Miniscript - Add Literal Boolean Operators

src/embit/descriptor/miniscript.py

@@ -54,11 +54,25 @@ def type(self):
 
     @classmethod
     def read_from(cls, s, taproot=False):
-        op, char = read_until(s, b"(")
+        def wrapped(m_script):
+            for w in reversed(wrappers):
+                if w not in WRAPPER_NAMES:
+                    raise MiniscriptError("Unknown wrapper")
+                WrapperCls = WRAPPERS[WRAPPER_NAMES.index(w)]
+                m_script = WrapperCls(m_script, taproot=taproot)
+            return m_script
+
+        op, char = read_until(s, b"(,)")
+        if char in (b",", b")"):
+            s.seek(-1, 1)
         op = op.decode()
         wrappers = ""
         if ":" in op:
             wrappers, op = op.split(":")
+        # handle boolean literals: 0 or 1
+        if op in ("0", "1"):
+            miniscript = JustOne() if op == "1" else JustZero()
+            return wrapped(miniscript)
         if char != b"(":
             raise MiniscriptError("Missing operator")
         if op not in OPERATOR_NAMES:
@@ -67,12 +81,7 @@ def read_from(cls, s, taproot=False):
         MiniscriptCls = OPERATORS[OPERATOR_NAMES.index(op)]
         args = MiniscriptCls.read_arguments(s, taproot=taproot)
         miniscript = MiniscriptCls(*args, taproot=taproot)
-        for w in reversed(wrappers):
-            if w not in WRAPPER_NAMES:
-                raise MiniscriptError("Unknown wrapper")
-            WrapperCls = WRAPPERS[WRAPPER_NAMES.index(w)]
-            miniscript = WrapperCls(miniscript, taproot=taproot)
-        return miniscript
+        return wrapped(miniscript)
 
     @classmethod
     def read_arguments(cls, s, taproot=False):
@@ -119,6 +128,28 @@ def len_args(self):
 ########### Known fragments (miniscript operators) ##############
 
 
+class JustZero(Miniscript):
+    TYPE = "B"
+    PROPS = "zud"
+
+    def inner_compile(self):
+        return Number(0).compile()
+
+    def __str__(self):
+        return "0"
+
+
+class JustOne(Miniscript):
+    TYPE = "B"
+    PROPS = "zu"
+
+    def inner_compile(self):
+        return Number(1).compile()
+
+    def __str__(self):
+        return "1"
+
+
 class OneArg(Miniscript):
     NARGS = 1
 

tests/tests/test_descriptor.py

@@ -5,6 +5,7 @@
 from embit.descriptor.miniscript import OPERATORS, WRAPPERS
 from embit.descriptor.errors import MiniscriptError
 from embit.descriptor.checksum import add_checksum, DescriptorError
+from embit.networks import NETWORKS
 from embit import ec
 
 
@@ -194,10 +195,13 @@ def test_miniscript_compat(self):
             "wsh(andor(thresh(1,pk(xpub6BaZSKgpaVvibu2k78QsqeDWXp92xLHZxiu1WoqLB9hKhsBf3miBUDX7PJLgSPvkj66ThVHTqdnbXpeu8crXFmDUd4HeM4s4miQS2xsv3Qb/*)),and_v(v:multi(2,03b506a1dbe57b4bf48c95e0c7d417b87dd3b4349d290d2e7e9ba72c912652d80a,0295e7f5d12a2061f1fd2286cefec592dff656a19f55f4f01305d6aa56630880ce),older(6)),thresh(2,pkh(xpub6AHA9hZDN11k2ijHMeS5QqHx2KP9aMBRhTDqANMnwVtdyw2TDYRmF8PjpvwUFcL1Et8Hj59S3gTSMcUQ5gAqTz3Wd8EsMTmF3DChhqPQBnU/*),a:pkh(xpub6AaffFGfH6WXfm6pwWzmUMuECQnoLeB3agMKaLyEBZ5ZVfwtnS5VJKqXBt8o5ooCWVy2H87GsZshp7DeKE25eWLyd1Ccuh2ZubQUkgpiVux/*))))#76jsyzdg",
             "wsh(or_d(pk([40259ab7/48'/1'/0'/2']tpubDFcY6nTiMAWBd5d2bS8JZvjcaLjC6GE6XnPAJAPUkVj5wa5Pyb4gumx1ZWvnXQ8tmorCmpAyai69K9hD2mGQUeNkuXfjztsfqnE5FMk1CCh/<0;1>/*),and_v(v:pkh([842a626e/48'/1'/0'/2']tpubDENBboujRvpkS8SgZsrpqG2BCUBoaAc4c57jHFe1NwKAtfVjDZDUadQKYv4pkAEF2afPv6TtQ2BoYFJAPLbuKpL1usiySERZekGo4JmnWhh/<0;1>/*),older(65535))))#deguz53x",
             "wsh(or_d(pk([40259ab7/48h/1h/0h/2h]tpubDFcY6nTiMAWBd5d2bS8JZvjcaLjC6GE6XnPAJAPUkVj5wa5Pyb4gumx1ZWvnXQ8tmorCmpAyai69K9hD2mGQUeNkuXfjztsfqnE5FMk1CCh/<0;1>/*),and_v(v:pkh([842a626e/48H/1H/0H/2H]tpubDENBboujRvpkS8SgZsrpqG2BCUBoaAc4c57jHFe1NwKAtfVjDZDUadQKYv4pkAEF2afPv6TtQ2BoYFJAPLbuKpL1usiySERZekGo4JmnWhh/<0;1>/*),older(65535))))#deguz53x",
+            "wsh(and_v(v:0,and_v(v:pk([40259ab7/48h/1h/0h/2h]tpubDFcY6nTiMAWBd5d2bS8JZvjcaLjC6GE6XnPAJAPUkVj5wa5Pyb4gumx1ZWvnXQ8tmorCmpAyai69K9hD2mGQUeNkuXfjztsfqnE5FMk1CCh/<0;1>/*),pk([40259ab7/48h/1h/0h/2h]tpubDFcY6nTiMAWBd5d2bS8JZvjcaLjC6GE6XnPAJAPUkVj5wa5Pyb4gumx1ZWvnXQ8tmorCmpAyai69K9hD2mGQUeNkuXfjztsfqnE5FMk1CCh/<0;1>/*))))",
+            "wsh(and_v(v:0,and_v(v:0,0)))",
         ]
 
         for desc in generalistic_descs:
-            Descriptor.from_string(desc)
+            desc = Descriptor.from_string(desc)
+            desc.derive(0, 0).address(network=NETWORKS["main"])
 
     def test_len(self):
         """Checks that len(miniscript) returns correct length"""