git.delta.rocks / jrsonnet / refs/commits / b915f23c48a1

difftreelog

refactor prepared signatures in IR

zvuulvvlYaroslav Bolyukin2026-03-21parent: #df5053d.patch.diff
in: master

15 files changed

modifiedcrates/jrsonnet-evaluator/src/async_import.rsdiffbeforeafterboth
before · crates/jrsonnet-evaluator/src/async_import.rs
1use std::rc::Rc;2use std::{any::Any, cell::RefCell, future::Future};34use jrsonnet_gcmodule::Acyclic;5use jrsonnet_parser::{6	ArgsDesc, AssertExpr, AssertStmt, BindSpec, CompSpec, Destruct, Expr, FieldMember, FieldName,7	ForSpecData, IfElse, IfSpecData, ImportKind, ObjBody, Param, ParamsDesc,8	ParserSettings, Slice, SliceDesc, Source, SourcePath, Spanned,9};10use rustc_hash::FxHashMap;1112use crate::{AsPathLike, FileData, ImportResolver, ResolvePathOwned, State};1314pub struct Import {15	path: ResolvePathOwned,16	expression: bool,17}1819pub struct FoundImports(Vec<Import>);2021// Visits all nodes, trying to find import statements22#[allow(clippy::too_many_lines)]23pub fn find_imports(expr: &Spanned<Expr>, out: &mut FoundImports) {24	fn in_destruct(dest: &Destruct, #[allow(unused_variables)] out: &mut FoundImports) {25		match dest {26			#[cfg(feature = "exp-destruct")]27			Destruct::Array {28				start,29				rest: _,30				end,31			} => {32				for dest in start {33					in_destruct(dest, out);34				}35				for dest in end {36					in_destruct(dest, out);37				}38			}39			#[cfg(feature = "exp-destruct")]40			Destruct::Object { fields, rest: _ } => {41				for (_, dest, default) in fields {42					if let Some(dest) = dest {43						in_destruct(dest, out);44					}45					if let Some(expr) = default {46						find_imports(expr, out);47					}48				}49			}50			#[cfg(feature = "exp-destruct")]51			Destruct::Skip => {}52			Destruct::Full(_) => {}53		}54	}55	fn in_compspec(specs: &[CompSpec], out: &mut FoundImports) {56		for spec in specs {57			match spec {58				CompSpec::IfSpec(IfSpecData(expr)) => find_imports(expr, out),59				CompSpec::ForSpec(ForSpecData(destruct, expr)) => {60					in_destruct(destruct, out);61					find_imports(expr, out);62				}63			}64		}65	}66	fn in_params(params: &ParamsDesc, out: &mut FoundImports) {67		for Param(dest, default) in &*params.0 {68			in_destruct(dest, out);69			if let Some(expr) = default {70				find_imports(expr, out);71			}72		}73	}74	fn in_bind(specs: &[BindSpec], out: &mut FoundImports) {75		for spec in specs {76			match spec {77				BindSpec::Field {78					into: dest,79					value: expr,80				} => {81					in_destruct(dest, out);82					find_imports(expr, out);83				}84				BindSpec::Function {85					name: _,86					params,87					value: expr,88				} => {89					in_params(params, out);90					find_imports(expr, out);91				}92			}93		}94	}95	fn in_args(ArgsDesc { unnamed, named }: &ArgsDesc, out: &mut FoundImports) {96		for expr in unnamed {97			find_imports(expr, out);98		}99		for (_, expr) in named {100			find_imports(expr, out);101		}102	}103	fn in_obj(obj: &ObjBody, out: &mut FoundImports) {104		match obj {105			ObjBody::MemberList(obj) => {106				for FieldMember {107					name,108					params,109					value,110					..111				} in &obj.fields112				{113					match name {114						FieldName::Fixed(_) => {}115						FieldName::Dyn(expr) => find_imports(expr, out),116					}117					if let Some(params) = params {118						in_params(params, out);119					}120					find_imports(value, out);121				}122				for _ in &*obj.locals {123					todo!()124				}125				for assert in &*obj.asserts {126					find_imports(&assert.0, out);127					if let Some(expr) = &assert.1 {128						find_imports(expr, out);129					}130				}131			}132			ObjBody::ObjComp(_) => todo!(),133		}134	}135	match &**expr {136		Expr::Import(_, v) => {137			if let Expr::Str(s) = &***v {138				out.0.push(Import {139					path: ResolvePathOwned::Str(s.to_string()),140					expression: matches!(&**expr, Expr::Import(ImportKind::Normal, _)),141				});142			}143			// Non-string import will fail in runtime144		}145146		Expr::Literal(_) | Expr::Str(_) | Expr::Num(_) | Expr::Var(_) => {}147148		Expr::Arr(arr) => {149			for expr in &**arr {150				find_imports(expr, out);151			}152		}153		Expr::ArrComp(expr, specs) => {154			find_imports(expr, out);155			in_compspec(specs, out);156		}157		Expr::Obj(obj) => in_obj(obj, out),158		Expr::ObjExtend(expr, obj) => {159			find_imports(expr, out);160			in_obj(obj, out);161		}162		Expr::BinaryOp(binop) => {163			find_imports(&binop.lhs, out);164			find_imports(&binop.rhs, out);165		}166		Expr::AssertExpr(assert) => {167			let AssertExpr {168				assert: AssertStmt(expr, expr2),169				rest,170			} = &**assert;171			find_imports(expr, out);172			if let Some(expr) = expr2 {173				find_imports(expr, out);174			}175			find_imports(rest, out);176		}177		Expr::LocalExpr(specs, expr) => {178			in_bind(specs, out);179			find_imports(expr, out);180		}181		Expr::Apply(expr, args, _) => {182			find_imports(expr, out);183			in_args(args, out);184		}185		Expr::Index { indexable, parts } => {186			find_imports(indexable, out);187			for part in parts {188				find_imports(&part.value, out);189			}190		}191		Expr::Function(params, expr) => {192			in_params(params, out);193			find_imports(expr, out);194		}195		Expr::IfElse(if_else) => {196			let IfElse {197				cond: IfSpecData(expr),198				cond_then,199				cond_else,200			} = &**if_else;201			find_imports(expr, out);202			find_imports(cond_then, out);203			if let Some(expr) = cond_else {204				find_imports(expr, out);205			}206		}207		Expr::Slice(slice) => {208			let Slice {209				value,210				slice: SliceDesc { start, end, step },211			} = &**slice;212			find_imports(value, out);213			if let Some(expr) = start {214				find_imports(expr, out);215			}216			if let Some(expr) = end {217				find_imports(expr, out);218			}219			if let Some(expr) = step {220				find_imports(expr, out);221			}222		}223		Expr::UnaryOp(_, expr) | Expr::ErrorStmt(expr) => {224			find_imports(expr, out);225		}226	}227}228229pub trait AsyncImportResolver {230	type Error;231	/// Resolves file path, e.g. `(/home/user/manifests, b.libjsonnet)` can correspond232	/// both to `/home/user/manifests/b.libjsonnet` and to `/home/user/${vendor}/b.libjsonnet`233	/// where `${vendor}` is a library path.234	///235	/// `from` should only be returned from [`ImportResolver::resolve`],236	/// or from other defined file, any other value may result in panic237	fn resolve_from(238		&self,239		from: &SourcePath,240		path: &dyn AsPathLike,241	) -> impl Future<Output = Result<SourcePath, Self::Error>>;242	fn resolve_from_default(243		&self,244		path: &dyn AsPathLike,245	) -> impl Future<Output = Result<SourcePath, Self::Error>> {246		async { self.resolve_from(&SourcePath::default(), path).await }247	}248249	/// Load resolved file250	/// This should only be called with value returned251	/// from [`ImportResolver::resolve_file`]/[`ImportResolver::resolve`],252	/// this cannot be resolved using associated type,253	/// as the evaluator uses object instead of generic for [`ImportResolver`]254	fn load_file_contents(255		&self,256		resolved: &SourcePath,257	) -> impl Future<Output = Result<Vec<u8>, Self::Error>>;258}259260#[derive(Acyclic)]261struct ResolvedImportResolver {262	resolved: RefCell<FxHashMap<(SourcePath, ResolvePathOwned), (SourcePath, bool)>>,263}264impl ImportResolver for ResolvedImportResolver {265	fn load_file_contents(&self, _resolved: &SourcePath) -> crate::Result<Vec<u8>> {266		unreachable!("all files should be loaded at this point");267	}268269	fn resolve_from(&self, from: &SourcePath, path: &dyn AsPathLike) -> crate::Result<SourcePath> {270		Ok(self271			.resolved272			.borrow()273			.get(&(from.clone(), path.as_path().to_owned()))274			.expect("all imports should be resolved at this point")275			.0276			.clone())277	}278279	fn resolve_from_default(&self, path: &dyn AsPathLike) -> crate::Result<SourcePath> {280		self.resolve_from(&SourcePath::default(), path)281	}282}283284enum Job {285	LoadFile { path: SourcePath, parse: bool },286	ParseFile(SourcePath),287	ResolveImport { from: SourcePath, import: Import },288}289290#[allow(clippy::future_not_send)]291pub async fn async_import<H>(s: State, handler: H, path: &dyn AsPathLike) -> Result<(), H::Error>292where293	H: AsyncImportResolver,294{295	let resolved = (s.import_resolver() as &dyn Any)296		.downcast_ref::<ResolvedImportResolver>()297		.expect("for async imports, import_resolver should be set to ResolvedImportResolver");298299	let mut resolved_map = resolved.resolved.borrow_mut();300301	let mut queue = vec![Job::LoadFile {302		path: handler.resolve_from_default(path).await?,303		parse: true,304	}];305	while let Some(job) = queue.pop() {306		match job {307			Job::LoadFile { path, parse } => {308				if !s.0.file_cache.borrow().contains_key(&path) {309					let data = handler.load_file_contents(&path).await?;310					s.0.file_cache311						.borrow_mut()312						.insert(path.clone(), FileData::new_bytes(data.as_slice().into()));313				}314				if parse {315					queue.push(Job::ParseFile(path));316				}317			}318			Job::ParseFile(path) => {319				if let Some(file) = s.0.file_cache.borrow_mut().get_mut(&path) {320					if file.parsed.is_none() {321						let Some(code) = file.get_string() else {322							continue;323						};324						let source = Source::new(path.clone(), code.clone());325						// If failed - then skip import326						file.parsed = jrsonnet_parser::parse(&code, &ParserSettings { source })327							.map(Rc::new)328							.ok();329						if let Some(parsed) = &file.parsed {330							let mut imports = FoundImports(vec![]);331							find_imports(parsed, &mut imports);332							for import in imports.0 {333								queue.push(Job::ResolveImport {334									from: path.clone(),335									import,336								});337							}338						}339					}340				}341			}342			Job::ResolveImport { from, import } => {343				if let Some((resolved, expression)) =344					resolved_map.get_mut(&(from.clone(), import.path.clone()))345				{346					if import.expression && !*expression {347						*expression = true;348						queue.push(Job::ParseFile(resolved.clone()));349					}350					continue;351				}352				let resolved = handler.resolve_from(&from, &import.path).await?;353				queue.push(Job::LoadFile {354					path: resolved,355					parse: import.expression,356				});357			}358		}359	}360	Ok(())361}
modifiedcrates/jrsonnet-evaluator/src/ctx.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/ctx.rs
+++ b/crates/jrsonnet-evaluator/src/ctx.rs
@@ -180,6 +180,12 @@
 		assert!(old.is_none(), "variable bound twice in single context call");
 		self
 	}
+	pub fn binds(&mut self, bindings: FxHashMap<IStr, Thunk<Val>>) -> &mut Self {
+		for (k, v) in bindings {
+			self.bind(k, v);
+		}
+		self
+	}
 	pub fn build(self) -> Context {
 		if let Some(parent) = self.extend {
 			parent.extend_bindings(self.bindings)
modifiedcrates/jrsonnet-evaluator/src/error.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/error.rs
+++ b/crates/jrsonnet-evaluator/src/error.rs
@@ -1,7 +1,7 @@
 use std::{
 	cmp::Ordering,
 	convert::Infallible,
-	fmt::{Debug, Display},
+	fmt::{self, Debug, Display},
 };
 
