simiplify

This commit is contained in:
Aleksey Kladov 2019-09-10 20:28:50 +03:00
parent 6e5198cd6d
commit 4fdaec99c0

View file

@ -354,20 +354,6 @@ fn expand_subtree(
Ok(tt::Subtree { delimiter: template.delimiter, token_trees: buf }) Ok(tt::Subtree { delimiter: template.delimiter, token_trees: buf })
} }
/// Reduce single token subtree to single token
/// In `tt` matcher case, all tt tokens will be braced by a Delimiter::None
/// which makes all sort of problems.
fn reduce_single_token(mut subtree: tt::Subtree) -> tt::TokenTree {
if subtree.delimiter != tt::Delimiter::None || subtree.token_trees.len() != 1 {
return subtree.into();
}
match subtree.token_trees.pop().unwrap() {
tt::TokenTree::Subtree(subtree) => reduce_single_token(subtree),
tt::TokenTree::Leaf(token) => token.into(),
}
}
fn expand_tt(template: &crate::TokenTree, ctx: &mut ExpandCtx) -> Result<Fragment, ExpandError> { fn expand_tt(template: &crate::TokenTree, ctx: &mut ExpandCtx) -> Result<Fragment, ExpandError> {
let res: tt::TokenTree = match template { let res: tt::TokenTree = match template {
crate::TokenTree::Subtree(subtree) => expand_subtree(subtree, ctx)?.into(), crate::TokenTree::Subtree(subtree) => expand_subtree(subtree, ctx)?.into(),
@ -454,7 +440,7 @@ fn expand_tt(template: &crate::TokenTree, ctx: &mut ExpandCtx) -> Result<Fragmen
// Check if it is a single token subtree without any delimiter // Check if it is a single token subtree without any delimiter
// e.g {Delimiter:None> ['>'] /Delimiter:None>} // e.g {Delimiter:None> ['>'] /Delimiter:None>}
reduce_single_token(tt::Subtree { delimiter: tt::Delimiter::None, token_trees: buf }) tt::Subtree { delimiter: tt::Delimiter::None, token_trees: buf }.into()
} }
crate::TokenTree::Leaf(leaf) => match leaf { crate::TokenTree::Leaf(leaf) => match leaf {
crate::Leaf::Ident(ident) => { crate::Leaf::Ident(ident) => {
@ -497,16 +483,7 @@ fn expand_tt(template: &crate::TokenTree, ctx: &mut ExpandCtx) -> Result<Fragmen
} else { } else {
let fragment = ctx.bindings.get(&v.text, &ctx.nesting)?.clone(); let fragment = ctx.bindings.get(&v.text, &ctx.nesting)?.clone();
ctx.var_expanded = true; ctx.var_expanded = true;
match fragment { return Ok(fragment);
Fragment::Tokens(tt) => {
if let tt::TokenTree::Subtree(subtree) = tt {
reduce_single_token(subtree)
} else {
tt
}
}
Fragment::Ast(_) => return Ok(fragment),
}
} }
} }
crate::Leaf::Literal(l) => tt::Leaf::from(tt::Literal { text: l.text.clone() }).into(), crate::Leaf::Literal(l) => tt::Leaf::from(tt::Literal { text: l.text.clone() }).into(),