2 files changed, 128 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..f9a6a26
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,118 @@
+mod utils;
+
+use js_sys::Array;
+
+use syntax::{
+    ast::{self, AstNode},
+    NodeOrToken, SourceFile, SyntaxElement, SyntaxError, SyntaxNode,
+};
+use wasm_bindgen::prelude::*;
+
+use std::{convert::From, str::FromStr};
+
+// When the `wee_alloc` feature is enabled, use `wee_alloc` as the global
+// allocator.
+#[cfg(feature = "wee_alloc")]
+#[global_allocator]
+static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
+
+#[wasm_bindgen]
+pub fn put_cst(source: &str) -> String {
+    let source_file = SourceFile::parse(source);
+    source_file.debug_dump()
+}
+
+// wrapper type to pass syntax elements to JS
+#[wasm_bindgen]
+#[derive(Debug, Clone)]
+pub struct SynNode {
+    node: SyntaxElement,
+}
+
+impl SynNode {
+    pub fn new(node: SyntaxElement) -> Self {
+        Self { node }
+    }
+}
+
+#[wasm_bindgen]
+impl SynNode {
+    pub fn children(&self) -> Vec<JsValue> {
+        match &self.node {
+            NodeOrToken::Node(n) => n
+                .children_with_tokens()
+                .map(SynNode::new)
+                .map(JsValue::from)
+                .collect(),
+            NodeOrToken::Token(_) => vec![],
+        }
+    }
+
+    pub fn is_token(&self) -> bool {
+        self.node.as_token().is_some()
+    }
+
+    pub fn to_string(&self) -> String {
+        format!("{:?}@{:?}", self.node.kind(), self.node.text_range(),)
+    }
+
+    pub fn from_str(s: &str) -> Result<JsValue, JsValue> {
+        FromStr::from_str(s)
+            .map(|p: SynNode| JsValue::from(p))
+            .map_err(JsValue::from)
+    }
+}
+
+impl FromStr for SynNode {
+    type Err = Array;
+    fn from_str(s: &str) -> Result<Self, Array> {
+        let source_file = SourceFile::parse(s);
+        if source_file.errors().is_empty() {
+            Ok(Self {
+                node: NodeOrToken::Node(source_file.ok().unwrap().syntax().clone()),
+            })
+        } else {
+            Err(source_file
+                .errors()
+                .into_iter()
+                .map(SynErr::new)
+                .map(JsValue::from)
+                .collect())
+        }
+    }
+}
+
+#[wasm_bindgen]
+#[derive(Debug, Clone)]
+struct SynErr {
+    err: SyntaxError,
+}
+
+impl SynErr {
+    pub fn new(err: &SyntaxError) -> Self {
+        Self { err: err.clone() }
+    }
+}
+
+#[wasm_bindgen]
+struct TextRange {
+    start: u32,
+    end: u32,
+}
+
+impl From<(u32, u32)> for TextRange {
+    fn from((start, end): (u32, u32)) -> Self {
+        TextRange { start, end }
+    }
+}
+
+#[wasm_bindgen]
+impl SynErr {
+    pub fn range(&self) -> TextRange {
+        let r = self.err.range();
+        (r.start().into(), r.end().into()).into()
+    }
+    pub fn to_string(&self) -> String {
+        self.err.to_string()
+    }
+}
diff --git a/src/utils.rs b/src/utils.rs
new file mode 100644
index 0000000..b1d7929
--- /dev/null
+++ b/src/utils.rs
@@ -0,0 +1,10 @@
+pub fn set_panic_hook() {
+    // When the `console_error_panic_hook` feature is enabled, we can call the
+    // `set_panic_hook` function at least once during initialization, and then
+    // we will get better error messages if our code ever panics.
+    //
+    // For more details see
+    // https://github.com/rustwasm/console_error_panic_hook#readme
+    #[cfg(feature = "console_error_panic_hook")]
+    console_error_panic_hook::set_once();
+}