 use jrsonnet_gcmodule::{Acyclic, Trace};
@@ -11,7 +11,7 @@
 use thiserror::Error;
 
 use crate::{
-	function::{builtin::ParamDefault, CallLocation},
+	function::{CallLocation, FunctionSignature, ParamDefault, ParamName},
 	stdlib::format::FormatError,
 	typed::TypeLocError,
 	val::ConvertNumValueError,
@@ -43,37 +43,7 @@
 			out.push_str(", ");
 		}
 		out.push_str(v as &str);
-	}
-	out
-}
-
-fn format_signature(sig: &FunctionSignature) -> String {
-	let mut out = String::new();
-	out.push_str("\nFunction has the following signature: ");
-	out.push('(');
-	if sig.is_empty() {
-		out.push_str("/*no arguments*/");
-	} else {
-		for (i, (name, default)) in sig.iter().enumerate() {
-			if i != 0 {
-				out.push_str(", ");
-			}
-			if let Some(name) = name {
-				out.push_str(name);
-			} else {
-				out.push_str("<unnamed>");
-			}
-			match default {
-				ParamDefault::None => {}
-				ParamDefault::Exists => out.push_str(" = <default>"),
-				ParamDefault::Literal(lit) => {
-					out.push_str(" = ");
-					out.push_str(lit);
-				}
-			}
-		}
 	}
-	out.push(')');
 	out
 }
 
@@ -103,8 +73,6 @@
 	heap.sort_by(|a, b| b.0.partial_cmp(&a.0).unwrap_or(Ordering::Equal));
 	heap.into_iter().map(|v| v.1).collect()
 }
-
-type FunctionSignature = Vec<(Option<IStr>, ParamDefault)>;
 
 /// Possible errors
 #[allow(missing_docs)]
@@ -148,13 +116,13 @@
 	#[error("only functions can be called, got {0}")]
 	OnlyFunctionsCanBeCalledGot(ValType),
 	#[error("parameter {0} is not defined")]
-	UnknownFunctionParameter(String),
+	UnknownFunctionParameter(IStr),
 	#[error("argument {0} is already bound")]
 	BindingParameterASecondTime(IStr),
-	#[error("too many args, function has {0}{sig}", sig = format_signature(.1))]
+	#[error("too many args, function has {0}\nFunction has the following signature: {1}")]
 	TooManyArgsFunctionHas(usize, FunctionSignature),
-	#[error("function argument is not passed: {}{}", .0.as_ref().map_or("<unnamed>", IStr::as_str), format_signature(.1))]
-	FunctionParameterNotBoundInCall(Option<IStr>, FunctionSignature),
+	#[error("function argument is not passed: {0}\nFunction has the following signature: {1}")]
+	FunctionParameterNotBoundInCall(ParamName, FunctionSignature),
 
