git.delta.rocks / jrsonnet / refs/commits / 58696dc4e430

1use proc_macro2::TokenStream;2use quote::quote;3use syn::{4	parenthesized,5	parse::{Parse, ParseStream},6	parse_macro_input,7	punctuated::Punctuated,8	spanned::Spanned,9	token::{self, Comma},10	Attribute, DeriveInput, Error, Expr, FnArg, GenericArgument, Ident, ItemFn, LitStr, Pat, Path,11	PathArguments, Result, ReturnType, Token, Type,12};1314fn parse_attr<A: Parse, I>(attrs: &[Attribute], ident: I) -> Result<Option<A>>15where16	Ident: PartialEq<I>,17{18	let attrs = attrs19		.iter()20		.filter(|a| a.path().is_ident(&ident))21		.collect::<Vec<_>>();22	if attrs.len() > 1 {23		return Err(Error::new(24			attrs[1].span(),25			"this attribute may be specified only once",26		));27	} else if attrs.is_empty() {28		return Ok(None);29	}30	let attr = attrs[0];31	let attr = attr.parse_args::<A>()?;3233	Ok(Some(attr))34}3536fn path_is(path: &Path, needed: &str) -> bool {37	path.leading_colon.is_none()38		&& !path.segments.is_empty()39		&& path.segments.iter().last().unwrap().ident == needed40}4142fn type_is_path<'ty>(ty: &'ty Type, needed: &str) -> Option<&'ty PathArguments> {43	match ty {44		Type::Path(path) if path.qself.is_none() && path_is(&path.path, needed) => {45			let args = &path.path.segments.iter().last().unwrap().arguments;46			Some(args)47		}48		_ => None,49	}50}5152fn extract_type_from_option(ty: &Type) -> Result<Option<&Type>> {53	let Some(args) = type_is_path(ty, "Option") else {54		return Ok(None);55	};56	// It should have only on angle-bracketed param ("<String>"):57	let PathArguments::AngleBracketed(params) = args else {58		return Err(Error::new(args.span(), "missing option generic"));59	};60	let generic_arg = params.args.iter().next().unwrap();61	// This argument must be a type:62	let GenericArgument::Type(ty) = generic_arg else {63		return Err(Error::new(64			generic_arg.span(),65			"option generic should be a type",66		));67	};68	Ok(Some(ty))69}7071struct Field {72	attrs: Vec<Attribute>,73	name: Ident,74	_colon: Token![:],75	ty: Type,76}77impl Parse for Field {78	fn parse(input: ParseStream) -> syn::Result<Self> {79		Ok(Self {80			attrs: input.call(Attribute::parse_outer)?,81			name: input.parse()?,82			_colon: input.parse()?,83			ty: input.parse()?,84		})85	}86}8788mod kw {89	syn::custom_keyword!(fields);90	syn::custom_keyword!(rename);91	syn::custom_keyword!(flatten);92	syn::custom_keyword!(add);93	syn::custom_keyword!(hide);94	syn::custom_keyword!(ok);95}9697struct EmptyAttr;98impl Parse for EmptyAttr {99	fn parse(_input: ParseStream) -> Result<Self> {100		Ok(Self)101	}102}103104struct BuiltinAttrs {105	fields: Vec<Field>,106}107impl Parse for BuiltinAttrs {108	fn parse(input: ParseStream) -> syn::Result<Self> {109		if input.is_empty() {110			return Ok(Self { fields: Vec::new() });111		}112		input.parse::<kw::fields>()?;113		let fields;114		parenthesized!(fields in input);115		let p = Punctuated::<Field, Comma>::parse_terminated(&fields)?;116		Ok(Self {117			fields: p.into_iter().collect(),118		})119	}120}121122enum ArgInfo {123	Normal {124		ty: Box<Type>,125		is_option: bool,126		name: Option<String>,127		cfg_attrs: Vec<Attribute>,128	},129	Lazy {130		is_option: bool,131		name: Option<String>,132	},133	Context,134	Location,135	This,136}137138impl ArgInfo {139	fn parse(name: &str, arg: &FnArg) -> Result<Self> {140		let FnArg::Typed(arg) = arg else {141			unreachable!