Support no_std (#332)

* Support `no_std`

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

* Fix typo

Signed-off-by: koushiro <koushiro.cqx@gmail.com>

.github/workflows/rust.yml

@@ -35,6 +35,16 @@ jobs:
       - uses: actions/checkout@master
       - run: cargo check --all-targets --all-features
 
+  compile-no-std:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Set up Rust
+        uses: hecrj/setup-rust-action@v1
+        with:
+          targets: 'thumbv6m-none-eabi'
+      - uses: actions/checkout@master
+      - run: cargo check --no-default-features --target thumbv6m-none-eabi
+
   test:
     strategy:
       matrix:

Cargo.toml

@@ -13,12 +13,15 @@ include = [
     "Cargo.toml",
 ]
 edition = "2018"
+resolver = "2"
 
 [lib]
 name = "sqlparser"
 path = "src/lib.rs"
 
 [features]
+default = ["std"]
+std = []
 # Enable JSON output in the `cli` example:
 json_example = ["serde_json", "serde"]
 

src/ast/data_type.rs

@@ -10,7 +10,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::fmt;
+#[cfg(not(feature = "std"))]
+use alloc::boxed::Box;
+use core::fmt;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};

src/ast/ddl.rs

@@ -13,7 +13,9 @@
 //! AST types specific to CREATE/ALTER variants of [Statement]
 //! (commonly referred to as Data Definition Language, or DDL)
 
-use std::fmt;
+#[cfg(not(feature = "std"))]
+use alloc::{boxed::Box, string::ToString, vec::Vec};
+use core::fmt;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};

src/ast/mod.rs

@@ -18,7 +18,13 @@ mod operator;
 mod query;
 mod value;
 
-use std::fmt;
+#[cfg(not(feature = "std"))]
+use alloc::{
+    boxed::Box,
+    string::{String, ToString},
+    vec::Vec,
+};
+use core::fmt;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};

src/ast/operator.rs

@@ -10,7 +10,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::fmt;
+use core::fmt;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};

src/ast/query.rs

@@ -10,6 +10,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#[cfg(not(feature = "std"))]
+use alloc::{boxed::Box, vec::Vec};
+
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};
 

src/ast/value.rs

@@ -10,7 +10,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use std::fmt;
+#[cfg(not(feature = "std"))]
+use alloc::string::String;
+use core::fmt;
 
 #[cfg(feature = "bigdecimal")]
 use bigdecimal::BigDecimal;

src/dialect/mod.rs

@@ -20,8 +20,8 @@ mod postgresql;
 mod snowflake;
 mod sqlite;
 
-use std::any::{Any, TypeId};
+use core::any::{Any, TypeId};
-use std::fmt::Debug;
+use core::fmt::Debug;
 
 pub use self::ansi::AnsiDialect;
 pub use self::generic::GenericDialect;

src/lib.rs

@@ -32,8 +32,13 @@
 //!
 //! println!("AST: {:?}", ast);
 //! ```
+
+#![cfg_attr(not(feature = "std"), no_std)]
 #![allow(clippy::upper_case_acronyms)]
 
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+
 pub mod ast;
 #[macro_use]
 pub mod dialect;

src/parser.rs

@@ -12,8 +12,15 @@
 
 //! SQL Parser
 
-use std::error::Error;
+#[cfg(not(feature = "std"))]
-use std::fmt;
+use alloc::{
+    boxed::Box,
+    format,
+    string::{String, ToString},
+    vec,
+    vec::Vec,
+};
+use core::fmt;
 
 use log::debug;
 
@@ -81,7 +88,8 @@ impl fmt::Display for ParserError {
     }
 }
 
-impl Error for ParserError {}
+#[cfg(feature = "std")]
+impl std::error::Error for ParserError {}
 
 pub struct Parser<'a> {
     tokens: Vec<Token>,

src/test_utils.rs

@@ -16,7 +16,15 @@
 //
 // Integration tests (i.e. everything under `tests/`) import this
 // via `tests/test_utils/mod.rs`.
-use std::fmt::Debug;
+
+#[cfg(not(feature = "std"))]
+use alloc::{
+    boxed::Box,
+    string::{String, ToString},
+    vec,
+    vec::Vec,
+};
+use core::fmt::Debug;
 
 use crate::ast::*;
 use crate::dialect::*;

src/tokenizer.rs

@@ -16,9 +16,17 @@
 //!
 //! The tokens then form the input for the parser, which outputs an Abstract Syntax Tree (AST).
 
-use std::fmt;
+#[cfg(not(feature = "std"))]
-use std::iter::Peekable;
+use alloc::{
-use std::str::Chars;
+    borrow::ToOwned,
+    format,
+    string::{String, ToString},
+    vec,
+    vec::Vec,
+};
+use core::fmt;
+use core::iter::Peekable;
+use core::str::Chars;
 
 #[cfg(feature = "serde")]
 use serde::{Deserialize, Serialize};