Merge pull request #629 from bstrie/exprs
Tentative beginning to implementing Parse for Expr types
diff --git a/src/expr.rs b/src/expr.rs
index ce12cea..8889be8 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -1897,6 +1897,56 @@
}
}
+ macro_rules! impl_by_parsing_expr {
+ ($expr_type:ty, $variant:ident, $msg:expr) => (
+ #[cfg(all(feature = "full", feature = "printing"))]
+ impl Parse for $expr_type {
+ fn parse(input: ParseStream) -> Result<Self> {
+ let mut expr: Expr = input.parse()?;
+ loop {
+ match expr {
+ Expr::$variant(inner) => return Ok(inner),
+ Expr::Group(ExprGroup { expr: next, .. }) => expr = *next,
+ _ => return Err(Error::new_spanned(expr, $msg))
+ }
+ }
+ }
+ }
+ )
+ }
+
+ impl_by_parsing_expr!(ExprBox, Box, "expected box expression");
+ impl_by_parsing_expr!(ExprInPlace, InPlace, "expected placement expression");
+ impl_by_parsing_expr!(ExprArray, Array, "expected slice literal expression");
+ impl_by_parsing_expr!(ExprCall, Call, "expected function call expression");
+ impl_by_parsing_expr!(ExprMethodCall, MethodCall, "expected method call expression");
+ impl_by_parsing_expr!(ExprTuple, Tuple, "expected tuple expression");
+ impl_by_parsing_expr!(ExprBinary, Binary, "expected binary operation");
+ impl_by_parsing_expr!(ExprUnary, Unary, "expected unary operation");
+ impl_by_parsing_expr!(ExprCast, Cast, "expected cast expression");
+ impl_by_parsing_expr!(ExprType, Type, "expected type ascription expression");
+ impl_by_parsing_expr!(ExprLet, Let, "expected let guard");
+ impl_by_parsing_expr!(ExprClosure, Closure, "expected closure expression");
+ impl_by_parsing_expr!(ExprUnsafe, Unsafe, "expected unsafe block");
+ impl_by_parsing_expr!(ExprBlock, Block, "expected blocked scope");
+ impl_by_parsing_expr!(ExprAssign, Assign, "expected assignment expression");
+ impl_by_parsing_expr!(ExprAssignOp, AssignOp, "expected compound assignment expression");
+ impl_by_parsing_expr!(ExprField, Field, "expected struct field access");
+ impl_by_parsing_expr!(ExprIndex, Index, "expected indexing expression");
+ impl_by_parsing_expr!(ExprRange, Range, "expected range expression");
+ impl_by_parsing_expr!(ExprReference, Reference, "expected referencing operation");
+ impl_by_parsing_expr!(ExprBreak, Break, "expected break expression");
+ impl_by_parsing_expr!(ExprContinue, Continue, "expected continue expression");
+ impl_by_parsing_expr!(ExprReturn, Return, "expected return expression");
+ impl_by_parsing_expr!(ExprMacro, Macro, "expected macro invocation expression");
+ impl_by_parsing_expr!(ExprStruct, Struct, "expected struct literal expression");
+ impl_by_parsing_expr!(ExprRepeat, Repeat, "expected array literal constructed from one repeated element");
+ impl_by_parsing_expr!(ExprParen, Paren, "expected parenthesized expression");
+ impl_by_parsing_expr!(ExprTry, Try, "expected try expression");
+ impl_by_parsing_expr!(ExprAsync, Async, "expected async block");
+ impl_by_parsing_expr!(ExprTryBlock, TryBlock, "expected try block");
+ impl_by_parsing_expr!(ExprYield, Yield, "expected yield expression");
+
#[cfg(feature = "full")]
fn expr_try_block(input: ParseStream) -> Result<ExprTryBlock> {
Ok(ExprTryBlock {
diff --git a/tests/test_expr.rs b/tests/test_expr.rs
new file mode 100644
index 0000000..666bfbf
--- /dev/null
+++ b/tests/test_expr.rs
@@ -0,0 +1,16 @@
+extern crate proc_macro2;
+extern crate syn;
+
+use std::str::FromStr;
+
+use proc_macro2::TokenStream;
+use syn::{Expr, parse2};
+
+#[test]
+fn test_expr_parse() {
+ let code = "..100u32";
+ let tt = TokenStream::from_str(code).unwrap();
+ let ast1: Expr = parse2(tt.clone()).unwrap();
+ let ast2: syn::ExprRange = parse2(tt).unwrap();
+ assert_eq!(ast1, Expr::Range(ast2));
+}