()142		};143		let ident = match &arg.pat as &Pat {144			Pat::Ident(i) => Some(i.ident.clone()),145			_ => None,146		};147		let ty = &arg.ty;148		if type_is_path(ty, "Context").is_some() {149			return Ok(Self::Context);150		} else if type_is_path(ty, "CallLocation").is_some() {151			return Ok(Self::Location);152		} else if type_is_path(ty, "Thunk").is_some() {153			return Ok(Self::Lazy {154				is_option: false,155				name: ident.map(|v| v.to_string()),156			});157		}158159		match ty as &Type {160			Type::Reference(r) if type_is_path(&r.elem, name).is_some() => return Ok(Self::This),161			_ => {}162		}163164		let (is_option, ty) = if let Some(ty) = extract_type_from_option(ty)? {165			if type_is_path(ty, "Thunk").is_some() {166				return Ok(Self::Lazy {167					is_option: true,168					name: ident.map(|v| v.to_string()),169				});170			}171172			(true, Box::new(ty.clone()))173		} else {174			(false, ty.clone())175		};176177		let cfg_attrs = arg178			.attrs179			.iter()180			.filter(|a| a.path().is_ident("cfg"))181			.cloned()182			.collect();183184		Ok(Self::Normal {185			ty,186			is_option,187			name: ident.map(|v| v.to_string()),188			cfg_attrs,189		})190	}191}192193#[proc_macro_attribute]194pub fn builtin(195	attr: proc_macro::TokenStream,196	item: proc_macro::TokenStream,197) -> proc_macro::TokenStream {198	let attr = parse_macro_input!(attr as BuiltinAttrs);199	let item_fn = item.clone();200	let item_fn: ItemFn = parse_macro_input!(item_fn);201202	match builtin_inner(attr, item_fn, item.into()) {203		Ok(v) => v.into(),204		Err(e) => e.into_compile_error().into(),205	}206}207208fn builtin_inner(209	attr: BuiltinAttrs,210	fun: ItemFn,211	item: proc_macro2::TokenStream,212) -> syn::Result<TokenStream> {213	let ReturnType::Type(_, result) = &fun.sig.output else {214		return Err(Error::new(215			fun.sig.span(),216			"builtin should return something",217		));218	};219220	let name = fun.sig.ident.to_string();221	let args = fun222		.sig223		.inputs224		.iter()225		.map(|arg| ArgInfo::parse(&name, arg))226		.collect::<Result<Vec<_>>>()?;227228	let params_desc = args.iter().flat_map(|a| match a {229		ArgInfo::Normal {230			is_option,231			name,232			cfg_attrs,233			..234		} => {235			let name = name236				.as_ref()237				.map(|n| quote! {ParamName::new_static(#n)})238				.unwrap_or_else(|| quote! {None});239			Some(quote! {240				#(#cfg_attrs)*241				BuiltinParam::new(#name, #is_option),242			})243		}244		ArgInfo::Lazy { is_option, name } => {245			let name = name246				.as_ref()247				.map(|n| quote! {ParamName::new_static(#n)})248				.unwrap_or_else(|| quote! {None});249			Some(quote! {250				BuiltinParam::new(#name, #is_option),251			})252		}253		ArgInfo::Context => None,254		ArgInfo::Location => None,255		ArgInfo::This => None,256	});257258	let mut id = 0usize;259	let pass = args260		.iter()261		.map(|a| match a {262			ArgInfo::Normal { .. } | ArgInfo::Lazy { .. } => {263				let cid = id;264				id += 1;265				(quote! {#cid}, a)266			}267			ArgInfo::Context | ArgInfo::Location | ArgInfo::This => {268				(quote! {compile_error!("should not use id")}, a)269			}270		})271		.map(|(id, a)| match a {272			ArgInfo::Normal {273				ty,274				is_option,275				name,276				cfg_attrs,277			} => {278				let name = name.as_ref().map(|v| v.as_str()).unwrap_or("<unnamed>");279				let eval = quote! {jrsonnet_evaluator::State::push_description(280					|| format!("argument <{}> evaluation", #name),281					|| <#ty>::from_untyped(value.evaluate()?),282				)?};283				let value = if *is_option {284					quote! {if let Some(value) = &parsed[#id] {285						Some(#eval)286					} else {287						None288					},}289				} else {290					quote! {{291						let value = parsed[#id].as_ref().expect("args shape is checked");292						#eval293					},}294				};295				quote! {296					#(#cfg_attrs)*297					#value298				}299			}300			ArgInfo::Lazy { is_option, .. } => {301				if *is_option {302					quote! {if let Some(value) = &parsed[#id] {303						Some(value.clone())304					} else {305						None306					}}307				} else {308					quote! {309						parsed[#id].as_ref().expect("args shape is correct").clone(),310					}311				}312			}313			