feat: allow no_std

Cargo.toml

@@ -4,7 +4,7 @@ description = "A JavaScript-like nested object-like structure non-fallible path
 repository = "https://github.com/FlakySL/dyn_path"
 license = "GPL-3.0"
 readme = "./README.md"
-version = "1.0.0"
+version = "1.0.1"
 edition = "2024"
 authors = ["Esteve Autet <[email protected]>", "Chiko <[email protected]>"]
 keywords = [
@@ -18,3 +18,8 @@ keywords = [
 
 [dev-dependencies]
 serde_json = "1.0.140"
+
+[features]
+default = ["std"]
+std = []
+alloc = []

src/lib.rs

@@ -1,3 +1,8 @@
+#![cfg_attr(not(feature = "std"), no_std)]
+
+#[cfg(all(not(feature = "std"), feature = "alloc"))]
+pub extern crate alloc;
+
 #[cfg(test)]
 mod test;
 
@@ -59,7 +64,7 @@ macro_rules! dyn_access {
     }};
 
     (@recurse $acc:expr, . $field:ident $($rest:tt)*) => {{
-        let __ = $acc.and_then(|v| v.get(::std::stringify!($field)));
+        let __ = $acc.and_then(|v| v.get(::core::stringify!($field)));
         $crate::dyn_access!(@recurse __, $($rest)*)
     }};
 
@@ -89,21 +94,23 @@ macro_rules! dyn_access {
 /// assert_eq!(display_path, r#"nested.path.at[2].with["no"]["head"]"#);
 /// ```
 /// Notice how the macro pre-computes the indexes and generates the target string.
+#[cfg(any(feature = "alloc", feature = "std"))]
 #[macro_export]
 macro_rules! dyn_path {
     ($head:ident $($rest:tt)*) => {{
-        use ::std::fmt::Write;
-        let mut __ = ::std::stringify!($head).to_string();
+        use ::core::fmt::Write;
+        use $crate::alloc::string::ToString;
+        let mut __ = ::core::stringify!($head).to_string();
         $crate::dyn_path!(@recurse __, $($rest)*)
     }};
 
     (@recurse $acc:expr, . $field:ident $($rest:tt)*) => {{
-        let _ = ::std::write!($acc, ".{}", ::std::stringify!($field));
+        let _ = ::core::write!($acc, ".{}", ::core::stringify!($field));
         $crate::dyn_path!(@recurse $acc, $($rest)*)
     }};
 
     (@recurse $acc:expr, [$idx:expr] $($rest:tt)*) => {{
-        let _ = ::std::write!($acc, "[{:?}]", ($idx));
+        let _ = ::core::write!($acc, "[{:?}]", ($idx));
         $crate::dyn_path!(@recurse $acc, $($rest)*)
     }};
 

src/test.rs

@@ -1,6 +1,8 @@
 use serde_json::{json, Value};
 
-use crate::{dyn_access, dyn_path};
+use crate::dyn_access;
+#[cfg(feature = "alloc")]
+use crate::dyn_path;
 
 const ERROR: &str = "nested value to exist.";
 
@@ -45,13 +47,14 @@ pub fn nested_access() {
 
 #[test]
 pub fn direct_expression() {
-    let vector = vec![map()];
-    let _1 = dyn_access!((vector[0]).very.nested[1])
+    let vector = (map(), ());
+    let _1 = dyn_access!((vector.0).very.nested[1])
         .expect(ERROR);
 
     assert_eq!(_1, "of");
 }
 
+#[cfg(feature = "alloc")]
 #[test]
 pub fn path_descriptor() {
     let _1 = dyn_path!(very.nested["value"].on.index[1 + 1]);