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Derive for Unscribe

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This commit is contained in:
Pantonshire committed 2021-05-20 13:08:20 +01:00
1 parent 1fab354030
commit 8f7f76d8ba
3 files changed
+160 -68
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enumscribe_derive/src/enums.rs
+16 -9
View File
@@ -31,7 +31,7 @@ pub(crate) enum VariantType<'a> {
case_insensitive: bool,
},
Other {
field_name: Option<&'a Ident> //use {} for constructor if Some, use () if None
field_name: Option<&'a Ident>
},
}
@@ -59,11 +59,8 @@ impl<'a> Variant<'a> {
VariantType::Ignore => Ok(None),
VariantType::Named { name, constructor, .. } => {
let pattern = match constructor {
VariantConstructor::None => quote! { #enum_ident::#variant_ident },
VariantConstructor::Paren => quote! { #enum_ident::#variant_ident() },
VariantConstructor::Brace => quote! { #enum_ident::#variant_ident{} }
};
let constructor_tokens = constructor.empty();
let pattern = quote! { #enum_ident::#variant_ident #constructor_tokens };
Ok(Some((pattern, named_fn(self, enum_ident, name)?)))
}
@@ -82,6 +79,16 @@ impl<'a> Variant<'a> {
}
}
impl VariantConstructor {
pub(crate) fn empty(&self) -> TokenStream2 {
match self {
VariantConstructor::None => quote! {},
VariantConstructor::Paren => quote! { () },
VariantConstructor::Brace => quote! { {} }
}
}
}
pub(crate) fn parse_enum(data: &DataEnum) -> MacroResult<Enum> {
let mut variants = Vec::with_capacity(data.variants.len());
let mut taken_names = HashSet::new();
@@ -182,10 +189,10 @@ pub(crate) fn parse_enum(data: &DataEnum) -> MacroResult<Enum> {
}
if case_insensitive {
taken_insensitive_names.insert(lowercase_name);
&mut taken_insensitive_names
} else {
taken_sensitive_names.insert(lowercase_name);
}
&mut taken_sensitive_names
}.insert(lowercase_name);
// Return an error if the variant has any fields
if variant.fields.len() != 0 {
enumscribe_derive/src/lib.rs
+135 -54
View File
@@ -4,13 +4,13 @@
use proc_macro::TokenStream;
use std::iter;
use proc_macro2::Ident;
use quote::quote;
use syn::{Data, DataEnum, DeriveInput};
use error::{MacroError, MacroResult};
use crate::enums::{Variant, VariantType};
use proc_macro2::Ident;
use crate::enums::{Variant, VariantType, VariantConstructor};
mod enums;
mod attribute;
@@ -40,7 +40,7 @@ fn derive_scribe<F, G, E>(
trait_return_type: TokenStream2,
named_fn: F,
other_fn: G,
ignore_err_fn: E
ignore_err_fn: E,
) -> TokenStream
where
F: Fn(&Variant, &Ident, &str) -> MacroResult<TokenStream2>,
@@ -82,7 +82,7 @@ fn derive_try_scribe<F, G>(
trait_return_type: TokenStream2,
named_fn: F,
other_fn: G,
ignore_result: TokenStream2
ignore_result: TokenStream2,
) -> TokenStream
where
F: Fn(&Variant, &Ident, &str) -> MacroResult<TokenStream2>,
@@ -129,19 +129,15 @@ fn derive_try_scribe<F, G>(
pub fn derive_scribe_static_str(input: TokenStream) -> TokenStream {
derive_scribe(
input,
quote! { ::enumscribe::ScribeStaticStr },
quote! { &'static str },
|_, _, name| Ok(quote! { #name }),
|variant, enum_ident, _| Err(MacroError::new(format!(
"cannot derive ScribeStaticStr for {} because the variant {} is marked as {}, so \
there is no &'static str associated with it\n\
hint: try deriving ScribeCowStr instead",
enum_ident.to_string(), variant.data.ident.to_string(), OTHER
), variant.span)),
|variant, enum_ident| MacroError::new(format!(
"cannot derive ScribeStaticStr for {} because the variant {} is marked as {}\n\
explanation: since {} is ignored, it cannot be guaranteed that the enum can \
@@ -149,7 +145,7 @@ pub fn derive_scribe_static_str(input: TokenStream) -> TokenStream {
hint: try deriving TryScribeStaticStr instead",
enum_ident.to_string(), variant.data.ident.to_string(), IGNORE,
variant.data.ident.to_string(),
), variant.span)
), variant.span),
)
}
@@ -157,22 +153,18 @@ pub fn derive_scribe_static_str(input: TokenStream) -> TokenStream {
pub fn derive_try_scribe_static_str(input: TokenStream) -> TokenStream {
derive_try_scribe(
input,
quote! { ::enumscribe::TryScribeStaticStr },
quote! { ::std::option::Option<&'static str> },
|_, _, name| Ok(quote! {
::std::option::Option::Some(#name)