ArgInfo::Context => quote! {ctx.clone(),},314			ArgInfo::Location => quote! {location,},315			ArgInfo::This => quote! {self,},316		});317318	let fields = attr.fields.iter().map(|field| {319		let attrs = &field.attrs;320		let name = &field.name;321		let ty = &field.ty;322		quote! {323			#(#attrs)*324			pub #name: #ty,325		}326	});327328	let name = &fun.sig.ident;329	let vis = &fun.vis;330	let static_ext = if attr.fields.is_empty() {331		quote! {332			impl #name {333				pub const INST: &'static dyn StaticBuiltin = &#name {};334			}335			impl StaticBuiltin for #name {}336		}337	} else {338		quote! {}339	};340	let static_derive_copy = if attr.fields.is_empty() {341		quote! {, Copy}342	} else {343		quote! {}344	};345346	Ok(quote! {347		#item348349		#[doc(hidden)]350		#[allow(non_camel_case_types)]351		#[derive(Clone, jrsonnet_gcmodule::Trace #static_derive_copy)]352		#vis struct #name {353			#(#fields)*354		}355		const _: () = {356			use ::jrsonnet_evaluator::{357				State, Val,358				function::{builtin::{Builtin, StaticBuiltin, BuiltinParam, ParamName}, CallLocation, ArgsLike, parse::parse_builtin_call},359				Result, Context, typed::Typed,360				parser::ExprLocation,361			};362			const PARAMS: &'static [BuiltinParam] = &[363				#(#params_desc)*364			];365366			#static_ext367			impl Builtin for #name368			where369				Self: 'static370			{371				fn name(&self) -> &str {372					stringify!(#name)373				}374				fn params(&self) -> &[BuiltinParam] {375					PARAMS376				}377				#[allow(unused_variable)]378				fn call(&self, ctx: Context, location: CallLocation, args: &dyn ArgsLike) -> Result<Val> {379					let parsed = parse_builtin_call(ctx.clone(), &PARAMS, args, false)?;380381					let result: #result = #name(#(#pass)*);382					<_ as Typed>::into_result(result)383				}384				fn as_any(&self) -> &dyn ::std::any::Any {385					self386				}387			}388		};389	})390}391392#[derive(Default)]393struct TypedAttr {394	rename: Option<String>,395	flatten: bool,396	/// flatten(ok) strategy for flattened optionals397	/// field would be None in case of any parsing error (as in serde)398	flatten_ok: bool,399	// Should it be `field+:` instead of `field:`400	add: bool,401	// Should it be `field::` instead of `field:`402	hide: bool,403}404impl Parse for TypedAttr {405	fn parse(input: ParseStream) -> syn::Result<Self> {406		let mut out = Self::default();407		loop {408			let lookahead = input.lookahead1();409			if lookahead.peek(kw::rename) {410				input.parse::<kw::rename>()?;411				input.parse::<Token![=]>()?;412				let name = input.parse::<LitStr>()?;413				if out.rename.is_some() {414					return Err(Error::new(415						name.span(),416						"rename attribute may only be specified once",417					));418				}419				out.rename = Some(name.value());420			} else if lookahead.peek(kw::flatten) {421				input.parse::<kw::flatten>()?;422				out.flatten = true;423				if input.peek(token::Paren) {424					let content;425					parenthesized!(content in input);426					let lookahead = content.lookahead1();427					if lookahead.peek(kw::ok) {428						content.parse::<kw::ok>()?;429						out.flatten_ok = true;430					} else {431						return Err(lookahead.error());432					}433				}434			} else if lookahead.peek(kw::add) {435				input.parse::<kw::add>()?;436				out.add = true;437			} else if lookahead.peek(kw::hide) {438				input.parse::<kw::hide>()?;439				out.hide = true;440			} else if input.is_empty() {441				break;442			} else {443				return Err(lookahead.error());444			}445			if input.peek(Token![,]) {446				input.parse::<Token![,]>()?;447			} else {448				break;449			}450		}451		Ok(out)452	}453}454455struct TypedField {456	attr: TypedAttr,457	ident: Ident,458	ty: Type,459	is_option: bool,460}461impl TypedField {462	fn parse(field: &syn::Field) -> Result<Self> {463		