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Refactor #133

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Oct 8, 2020
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5 changes: 3 additions & 2 deletions strum_macros/src/helpers/case_style.rs
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
use heck::{CamelCase, KebabCase, MixedCase, ShoutySnakeCase, SnakeCase, TitleCase};
use syn::Ident;

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
pub enum CaseStyle {
Expand Down Expand Up @@ -53,7 +54,7 @@ pub trait CaseStyleHelpers {
fn convert_case(&self, case_style: Option<CaseStyle>) -> String;
}

impl CaseStyleHelpers for syn::Ident {
impl CaseStyleHelpers for Ident {
fn convert_case(&self, case_style: Option<CaseStyle>) -> String {
let ident_string = self.to_string();
if let Some(case_style) = case_style {
Expand Down Expand Up @@ -86,7 +87,7 @@ impl CaseStyleHelpers for syn::Ident {

#[test]
fn test_convert_case() {
let id = syn::Ident::new("test_me", proc_macro2::Span::call_site());
let id = Ident::new("test_me", proc_macro2::Span::call_site());
assert_eq!("testMe", id.convert_case(Some(CaseStyle::CamelCase)));
assert_eq!("TestMe", id.convert_case(Some(CaseStyle::PascalCase)));
}
62 changes: 37 additions & 25 deletions strum_macros/src/helpers/has_metadata.rs
Original file line number Diff line number Diff line change
@@ -1,44 +1,56 @@
///Represents a type that can have strum metadata associated with it.
use syn::{Attribute, DeriveInput, Meta, NestedMeta, Variant};

/// Represents a type that can have strum metadata associated with it.
pub trait HasMetadata {
/// Get all the metadata associated with a specific "tag".
/// All of strum's metadata is nested inside a path such as
/// #[strum(...)] so this let's us quickly filter down to only our metadata.
fn get_metadata(&self, ident: &str) -> Vec<syn::Meta>;
fn get_metadata(&self, ident: &str) -> syn::Result<Vec<Meta>>;
}

fn get_metadata_inner<'a>(
ident: &str,
it: impl IntoIterator<Item = &'a syn::Attribute>,
) -> Vec<syn::Meta> {
it.into_iter()
.filter(|attr| attr.path.is_ident(ident))
.map(|attr| attr.parse_meta().unwrap())
.filter_map(|meta| match meta {
syn::Meta::List(syn::MetaList { path, nested, .. }) => {
if path.is_ident(ident) {
Some(nested)
} else {
None
it: impl IntoIterator<Item = &'a Attribute>,
) -> syn::Result<Vec<Meta>> {
let mut res = Vec::new();

for attr in it {
if !attr.path.is_ident(ident) {
continue;
}

let meta = attr.parse_meta()?;
let nested = match meta {
Meta::List(syn::MetaList { nested, .. }) => nested,
_ => {
return Err(syn::Error::new_spanned(
meta,
"unrecognized strum attribute form",
))
}
};

for nested_meta in nested {
match nested_meta {
NestedMeta::Meta(meta) => res.push(meta),
NestedMeta::Lit(lit) => {
return Err(syn::Error::new_spanned(lit, "unexpected literal"))
}
}
_ => None,
})
.flat_map(|id| id)
.map(|nested| match nested {
syn::NestedMeta::Meta(meta) => meta,
_ => panic!("unexpected literal parsing strum attributes"),
})
.collect()
}
}

Ok(res)
}

impl HasMetadata for syn::Variant {
fn get_metadata(&self, ident: &str) -> Vec<syn::Meta> {
impl HasMetadata for Variant {
fn get_metadata(&self, ident: &str) -> syn::Result<Vec<Meta>> {
get_metadata_inner(ident, &self.attrs)
}
}

impl HasMetadata for syn::DeriveInput {
fn get_metadata(&self, ident: &str) -> Vec<syn::Meta> {
impl HasMetadata for DeriveInput {
fn get_metadata(&self, ident: &str) -> syn::Result<Vec<Meta>> {
get_metadata_inner(ident, &self.attrs)
}
}
54 changes: 27 additions & 27 deletions strum_macros/src/helpers/meta_helpers.rs
Original file line number Diff line number Diff line change
@@ -1,63 +1,63 @@
use syn::{Meta, MetaList, NestedMeta};
use syn::{Lit, Meta, MetaList, MetaNameValue, NestedMeta, Path};

pub trait MetaHelpers {
fn expect_metalist(&self, msg: &str) -> &MetaList;
fn expect_path(&self, msg: &str) -> &syn::Path;
fn expect_namevalue(&self, msg: &str) -> &syn::MetaNameValue;
fn expect_metalist(&self, msg: &str) -> syn::Result<&MetaList>;
fn expect_path(&self, msg: &str) -> syn::Result<&Path>;
fn expect_namevalue(&self, msg: &str) -> syn::Result<&MetaNameValue>;
}