 	#[error("external variable is not defined: {0}")]
 	UndefinedExternalVariable(IStr),
modifiedcrates/jrsonnet-evaluator/src/evaluate/destructure.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/evaluate/destructure.rs
+++ b/crates/jrsonnet-evaluator/src/evaluate/destructure.rs
@@ -170,7 +170,7 @@
 			let value = value.clone();
 			let data = {
 				let fctx = fctx.clone();
-				Thunk!(move || name.map_or_else(
+				Thunk!(move || name.0.map_or_else(
 					|| evaluate(fctx.unwrap(), &value),
 					|name| evaluate_named(fctx.unwrap(), &value, name),
 				))
modifiedcrates/jrsonnet-evaluator/src/evaluate/mod.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/evaluate/mod.rs
+++ b/crates/jrsonnet-evaluator/src/evaluate/mod.rs
@@ -3,15 +3,27 @@
 use jrsonnet_gcmodule::{Cc, Trace};
 use jrsonnet_interner::IStr;
 use jrsonnet_parser::{
-	ArgsDesc, AssertStmt, BinaryOpType, BindSpec, CompSpec, Expr, FieldMember, FieldName,
-	ForSpecData, IfSpecData, ImportKind, LiteralType, ObjBody, ObjMembers, ParamsDesc, Spanned,
+	function::ParamName, ArgsDesc, AssertStmt, BinaryOpType, BindSpec, CompSpec, Expr, ExprParams,
+	FieldMember, FieldName, ForSpecData, IfSpecData, ImportKind, LiteralType, ObjBody, ObjMembers,
+	Spanned,
 };
 use jrsonnet_types::ValType;
 use rustc_hash::FxHashMap;
 
 use self::destructure::destruct;
 use crate::{
-	Context, Error, ObjValue, ObjValueBuilder, ObjectAssertion, Pending, Result, ResultExt, SupThis, Unbound, Val, arr::ArrValue, bail, destructure::evaluate_dest, error::{ErrorKind::*, suggest_object_fields}, evaluate::operator::{evaluate_add_op, evaluate_binary_op_special, evaluate_unary_op}, function::{CallLocation, FuncDesc, FuncVal, builtin::{ParamDefault, ParamName, ParamParse}}, gc::WithCapacityExt as _, in_frame, typed::Typed, val::{CachedUnbound, IndexableVal, NumValue, StrValue, Thunk}, with_state
+	arr::ArrValue,
+	bail,
+	destructure::evaluate_dest,
+	error::{suggest_object_fields, ErrorKind::*},
+	evaluate::operator::{evaluate_add_op, evaluate_binary_op_special, evaluate_unary_op},
+	function::{CallLocation, FuncDesc, FuncVal},
+	gc::WithCapacityExt as _,
+	in_frame,
+	typed::Typed,
+	val::{CachedUnbound, IndexableVal, NumValue, StrValue, Thunk},
+	with_state, Context, Error, ObjValue, ObjValueBuilder, ObjectAssertion, Pending, Result,
+	ResultExt, SupThis, Unbound, Val,
 };
 pub mod destructure;
 pub mod operator;
@@ -71,21 +83,12 @@
 pub fn evaluate_method(
 	ctx: Context,
 	name: IStr,
-	params: ParamsDesc,
+	params: ExprParams,
 	body: Rc<Spanned<Expr>>,
 ) -> Val {
 	Val::Func(FuncVal::Normal(Cc::new(FuncDesc {
 		name,
 		ctx,
-		params_parse: params
-			.iter()
-			.map(|p| {
-				ParamParse::new(
-					p.0.name().map_or(ParamName::ANONYMOUS, ParamName::new),
-					ParamDefault::exists(p.1.is_some()),
-				)
-			})
-			.collect(),
 		params,
 		body,
 	})))
@@ -125,7 +128,7 @@
 			Val::Arr(list) => {
 				for item in list.iter_lazy() {
 					let fctx = Pending::new();
-					let mut new_bindings = FxHashMap::with_capacity(var.capacity_hint());
+					let mut new_bindings = FxHashMap::with_capacity(var.binds_len());
 					destruct(var, item, fctx.clone(), &mut new_bindings)?;
 					let ctx = ctx.clone().extend_bindings(new_bindings).into_future(fctx);
 
@@ -178,7 +181,7 @@
 		fn bind(&self, sup_this: SupThis) -> Result<Context> {
 			let fctx = Context::new_future();
 			let mut new_bindings =
-				FxHashMap::with_capacity(self.locals.iter().map(BindSpec::capacity_hint).sum());
+				FxHashMap::with_capacity(self.locals.iter().map(BindSpec::binds_len).sum());
 			for b in self.locals.iter() {
 				evaluate_dest(b, fctx.clone(), &mut new_bindings)?;
 			}
@@ -249,7 +252,7 @@
 			struct UnboundMethod<B: Trace> {
 				uctx: B,
 				value: Rc<Spanned<Expr>>,
-				params: ParamsDesc,
+				params: ExprParams,
 				name: IStr,
 			}
 			impl<B: Unbound<Bound = Context>> Unbound for UnboundMethod<B> {
@@ -376,6 +379,13 @@
 	Ok(())
 }
 
+pub fn evaluate_named_param(ctx: Context, expr: &Spanned<Expr>, name: ParamName) -> Result<Val> {
+	match name.0 {
+		Some(name) => evaluate_named(ctx, expr, name),
+		None => evaluate(ctx, expr),
+	}
+}
+
 pub fn evaluate_named(ctx: Context, expr: &Spanned<Expr>, name: IStr) -> Result<Val> {
 	use Expr::*;
 	Ok(match &**expr {
@@ -551,7 +561,7 @@
 		})?,
 		LocalExpr(bindings, returned) => {
 			let mut new_bindings: FxHashMap<IStr, Thunk<Val>> =
-				FxHashMap::with_capacity(bindings.iter().map(BindSpec::capacity_hint).sum());
+				FxHashMap::with_capacity(bindings.iter().map(BindSpec::binds_len).sum());
 			let fctx = Context::new_future();
 			for b in bindings {
 				evaluate_dest(b, fctx.clone(), &mut new_bindings)?;
modifiedcrates/jrsonnet-evaluator/src/function/builtin.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/function/builtin.rs
+++ b/crates/jrsonnet-evaluator/src/function/builtin.rs
@@ -1,82 +1,25 @@
 use std::any::Any;
+use std::fmt;
 
 use jrsonnet_gcmodule::{cc_dyn, Acyclic, Trace, TraceBox};
 use jrsonnet_interner::IStr;
+use jrsonnet_parser::function::{FunctionSignature, ParamDefault, ParamName, ParamParse};
 
 use super::{arglike::ArgsLike, parse::parse_builtin_call, CallLocation};
 use crate::{Context, Result, Val};
 