}),
|variant, enum_ident, _| Err(MacroError::new(format!(
"cannot derive TryScribeStaticStr for {} because the variant {} is marked as {}, so \
there is no &'static str associated with it\n\
hint: try deriving TryScribeCowStr instead",
enum_ident.to_string(), variant.data.ident.to_string(), OTHER
), variant.span)),
quote! { ::std::option::Option::None }
quote! { ::std::option::Option::None },
)
}
@@ -180,18 +172,14 @@ pub fn derive_try_scribe_static_str(input: TokenStream) -> TokenStream {
pub fn derive_scribe_string(input: TokenStream) -> TokenStream {
derive_scribe(
input,
quote! { ::enumscribe::ScribeString },
quote! { ::std::string::String },
|_, _, name| Ok(quote! {
<_ as ::std::borrow::ToOwned>::to_owned(#name)
}),
|_, _, field| Ok(quote! {
<_ as ::std::convert::Into<::std::string::String>>::into(#field)
}),
|variant, enum_ident| MacroError::new(format!(
"cannot derive ScribeString for {} because the variant {} is marked as {}\n\
explanation: since {} is ignored, it cannot be guaranteed that the enum can \
@@ -199,7 +187,7 @@ pub fn derive_scribe_string(input: TokenStream) -> TokenStream {
hint: try deriving TryScribeString instead",
enum_ident.to_string(), variant.data.ident.to_string(), IGNORE,
variant.data.ident.to_string(),
), variant.span)
), variant.span),
)
}
@@ -207,23 +195,19 @@ pub fn derive_scribe_string(input: TokenStream) -> TokenStream {
pub fn derive_try_scribe_string(input: TokenStream) -> TokenStream {
derive_try_scribe(
input,
quote! { ::enumscribe::TryScribeString },
quote! { ::std::option::Option<::std::string::String> },
|_, _, name| Ok(quote! {
::std::option::Option::Some(
<_ as ::std::borrow::ToOwned>::to_owned(#name)
)
}),
|_, _, field| Ok(quote! {
::std::option::Option::Some(
<_ as ::std::convert::Into<::std::string::String>>::into(#field)
)
}),
quote! { ::std::option::Option::None }
quote! { ::std::option::Option::None },
)
}
@@ -231,20 +215,16 @@ pub fn derive_try_scribe_string(input: TokenStream) -> TokenStream {
pub fn derive_scribe_cow_str(input: TokenStream) -> TokenStream {
derive_scribe(
input,
quote! { ::enumscribe::ScribeCowStr },
quote! { ::std::borrow::Cow<'static, str> },
|_, _, name| Ok(quote! {
::std::borrow::Cow::Borrowed(#name)
}),
|_, _, field| Ok(quote! {
::std::borrow::Cow::Owned(
<_ as ::std::convert::Into<::std::string::String>>::into(#field)
)
}),
|variant, enum_ident| MacroError::new(format!(
"cannot derive ScribeCowStr for {} because the variant {} is marked as {}\n\
explanation: since {} is ignored, it cannot be guaranteed that the enum can \
@@ -252,7 +232,7 @@ pub fn derive_scribe_cow_str(input: TokenStream) -> TokenStream {
hint: try deriving TryScribeCowStr instead",
enum_ident.to_string(), variant.data.ident.to_string(), IGNORE,
variant.data.ident.to_string(),
), variant.span)
), variant.span),
)
}
@@ -260,16 +240,13 @@ pub fn derive_scribe_cow_str(input: TokenStream) -> TokenStream {
pub fn derive_try_scribe_cow_str(input: TokenStream) -> TokenStream {
derive_try_scribe(
input,
quote! { ::enumscribe::TryScribeCowStr },
quote! { ::std::option::Option<::std::borrow::Cow<'static, str>> },
|_, _, name| Ok(quote! {
::std::option::Option::Some(
::std::borrow::Cow::Borrowed(#name)
)
}),
|_, _, field| Ok(quote! {
::std::option::Option::Some(
::std::borrow::Cow::Owned(
@@ -277,38 +254,142 @@ pub fn derive_try_scribe_cow_str(input: TokenStream) -> TokenStream {
)
)
}),
quote! { ::std::option::Option::None }
quote! { ::std::option::Option::None },
)
}
#[proc_macro_derive(Unscribe, attributes(enumscribe))]
pub fn derive_unscribe(input: TokenStream) -> TokenStream {
// let input: DeriveInput = syn::parse(input)
// .expect("failed to parse input");
//
// let enum_data = proc_try!(get_enum_data(&input));
// let parsed_enum = proc_try!(enums::parse_enum(enum_data));
//
// let enum_ident = &input.ident;
//
// let mut other_arm = None;
// let mut case_sensitive_arms = Vec::new();
// let mut case_insensitive_arms = Vec::new();
//
// for variant in parsed_enum.variants.iter() {
// match variant.v_type {
// VariantType::Ignore => {}
// VariantType::Named { .. } => {}
// VariantType::Other { .. } => {}
// }
// }