let attr = parse_attr::<TypedAttr, _>(&field.attrs, "typed")?.unwrap_or_default();464		let Some(ident) = field.ident.clone() else {465			return Err(Error::new(466				field.span(),467				"this field should appear in output object, but it has no visible name",468			));469		};470		let (is_option, ty) = if let Some(ty) = extract_type_from_option(&field.ty)? {471			(true, ty.clone())472		} else {473			(false, field.ty.clone())474		};475		if is_option && attr.flatten {476			if !attr.flatten_ok {477				return Err(Error::new(478					field.span(),479					"strategy should be set when flattening Option",480				));481			}482		} else if attr.flatten_ok {483			return Err(Error::new(484				field.span(),485				"flatten(ok) is only useable on optional fields",486			));487		}488489		Ok(Self {490			attr,491			ident,492			ty,493			is_option,494		})495	}496	/// None if this field is flattened in jsonnet output497	fn name(&self) -> Option<String> {498		if self.attr.flatten {499			return None;500		}501		Some(502			self.attr503				.rename504				.clone()505				.unwrap_or_else(|| self.ident.to_string()),506		)507	}508509	fn expand_field(&self) -> Option<TokenStream> {510		if self.is_option {511			return None;512		}513		let name = self.name()?;514		let ty = &self.ty;515		Some(quote! {516			(#name, <#ty as Typed>::TYPE)517		})518	}519	fn expand_parse(&self) -> TokenStream {520		let ident = &self.ident;521		let ty = &self.ty;522		if self.attr.flatten {523			// optional flatten is handled in same way as serde524			return if self.is_option {525				quote! {526					#ident: <#ty as TypedObj>::parse(&obj).ok(),527				}528			} else {529				quote! {530					#ident: <#ty as TypedObj>::parse(&obj)?,531				}532			};533		};534535		let name = self.name().unwrap();536		let value = if self.is_option {537			quote! {538				if let Some(value) = obj.get(#name.into())? {539					Some(<#ty as Typed>::from_untyped(value)?)540				} else {541					None542				}543			}544		} else {545			quote! {546				<#ty as Typed>::from_untyped(obj.get(#name.into())?.ok_or_else(|| ErrorKind::NoSuchField(#name.into(), vec![]))?)?547			}548		};549550		quote! {551			#ident: #value,552		}553	}554	fn expand_serialize(&self) -> Result<TokenStream> {555		let ident = &self.ident;556		let ty = &self.ty;557		Ok(if let Some(name) = self.name() {558			let hide = if self.attr.hide {559				quote! {.hide()}560			} else {561				quote! {}562			};563			let add = if self.attr.add {564				quote! {.add()}565			} else {566				quote! {}567			};568			if self.is_option {569				quote! {570					if let Some(value) = self.#ident {571						out.field(#name)572							#hide573							#add574							.try_value(<#ty as Typed>::into_untyped(value)?)?;575					}576				}577			} else {578				quote! {579					out.field(#name)580						#hide581						#add582						.try_value(<#ty as Typed>::into_untyped(self.#ident)?)?;583				}584			}585		} else if self.is_option {586			quote! {587				if let Some(value) = self.#ident {588					<#ty as TypedObj>::serialize(value, out)?;589				}590			}591		} else {592			quote! {593				<#ty as TypedObj>::serialize(self.#ident, out)?;594			}595		})596	}597}598599#[proc_macro_derive(Typed, attributes(typed))]600pub fn derive_typed(item: proc_macro::TokenStream) -> proc_macro::TokenStream {601	let input = parse_macro_input!