impl MetaHelpers for syn::Meta {
fn expect_metalist(&self, msg: &str) -> &MetaList {
impl MetaHelpers for Meta {
fn expect_metalist(&self, msg: &str) -> syn::Result<&MetaList> {
match self {
Meta::List(list) => list,
_ => panic!("{}", msg),
Meta::List(list) => Ok(list),
_ => Err(syn::Error::new_spanned(self, msg)),
}
}

fn expect_path(&self, msg: &str) -> &syn::Path {
fn expect_path(&self, msg: &str) -> syn::Result<&Path> {
match self {
Meta::Path(path) => path,
_ => panic!("{}", msg),
Meta::Path(path) => Ok(path),
_ => Err(syn::Error::new_spanned(self, msg)),
}
}

fn expect_namevalue(&self, msg: &str) -> &syn::MetaNameValue {
fn expect_namevalue(&self, msg: &str) -> syn::Result<&MetaNameValue> {
match self {
Meta::NameValue(pair) => pair,
_ => panic!("{}", msg),
Meta::NameValue(pair) => Ok(pair),
_ => Err(syn::Error::new_spanned(self, msg)),
}
}
}

pub trait NestedMetaHelpers {
fn expect_meta(&self, msg: &str) -> &syn::Meta;
fn expect_lit(&self, msg: &str) -> &syn::Lit;
fn expect_meta(&self, msg: &str) -> syn::Result<&Meta>;
fn expect_lit(&self, msg: &str) -> syn::Result<&Lit>;
}

impl NestedMetaHelpers for NestedMeta {
fn expect_meta(&self, msg: &str) -> &Meta {
fn expect_meta(&self, msg: &str) -> syn::Result<&Meta> {
match self {
syn::NestedMeta::Meta(m) => m,
_ => panic!("{}", msg),
NestedMeta::Meta(m) => Ok(m),
_ => Err(syn::Error::new_spanned(self, msg)),
}
}
fn expect_lit(&self, msg: &str) -> &syn::Lit {
fn expect_lit(&self, msg: &str) -> syn::Result<&Lit> {
match self {
syn::NestedMeta::Lit(l) => l,
_ => panic!("{}", msg),
NestedMeta::Lit(l) => Ok(l),
_ => Err(syn::Error::new_spanned(self, msg)),
}
}
}

pub trait LitHelpers {
fn expect_string(&self, msg: &str) -> String;
fn expect_string(&self, msg: &str) -> syn::Result<String>;
}

impl LitHelpers for syn::Lit {
fn expect_string(&self, msg: &str) -> String {
impl LitHelpers for Lit {
fn expect_string(&self, msg: &str) -> syn::Result<String> {
match self {
syn::Lit::Str(s) => s.value(),
_ => panic!("{}", msg),
Lit::Str(s) => Ok(s.value()),
_ => Err(syn::Error::new_spanned(self, msg)),
}
}
}
35 changes: 20 additions & 15 deletions strum_macros/src/helpers/type_props.rs
Original file line number Diff line number Diff line change
@@ -1,38 +1,39 @@
use std::convert::From;
use std::default::Default;
use syn::{DeriveInput, Lit, Meta, Path};

use crate::helpers::case_style::CaseStyle;
use crate::helpers::has_metadata::HasMetadata;
use crate::helpers::{MetaHelpers, NestedMetaHelpers};

pub trait HasTypeProperties {
fn get_type_properties(&self) -> StrumTypeProperties;
fn get_type_properties(&self) -> syn::Result<StrumTypeProperties>;
}

#[derive(Debug, Clone, Eq, PartialEq, Default)]
pub struct StrumTypeProperties {
pub case_style: Option<CaseStyle>,
pub discriminant_derives: Vec<syn::Path>,
pub discriminant_name: Option<syn::Path>,
pub discriminant_others: Vec<syn::Meta>,
pub discriminant_derives: Vec<Path>,
pub discriminant_name: Option<Path>,
pub discriminant_others: Vec<Meta>,
}

impl HasTypeProperties for syn::DeriveInput {
fn get_type_properties(&self) -> StrumTypeProperties {
impl HasTypeProperties for DeriveInput {
fn get_type_properties(&self) -> syn::Result<StrumTypeProperties> {
let mut output = StrumTypeProperties::default();

let strum_meta = self.get_metadata("strum");
let discriminants_meta = self.get_metadata("strum_discriminants");
let strum_meta = self.get_metadata("strum")?;
let discriminants_meta = self.get_metadata("strum_discriminants")?;

for meta in strum_meta {
let meta = match meta {
syn::Meta::NameValue(mv) => mv,
Meta::NameValue(mv) => mv,
_ => panic!("strum on types only supports key-values"),
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Can we return an Err here was well?

};

if meta.path.is_ident("serialize_all") {
let style = match meta.lit {
syn::Lit::Str(s) => s.value(),
Lit::Str(s) => s.value(),
_ => panic!("expected string value for 'serialize_all'"),
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Here as well.

