start tt convertions boilerplate

crates/ra_hir/src/macros.rs

@@ -16,6 +16,7 @@ use std::sync::Arc;
 
 use ra_syntax::{
     TextRange, TextUnit, SourceFile, AstNode, SyntaxNode, TreeArc, SyntaxNodePtr,
+    SyntaxKind::*,
     ast::{self, NameOwner},
 };
 
@@ -201,6 +202,39 @@ pub(crate) fn expand_macro_invocation(
     def.expand(input).map(Arc::new)
 }
 
-fn macro_call_to_tt(call: &ast::MacroCall) -> Option<tt::TokenTree> {
-    None
+fn macro_call_to_tt(call: &ast::MacroCall) -> Option<tt::Subtree> {
+    let tt = call.token_tree()?;
+    convert_tt(tt.syntax())
+}
+
+fn convert_tt(tt: &SyntaxNode) -> Option<tt::Subtree> {
+    let first_child = tt.first_child()?;
+    let last_child = tt.last_child()?;
+    let delimiter = match (first_child.kind(), last_child.kind()) {
+        (L_PAREN, R_PAREN) => tt::Delimiter::Parenthesis,
+        (L_CURLY, R_CURLY) => tt::Delimiter::Brace,
+        (L_BRACK, R_BRACK) => tt::Delimiter::Bracket,
+        _ => return None,
+    };
+    let mut token_trees = Vec::new();
+    for child in tt.children().skip(1) {
+        if child == first_child || child == last_child || child.kind().is_trivia() {
+            continue;
+        }
+        let child = if child.kind() == TOKEN_TREE {
+            convert_tt(child)?.into()
+        } else if child.kind().is_keyword() {
+            let text = child.leaf_text().unwrap().clone();
+            tt::Leaf::from(tt::Ident { text }).into()
+        } else {
+            return None;
+        };
+        token_trees.push(child)
+    }
+
+    let res = tt::Subtree {
+        delimiter,
+        token_trees,
+    };
+    Some(res)
 }

crates/ra_hir/src/macros/tt.rs

@@ -4,16 +4,18 @@ pub(crate) enum TokenTree {
     Leaf(Leaf),
     Subtree(Subtree),
 }
+impl_froms!(TokenTree: Leaf, Subtree);
 
 pub(crate) enum Leaf {
     Literal(Literal),
     Punct(Punct),
     Ident(Ident),
 }
+impl_froms!(Leaf: Literal, Punct, Ident);
 
 pub(crate) struct Subtree {
-    delimiter: Delimiter,
-    token_trees: Vec<TokenTree>,
+    pub(crate) delimiter: Delimiter,
+    pub(crate) token_trees: Vec<TokenTree>,
 }
 
 pub(crate) enum Delimiter {
@@ -24,13 +26,13 @@ pub(crate) enum Delimiter {
 }
 
 pub(crate) struct Literal {
-    text: SmolStr,
+    pub(crate) text: SmolStr,
 }
 
 pub(crate) struct Punct {
-    char: char,
+    pub(crate) char: char,
 }
 
 pub(crate) struct Ident {
-    text: SmolStr,
+    pub(crate) text: SmolStr,
 }