(item as DeriveInput);602603	match derive_typed_inner(input) {604		Ok(v) => v.into(),605		Err(e) => e.to_compile_error().into(),606	}607}608609fn derive_typed_inner(input: DeriveInput) -> Result<TokenStream> {610	let syn::Data::Struct(data) = &input.data else {611		return Err(Error::new(input.span(), "only structs supported"));612	};613614	let ident = &input.ident;615	let fields = data616		.fields617		.iter()618		.map(TypedField::parse)619		.collect::<Result<Vec<_>>>()?;620621	let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();622623	let typed = {624		let fields = fields625			.iter()626			.flat_map(TypedField::expand_field)627			.collect::<Vec<_>>();628		quote! {629			impl #impl_generics Typed for #ident #ty_generics #where_clause {630				const TYPE: &'static ComplexValType = &ComplexValType::ObjectRef(&[631					#(#fields,)*632				]);633634				fn from_untyped(value: Val) -> JrResult<Self> {635					let obj = value.as_obj().expect("shape is correct");636					Self::parse(&obj)637				}638639				fn into_untyped(value: Self) -> JrResult<Val> {640					let mut out = ObjValueBuilder::new();641					value.serialize(&mut out)?;642					Ok(Val::Obj(out.build()))643				}644645			}646		}647	};648649	let fields_parse = fields.iter().map(TypedField::expand_parse);650	let fields_serialize = fields651		.iter()652		.map(TypedField::expand_serialize)653		.collect::<Result<Vec<_>>>()?;654655	Ok(quote! {656		const _: () = {657			use ::jrsonnet_evaluator::{658				typed::{ComplexValType, Typed, TypedObj, CheckType},659				Val, State,660				error::{ErrorKind, Result as JrResult},661				ObjValueBuilder, ObjValue,662			};663664			#typed665666			impl #impl_generics TypedObj for #ident #ty_generics #where_clause {667				fn serialize(self, out: &mut ObjValueBuilder) -> JrResult<()> {668					#(#fields_serialize)*669670					Ok(())671				}672				fn parse(obj: &ObjValue) -> JrResult<Self> {673					Ok(Self {674						#(#fields_parse)*675					})676				}677			}678		};679	})680}681682struct FormatInput {683	formatting: LitStr,684	arguments: Vec<Expr>,685}686impl Parse for FormatInput {687	fn parse(input: ParseStream) -> Result<Self> {688		let formatting = input.parse()?;689		let mut arguments = Vec::new();690691		while input.peek(Token![,]) {692			input.parse::<Token![,]>()?;693			if input.is_empty() {694				// Trailing comma695				break;696			}697			let expr = input.parse()?;698			arguments.push(expr);699		}700701		if !input.is_empty() {702			return Err(syn::Error::new(input.span(), "unexpected trailing input"));703		}704705		Ok(Self {706			formatting,707			arguments,708		})709	}710}711fn is_format_str(i: &str) -> bool {712	let mut is_plain = true;713	// -1 = {714	// +1 = }715	let mut is_bracket = 0i8;716	for ele in i.chars() {717		match ele {718			'{' if is_bracket == -1 => {719				is_bracket = 0;720			}721			'}' if is_bracket == -1 => {722				is_plain = false;723				break;724			}725			'}' if is_bracket == 1 => {726				is_bracket = 0;727			}728			'{' if is_bracket == 1 => {729				is_plain = false;730				break;731			}732			'{' => {733				is_bracket = -1;734			}735			'}' => {736				is_bracket = 1;737			}738			_ if is_bracket != 0 => {739				is_plain = false;740				break;741			}742			_ => {}743		}744	}745	!is_plain || is_bracket != 0746}747impl FormatInput {748	fn expand(self) -> TokenStream {749		let format = self.formatting;750		if is_format_str(&format.value()) {751			let args = self.arguments;752			quote! {753				::jrsonnet_evaluator::IStr::from(format!(#format #(, #args)*))754			}755		} else {756			if let Some(first) = self.arguments.first() {757				return syn::Error::new(758					first.span(),759					"string has no formatting codes, it should not have the arguments",760				)761				.into_compile_error();762			}763			quote! {764				::jrsonnet_evaluator::IStr::from(#format)765			}766		}767	}768}769770/// IStr formatting helper771///772/// Using `format!("literal with no codes").into()` is slower than just `"literal with no codes".into()`773/// This macro looks for formatting codes in the input string, and uses774/// `format!()` only when necessary775#[proc_macro]776pub fn format_istr(input: proc_macro::TokenStream) -> proc_macro::TokenStream {777	let input = parse_macro_input!(input as FormatInput);778	input.expand().into()779}