};

Expand All @@ -48,12 +49,16 @@ impl HasTypeProperties for syn::DeriveInput {

for meta in discriminants_meta {
match meta {
syn::Meta::List(ref ls) => {
Meta::List(ref ls) => {
if ls.path.is_ident("derive") {
let paths = ls
.nested
.iter()
.map(|meta| meta.expect_meta("unexpected literal").path().clone());
.map(|meta| {
let meta = meta.expect_meta("unexpected literal")?;
Ok(meta.path().clone())
})
.collect::<syn::Result<Vec<_>>>()?;

output.discriminant_derives.extend(paths);
} else if ls.path.is_ident("name") {
Expand All @@ -63,8 +68,8 @@ impl HasTypeProperties for syn::DeriveInput {

let value = ls.nested.first().expect("unexpected error");
let name = value
.expect_meta("unexpected literal")
.expect_path("name must be an identifier");
.expect_meta("unexpected literal")?
.expect_path("name must be an identifier")?;

if output.discriminant_name.is_some() {
panic!("multiple occurrences of 'name'");
Expand All @@ -81,6 +86,6 @@ impl HasTypeProperties for syn::DeriveInput {
}
}

output
Ok(output)
}
}
33 changes: 17 additions & 16 deletions strum_macros/src/helpers/variant_props.rs
Original file line number Diff line number Diff line change
@@ -1,12 +1,13 @@
use std::collections::HashMap;
use std::default::Default;
use syn::{Ident, Meta, Variant};

use crate::helpers::case_style::{CaseStyle, CaseStyleHelpers};
use crate::helpers::has_metadata::HasMetadata;
use crate::helpers::{LitHelpers, MetaHelpers, NestedMetaHelpers};

pub trait HasStrumVariantProperties {
fn get_variant_properties(&self) -> StrumVariantProperties;
fn get_variant_properties(&self) -> syn::Result<StrumVariantProperties>;
}

#[derive(Clone, Eq, PartialEq, Debug, Default)]
Expand All @@ -18,7 +19,7 @@ pub struct StrumVariantProperties {
pub string_props: HashMap<String, String>,
serialize: Vec<String>,
to_string: Option<String>,
ident: Option<syn::Ident>,
ident: Option<Ident>,
}

impl StrumVariantProperties {
Expand Down Expand Up @@ -58,34 +59,34 @@ impl StrumVariantProperties {
}
}

impl HasStrumVariantProperties for syn::Variant {
fn get_variant_properties(&self) -> StrumVariantProperties {
impl HasStrumVariantProperties for Variant {
fn get_variant_properties(&self) -> syn::Result<StrumVariantProperties> {
let mut output = StrumVariantProperties::default();
output.ident = Some(self.ident.clone());

for meta in self.get_metadata("strum") {
for meta in self.get_metadata("strum")? {
match meta {
syn::Meta::NameValue(syn::MetaNameValue { path, lit, .. }) => {
Meta::NameValue(syn::MetaNameValue { path, lit, .. }) => {
if path.is_ident("message") {
if output.message.is_some() {
panic!("message is set twice on the same variant");
}

output.message = Some(lit.expect_string("expected string"));
output.message = Some(lit.expect_string("expected string")?);
} else if path.is_ident("detailed_message") {
if output.detailed_message.is_some() {
panic!("detailed message set twice on the same variant");
}

output.detailed_message = Some(lit.expect_string("expected string"));
output.detailed_message = Some(lit.expect_string("expected string")?);
} else if path.is_ident("serialize") {
output.serialize.push(lit.expect_string("expected string"));
output.serialize.push(lit.expect_string("expected string")?);
} else if path.is_ident("to_string") {
if output.to_string.is_some() {
panic!("to_string is set twice on the same variant");
}

output.to_string = Some(lit.expect_string("expected string"));
output.to_string = Some(lit.expect_string("expected string")?);
} else if path.is_ident("disabled") {
panic!("this method is deprecated. Prefer #[strum(disabled)] instead of #[strum(disabled=\"true\")]");
} else if path.is_ident("default") {
Expand All @@ -94,7 +95,7 @@ impl HasStrumVariantProperties for syn::Variant {
panic!("unrecognized value in strum(..) attribute");
}
}
syn::Meta::Path(p) => {
Meta::Path(p) => {
if p.is_ident("disabled") {
output.is_disabled = true;
} else if p.is_ident("default") {
Expand All @@ -103,20 +104,20 @@ impl HasStrumVariantProperties for syn::Variant {
panic!("unrecognized value in strum(..) attribute");
}
}
syn::Meta::List(syn::MetaList { path, nested, .. }) => {
Meta::List(syn::MetaList { path, nested, .. }) => {
if path.is_ident("props") {
for p in nested {
let p = p
.expect_meta("unexpected literal found in props")
.expect_namevalue("props must be key-value pairs");
.expect_meta("unexpected literal found in props")?
.expect_namevalue("props must be key-value pairs")?;

let key = p
.path
.get_ident()
.expect("key must be an identifier")
.to_string();

let value = p.lit.expect_string("expected string");
let value = p.lit.expect_string("expected string")?;
output.string_props.insert(key, value);
}
} else {
Expand All @@ -126,6 +127,6 @@ impl HasStrumVariantProperties for syn::Variant {
}
}

output
Ok(output)
}
}
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