From d085cad4370ab9759e616a7a4513f78cfe0b21be Mon Sep 17 00:00:00 2001
From: Akshay <nerdy@peppe.rs>
Date: Sun, 31 Oct 2021 14:35:26 +0530
Subject: rework macros crate, add attr parser for explainations

---
 macros/src/lib.rs | 173 ++++--------------------------------------------------
 1 file changed, 11 insertions(+), 162 deletions(-)

(limited to 'macros/src/lib.rs')

diff --git a/macros/src/lib.rs b/macros/src/lib.rs
index 127b4cb..86fa509 100644
--- a/macros/src/lib.rs
+++ b/macros/src/lib.rs
@@ -1,44 +1,12 @@
-use std::collections::HashMap;
+mod explain;
+mod metadata;
 
+use explain::generate_explain_impl;
+use metadata::{generate_meta_impl, RawLintMeta};
 use proc_macro::TokenStream;
 use proc_macro2::TokenStream as TokenStream2;
-
-use quote::{format_ident, quote};
-use syn::{
-    parse::{Parse, ParseStream, Result as ParseResult},
-    parse_macro_input,
-    punctuated::Punctuated,
-    Expr, Ident, ItemStruct, Lit, Token,
-};
-
-struct KeyValue {
-    key: Ident,
-    _eq: Token![=],
-    value: Expr,
-}
-
-impl Parse for KeyValue {
-    fn parse(input: ParseStream) -> ParseResult<Self> {
-        Ok(Self {
-            key: input.parse()?,
-            _eq: input.parse()?,
-            value: input.parse()?,
-        })
-    }
-}
-
-struct LintMeta(HashMap<Ident, Expr>);
-
-impl Parse for LintMeta {
-    fn parse(input: ParseStream) -> ParseResult<Self> {
-        Ok(Self(
-            Punctuated::<KeyValue, Token![,]>::parse_terminated(input)?
-                .into_iter()
-                .map(|item| (item.key, item.value))
-                .collect(),
-        ))
-    }
-}
+use quote::quote;
+use syn::{parse_macro_input, Ident, ItemStruct};
 
 fn generate_self_impl(struct_name: &Ident) -> TokenStream2 {
     quote! {
@@ -50,136 +18,16 @@ fn generate_self_impl(struct_name: &Ident) -> TokenStream2 {
     }
 }
 
-fn generate_meta_impl(struct_name: &Ident, meta: &LintMeta) -> TokenStream2 {
-    let name_fn = generate_name_fn(meta);
-    let note_fn = generate_note_fn(meta);
-    let code_fn = generate_code_fn(meta);
-    let report_fn = generate_report_fn();
-    let match_with_fn = generate_match_with_fn(meta);
-    let match_kind = generate_match_kind(meta);
-    quote! {
-        impl Metadata for #struct_name {
-            #name_fn
-            #note_fn
-            #code_fn
-            #report_fn
-            #match_with_fn
-            #match_kind
-        }
-    }
-}
-
-fn generate_name_fn(meta: &LintMeta) -> TokenStream2 {
-    let name = meta
-        .0
-        .get(&format_ident!("name"))
-        .unwrap_or_else(|| panic!("`name` not present"));
-    if let syn::Expr::Lit(name_lit) = name {
-        if let Lit::Str(name_str) = &name_lit.lit {
-            return quote! {
-                fn name() -> &'static str {
-                    #name_str
-                }
-            };
-        }
-    }
-    panic!("Invalid value for `name`");
-}
-
-fn generate_note_fn(meta: &LintMeta) -> TokenStream2 {
-    let note = meta
-        .0
-        .get(&format_ident!("note"))
-        .unwrap_or_else(|| panic!("`note` not present"));
-    if let syn::Expr::Lit(note_lit) = note {
-        if let Lit::Str(note_str) = &note_lit.lit {
-            return quote! {
-                fn note() -> &'static str {
-                    #note_str
-                }
-            };
-        }
-    }
-    panic!("Invalid value for `note`");
-}
-
-fn generate_code_fn(meta: &LintMeta) -> TokenStream2 {
-    let code = meta
-        .0
-        .get(&format_ident!("code"))
-        .unwrap_or_else(|| panic!("`code` not present"));
-    if let syn::Expr::Lit(code_lit) = code {
-        if let Lit::Int(code_int) = &code_lit.lit {
-            return quote! {
-                fn code() -> u32 {
-                    #code_int
-                }
-            };
-        }
-    }
-    panic!("Invalid value for `note`");
-}
-
-fn generate_report_fn() -> TokenStream2 {
-    quote! {
-        fn report() -> Report {
-            Report::new(Self::note(), Self::code())
-        }
-    }
-}
-
-fn generate_match_with_fn(meta: &LintMeta) -> TokenStream2 {
-    let match_with_lit = meta
-        .0
-        .get(&format_ident!("match_with"))
-        .unwrap_or_else(|| panic!("`match_with` not present"));
-    if let syn::Expr::Path(match_path) = match_with_lit {
-        quote! {
-            fn match_with(&self, with: &SyntaxKind) -> bool {
-                #match_path == *with
-            }
-        }
-    } else if let syn::Expr::Array(array_expr) = match_with_lit {
-        quote! {
-            fn match_with(&self, with: &SyntaxKind) -> bool {
-                #array_expr.contains(with)
-            }
-        }
-    } else {
-        panic!("`match_with` has non-path value")
-    }
-}
-
-fn generate_match_kind(meta: &LintMeta) -> TokenStream2 {
-    let match_with_lit = meta
-        .0
-        .get(&format_ident!("match_with"))
-        .unwrap_or_else(|| panic!("`match_with` not present"));
-    if let syn::Expr::Path(match_path) = match_with_lit {
-        quote! {
-            fn match_kind(&self) -> Vec<SyntaxKind> {
-                vec![#match_path]
-            }
-        }
-    } else if let syn::Expr::Array(array_expr) = match_with_lit {
-        quote! {
-            fn match_kind(&self) -> Vec<SyntaxKind> {
-                #array_expr.to_vec()
-            }
-        }
-    } else {
-        panic!("`match_with` has non-path value")
-    }
-}
-
 #[proc_macro_attribute]
 pub fn lint(attr: TokenStream, item: TokenStream) -> TokenStream {
     let struct_item = parse_macro_input!(item as ItemStruct);
-    let meta = parse_macro_input!(attr as LintMeta);
+    let meta = parse_macro_input!(attr as RawLintMeta);
 
     let struct_name = &struct_item.ident;
     let self_impl = generate_self_impl(struct_name);
     let meta_impl = generate_meta_impl(struct_name, &meta);
+    let explain_impl = generate_explain_impl(&struct_item);
+
     (quote! {
         #struct_item
 
@@ -189,8 +37,9 @@ pub fn lint(attr: TokenStream, item: TokenStream) -> TokenStream {
 
         #self_impl
         #meta_impl
+        #explain_impl
 
-        impl Lint for #struct_name {}
+        impl crate::Lint for #struct_name {}
     })
     .into()
 }
-- 
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