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xso-proc: add support for parsing attributes into Strings

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This is bare-bones and is missing many features which we intend to add
in future commits, such as parsing from attributes whose names differ
from the field names and parsing into non-String types.
This commit is contained in:
Jonas Schäfer 2024-06-23 09:06:32 +02:00
commit 212c5c4a83
10 changed files with 665 additions and 50 deletions
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144
xso-proc/src/compound.rs
View file

@ -7,29 +7,41 @@
//! Handling of the insides of compound structures (structs and enum variants)
use proc_macro2::{Span, TokenStream};
use quote::{quote, ToTokens};
use quote::quote;
use syn::*;
use crate::error_message::ParentRef;
use crate::field::{FieldBuilderPart, FieldDef, FieldIteratorPart, FieldTempInit};
use crate::scope::{mangle_member, FromEventsScope, IntoEventsScope};
use crate::state::{FromEventsSubmachine, IntoEventsSubmachine, State};
use crate::types::qname_ty;
/// A struct or enum variant's contents.
pub(crate) struct Compound;
pub(crate) struct Compound {
/// The fields of this compound.
fields: Vec<FieldDef>,
}
impl Compound {
/// Construct a compound from fields.
pub(crate) fn from_fields(compound_fields: &Fields) -> Result<Self> {
match compound_fields {
Fields::Unit => (),
other => {
return Err(Error::new_spanned(
other,
"cannot derive on non-unit struct (yet!)",
))
}
let mut fields = Vec::with_capacity(compound_fields.len());
for (i, field) in compound_fields.iter().enumerate() {
let index = match i.try_into() {
Ok(v) => v,
// we are converting to u32, are you crazy?!
// (u32, because syn::Member::Index needs that.)
Err(_) => {
return Err(Error::new_spanned(
field,
"okay, mate, that are way too many fields. get your life together.",
))
}
};
fields.push(FieldDef::from_field(field, index)?);
}
Ok(Self)
Ok(Self { fields })
}
/// Make and return a set of states which is used to construct the target
@ -40,9 +52,12 @@ impl Compound {
pub(crate) fn make_from_events_statemachine(
&self,
state_ty_ident: &Ident,
output_cons: &Path,
output_name: &ParentRef,
state_prefix: &str,
) -> Result<FromEventsSubmachine> {
let scope = FromEventsScope::new();
let FromEventsScope { ref attrs, .. } = scope;
let default_state_ident = quote::format_ident!("{}Default", state_prefix);
let builder_data_ident = quote::format_ident!("__data");
let builder_data_ty: Type = TypePath {
@ -52,9 +67,44 @@ impl Compound {
.into();
let mut states = Vec::new();
let readable_name = output_cons.to_token_stream().to_string();
let unknown_attr_err = format!("Unknown attribute in {} element.", readable_name);
let unknown_child_err = format!("Unknown child in {} element.", readable_name);
let mut builder_data_def = TokenStream::default();
let mut builder_data_init = TokenStream::default();
let mut output_cons = TokenStream::default();
for field in self.fields.iter() {
let member = field.member();
let builder_field_name = mangle_member(member);
let part = field.make_builder_part(&scope, &output_name)?;
match part {
FieldBuilderPart::Init {
value: FieldTempInit { ty, init },
} => {
builder_data_def.extend(quote! {
#builder_field_name: #ty,
});
builder_data_init.extend(quote! {
#builder_field_name: #init,
});
output_cons.extend(quote! {
#member: #builder_data_ident.#builder_field_name,
});
}
}
}
let unknown_attr_err = format!("Unknown attribute in {}.", output_name);
let unknown_child_err = format!("Unknown child in {}.", output_name);
let output_cons = match output_name {
ParentRef::Named(ref path) => {
quote! {
#path { #output_cons }
}
}
};
states.push(State::new_with_builder(
default_state_ident.clone(),
@ -86,18 +136,21 @@ impl Compound {
Ok(FromEventsSubmachine {
defs: quote! {
struct #builder_data_ty;
struct #builder_data_ty {
#builder_data_def
}
},
states,
init: quote! {
if attrs.len() > 0 {
let #builder_data_ident = #builder_data_ty {
#builder_data_init
};
if #attrs.len() > 0 {
return ::core::result::Result::Err(::xso::error::Error::Other(
#unknown_attr_err,
).into());
}
::core::result::Result::Ok(#state_ty_ident::#default_state_ident {
#builder_data_ident: #builder_data_ty,
})
::core::result::Result::Ok(#state_ty_ident::#default_state_ident { #builder_data_ident })
},
})
}
@ -116,23 +169,54 @@ impl Compound {
input_name: &Path,
state_prefix: &str,
) -> Result<IntoEventsSubmachine> {
let scope = IntoEventsScope::new();
let IntoEventsScope { ref attrs, .. } = scope;
let start_element_state_ident = quote::format_ident!("{}StartElement", state_prefix);
let end_element_state_ident = quote::format_ident!("{}EndElement", state_prefix);
let name_ident = quote::format_ident!("name");
let mut states = Vec::new();
let mut init_body = TokenStream::default();
let mut destructure = TokenStream::default();
let mut start_init = TokenStream::default();
states.push(
State::new(start_element_state_ident.clone())
.with_field(&name_ident, &qname_ty(Span::call_site()))
.with_impl(quote! {
::core::option::Option::Some(::xso::exports::rxml::Event::StartElement(
::xso::exports::rxml::parser::EventMetrics::zero(),
#name_ident,
::xso::exports::rxml::AttrMap::new(),
))
}),
.with_field(&name_ident, &qname_ty(Span::call_site())),
);
for field in self.fields.iter() {
let member = field.member();
let bound_name = mangle_member(member);
let part = field.make_iterator_part(&scope, &bound_name)?;
match part {
FieldIteratorPart::Header { setter } => {
destructure.extend(quote! {
#member: #bound_name,
});
init_body.extend(setter);
start_init.extend(quote! {
#bound_name,
});
states[0].add_field(&bound_name, field.ty());
}
}
}
states[0].set_impl(quote! {
{
let mut #attrs = ::xso::exports::rxml::AttrMap::new();
#init_body
::core::option::Option::Some(::xso::exports::rxml::Event::StartElement(
::xso::exports::rxml::parser::EventMetrics::zero(),
#name_ident,
#attrs,
))
}
});
states.push(
State::new(end_element_state_ident.clone()).with_impl(quote! {
::core::option::Option::Some(::xso::exports::rxml::Event::EndElement(
@ -145,10 +229,10 @@ impl Compound {
defs: TokenStream::default(),
states,
destructure: quote! {
#input_name
#input_name { #destructure }
},
init: quote! {
Self::#start_element_state_ident { #name_ident }
Self::#start_element_state_ident { #name_ident, #start_init }
},
})
}