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feat(label): use macro magic instead of optional flag for optional la…
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…bels
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@zkat
zkat committed Apr 18, 2022
1 parent ea55f45 commit 9da62cd
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Showing 4 changed files with 73 additions and 119 deletions.
158 changes: 53 additions & 105 deletions miette-derive/src/label.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -18,35 +18,21 @@ pub struct Labels(Vec<Label>);

struct Label {
label: Option<Display>,
optional: bool,
ty: syn::Type,
span: syn::Member,
}

struct LabelAttr {
label: Option<Display>,
optional: bool,
}

impl Parse for LabelAttr {
fn parse(input: ParseStream) -> syn::Result<Self> {
let la = input.lookahead1();
let (label, optional) = if la.peek(syn::token::Paren) {
let label = if la.peek(syn::token::Paren) {
// #[label("{}", x)]
let content;
parenthesized!(content in input);
let optional = if content.peek(syn::Ident) {
let ident = content.parse::<syn::Ident>()?;
if ident == "optional" {
if content.peek(syn::Token![,]) {
content.parse::<syn::Token![,]>()?;
}
true
} else {
false
}
} else {
false
};
if content.peek(syn::LitStr) {
let fmt = content.parse()?;
let args = if content.is_empty() {
Expand All @@ -59,27 +45,22 @@ impl Parse for LabelAttr {
args,
has_bonus_display: false,
};
(Some(display), optional)
} else if optional {
(None, optional)
Some(display)
} else {
return Err(syn::Error::new(input.span(), "Invalid argument to label() attribute. The first argument must be a literal string or the identifier `optional`"));
return Err(syn::Error::new(input.span(), "Invalid argument to label() attribute. The first argument must be a literal string."));
}
} else if la.peek(Token![=]) {
// #[label = "blabla"]
input.parse::<Token![=]>()?;
(
Some(Display {
fmt: input.parse()?,
args: TokenStream::new(),
has_bonus_display: false,
}),
false,
)
Some(Display {
fmt: input.parse()?,
args: TokenStream::new(),
has_bonus_display: false,
})
} else {
(None, false)
None
};
Ok(LabelAttr { label, optional })
Ok(LabelAttr { label })
}
}

Expand Down Expand Up @@ -107,12 +88,11 @@ impl Labels {
span: field.span(),
})
};
let LabelAttr { label, optional } =
syn::parse2::<LabelAttr>(attr.tokens.clone())?;
let LabelAttr { label } = syn::parse2::<LabelAttr>(attr.tokens.clone())?;
labels.push(Label {
label,
span,
optional,
ty: field.ty.clone(),
});
}
}
Expand All @@ -127,50 +107,31 @@ impl Labels {
pub(crate) fn gen_struct(&self, fields: &syn::Fields) -> Option<TokenStream> {
let (display_pat, display_members) = display_pat_members(fields);
let labels = self.0.iter().map(|highlight| {
let Label {
span,
label,
optional,
} = highlight;
let Label { span, label, ty } = highlight;
let var = quote! { __miette_internal_var };
if let Some(display) = label {
let (fmt, args) = display.expand_shorthand_cloned(&display_members);
if *optional {
quote! {
self.#span.clone().map(|#var|
miette::LabeledSpan::new_with_span(
std::option::Option::Some(format!(#fmt #args)),
#var,
))
}
} else {
quote! {
Some(miette::LabeledSpan::new_with_span(
std::option::Option::Some(format!(#fmt #args)),
self.#span.clone(),
))
}
}
} else if *optional {
quote! {
self.#span.clone().map(|#var|
miette::LabeledSpan::new_with_span(
std::option::Option::None,
#var,
miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#span)
.map(|#var| miette::LabeledSpan::new_with_span(
std::option::Option::Some(format!(#fmt #args)),
#var.clone(),
))
}
} else {
quote! {
Some(miette::LabeledSpan::new_with_span(
miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(&self.#span)
.map(|#var| miette::LabeledSpan::new_with_span(
std::option::Option::None,
self.#span.clone(),
#var.clone(),
))
}
}
});
Some(quote! {
#[allow(unused_variables)]
fn labels(&self) -> std::option::Option<std::boxed::Box<dyn std::iter::Iterator<Item = miette::LabeledSpan> + '_>> {
use miette::macro_helpers::ToOption;
let Self #display_pat = self;
std::option::Option::Some(Box::new(vec![
#(#labels),*
Expand All @@ -186,59 +147,46 @@ impl Labels {
|ident, fields, DiagnosticConcreteArgs { labels, .. }| {
let (display_pat, display_members) = display_pat_members(fields);
labels.as_ref().and_then(|labels| {
let variant_labels = labels.0.iter().map(|label| {
let Label { span, label, optional } = label;
let field = match &span {
syn::Member::Named(ident) => ident.clone(),
syn::Member::Unnamed(syn::Index { index, .. }) => {
format_ident!("_{}", index)
}
};
let var = quote! { __miette_internal_var };
if let Some(display) = label {
let (fmt, args) = display.expand_shorthand_cloned(&display_members);
if *optional {
let variant_labels = labels.0.iter().map(|label| {
let Label { span, label, ty } = label;
let field = match &span {
syn::Member::Named(ident) => ident.clone(),
syn::Member::Unnamed(syn::Index { index, .. }) => {
format_ident!("_{}", index)
}
};
let var = quote! { __miette_internal_var };
if let Some(display) = label {
let (fmt, args) = display.expand_shorthand_cloned(&display_members);
quote! {
#field.clone().map(|#var|
miette::LabeledSpan::new_with_span(
std::option::Option::Some(format!(#fmt #args)),
#var,
miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(#field)
.map(|#var| miette::LabeledSpan::new_with_span(
std::option::Option::Some(format!(#fmt #args)),
#var.clone(),
))
}
} else {
quote! {
Some(miette::LabeledSpan::new_with_span(
std::option::Option::Some(format!(#fmt #args)),
#field.clone(),
miette::macro_helpers::OptionalWrapper::<#ty>::new().to_option(#field)
.map(|#var| miette::LabeledSpan::new_with_span(
std::option::Option::None,
#var.clone(),
))
}
}
} else if *optional {
quote! {
#field.clone().map(|#var|
miette::LabeledSpan::new_with_span(
std::option::Option::None,
#var,
))
}
} else {
quote! {
Some(miette::LabeledSpan::new_with_span(
std::option::Option::None,
#field.clone(),
))
}
});
let variant_name = ident.clone();
match &fields {
syn::Fields::Unit => None,
_ => Some(quote! {
Self::#variant_name #display_pat => {
use miette::macro_helpers::ToOption;
std::option::Option::Some(std::boxed::Box::new(vec![
#(#variant_labels),*
].into_iter().filter(Option::is_some).map(Option::unwrap)))
}
}),
}
});
let variant_name = ident.clone();
match &fields {
syn::Fields::Unit => None,
_ => Some(quote! {
Self::#variant_name #display_pat => std::option::Option::Some(std::boxed::Box::new(vec![
#(#variant_labels),*
].into_iter().filter(Option::is_some).map(Option::unwrap))),
}),
}
})
},
)
Expand Down
8 changes: 4 additions & 4 deletions src/lib.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -369,12 +369,12 @@
//! #[label("This is bad")]
//! snip2: (usize, usize), // `(usize, usize)` is `Into<SourceSpan>`!
//!
//! // Snippets can be optional, by tagging them as such:
//! #[label(optional, "some text")]
//! // Snippets can be optional, by using Option:
//! #[label("some text")]
//! snip3: Option<SourceSpan>,
//!
//! // with or without label text
//! #[label(optional)]
//! #[label]
//! snip4: Option<SourceSpan>,
//! }
//! ```
Expand Down Expand Up @@ -407,7 +407,7 @@
//! #[diagnostic()]
//! struct Foo {
//! #[help]
//! advice: Option<String>,
//! advice: Option<String>, // Can also just be `String`
//! }
//!
//! let err = Foo {
Expand Down
10 changes: 8 additions & 2 deletions src/macro_helpers.rs
View file
Original file line number Diff line number Diff line change
@@ -1,6 +1,9 @@
// Huge thanks to @jam1gamer for this hack:
// https://twitter.com/jam1garner/status/1515887996444323840