-#[derive(Clone, Acyclic)]
-pub struct ParamName(Option<IStr>);
-impl ParamName {
-	pub const ANONYMOUS: Self = Self(None);
-	pub fn new(name: IStr) -> Self {
-		Self(Some(name))
-	}
-	pub fn as_str(&self) -> Option<&str> {
-		self.0.as_deref()
-	}
-	pub fn is_anonymous(&self) -> bool {
-		self.0.is_none()
-	}
-}
-impl PartialEq<IStr> for ParamName {
-	fn eq(&self, other: &IStr) -> bool {
-		self.0
-			.as_ref()
-			.map_or(false, |s| s.as_bytes() == other.as_bytes())
-	}
-}
-
-#[derive(Clone, Copy, Debug, Acyclic)]
-pub enum ParamDefault {
-	None,
-	Exists,
-	Literal(&'static str),
-}
-impl ParamDefault {
-	pub const fn exists(is_exists: bool) -> Self {
-		if is_exists {
-			Self::Exists
-		} else {
-			Self::None
-		}
-	}
-}
-
 #[macro_export]
 macro_rules! params {
 	(@name unnamed) => { ParamName::ANONYMOUS };
 	(@name named $name:literal) => { ParamName::new($crate::IStr::from($name)) };
 	($($(#[$meta:meta])* [$kind:ident $(($lit:literal))? => $default:expr]),* $(,)?) => {
 		thread_local! {
-			static PARAMS: [ParamParse; { const N: usize = <[u8]>::len(&[$($(#[$meta])* 0u8),*]); N }] = [
+			static PARAMS: FunctionSignature = FunctionSignature::new([
 				$($(#[$meta])* ParamParse::new(params!(@name $kind $($lit)?), $default)),*
-			];
+			].into());
 		}
 	};
-}
-
-#[derive(Clone, Acyclic)]
-pub struct ParamParse {
-	name: ParamName,
-	default: ParamDefault,
 }
-impl ParamParse {
-	pub fn new(name: ParamName, default: ParamDefault) -> Self {
-		Self { name, default }
-	}
-	/// Parameter name for named call parsing
-	pub fn name(&self) -> &ParamName {
-		&self.name
-	}
-	pub fn default(&self) -> ParamDefault {
-		self.default
-	}
-	pub fn has_default(&self) -> bool {
-		!matches!(self.default, ParamDefault::None)
-	}
-}
 
 cc_dyn!(
 	#[derive(Clone)]
@@ -89,7 +32,7 @@
 		self.0.name()
 	}
 
-	fn params(&self) -> &[ParamParse] {
+	fn params(&self) -> FunctionSignature {
 		self.0.params()
 	}
 
@@ -109,7 +52,7 @@
 	/// Function name to be used in stack traces
 	fn name(&self) -> &str;
 	/// Parameter names for named calls
-	fn params(&self) -> &[ParamParse];
+	fn params(&self) -> FunctionSignature;
 	/// Call the builtin
 	fn call(&self, ctx: Context, loc: CallLocation<'_>, args: &dyn ArgsLike) -> Result<Val>;
 
@@ -126,20 +69,19 @@
 
 #[derive(Trace)]
 pub struct NativeCallback {
-	pub(crate) params: Vec<ParamParse>,
+	pub(crate) params: FunctionSignature,
 	handler: TraceBox<dyn NativeCallbackHandler>,
 }
 impl NativeCallback {
 	#[deprecated = "prefer using builtins directly, use this interface only for bindings"]
 	pub fn new(params: Vec<String>, handler: impl NativeCallbackHandler) -> Self {
 		Self {
-			params: params
-				.into_iter()
-				.map(|n| ParamParse {
-					name: ParamName::new(n.into()),
-					default: ParamDefault::None,
-				})
-				.collect(),
+			params: FunctionSignature::new(
+				params
+					.into_iter()
+					.map(|n| ParamParse::new(ParamName::new(n.into()), ParamDefault::None))
+					.collect(),
+			),
 			handler: TraceBox(Box::new(handler)),
 		}
 	}
@@ -152,12 +94,12 @@
 		"<native>"
 	}
 
-	fn params(&self) -> &[ParamParse] {
-		&self.params
+	fn params(&self) -> FunctionSignature {
+		self.params.clone()
 	}
 
 	fn call(&self, ctx: Context, _loc: CallLocation<'_>, args: &dyn ArgsLike) -> Result<Val> {
-		let args = parse_builtin_call(ctx, &self.params, args, true)?;
+		let args = parse_builtin_call(ctx, self.params.clone(), args, true)?;
 		let args = args
 			.into_iter()
 			.map(|a| a.expect("legacy natives have no default params"))
modifiedcrates/jrsonnet-evaluator/src/function/mod.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/function/mod.rs
+++ b/crates/jrsonnet-evaluator/src/function/mod.rs
@@ -5,23 +5,26 @@
 use jrsonnet_gcmodule::{Cc, Trace};
 use jrsonnet_interner::IStr;
 pub use jrsonnet_macros::builtin;
-use jrsonnet_parser::{Destruct, Expr, ParamsDesc, Span, Spanned};
+use jrsonnet_parser::{Destruct, Expr, ExprParams, Span, Spanned};
 
 use self::{
 	arglike::OptionalContext,
-	builtin::{Builtin, ParamParse, StaticBuiltin},
+	builtin::{Builtin, StaticBuiltin},
 	native::NativeDesc,
 	parse::{parse_default_function_call, parse_function_call},
 };
 use crate::{
-	bail, error::ErrorKind::*, evaluate, evaluate_trivial, function::builtin::BuiltinFunc, Context,
-	ContextBuilder, Result, Thunk, Val,
+	bail, error::ErrorKind::*, evaluate, evaluate_trivial, function::builtin::BuiltinFunc, params,
+	Context, ContextBuilder, Result, Thunk, Val,
 };
 
 pub mod arglike;
 pub mod builtin;
 pub mod native;
 pub mod parse;
+pub mod prepared;
+
+pub use jrsonnet_parser::function::*;
 
 /// Function callsite location.
 /// Either from other jsonnet code, specified by expression location, or from native (without location).
@@ -66,12 +69,9 @@
 	pub ctx: Context,
 
 	/// Function parameter definition
-	pub params: ParamsDesc,
+	pub params: ExprParams,
 	/// Function body
 	pub body: Rc<Spanned<Expr>>,
-
-	#[educe(PartialEq = false, Debug = false)]
-	pub(crate) params_parse: Vec<ParamParse>,
 }
 impl FuncDesc {
 	/// Create body context, but fill arguments without defaults with lazy error
@@ -139,24 +139,18 @@
 		Self::StaticBuiltin(static_builtin)
 	}
 
-	pub fn params(&self) -> &[ParamParse] {
+	pub fn params(&self) -> FunctionSignature {
 		match self {
 			Self::Id => ID.params(),
 			Self::StaticBuiltin(i) => i.params(),
 			Self::Builtin(i) => i.params(),
-			Self::Normal(p) => &p.params_parse,
-			Self::Thunk(_) => &[],
+			Self::Normal(p) => p.params.signature.clone(),
+			Self::Thunk(_) => FunctionSignature::empty(),
 		}
 	}
 	/// Amount of non-default required arguments
 	pub fn params_len(&self) -> usize {
-		match self {
-			Self::Id => 1,
-			Self::Normal(n) => n.params.iter().filter(|p| p.1.is_none()).count(),
-			Self::StaticBuiltin(i) => i.params().iter().filter(|p| !p.has_default()).count(),
-			Self::Builtin(i) => i.params().iter().filter(|p| !p.has_default()).count(),
-			Self::Thunk(_) => 0,
-		}
+		self.params().iter().filter(|p| !p.has_default()).count()
 	}
 	/// Function name, as defined in code.
 	pub fn name(&self) -> IStr {
@@ -185,8 +179,8 @@
 				evaluate(body_ctx, &func.body)
 			}
 			Self::Thunk(thunk) => {
-				if args.is_empty() {
-					bail!(TooManyArgsFunctionHas(0, vec![],))
+				if !args.is_empty() {
+					bail!(TooManyArgsFunctionHas(0, FunctionSignature::empty()))
 				}
 				thunk.evaluate()
 			}
@@ -223,12 +217,13 @@
 				if desc.params.len() != 1 {
 					return false;
 				}
-				let param = &desc.params[0];
-				if param.1.is_some() {
+				let param = &desc.params.exprs[0];
+				if param.default.is_some() {
 					return false;
 				}
+
 				#[allow(clippy::infallible_destructuring_match)]
-				let id = match &param.0 {
+				let id = match &param.destruct {
 					Destruct::Full(id) => id,
 					#[cfg(feature = "exp-destruct")]
 					_ => return false,
modifiedcrates/jrsonnet-evaluator/src/function/parse.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/function/parse.rs
+++ b/crates/jrsonnet-evaluator/src/function/parse.rs
@@ -1,16 +1,15 @@
 use std::mem::replace;
 
 use jrsonnet_interner::IStr;
-use jrsonnet_parser::ParamsDesc;
+use jrsonnet_parser::{function::FunctionSignature, ExprParams};
 use rustc_hash::FxHashMap;
 
