -> bool {
@ -326,27 +322,23 @@ mod parsing {
}
}
// ast_enum! parsing
pub struct AstEnum(pub Vec<AstItem>);
impl Parse for AstEnum {
fn parse(input: ParseStream) -> Result<Self> {
input.call(Attribute::parse_outer)?;
input.parse::<Token![pub]>()?;
input.parse::<Token![enum]>()?;
let ident: Ident = input.parse()?;
let no_visit = no_visit(input);
let rest: TokenStream = input.parse()?;
Ok(AstEnum(if no_visit {
vec![]
} else {
vec![AstItem {
ast: syn::parse2(quote! {
pub enum #ident #rest
})?,
features: vec![],
}]
}))
}
pub fn ast_enum(input: ParseStream) -> Result<Option<AstItem>> {
input.call(Attribute::parse_outer)?;
input.parse::<Token![pub]>()?;
input.parse::<Token![enum]>()?;
let ident: Ident = input.parse()?;
let no_visit = no_visit(input);
let rest: TokenStream = input.parse()?;
Ok(if no_visit {
None
} else {
Some(AstItem {
ast: syn::parse2(quote! {
pub enum #ident #rest
})?,
features: vec![],
})
})
}
// A single variant of an ast_enum_of_structs!
@ -372,47 +364,42 @@ mod parsing {
})
}
// ast_enum_of_structs! parsing
pub struct AstEnumOfStructs(pub Vec<AstItem>);
impl Parse for AstEnumOfStructs {
fn parse(input: ParseStream) -> Result<Self> {
input.call(Attribute::parse_outer)?;
input.parse::<Token![pub]>()?;
input.parse::<Token![enum]>()?;
let ident: Ident = input.parse()?;
skip_manual_extra_traits(input);
pub fn ast_enum_of_structs(input: ParseStream) -> Result<AstItem> {
input.call(Attribute::parse_outer)?;
input.parse::<Token![pub]>()?;
input.parse::<Token![enum]>()?;
let ident: Ident = input.parse()?;
skip_manual_extra_traits(input);
let content;
braced!(content in input);
let mut variants = Vec::new();
while !content.is_empty() {
variants.push(content.call(eos_variant)?);
}
if let Some(ident) = input.parse::<Option<Ident>>()? {
assert_eq!(ident, "do_not_generate_to_tokens");
}
let enum_item = {
let variants = variants.iter().map(|v| {
let name = v.name.clone();
match v.member {
Some(ref member) => quote!(#name(#member)),
None => quote!(#name),
}
});
parse_quote! {
pub enum #ident {
#(#variants),*
}
}
};
let items = vec![AstItem {
ast: enum_item,
features: vec![],
}];
Ok(AstEnumOfStructs(items))
let content;
braced!(content in input);
let mut variants = Vec::new();
while !content.is_empty() {
variants.push(content.call(eos_variant)?);
}
if let Some(ident) = input.parse::<Option<Ident>>()? {
assert_eq!(ident, "do_not_generate_to_tokens");
}
let enum_item = {
let variants = variants.iter().map(|v| {
let name = v.name.clone();
match v.member {
Some(ref member) => quote!(#name(#member)),
None => quote!(#name),
}
});
parse_quote! {
pub enum #ident {
#(#variants),*
}
}
};
Ok(AstItem {
ast: enum_item,
features: vec![],
})
}
mod kw {
@ -569,13 +556,13 @@ fn load_file<P: AsRef<Path>>(
let features = get_features(&item.attrs, features);
// Try to parse the AstItem declaration out of the item.
let tts = &item.mac.tokens;
let tts = item.mac.tokens.clone();
let found = if item.mac.path.is_ident("ast_struct") {
syn::parse2::<parsing::AstStruct>(quote!(#tts))?.0
Some(parsing::ast_struct.parse2(tts)?)
} else if item.mac.path.is_ident("ast_enum") {
syn::parse2::<parsing::AstEnum>(quote!(#tts))?.0
parsing::ast_enum.parse2(tts)?
} else if item.mac.path.is_ident("ast_enum_of_structs") {
syn::parse2::<parsing::AstEnumOfStructs>(quote!(#tts))?.0
Some(parsing::ast_enum_of_structs.parse2(tts)?)
} else {
continue;
};