Merge pull request #122 from greyblake/no-std-support

Support no_std

.github/workflows/ci.yml

@@ -103,11 +103,20 @@ jobs:
         uses: actions-rs/toolchain@v1
         with:
           toolchain: stable
+          target: thumbv7m-none-eabi   # Needed for no_std_example
 
       - name: Run examples
         run: |
-          for example in $(ls ./examples/); do
-            cargo run --bin $example
+          set -euxo pipefail
+          ROOT_DIR=$(pwd)
+          for EXAMPLE in `ls examples`; do
+            cd $ROOT_DIR/examples/$EXAMPLE;
+            if [[ "$EXAMPLE" == "no_std_example" ]]
+            then
+              cargo build
+            else
+              cargo run
+            fi
           done
 
   typos:

CHANGELOG.md

@@ -1,5 +1,6 @@
 ### v0.4.1 - xxxx-xx-xx
 
+* Support `no_std` ( the dependency needs to be declared as `nutype = { default-features = false }` )
 * Support integration with [`arbitrary`](https://crates.io/crates/arbitrary) crate (see `arbitrary` feature).
   * Support `Arbitrary` for integer types
   * Support `Arbitrary` for float types

Cargo.toml

@@ -7,5 +7,16 @@ members = [
     "nutype_macros",
     "test_suite",
     "dummy",
-    "examples/*",
+
+    # All examples except "no_std_example" are tested in the test suite
+    "examples/any_arbitrary",
+    "examples/float_arbitrary",
+    "examples/float_sortable",
+    "examples/integer_arbitrary",
+    "examples/integer_bounded",
+    "examples/new_unchecked_example",
+    # "examples/no_std_example",
+    "examples/serde_complex",
+    "examples/string_bounded_len",
+    "examples/string_regex_email",
 ]

Justfile

@@ -27,7 +27,18 @@ clippy:
 	cargo clippy -- -D warnings
 
 examples:
-  for example in `ls examples`; do cargo run --bin $example; done
+    #!/usr/bin/env bash
+    set -euxo pipefail
+    ROOT_DIR=$(pwd)
+    for EXAMPLE in `ls examples`; do
+        cd $ROOT_DIR/examples/$EXAMPLE;
+        if [[ "$EXAMPLE" == "no_std_example" ]]
+        then
+            cargo build
+        else
+            cargo run
+        fi
+    done
 
 typos:
     which typos >/dev/null || cargo install typos-cli

README.md

@@ -354,10 +354,12 @@ assert_eq!(name.into_inner(), " boo ");
 
 ## Feature flags
 
-* `serde` - integrations with [`serde`](https://crates.io/crates/serde) crate. Allows to derive `Serialize` and `Deserialize` traits.
+* `arbitrary` - enables derive of [`arbitrary::Arbitrary`](https://docs.rs/arbitrary/latest/arbitrary/trait.Arbitrary.html).
+* `new_unchecked` - enables generation of unsafe `::new_unchecked()` function.
 * `regex` - allows to use `regex = ` validation on string-based types. Note: your crate also has to explicitly have `regex` and `lazy_static` within dependencies.
+* `serde` - integrations with [`serde`](https://crates.io/crates/serde) crate. Allows to derive `Serialize` and `Deserialize` traits.
 * `schemars08` - allows to derive [`JsonSchema`](https://docs.rs/schemars/0.8.12/schemars/trait.JsonSchema.html) trait of [schemars](https://crates.io/crates/schemars) crate. Note that at the moment validation rules are not respected.
-* `new_unchecked` - enables generation of unsafe `::new_unchecked()` function.
+* `std` - enabled by default. Use `default-features = false` to disable.
 
 ## When nutype is a good fit for you?
 

examples/no_std_example/.cargo/config

@@ -0,0 +1,2 @@
+[build]
+target = "thumbv7m-none-eabi"

examples/no_std_example/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "no_std_example"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+nutype = { path = "../../nutype", default-features = false }
+
+# Exclude this package from the common workspace, since it's no_std.
+[workspace]

examples/no_std_example/src/main.rs

@@ -0,0 +1,74 @@
+// This example exists to ensure that code generated by nutype macro
+// can compile in no_std environment.
+#![no_main]
+#![no_std]
+
+use core::panic::PanicInfo;
+use nutype::nutype;
+
+#[panic_handler]
+fn panic(_panic: &PanicInfo<'_>) -> ! {
+    loop {}
+}
+
+// Integer
+#[nutype(
+    validate(greater_or_equal = 1, less_or_equal = 6),
+    sanitize(with = |x| x),
+    derive(
+        Debug,
+        Clone,
+        PartialEq,
+        Eq,
+        PartialOrd,
+        Ord,
+        FromStr,
+        AsRef,
+        Deref,
+        TryFrom,
+        Into,
+        Hash,
+        Borrow,
+        Display,
+        Default,
+    ),
+    default = 4
+)]
+struct GermanTaxClass(i64);
+
+// Float
+#[nutype(
+    validate(greater_or_equal = 0.0, less_or_equal = 1024.0, finite),
+    sanitize(with = |x| x),
+    derive(
+        Debug,
+        Clone,
+        PartialEq,
+        Eq,
+        PartialOrd,
+        Ord,
+        FromStr,
+        AsRef,
+        Deref,
+        TryFrom,
+        Into,
+        Borrow,
+        Display,
+        Default,
+    ),
+    default = 0.0
+)]
+struct Width(f64);
+
+// NOTE: strings are not working yet with no_std
+
+// Any other type
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub struct Point {
+    x: i32,
+    y: i32,
+}
+#[nutype(derive(
+    Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord, AsRef, Into, From, Deref, Borrow, Hash
+))]
+pub struct Location(Point);

nutype/Cargo.toml

@@ -18,6 +18,9 @@ categories = ["data-structures", "rust-patterns"]
 nutype_macros = { version = "0.4.0", path = "../nutype_macros" }
 
