From 56afbaa6667dc74faea202ab6e8a43e18d3775ad Mon Sep 17 00:00:00 2001
From: Jannik Obermann <50554200+jannik4@users.noreply.github.com>
Date: Sun, 26 Feb 2023 11:25:06 +0100
Subject: [PATCH] Add logos(crate = "...") attribute (#268)

* Add logos(crate = "...") attribute

* Use logos-derive per path
---
 logos-codegen/src/lib.rs        | 13 ++++++++----
 logos-codegen/src/parser/mod.rs | 18 ++++++++++++++++-
 logos/Cargo.toml                |  2 +-
 tests/tests/crate_.rs           | 36 +++++++++++++++++++++++++++++++++
 4 files changed, 63 insertions(+), 6 deletions(-)
 create mode 100644 tests/tests/crate_.rs

diff --git a/logos-codegen/src/lib.rs b/logos-codegen/src/lib.rs
index d7dd667d..60ffe6fa 100644
--- a/logos-codegen/src/lib.rs
+++ b/logos-codegen/src/lib.rs
@@ -26,6 +26,7 @@ use util::MaybeVoid;
 use proc_macro2::Span;
 use proc_macro2::TokenStream;
 use quote::quote;
+use syn::parse_quote;
 use syn::spanned::Spanned;
 use syn::{Fields, ItemEnum};
 
@@ -211,6 +212,10 @@ pub fn generate(input: TokenStream) -> TokenStream {
         Mode::Utf8 => quote!(str),
         Mode::Binary => quote!([u8]),
     };
+    let logos_path = parser
+        .logos_path
+        .take()
+        .unwrap_or_else(|| parse_quote!(::logos));
 
     let error_def = match error {
         Some(error) => Some(quote!(const ERROR: Self = #name::#error;)),
@@ -225,14 +230,14 @@ pub fn generate(input: TokenStream) -> TokenStream {
 
     let impl_logos = |body| {
         quote! {
-            impl<'s> ::logos::Logos<'s> for #this {
+            impl<'s> #logos_path::Logos<'s> for #this {
                 type Extras = #extras;
 
                 type Source = #source;
 
                 #error_def
 
-                fn lex(lex: &mut ::logos::Lexer<'s, Self>) {
+                fn lex(lex: &mut #logos_path::Lexer<'s, Self>) {
                     #body
                 }
             }
@@ -297,9 +302,9 @@ pub fn generate(input: TokenStream) -> TokenStream {
 
     let body = generator.generate();
     let tokens = impl_logos(quote! {
-        use ::logos::internal::{LexerInternal, CallbackResult};
+        use #logos_path::internal::{LexerInternal, CallbackResult};
 
-        type Lexer<'s> = ::logos::Lexer<'s, #this>;
+        type Lexer<'s> = #logos_path::Lexer<'s, #this>;
 
         fn _end<'s>(lex: &mut Lexer<'s>) {
             lex.end()
diff --git a/logos-codegen/src/parser/mod.rs b/logos-codegen/src/parser/mod.rs
index f38eb850..960c0cb6 100644
--- a/logos-codegen/src/parser/mod.rs
+++ b/logos-codegen/src/parser/mod.rs
@@ -2,7 +2,7 @@ use beef::lean::Cow;
 use proc_macro2::{Span, TokenStream, TokenTree};
 use quote::quote;
 use syn::spanned::Spanned;
-use syn::{Attribute, GenericParam, Lit, Type};
+use syn::{Attribute, GenericParam, Lit, Path, Type};
 
 use crate::error::Errors;
 use crate::leaf::{Callback, InlineCallback};
@@ -27,6 +27,7 @@ pub struct Parser {
     pub mode: Mode,
     pub extras: MaybeVoid,
     pub subpatterns: Subpatterns,
+    pub logos_path: Option<Path>,
     types: TypeParams,
 }
 
@@ -129,6 +130,21 @@ impl Parser {
                 ("subpattern", _) => {
                     self.err(r#"Expected: subpattern name = r"regex""#, name.span());
                 }
+                ("crate", NestedValue::Assign(value)) => {
+                    let value = syn::parse2::<Lit>(value).ok().and_then(|lit| match lit {
+                        Lit::Str(string) => syn::parse_str(&string.value()).ok(),
+                        _ => None,
+                    });
+                    match value {
+                        Some(logos_path) => self.logos_path = Some(logos_path),
+                        None => {
+                            self.err(r#"Expected: crate = "some::path::to::logos""#, name.span());
+                        }
+                    }
+                }
+                ("crate", _) => {
+                    self.err(r#"Expected: crate = "some::path::to::logos""#, name.span());
+                }
                 (unknown, _) => {
                     self.err(
                         format!("Unknown nested attribute: {}", unknown),
diff --git a/logos/Cargo.toml b/logos/Cargo.toml
index 801672c2..2925f117 100644
--- a/logos/Cargo.toml
+++ b/logos/Cargo.toml
@@ -12,7 +12,7 @@ readme = "../README.md"
 edition = "2018"
 
 [dependencies]
-logos-derive = { version = "0.12.1", optional = true }
+logos-derive = { path = "../logos-derive", version = "0.12.1", optional = true }
 
 [features]
 default = ["export_derive", "std"]
diff --git a/tests/tests/crate_.rs b/tests/tests/crate_.rs
new file mode 100644
index 00000000..e9156586
--- /dev/null
+++ b/tests/tests/crate_.rs
@@ -0,0 +1,36 @@
+use logos_derive::Logos;
+use tests::assert_lex;
+
+mod some {
+    pub mod path {
+        pub use logos as _logos;
+    }
+}
+
+#[derive(Logos, Debug, Clone, Copy, PartialEq)]
+#[logos(crate = "some::path::_logos")]
+enum Token {
+    #[regex(r"[ \t\n\f]+", logos::skip)]
+    #[error]
+    Error,
+
+    #[regex("-?[0-9]+")]
+    LiteralInteger,
+
+    #[token("'")]
+    SingleQuote,
+}
+
+#[test]
+fn simple() {
+    assert_lex(
+        "' -1'2  '",
+        &[
+            (Token::SingleQuote, "'", 0..1),
+            (Token::LiteralInteger, "-1", 2..4),
+            (Token::SingleQuote, "'", 4..5),
+            (Token::LiteralInteger, "2", 5..6),
+            (Token::SingleQuote, "'", 8..9),
+        ],
+    );
+}