From 077592a12fd982de3e69572a4c738dd4468617f9 Mon Sep 17 00:00:00 2001
From: Phil Ellison <phil.j.ellison@gmail.com>
Date: Mon, 28 Dec 2020 18:29:58 +0000
Subject: Initial implementation of view-hir command

---
 crates/ide/src/view_hir.rs | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 crates/ide/src/view_hir.rs

(limited to 'crates/ide/src/view_hir.rs')

diff --git a/crates/ide/src/view_hir.rs b/crates/ide/src/view_hir.rs
new file mode 100644
index 000000000..e48f2cfe0
--- /dev/null
+++ b/crates/ide/src/view_hir.rs
@@ -0,0 +1,39 @@
+use hir::{Function, Semantics};
+use hir::db::DefDatabase;
+use ide_db::base_db::FilePosition;
+use ide_db::RootDatabase;
+use syntax::{AstNode, algo::find_node_at_offset, ast};
+use std::fmt::Write;
+
+// Feature: View hir
+//
+// |===
+// | Editor  | Action Name
+//
+// | VS Code | **Rust Analyzer: View Hir**
+// |===
+pub(crate) fn view_hir(db: &RootDatabase, position: FilePosition) -> String {
+    body_hir(db, position).unwrap_or("Not inside a function body".to_string())
+}
+
+fn body_hir(db: &RootDatabase, position: FilePosition) -> Option<String> {
+    let sema = Semantics::new(db);
+    let source_file = sema.parse(position.file_id);
+
+    let function = find_node_at_offset::<ast::Fn>(
+        source_file.syntax(),
+        position.offset,
+    )?;
+
+    let function: Function = sema.to_def(&function)?;
+    let body = db.body(function.id.into());
+
+    let mut result = String::new();
+    writeln!(&mut result, "== Body expressions ==").ok()?;
+
+    for (id, expr) in body.exprs.iter() {
+        writeln!(&mut result, "{:?}: {:?}", id, expr).ok()?;
+    }
+
+    Some(result)
+}
\ No newline at end of file
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