 [features]
+default = ["std"]
+
+std = ["nutype_macros/std"]
 serde = ["nutype_macros/serde"]
 regex = ["nutype_macros/regex"]
 schemars08 = ["nutype_macros/schemars08"]

nutype/src/lib.rs

@@ -383,10 +383,12 @@
 //!
 //! ## Feature flags
 //!
-//! * `serde` - integrations with [`serde`](https://crates.io/crates/serde) crate. Allows to derive `Serialize` and `Deserialize` traits.
+//! * `arbitrary` - enables derive of [`arbitrary::Arbitrary`](https://docs.rs/arbitrary/latest/arbitrary/trait.Arbitrary.html).
 //! * `new_unchecked` - enables generation of unsafe `::new_unchecked()` function.
-//! * `schemars08` - allows to derive [`JsonSchema`](https://docs.rs/schemars/0.8.12/schemars/trait.JsonSchema.html) trait of [schemars](https://crates.io/crates/schemars) crate. Note that at the moment validation rules are not respected.
 //! * `regex` - allows to use `regex = ` validation on string-based types. Note: your crate also has to explicitly have `regex` and `lazy_static` within dependencies.
+//! * `serde` - integrations with [`serde`](https://crates.io/crates/serde) crate. Allows to derive `Serialize` and `Deserialize` traits.
+//! * `schemars08` - allows to derive [`JsonSchema`](https://docs.rs/schemars/0.8.12/schemars/trait.JsonSchema.html) trait of [schemars](https://crates.io/crates/schemars) crate. Note that at the moment validation rules are not respected.
+//! * `std` - enabled by default. Use `default-features = false` to disable.
 //!
 //! ## Support Ukrainian military forces 🇺🇦
 //!
@@ -404,6 +406,9 @@
 //!
 //! Thank you.
 
+// Set `no_std` flag if `std` feature is disabled.
+#![cfg_attr(not(feature = "std"), no_std)]
+
 pub use nutype_macros::nutype;
 
 #[cfg(test)]

nutype_macros/Cargo.toml

@@ -30,6 +30,7 @@ urlencoding = "2.0"
 proc-macro = true
 
 [features]
+std = []
 serde = []
 schemars08 = []
 new_unchecked = []

nutype_macros/src/common/gen/error.rs

@@ -1,3 +1,4 @@
+use cfg_if::cfg_if;
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote};
 
@@ -8,12 +9,21 @@ pub fn gen_error_type_name(type_name: &TypeName) -> ErrorTypeName {
     ErrorTypeName::new(ident)
 }
 
+// NOTE: There is no `::core::error::Error` yet in stable Rust.
+// So for `no_std` we just don't implement `Error` trait.
+#[allow(unused_variables)]
 pub fn gen_impl_error_trait(error_type_name: &ErrorTypeName) -> TokenStream {
-    quote! {
-        impl ::std::error::Error for #error_type_name {
-            fn source(&self) -> Option<&(dyn ::std::error::Error + 'static)> {
-                None
+    cfg_if! {
+        if #[cfg(feature = "std")] {
+            quote! {
+                impl ::std::error::Error for #error_type_name {
+                    fn source(&self) -> Option<&(dyn ::std::error::Error + 'static)> {
+                        None
+                    }
+                }
             }
+        } else {
+            quote!{}
         }
     }
 }

nutype_macros/src/common/gen/parse_error.rs

@@ -1,3 +1,4 @@
+use cfg_if::cfg_if;
 use proc_macro2::TokenStream;
 use quote::{format_ident, quote};
 
@@ -55,11 +56,19 @@ pub fn gen_def_parse_error(
         }
     };
 
-    let impl_std_error = quote! {
-        impl ::std::error::Error for #parse_error_type_name {
-            fn source(&self) -> Option<&(dyn ::std::error::Error + 'static)> {
-                None
-            }
+    cfg_if! {
+        if #[cfg(feature = "std")] {
+            let impl_std_error = quote! {
+                impl ::std::error::Error for #parse_error_type_name {
+                    fn source(&self) -> Option<&(dyn ::std::error::Error + 'static)> {
+                        None
+                    }
+                }
+            };
+        } else {
+            // NOTE: There is no `::core::error::Error` yet in stable Rust.
+            // So for `no_std` we just don't implement `Error` trait.
+            let impl_std_error = quote! {};
         }
     };
 

nutype_macros/src/float/gen/traits/arbitrary.rs

@@ -373,7 +373,7 @@ fn generate_float_with_condition(
                     for i in 0..1000 {
                         // With every iteration we modify next single byte by adding `i` value to
                         // it.
-                        let index = i % std::mem::size_of::<#inner_type>();
+                        let index = i % core::mem::size_of::<#inner_type>();
                         bytes[index] = bytes[index].wrapping_add((i % 256) as u8);
 
                         // Try to convert the bytes back to float in both BE and NE formats and see