let input: DeriveInput = syn::parse(input)
.expect("failed to parse input");
todo!()
let enum_data = proc_try!(get_enum_data(&input));
let parsed_enum = proc_try!(enums::parse_enum(enum_data));
let enum_ident = &input.ident;
let mut all_ignored = true;
let mut other_arm = None;
let mut case_sensitive_arms = Vec::new();
let mut case_insensitive_arms = Vec::new();
let to_unscribe_ident = quote! { __enumscribe_to_unscribe };
for variant in parsed_enum.variants.iter() {
let variant_ident = &variant.data.ident;
match &variant.v_type {
VariantType::Ignore => (),
VariantType::Named { name, constructor, case_insensitive } => {
all_ignored = false;
let match_pattern = if *case_insensitive {
let lowercase_name = name.to_lowercase();
quote! { #lowercase_name }
} else {
quote! { #name }
};
let constructor_tokens = constructor.empty();
let match_result = quote! { #enum_ident::#variant_ident #constructor_tokens };
if *case_insensitive {
&mut case_insensitive_arms
} else {
&mut case_sensitive_arms
}.push(quote! { #match_pattern => #match_result });
}
VariantType::Other { field_name } => {
all_ignored = false;
let unscribe_value = quote! { <_ as ::std::convert::Into<_>>::into(#to_unscribe_ident) };
let match_result = match field_name {
None => quote! {
#enum_ident::#variant_ident(#unscribe_value)
},
Some(field_name) => quote! {
#enum_ident::#variant_ident { #field_name: #unscribe_value }
}
};
other_arm = Some(quote! { _ => #match_result })
}
}
}
if all_ignored {
return MacroError::new(format!(
"cannot derive Unscribe for {} because all variants are marked as {}\n\
hint: introduce at least one variant that is not marked as {}",
enum_ident.to_string(), IGNORE, IGNORE
), enum_ident.span()).into()
}
let other_arm = match other_arm {
Some(other_arm) => other_arm,
None => return MacroError::new(format!(
"cannot derive Unscribe for {} because no variant is marked as {}\n\
explanation: since there is no {} variant, it cannot be guaranteed that every string \
can be successfully converted to a variant of {}\n\
hint: either introduce an {} variant, or try deriving TryUnscribe instead",
enum_ident.to_string(), OTHER, OTHER, enum_ident.to_string(), OTHER
), enum_ident.span()).into()
};
let case_insensitive_match = if case_insensitive_arms.is_empty() {
None
} else {
Some(quote! {
let __enumscribe_unscribe_lowercase = #to_unscribe_ident.to_lowercase();
match __enumscribe_unscribe_lowercase.as_str() {
#(#case_insensitive_arms,)*
#other_arm,
}
})
};
let main_match = match (case_sensitive_arms.is_empty(), case_insensitive_match) {
(true, None) => quote! {
match #to_unscribe_ident {
#other_arm,
}
},
(false, None) => quote! {
match #to_unscribe_ident {
#(#case_sensitive_arms,)*
#other_arm,
}
},
(true, Some(case_insensitive_match)) => {
case_insensitive_match
},
(false, Some(case_insensitive_match)) => quote! {
match #to_unscribe_ident {
#(#case_sensitive_arms,)*
_ => { #case_insensitive_match },
}
}
};
(quote! {
impl ::enumscribe::Unscribe for #enum_ident {
fn unscribe(#to_unscribe_ident: &str) -> Self {
#main_match
}
}
}).into()
}
#[proc_macro_derive(TryUnscribe, attributes(enumscribe))]
pub fn derive_try_unscribe(input: TokenStream) -> TokenStream {
//TODO: make sure at least one variant is non-ignore
todo!()
}
enumscribe_examples/examples/airports.rs
+9 -5
View File
@@ -1,13 +1,13 @@
use enumscribe::*;
#[derive(TryScribeCowStr)]
#[derive(TryScribeCowStr, Unscribe, Eq, PartialEq, Debug)]
enum Airport {
#[enumscribe(str = "LHR", case_insensitive)]
#[enumscribe(str = "LHR")]
Heathrow,
#[enumscribe(str = "LGW", case_insensitive)]
Gatwick,
Gatwick(),
#[enumscribe(str = "LTN", case_insensitive)]
Luton,
Luton {},
#[enumscribe(str = "BHX", case_insensitive, ignore)]
BirminghamInternational,
#[enumscribe(other)]
@@ -15,9 +15,13 @@ enum Airport {
}
fn main() {
let luton = Airport::Luton;
let luton = Airport::Luton {};
println!("Hello, {:?}!", luton.try_scribe());
let other = Airport::Other("Dedicated EasyJet-only airport".to_owned());
println!("Hello, {:?}!", other.try_scribe());
println!("{:?}", Airport::unscribe("LHR"));
println!("{:?}", Airport::unscribe("lhr"));
println!("{:?}", Airport::unscribe("lgw"));
}