-use super::{arglike::ArgsLike, builtin::ParamParse};
+use super::arglike::ArgsLike;
 use crate::{
 	bail,
 	destructure::destruct,
 	error::{ErrorKind::*, Result},
-	evaluate_named,
-	function::builtin::ParamDefault,
+	evaluate_named, evaluate_named_param,
 	gc::WithCapacityExt as _,
 	Context, Pending, Thunk, Val,
 };
@@ -26,19 +25,15 @@
 pub fn parse_function_call(
 	ctx: Context,
 	body_ctx: Context,
-	params: &ParamsDesc,
+	params: &ExprParams,
 	args: &dyn ArgsLike,
 	tailstrict: bool,
 ) -> Result<Context> {
-	let mut passed_args =
-		FxHashMap::with_capacity(params.iter().map(|p| p.0.capacity_hint()).sum());
-	if args.unnamed_len() > params.len() {
+	let mut passed_args = FxHashMap::with_capacity(params.binds_len());
+	if args.unnamed_len() > params.signature.len() {
 		bail!(TooManyArgsFunctionHas(
-			params.len(),
-			params
-				.iter()
-				.map(|p| (p.0.name(), ParamDefault::exists(p.1.is_some())))
-				.collect()
+			params.signature.len(),
+			params.signature.clone(),
 		))
 	}
 
@@ -46,9 +41,8 @@
 	let mut filled_positionals = 0;
 
 	args.unnamed_iter(ctx.clone(), tailstrict, &mut |id, arg| {
-		let name = params[id].0.clone();
 		destruct(
-			&name,
+			&params.exprs[id].destruct,
 			arg,
 			Pending::new_filled(ctx.clone()),
 			&mut passed_args,
@@ -59,8 +53,8 @@
 
 	args.named_iter(ctx, tailstrict, &mut |name, value| {
 		// FIXME: O(n) for arg existence check
-		if !params.iter().any(|p| p.0.name().as_ref() == Some(name)) {
-			bail!(UnknownFunctionParameter((name as &str).to_owned()));
+		if !params.exprs.iter().any(|p| &p.destruct.name() == name) {
+			bail!(UnknownFunctionParameter(name.clone()));
 		}
 		if passed_args.insert(name.clone(), value).is_some() {
 			bail!(BindingParameterASecondTime(name.clone()));
@@ -73,14 +67,16 @@
 		// Some args are unset, but maybe we have defaults for them
 		// Default values should be created in newly created context
 		let fctx = Context::new_future();
-		let mut defaults = FxHashMap::with_capacity(
-			params.iter().map(|p| p.0.capacity_hint()).sum::<usize>()
-				- filled_named
-				- filled_positionals,
-		);
+		let mut defaults =
+			FxHashMap::with_capacity(params.binds_len() - filled_named - filled_positionals);
 
-		for (idx, param) in params.iter().enumerate().filter(|p| p.1 .1.is_some()) {
-			if let Some(name) = param.0.name() {
+		for (idx, into, default) in params
+			.exprs
+			.iter()
+			.enumerate()
+			.filter_map(|(i, p)| Some((i, &p.destruct, p.default.as_ref()?)))
+		{
+			if let Some(name) = into.name().0 {
 				if passed_args.contains_key(&name) {
 					continue;
 				}
@@ -89,17 +85,17 @@
 			}
 
 			destruct(
-				&param.0,
+				&into,
 				{
 					let ctx = fctx.clone();
-					let name = param.0.name().unwrap_or_else(|| "<destruct>".into());
-					let value = param.1.clone().expect("default exists");
-					Thunk!(move || evaluate_named(ctx.unwrap(), &value, name))
+					let name = into.name();
+					let value = default.clone();
+					Thunk!(move || evaluate_named_param(ctx.unwrap(), &value, name))
 				},
 				fctx.clone(),
 				&mut defaults,
 			)?;
-			if param.0.name().is_some() {
+			if !into.name().is_anonymous() {
 				filled_named += 1;
 			} else {
 				filled_positionals += 1;
@@ -108,20 +104,17 @@
 
 		// Some args still weren't filled
 		if filled_named + filled_positionals != params.len() {
-			for param in params.iter().skip(args.unnamed_len()) {
+			for param in params.exprs.iter().skip(args.unnamed_len()) {
 				let mut found = false;
 				args.named_names(&mut |name| {
-					if Some(name) == param.0.name().as_ref() {
+					if &param.destruct.name() == name {
 						found = true;
 					}
 				});
 				if !found {
 					bail!(FunctionParameterNotBoundInCall(
-						param.0.clone().name(),
-						params
-							.iter()
-							.map(|p| (p.0.name(), ParamDefault::exists(p.1.is_some())))
-							.collect()
+						param.destruct.name(),
+						params.signature.clone()
 					));
 				}
 			}
@@ -147,19 +140,13 @@
 /// * `tailstrict`: if set to `true` function arguments are eagerly executed, otherwise - lazily
 pub fn parse_builtin_call(
 	ctx: Context,
-	params: &[ParamParse],
+	params: FunctionSignature,
 	args: &dyn ArgsLike,
 	tailstrict: bool,
 ) -> Result<Vec<Option<Thunk<Val>>>> {
 	let mut passed_args: Vec<Option<Thunk<Val>>> = vec![None; params.len()];
 	if args.unnamed_len() > params.len() {
-		bail!(TooManyArgsFunctionHas(
-			params.len(),
-			params
-				.iter()
-				.map(|p| (p.name().as_str().map(IStr::from), p.default()))
-				.collect()
-		))
+		bail!(TooManyArgsFunctionHas(params.len(), params,))
 	}
 
 	let mut filled_args = 0;
@@ -175,7 +162,7 @@
 		let id = params
 			.iter()
 			.position(|p| p.name() == name)
-			.ok_or_else(|| UnknownFunctionParameter((name as &str).to_owned()))?;
+			.ok_or_else(|| UnknownFunctionParameter(name.clone()))?;
 		if replace(&mut passed_args[id], Some(arg)).is_some() {
 			bail!(BindingParameterASecondTime(name.clone()));
 		}
@@ -202,11 +189,8 @@
 				});
 				if !found {
 					bail!(FunctionParameterNotBoundInCall(
-						param.name().as_str().map(IStr::from),
-						params
-							.iter()
-							.map(|p| (p.name().as_str().map(IStr::from), p.default()))
-							.collect()
+						param.name().clone(),
+						params,
 					));
 				}
 			}
@@ -218,36 +202,33 @@
 