#[doc(hidden)]
pub trait IsOption {}
impl <T> IsOption for Option<T> {}
impl<T> IsOption for Option<T> {}

#[doc(hidden)]
#[derive(Debug, Default)]
Expand All @@ -18,7 +21,10 @@ pub trait ToOption {
fn to_option<T>(self, value: T) -> Option<T>;
}

impl<T> OptionalWrapper<T> where T: IsOption {
impl<T> OptionalWrapper<T>
where
T: IsOption,
{
#[doc(hidden)]
pub fn to_option(self, value: &T) -> &T {
value
Expand Down
16 changes: 8 additions & 8 deletions tests/derive.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -319,9 +319,9 @@ fn test_snippet_named_struct() {
var2: (usize, usize),
#[label]
var3: (usize, usize),
#[label(optional, "var 4")]
#[label("var 4")]
var4: Option<(usize, usize)>,
#[label(optional)]
#[label]
var5: Option<(usize, usize)>,
}
}
Expand All @@ -336,8 +336,8 @@ fn test_snippet_unnamed_struct() {
#[label("{0}")] SourceSpan,
#[label = "idk"] SourceSpan,
#[label] SourceSpan,
#[label(optional, "foo")] Option<SourceSpan>,
#[label(optional)] Option<SourceSpan>,
#[label("foo")] Option<SourceSpan>,
#[label] Option<SourceSpan>,
);
}

Expand All @@ -358,9 +358,9 @@ fn test_snippet_enum() {
var1: SourceSpan,
#[label]
var2: SourceSpan,
#[label(optional, "var 3")]
#[label("var 3")]
var3: Option<(usize, usize)>,
#[label(optional)]
#[label]
var4: Option<(usize, usize)>,
},
#[diagnostic(code(foo::b))]
Expand All @@ -370,8 +370,8 @@ fn test_snippet_enum() {
#[label("{1}")] SourceSpan,
#[label = "blorp"] SourceSpan,
#[label] SourceSpan,
#[label(optional, "foo")] Option<SourceSpan>,
#[label(optional)] Option<SourceSpan>,
#[label("foo")] Option<SourceSpan>,
#[label] Option<SourceSpan>,
),
}
}
Expand Down

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