diff options
author | Nadrieril Feneanar | 2019-04-06 00:43:09 +0200 |
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committer | GitHub | 2019-04-06 00:43:09 +0200 |
commit | 5eccde86fc3ccdeb34c9f8bb44de33d25e77f30c (patch) | |
tree | 76d0f0fc848887d2945d586b58847575ca31d0da /dhall_generator/src/dhall_expr.rs | |
parent | f78af6d1e7f6c1dc39bde6cf97138327004ddb06 (diff) | |
parent | 6a675a13fcfafa057c44db84c3b0ca3b344cfdab (diff) |
Merge pull request #48 from Nadrieril/exprf
Move recursion out of Expr for enhanced genericity
Diffstat (limited to '')
-rw-r--r-- | dhall_generator/src/dhall_expr.rs | 164 |
1 files changed, 74 insertions, 90 deletions
diff --git a/dhall_generator/src/dhall_expr.rs b/dhall_generator/src/dhall_expr.rs index 41e558b..9da23b6 100644 --- a/dhall_generator/src/dhall_expr.rs +++ b/dhall_generator/src/dhall_expr.rs @@ -4,113 +4,123 @@ use dhall_core::*; use proc_macro2::TokenStream; use quote::quote; use std::collections::BTreeMap; -use std::rc::Rc; pub fn dhall_expr(input: proc_macro::TokenStream) -> proc_macro::TokenStream { let input_str = input.to_string(); let expr: SubExpr<X, Import> = parse_expr(&input_str).unwrap(); let no_import = |_: &Import| -> X { panic!("Don't use import in dhall!()") }; - let expr = rc(expr.map_embed(&no_import)); - let output = dhall_to_tokenstream_bx(&expr, &Context::new()); + let expr = rc(expr.as_ref().map_embed(&no_import)); + let output = quote_subexpr(&expr, &Context::new()); output.into() } -// Returns an expression of type Expr<_, _>. Expects interpolated variables -// to be of type Rc<Expr<_, _>>. -fn dhall_to_tokenstream( - expr: &DhallExpr, - ctx: &Context<Label, ()>, -) -> TokenStream { - use dhall_core::Expr::*; - match expr.as_ref() { - Var(_) => { - let v = dhall_to_tokenstream_bx(expr, ctx); - quote! { *#v } - } +// Returns an expression of type ExprF<T, _, _>, where T is the +// type of the subexpressions after interpolation. +pub fn quote_expr<TS>(expr: ExprF<TS, Label, X, X>) -> TokenStream +where + TS: quote::ToTokens + std::fmt::Debug, +{ + let quote_map = |m: BTreeMap<Label, TS>| -> TokenStream { + let entries = m.into_iter().map(|(k, v)| { + let k = quote_label(&k); + quote!(m.insert(#k, #v);) + }); + quote! { { + use std::collections::BTreeMap; + let mut m = BTreeMap::new(); + #( #entries )* + m + } } + }; + + let quote_vec = |e: Vec<TS>| -> TokenStream { + quote! { vec![ #(#e),* ] } + }; + + use dhall_core::ExprF::*; + match expr { + Var(_) => unreachable!(), Pi(x, t, b) => { - let t = dhall_to_tokenstream_bx(t, ctx); - let b = dhall_to_tokenstream_bx(b, &ctx.insert(x.clone(), ())); - let x = label_to_tokenstream(x); - quote! { dhall_core::Expr::Pi(#x, #t, #b) } + let x = quote_label(&x); + quote! { dhall_core::ExprF::Pi(#x, #t, #b) } } Lam(x, t, b) => { - let t = dhall_to_tokenstream_bx(t, ctx); - let b = dhall_to_tokenstream_bx(b, &ctx.insert(x.clone(), ())); - let x = label_to_tokenstream(x); - quote! { dhall_core::Expr::Lam(#x, #t, #b) } + let x = quote_label(&x); + quote! { dhall_core::ExprF::Lam(#x, #t, #b) } } App(f, a) => { - let f = dhall_to_tokenstream_bx(f, ctx); - let a = vec_to_tokenstream(a, ctx); - quote! { dhall_core::Expr::App(#f, #a) } + let a = quote_vec(a); + quote! { dhall_core::ExprF::App(#f, #a) } } Const(c) => { - let c = const_to_tokenstream(*c); - quote! { dhall_core::Expr::Const(#c) } + let c = quote_const(c); + quote! { dhall_core::ExprF::Const(#c) } } Builtin(b) => { - let b = builtin_to_tokenstream(*b); - quote! { dhall_core::Expr::Builtin(#b) } + let b = quote_builtin(b); + quote! { dhall_core::ExprF::Builtin(#b) } } BinOp(o, a, b) => { - let o = binop_to_tokenstream(*o); - let a = dhall_to_tokenstream_bx(a, ctx); - let b = dhall_to_tokenstream_bx(b, ctx); - quote! { dhall_core::Expr::BinOp(#o, #a, #b) } + let o = quote_binop(o); + quote! { dhall_core::ExprF::BinOp(#o, #a, #b) } } NaturalLit(n) => { - quote! { dhall_core::Expr::NaturalLit(#n) } + quote! { dhall_core::ExprF::NaturalLit(#n) } } BoolLit(b) => { - quote! { dhall_core::Expr::BoolLit(#b) } + quote! { dhall_core::ExprF::BoolLit(#b) } } EmptyOptionalLit(x) => { - let x = dhall_to_tokenstream_bx(x, ctx); - quote! { dhall_core::Expr::EmptyOptionalLit(#x) } + quote! { dhall_core::ExprF::EmptyOptionalLit(#x) } } NEOptionalLit(x) => { - let x = dhall_to_tokenstream_bx(x, ctx); - quote! { dhall_core::Expr::NEOptionalLit(#x) } + quote! { dhall_core::ExprF::NEOptionalLit(#x) } } EmptyListLit(t) => { - let t = dhall_to_tokenstream_bx(t, ctx); - quote! { dhall_core::Expr::EmptyListLit(#t) } + quote! { dhall_core::ExprF::EmptyListLit(#t) } } NEListLit(es) => { - let es = vec_to_tokenstream(es, ctx); - quote! { dhall_core::Expr::NEListLit(#es) } + let es = quote_vec(es); + quote! { dhall_core::ExprF::NEListLit(#es) } } RecordType(m) => { - let m = map_to_tokenstream(m, ctx); - quote! { dhall_core::Expr::RecordType(#m) } + let m = quote_map(m); + quote! { dhall_core::ExprF::RecordType(#m) } } RecordLit(m) => { - let m = map_to_tokenstream(m, ctx); - quote! { dhall_core::Expr::RecordLit(#m) } + let m = quote_map(m); + quote! { dhall_core::ExprF::RecordLit(#m) } } UnionType(m) => { - let m = map_to_tokenstream(m, ctx); - quote! { dhall_core::Expr::UnionType(#m) } + let m = quote_map(m); + quote! { dhall_core::ExprF::UnionType(#m) } } e => unimplemented!("{:?}", e), } } -// Returns an expression of type Rc<Expr<_, _>> -fn dhall_to_tokenstream_bx( - expr: &DhallExpr, +// Returns an expression of type SubExpr<_, _>. Expects interpolated variables +// to be of type SubExpr<_, _>. +fn quote_subexpr( + expr: &SubExpr<X, X>, ctx: &Context<Label, ()>, ) -> TokenStream { - use dhall_core::Expr::*; - match expr.as_ref() { - Var(V(s, n)) => { - match ctx.lookup(&s, *n) { + use dhall_core::ExprF::*; + match expr.as_ref().map_ref( + |e| quote_subexpr(e, ctx), + |l, e| quote_subexpr(e, &ctx.insert(l.clone(), ())), + |_| unreachable!(), + |_| unreachable!(), + |l| l.clone(), + ) { + Var(V(ref s, n)) => { + match ctx.lookup(s, n) { // Non-free variable; interpolates as itself Some(()) => { let s: String = s.into(); let var = quote! { dhall_core::V(#s.into(), #n) }; - bx(quote! { dhall_core::Expr::Var(#var) }) + bx(quote! { dhall_core::ExprF::Var(#var) }) } // Free variable; interpolates as a rust variable None => { @@ -124,51 +134,25 @@ fn dhall_to_tokenstream_bx( } } } - _ => bx(dhall_to_tokenstream(expr, ctx)), + e => bx(quote_expr(e)), } } -fn builtin_to_tokenstream(b: Builtin) -> TokenStream { +fn quote_builtin(b: Builtin) -> TokenStream { format!("dhall_core::Builtin::{:?}", b).parse().unwrap() } -fn const_to_tokenstream(c: Const) -> TokenStream { +fn quote_const(c: Const) -> TokenStream { format!("dhall_core::Const::{:?}", c).parse().unwrap() } -fn binop_to_tokenstream(b: BinOp) -> TokenStream { +fn quote_binop(b: BinOp) -> TokenStream { format!("dhall_core::BinOp::{:?}", b).parse().unwrap() } -fn label_to_tokenstream(l: &Label) -> TokenStream { +fn quote_label(l: &Label) -> TokenStream { let l = String::from(l); - quote! { #l.into() } -} - -fn map_to_tokenstream( - m: &BTreeMap<Label, Rc<Expr<X, X>>>, - ctx: &Context<Label, ()>, -) -> TokenStream { - let (keys, values): (Vec<TokenStream>, Vec<TokenStream>) = m - .iter() - .map(|(k, v)| { - (label_to_tokenstream(k), dhall_to_tokenstream_bx(&*v, ctx)) - }) - .unzip(); - quote! { { - use std::collections::BTreeMap; - let mut m = BTreeMap::new(); - #( m.insert(#keys, #values); )* - m - } } -} - -fn vec_to_tokenstream( - e: &Vec<DhallExpr>, - ctx: &Context<Label, ()>, -) -> TokenStream { - let e = e.iter().map(|x| dhall_to_tokenstream_bx(x, ctx)); - quote! { vec![ #(#e),* ] } + quote! { dhall_core::Label::from(#l) } } fn bx(x: TokenStream) -> TokenStream { |