 /// Creates Context, which has all argument default values applied
 /// and with unbound values causing error to be returned
-pub fn parse_default_function_call(body_ctx: Context, params: &ParamsDesc) -> Result<Context> {
+pub fn parse_default_function_call(body_ctx: Context, params: &ExprParams) -> Result<Context> {
 	let fctx = Context::new_future();
 
-	let mut bindings = FxHashMap::with_capacity(params.iter().map(|p| p.0.capacity_hint()).sum());
+	let mut bindings = FxHashMap::with_capacity(params.binds_len());
 
-	for param in params.iter() {
-		if let Some(v) = &param.1 {
+	for param in params.exprs.iter() {
+		if let Some(v) = &param.default {
 			destruct(
-				&param.0.clone(),
+				&param.destruct.clone(),
 				{
 					let ctx = fctx.clone();
-					let name = param.0.name().unwrap_or_else(|| "<destruct>".into());
+					let name = param.destruct.name();
 					let value = v.clone();
-					Thunk!(move || evaluate_named(ctx.unwrap(), &value, name))
+					Thunk!(move || evaluate_named_param(ctx.unwrap(), &value, name))
 				},
 				fctx.clone(),
 				&mut bindings,
 			)?;
 		} else {
 			destruct(
-				&param.0,
+				&param.destruct,
 				{
-					let param_name = param.0.name().unwrap_or_else(|| "<destruct>".into());
+					let param_name = param.destruct.name();
 					let params = params.clone();
 					Thunk!(move || Err(FunctionParameterNotBoundInCall(
-						Some(param_name),
-						params
-							.iter()
-							.map(|p| (p.0.name(), ParamDefault::exists(p.1.is_some())))
-							.collect(),
+						param_name,
+						params.signature.clone()
 					)
 					.into()))
 				},
addedcrates/jrsonnet-evaluator/src/function/prepared.rsdiffbeforeafterboth
--- /dev/null
+++ b/crates/jrsonnet-evaluator/src/function/prepared.rs
@@ -0,0 +1,165 @@
+use jrsonnet_parser::function::FunctionSignature;
+use jrsonnet_parser::{ExprParams, IStr};
+use rustc_hash::{FxHashMap, FxHashSet};
+
+use crate::destructure::destruct;
+use crate::gc::WithCapacityExt;
+use crate::val::ThunkValue as _;
+use crate::{bail, error::ErrorKind::*, Result};
+use crate::{evaluate_named, evaluate_named_param, Context, ContextBuilder, Pending, Thunk, Val};
+
+pub struct PreparedCall {
+	// Param, named input.
+	named: Vec<(usize, usize)>,
+	defaults: Vec<usize>,
+}
+
+pub fn prepare_call(
+	params: FunctionSignature,
+	unnamed: usize,
+	named: &[IStr],
+) -> Result<PreparedCall> {
+	if unnamed > params.len() {
+		bail!(TooManyArgsFunctionHas(params.len(), params))
+	}
+
+	let expected_defaults = params.len() - unnamed - named.len();
+	let mut ops = PreparedCall {
+		named: Vec::with_capacity(named.len()),
+		defaults: Vec::with_capacity(expected_defaults),
+	};
+
+	// FIXME: bitmask
+	let mut passed: FxHashSet<usize> = (0..unnamed).collect();
+
+	for (input_id, name) in named.iter().enumerate() {
+		// FIXME: O(n) for arg existence check
+		let Some(param_idx) = params.iter().position(|p| p.name() == name) else {
+			bail!(UnknownFunctionParameter(name.clone()));
+		};
+		if !passed.insert(param_idx) {
+			bail!(BindingParameterASecondTime(name.clone()));
+		}
+		ops.named.push((param_idx, input_id));
+	}
+
+	if named.len() + unnamed < params.len() {
+		let mut defaults = 0;
+
+		for (param_id, param) in params
+			.iter()
+			.enumerate()
+			.skip(unnamed)
+			.filter(|p| p.1.has_default())
+		{
+			// Skip already passed parameters
+			if !param.name().is_anonymous() && passed.contains(&param_id) {
+				continue;
+			}
+			defaults += 1;
+
+			ops.defaults.push(param_id);
+		}
+
+		// Some args still weren't filled
+		if defaults != expected_defaults {
+			for param in params.iter().skip(unnamed) {
+				let mut found = false;
+				for name in named {
+					if param.name() == name {
+						found = true;
+					}
+				}
+				if !found {
+					bail!(FunctionParameterNotBoundInCall(
+						param.name().clone(),
+						params
+					));
+				}
+			}
+			unreachable!();
+		}
+	}
+
+	Ok(ops)
+}
+pub fn parse_prepared_function_call(
+	body_ctx: Context,
+	prepared: &PreparedCall,
+	params: &ExprParams,
+	unnamed: &[Thunk<Val>],
+	named: &[Thunk<Val>],
+) -> Result<Context> {
+	let mut passed_args = FxHashMap::with_capacity(params.binds_len());
+
+	let destruct_ctx = Pending::new();
+
+	for (param_idx, unnamed) in unnamed.iter().enumerate() {
+		destruct(
+			&params.exprs[param_idx].destruct,
+			unnamed.clone(),
+			destruct_ctx.clone(),
+			&mut passed_args,
+		)?;
+	}
+
+	for (param_idx, arg_idx) in prepared.named.iter().copied() {
+		destruct(
+			&params.exprs[param_idx].destruct,
+			named[arg_idx].clone(),
+			destruct_ctx.clone(),
+			&mut passed_args,
+		)?;
+	}
+
+	if prepared.defaults.is_empty() {
+		let body_ctx = body_ctx
+			.extend_bindings(passed_args)
+			.into_future(destruct_ctx);
+		Ok(body_ctx)
+	} else {
+		let fctx = Context::new_future();
+		let mut defaults = FxHashMap::with_capacity(params.binds_len() - passed_args.len());
+		for param_idx in prepared.defaults.iter().copied() {
+			// let param = params.0.rc_idx(param_idx);
+			destruct(
+				&params.exprs[param_idx].destruct,
+				{
+					let ctx = fctx.clone();
+					let params = params.clone();
+					Thunk!(move || {
+						let param = &params.exprs[param_idx];
+						let name = param.destruct.name();
+						let value = param.default.as_ref().expect("default exists");
+						evaluate_named_param(ctx.unwrap(), value, name)
+					})
+				},
+				fctx.clone(),
+				&mut defaults,
+			)?;
+		}
+
+		let mut ctx = ContextBuilder::extend(body_ctx);
+		ctx.binds(passed_args);
+		ctx.binds(defaults);
+		Ok(ctx.build().into_future(fctx).into_future(destruct_ctx))
+	}
+}
+pub fn parse_prepared_builtin_call(
+	prepared: &PreparedCall,
+	params: FunctionSignature,
+	unnamed: &[Thunk<Val>],
+	named: &[Thunk<Val>],
+) -> Result<Vec<Option<Thunk<Val>>>> {
+	let mut passed_args = vec![None; params.len()];
+
+	for (param_idx, unnamed) in unnamed.iter().enumerate() {
+		passed_args[param_idx] = Some(unnamed.clone());
+	}
+
+	for (param_idx, arg_idx) in prepared.named.iter().copied() {
+		passed_args[param_idx] = Some(named[arg_idx].clone());
+	}
+
+	Ok(passed_args)
+}
modifiedcrates/jrsonnet-evaluator/src/stack.rsdiffbeforeafterboth
--- a/crates/jrsonnet-evaluator/src/stack.rs
+++ b/crates/jrsonnet-evaluator/src/stack.rs
@@ -20,6 +20,7 @@
 type NightlyLocalKey<T> = std::thread::LocalKey<T>;
 
