From 8a987f6c3cffd37437adca6c133fab989233a308 Mon Sep 17 00:00:00 2001
From: Akshay Nair <phenax5@gmail.com>
Date: Fri, 25 Aug 2023 10:48:55 +0530
Subject: feat: adds let bindings

---
 TODO.norg   |  4 ++--
 src/eval.ts | 26 ++++++++++++++++++++------
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/TODO.norg b/TODO.norg
index 3d052cf..348b06f 100644
--- a/TODO.norg
+++ b/TODO.norg
@@ -6,8 +6,8 @@
   - (x) analog + digital clock example
   - (x) error handling try
   - (x) Scoped catch on try
-  - ( ) `do` expression
-  - ( ) `let` expression
+  - (x) `do` expression
+  - (x) `let` expression
   - ( ) `has-class`
   - ( ) `add-class` & `remove-class` should use self if id is not specified?
   - ( ) Update `--cssx-text` on update
diff --git a/src/eval.ts b/src/eval.ts
index 1b5aace..2dde4c1 100644
--- a/src/eval.ts
+++ b/src/eval.ts
@@ -130,6 +130,13 @@ const getFunctions = (
     })
   }
 
+  const jsEval = async () => {
+    const js = await evalExprAsString(args[0], actions)
+    const result = js && (await actions.jsEval(js))
+    if (result === undefined || result === null) return EvalValue.Void()
+    return EvalValue.Value(result)
+  }
+
   return matchString<Promise<EvalValue>>(name, {
     'add-class': async () => {
       const id = evalValueToString(await evalExpr(args[0], actions))
@@ -161,12 +168,9 @@ const getFunctions = (
       num !== undefined ? await actions.delay(num) : undefined
       return EvalValue.Void()
     },
-    'js-eval': async () => {
-      const js = await evalExprAsString(args[0], actions)
-      const result = js && (await actions.jsEval(js))
-      if (result === undefined || result === null) return EvalValue.Void()
-      return EvalValue.Value(result)
-    },
+
+    'js-eval': jsEval,
+    'js-expr': jsEval,
 
     'load-cssx': async () => {
       const id = evalValueToString(await evalExpr(args[0], actions))
@@ -340,6 +344,16 @@ const getFunctions = (
       return result
     },
 
+    let: async () => {
+      const varName = await evalExprAsString(args[0], actions)
+      const result = await evalExpr(args[1], actions)
+      if (!varName) return EvalValue.Void()
+
+      return actions.evaluateInScope([args[2]], {
+        [varName]: result,
+      })
+    },
+
     _: () => Promise.reject(new Error(`Not implemented: ${name}`)),
   })
 }
-- 
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