restructure core data structure to support primitive stump/stubs (#10)

Author: thiennamdinh

CHANGELOG

@@ -2,6 +2,12 @@
 The purpose of this changelog is to document new features and breaking changes that are most likely to affect developers
 ------------------------------------------------------------------------------------------------------------------------
 
+--- v1.0.4 (2025.09.14) ---
+
+- Modify core merkle tree structure to support "stumps" and branch digest propogation
+- Implement sync-stub and sync-cut s7 primitives to work with stumps
+- Consolidate sync-pair? and sync-null? into a more general sync-node? type
+
 --- v1.0.3 (2025.08.25) ---
 
 - Add caching mechanism that enforces exactly one unique request per second

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "journal-sdk"
-version = "1.0.3"
+version = "1.0.4"
 edition = "2021"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

lisp/blockchain.scm

@@ -23,7 +23,7 @@
          (define (sync-caddr x) (sync-car (sync-cdr (sync-cdr x))))
 
          (define (sync-null-pair? x)
-           (and (sync-pair? x) (sync-null? x)))
+           (and (sync-node? x) (sync-null? x)))
 
          (define (sync-leaf? x) (and (not (sync-null-pair? x)) (equal? (sync-car x) (sync-cdr x))))
 

lisp/evaluator.scm

@@ -4,7 +4,7 @@
        ;; --- verifiable map ---
 
        (define (nth-bit x n)
-	     (zero? (logand (byte-vector-ref (sync-pair->byte-vector x) (floor (/ n 8)))
+	     (zero? (logand (byte-vector-ref (sync-digest x) (floor (/ n 8)))
 			            (ash 1 (modulo n 8)))))
 
        (define (sync-caar x) (sync-car (sync-car x)))
@@ -95,11 +95,11 @@
        (define (meta-find sp)
 	     (let ((a-find (lambda (x) (byte-vector->expression x))))
 	       (let p-find ((sp sp))
-	         (if (sync-pair? (sync-car sp))
+	         (if (sync-node? (sync-car sp))
 		         (cons (p-find (sync-car sp)) (p-find (sync-cdr sp)))
 		         (let ((type (a-find (sync-car sp)))
 		               (value-sp (sync-cdr sp)))
-		           (let ((value (if (sync-pair? value-sp) (p-find value-sp) (a-find value-sp))))
+		           (let ((value (if (sync-node? value-sp) (p-find value-sp) (a-find value-sp))))
 		             (case type
 		               ((procedure?) (eval value))
 		               (else value))))))))

lisp/rdf.scm

@@ -16,7 +16,7 @@
        (define (sync-cddr x) (sync-cdr (sync-cdr x)))
 
        (define (sync-null-pair? x)
-         (and (sync-pair? x) (sync-null? x)))
+         (and (sync-node? x) (sync-null? x)))
 
        (define (sync-leaf? x) (and (not (sync-null-pair? x)) (equal? (sync-car x) (sync-cdr x))))
 

src/evaluator.rs

@@ -223,9 +223,15 @@ fn primitive_byte_vector_to_expression() -> Primitive {
             bytes.push(s7_byte_vector_ref(arg, i))
         }
         bytes.push(0);
-        let c_string =
-            CString::from_vec_with_nul(bytes).expect("Invalid C string: missing null terminator");
-        s7_eval_c_string(sc, c_string.as_ptr())
+
+        match CString::from_vec_with_nul(bytes) {
+            Ok(c_string) => s7_eval_c_string(sc, c_string.as_ptr()),
+            Err(_) => s7_error(
+                sc,
+                s7_make_symbol(sc, c"encoding-error".as_ptr()),
+                s7_list(sc, 1, s7_make_string(sc, c"Byte vector string is malformed".as_ptr()))
+            )
+        }
     }
 
     Primitive::new(