 #[cfg(nightly)]
+#[macro_export]
 macro_rules! const_tls {
 	(const $name:ident: $t:ty = $expr:expr;) => {
 		#[thread_local]
@@ -27,6 +28,7 @@
 	};
 }
 #[cfg(not(nightly))]
+#[macro_export]
 macro_rules! const_tls {
 	(const $name:ident: $t:ty = $expr:expr;) => {
 		thread_local! {
modifiedcrates/jrsonnet-macros/src/lib.rsdiffbeforeafterboth
--- a/crates/jrsonnet-macros/src/lib.rs
+++ b/crates/jrsonnet-macros/src/lib.rs
@@ -239,7 +239,9 @@
 			cfg_attrs,
 			..
 		} => {
-			let name = name.as_ref().map_or_else(|| quote! {unnamed}, |n| quote! {named(#n)});
+			let name = name
+				.as_ref()
+				.map_or_else(|| quote! {unnamed}, |n| quote! {named(#n)});
 			let default = match optionality {
 				Optionality::Required => quote!(ParamDefault::None),
 				Optionality::Optional => quote!(ParamDefault::Exists),
@@ -251,7 +253,9 @@
 			})
 		}
 		ArgInfo::Lazy { is_option, name } => {
-			let name = name.as_ref().map_or_else(|| quote! {unnamed}, |n| quote! {named(#n)});
+			let name = name
+				.as_ref()
+				.map_or_else(|| quote! {unnamed}, |n| quote! {named(#n)});
 			Some(quote! {
 				[#name => ParamDefault::exists(#is_option)],
 			})
@@ -364,7 +368,7 @@
 		const _: () = {
 			use ::jrsonnet_evaluator::{
 				State, Val,
-				function::{builtin::{Builtin, StaticBuiltin, ParamParse, ParamName, ParamDefault}, CallLocation, ArgsLike, parse::parse_builtin_call},
+				function::{builtin::{Builtin, StaticBuiltin}, FunctionSignature, ParamParse, ParamName, ParamDefault, CallLocation, ArgsLike, parse::parse_builtin_call},
 				Result, Context, typed::Typed,
 				parser::Span, params,
 			};
@@ -380,11 +384,8 @@
 				fn name(&self) -> &str {
 					stringify!(#name)
 				}
-				fn params(&self) -> &[ParamParse] {
-					/// Safety: ParamParse contains IStr, which is thread-local, thus neither Send or Sync
-					/// The result of this transmute can not outlive the thread, thus 'static here is equivalent to the
-					/// nightly-only 'thread
-					PARAMS.with(|p| unsafe { std::mem::transmute::<&[ParamParse], &'static [ParamParse]>(p.as_slice()) })
+				fn params(&self) -> FunctionSignature {
+					PARAMS.with(|p| p.clone())
 				}
 				#[allow(unused_variables)]
 				fn call(&self, ctx: Context, location: CallLocation, args: &dyn ArgsLike) -> Result<Val> {
modifiedcrates/jrsonnet-parser/src/expr.rsdiffbeforeafterboth
--- a/crates/jrsonnet-parser/src/expr.rs
+++ b/crates/jrsonnet-parser/src/expr.rs
@@ -7,7 +7,10 @@
 use jrsonnet_gcmodule::Acyclic;
 use jrsonnet_interner::IStr;
 
-use crate::source::Source;
+use crate::{
+	function::{FunctionSignature, ParamDefault, ParamName, ParamParse},
+	source::Source,
+};
 
 #[derive(Debug, PartialEq, Acyclic)]
 pub enum FieldName {
@@ -41,7 +44,7 @@
 pub struct FieldMember {
 	pub name: FieldName,
 	pub plus: bool,
-	pub params: Option<ParamsDesc>,
+	pub params: Option<ExprParams>,
 	pub visibility: Visibility,
 	pub value: Rc<Spanned<Expr>>,
 }
@@ -147,16 +150,41 @@
 
 /// name, default value
 #[derive(Debug, PartialEq, Acyclic)]
-pub struct Param(pub Destruct, pub Option<Rc<Spanned<Expr>>>);
+pub struct ExprParam {
+	pub destruct: Destruct,
+	pub default: Option<Rc<Spanned<Expr>>>,
+}
 
 /// Defined function parameters
 #[derive(Debug, Clone, PartialEq, Acyclic)]
-pub struct ParamsDesc(pub Rc<Vec<Param>>);
-
-impl Deref for ParamsDesc {
-	type Target = Vec<Param>;
-	fn deref(&self) -> &Self::Target {
-		&self.0
+pub struct ExprParams {
+	pub exprs: Rc<Vec<ExprParam>>,
+	pub signature: FunctionSignature,
+	binds_len: usize,
+}
+impl ExprParams {
+	pub fn len(&self) -> usize {
+		self.exprs.len()
+	}
+	pub fn binds_len(&self) -> usize {
+		self.binds_len
+	}
+	pub fn new(exprs: Vec<ExprParam>) -> Self {
+		Self {
+			signature: FunctionSignature::new(
+				exprs
+					.iter()
+					.map(|p| {
+						ParamParse::new(
+							p.destruct.name(),
+							ParamDefault::exists(p.default.is_some()),
+						)
+					})
+					.collect(),
+			),
+			binds_len: exprs.iter().map(|v| v.destruct.binds_len()).sum(),
+			exprs: Rc::new(exprs),
+		}
 	}
 }
 
