HS: sourceInfo API (sourceFor / lineFor / node-get)

lib/hyperscript/runtime.sx

@@ -2525,3 +2525,57 @@
   (fn
     (fn-name args)
     (let ((fn (host-global fn-name))) (if fn (host-call-fn fn args) nil))))
+
+;; ── SourceInfo API ────────────────────────────────────────────────
+
+(define
+  hs-source-for
+  (fn
+    (node)
+    (substring (get node :src) (get node :start) (get node :end))))
+
+(define
+  hs-line-for
+  (fn
+    (node)
+    (let
+      ((lines (split (get node :src) "\n"))
+        (line-idx (- (get node :line) 1)))
+      (if (< line-idx (len lines)) (nth lines line-idx) ""))))
+
+(define
+  hs-node-get
+  (fn
+    (node key)
+    (get (get node :fields) key)))
+
+(define
+  hs-src
+  (fn (src-str)
+    (hs-source-for (hs-parse-ast src-str))))
+
+(define
+  hs-src-at
+  (fn
+    (src-str path)
+    (define
+      walk
+      (fn
+        (node keys)
+        (if (or (nil? keys) (= (len keys) 0))
+          node
+          (walk (hs-node-get node (first keys)) (rest keys)))))
+    (hs-source-for (walk (hs-parse-ast src-str) path))))
+
+(define
+  hs-line-at
+  (fn
+    (src-str path)
+    (define
+      walk
+      (fn
+        (node keys)
+        (if (or (nil? keys) (= (len keys) 0))
+          node
+          (walk (hs-node-get node (first keys)) (rest keys)))))
+    (hs-line-for (walk (hs-parse-ast src-str) path))))