@@ -198,14 +226,14 @@
 }
 impl Destruct {
 	/// Name of destructure, used for function parameter names
-	pub fn name(&self) -> Option<IStr> {
-		match self {
+	pub fn name(&self) -> ParamName {
+		ParamName(match self {
 			Self::Full(name) => Some(name.clone()),
 			#[cfg(feature = "exp-destruct")]
 			_ => None,
-		}
+		})
 	}
-	pub fn capacity_hint(&self) -> usize {
+	pub fn binds_len(&self) -> usize {
 		#[cfg(feature = "exp-destruct")]
 		fn cap_rest(rest: &Option<DestructRest>) -> usize {
 			match rest {
@@ -220,8 +248,8 @@
 			Self::Skip => 0,
 			#[cfg(feature = "exp-destruct")]
 			Self::Array { start, rest, end } => {
-				start.iter().map(Destruct::capacity_hint).sum::<usize>()
-					+ end.iter().map(Destruct::capacity_hint).sum::<usize>()
+				start.iter().map(Destruct::binds_len).sum::<usize>()
+					+ end.iter().map(Destruct::binds_len).sum::<usize>()
 					+ cap_rest(rest)
 			}
 			#[cfg(feature = "exp-destruct")]
@@ -248,14 +276,14 @@
 	},
 	Function {
 		name: IStr,
-		params: ParamsDesc,
+		params: ExprParams,
 		value: Rc<Spanned<Expr>>,
 	},
 }
 impl BindSpec {
-	pub fn capacity_hint(&self) -> usize {
+	pub fn binds_len(&self) -> usize {
 		match self {
-			BindSpec::Field { into, .. } => into.capacity_hint(),
+			BindSpec::Field { into, .. } => into.binds_len(),
 			BindSpec::Function { .. } => 1,
 		}
 	}
@@ -396,7 +424,7 @@
 		parts: Vec<IndexPart>,
 	},
 	/// function(x) x
-	Function(ParamsDesc, Rc<Spanned<Expr>>),
+	Function(ExprParams, Rc<Spanned<Expr>>),
 	/// if true == false then 1 else 2
 	IfElse(Box<IfElse>),
 	Slice(Box<Slice>),
addedcrates/jrsonnet-parser/src/function.rsdiffbeforeafterboth
--- /dev/null
+++ b/crates/jrsonnet-parser/src/function.rs
@@ -0,0 +1,126 @@
+use std::fmt;
+use std::ops::Deref;
+use std::rc::Rc;
+
+use jrsonnet_gcmodule::Acyclic;
+use jrsonnet_interner::IStr;
+
+#[derive(Clone, Acyclic, Debug, PartialEq, Eq)]
+pub struct ParamName(pub Option<IStr>);
+impl ParamName {
+	pub const ANONYMOUS: Self = Self(None);
+	pub fn new(name: IStr) -> Self {
+		Self(Some(name))
+	}
+	pub fn as_str(&self) -> Option<&str> {
+		self.0.as_deref()
+	}
+	pub fn is_anonymous(&self) -> bool {
+		self.0.is_none()
+	}
+}
+impl PartialEq<IStr> for ParamName {
+	fn eq(&self, other: &IStr) -> bool {
+		self.0
+			.as_ref()
+			.map_or(false, |s| s.as_bytes() == other.as_bytes())
+	}
+}
+
+impl fmt::Display for ParamName {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match &self.0 {
+			Some(v) => write!(f, "{v}"),
+			None => write!(f, "<unnamed>"),
+		}
+	}
+}
+
+#[derive(Clone, Copy, Debug, Acyclic, PartialEq, Eq)]
+pub enum ParamDefault {
+	None,
+	Exists,
+	Literal(&'static str),
+}
+impl ParamDefault {
+	pub const fn exists(is_exists: bool) -> Self {
+		if is_exists {
+			Self::Exists
+		} else {
+			Self::None
+		}
+	}
+}
+impl fmt::Display for ParamDefault {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		match self {
+			ParamDefault::None => Ok(()),
+			ParamDefault::Exists => write!(f, " = <default>"),
+			ParamDefault::Literal(lit) => write!(f, " = {lit}"),
+		}
+	}
+}
+
+#[derive(Clone, Acyclic, Debug, PartialEq, Eq)]
+pub struct ParamParse {
+	name: ParamName,
+	default: ParamDefault,
+}
+impl ParamParse {
+	pub fn new(name: ParamName, default: ParamDefault) -> Self {
+		Self { name, default }
+	}
+	/// Parameter name for named call parsing
+	pub fn name(&self) -> &ParamName {
+		&self.name
+	}
+	pub fn default(&self) -> ParamDefault {
+		self.default
+	}
+	pub fn has_default(&self) -> bool {
+		!matches!(self.default, ParamDefault::None)
+	}
+}
+impl fmt::Display for ParamParse {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		write!(f, "{}{}", self.name, self.default)
+	}
+}
+
+#[derive(Debug, Clone, Acyclic, PartialEq, Eq)]
+pub struct FunctionSignature(Rc<[ParamParse]>);
+impl Deref for FunctionSignature {
+	type Target = [ParamParse];
+
+	fn deref(&self) -> &Self::Target {
+		&self.0
+	}
+}
+
+thread_local! {
+	static EMPTY_SIGNATURE: FunctionSignature = FunctionSignature::new([].into());
+}
+
+impl FunctionSignature {
+	pub fn new(v: Rc<[ParamParse]>) -> Self {
+		Self(v)
+	}
+	pub fn empty() -> Self {
+		EMPTY_SIGNATURE.with(|p| p.clone())
+	}
+}
+impl fmt::Display for FunctionSignature {
+	fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+		if self.0.is_empty() {
+			return write!(f, "(/*no arguments*/)");
+		}
+		write!(f, "(")?;
+		for (i, par) in self.0.iter().enumerate() {
+			if i != 0 {
+				write!(f, ", ")?;
+			}
+			write!(f, "{par}")?;
+		}
+		write!(f, ")")
+	}
+}
modifiedcrates/jrsonnet-parser/src/lib.rsdiffbeforeafterboth
--- a/crates/jrsonnet-parser/src/lib.rs
+++ b/crates/jrsonnet-parser/src/lib.rs
@@ -7,9 +7,11 @@
 pub use expr::*;
 pub use jrsonnet_interner::IStr;
 pub use peg;
+pub mod function;
 mod location;
 mod source;
 mod unescape;
+
 pub use location::CodeLocation;
 pub use source::{
 	Source, SourceDefaultIgnoreJpath, SourceDirectory, SourceFifo, SourceFile, SourcePath,
@@ -68,10 +70,10 @@
 		rule keyword(id: &'static str) -> ()
 			= ##parse_string_literal(id) end_of_ident()
 
-		pub rule param(s: &ParserSettings) -> expr::Param = name:destruct(s) expr:(_ "=" _ expr:expr(s){expr})? { expr::Param(name, expr.map(Rc::new)) }
-		pub rule params(s: &ParserSettings) -> expr::ParamsDesc
-			= params:param(s) ** comma() comma()? { expr::ParamsDesc(Rc::new(params)) }
-			/ { expr::ParamsDesc(Rc::new(Vec::new())) }
+		pub rule param(s: &ParserSettings) -> expr::ExprParam = destruct:destruct(s) expr:(_ "=" _ expr:expr(s){expr})? { expr::ExprParam { destruct, default: expr.map(Rc::new) } }
+		pub rule params(s: &ParserSettings) -> expr::ExprParams
+			= params:param(s) ** comma() comma()? { expr::ExprParams::new(params) }
+			/ { expr::ExprParams::new(Vec::new()) }
 
 		pub rule arg(s: &ParserSettings) -> (Option<IStr>, Rc<Spanned<Expr>>)
 			= name:(quiet! { (s:id() _ "=" !['='] _ {s})? } / expected!("<argument name>")) expr:expr(s) {(name, Rc::new(expr))}
modifiedcrates/jrsonnet-parser/src/snapshots/jrsonnet_parser__tests__default_param_before_nondefault.snapdiffbeforeafterboth
--- a/crates/jrsonnet-parser/src/snapshots/jrsonnet_parser__tests__default_param_before_nondefault.snap
+++ b/crates/jrsonnet-parser/src/snapshots/jrsonnet_parser__tests__default_param_before_nondefault.snap
@@ -6,26 +6,47 @@
     [
         Function {
             name: "x",
-            params: ParamsDesc(
-                [
-                    Param(
-                        Full(
+            params: ExprParams {
+                exprs: [
+                    ExprParam {
+                        destruct: Full(
                             "foo",
                         ),
-                        Some(
+                        default: Some(
                             Str(
                                 "foo",
                             ) from virtual:<test>:14-19,
                         ),
-                    ),
-                    Param(
-                        Full(
+                    },
+                    ExprParam {
+                        destruct: Full(
                             "bar",
                         ),
-                        None,
-                    ),
+                        default: None,
+                    },
                 ],
-            ),
+                signature: FunctionSignature(
+                    [
+                        ParamParse {
+                            name: ParamName(
+                                Some(
+                                    "foo",
+                                ),
+                            ),
+                            default: Exists,
+                        },
+                        ParamParse {
+                            name: ParamName(
+                                Some(
+                                    "bar",
+                                ),
+                            ),
+                            default: None,
+                        },
+                    ],
+                ),
+                binds_len: 2,
+            },
             value: Literal(
                 Null,
             ) from virtual:<test>:28-32,