diff --git a/bu4/linking/constructs/llambda.py b/bu4/linking/constructs/llambda.py
index 5bc3aa4..67bec92 100644
--- a/bu4/linking/constructs/llambda.py
+++ b/bu4/linking/constructs/llambda.py
@@ -18,7 +18,7 @@ class LLambda(Linked):
 
     def evaluable(self, env: envtype) -> Evaluable:
         return ELambda(
-            {name: container for name, container in env.items() if name in self.future},
+            {name: env[name] for name in self.future},
             self.name,
             self.value
         )
diff --git a/bu4/parsing/abstractparser.py b/bu4/parsing/abstractparser.py
index 85f0b8d..6e0738b 100644
--- a/bu4/parsing/abstractparser.py
+++ b/bu4/parsing/abstractparser.py
@@ -1,8 +1,12 @@
 #  Copyright (c) PARRRATE T&V 2021. All rights reserved.
 
+
 __all__ = ('AbstractParser',)
 
 
 class AbstractParser:
     def read(self) -> int:
         raise NotImplementedError
+
+    def parse_name(self) -> bytes:
+        raise NotImplementedError
diff --git a/bu4/parsing/extensions/extension.py b/bu4/parsing/extensions/extension.py
new file mode 100644
index 0000000..499390b
--- /dev/null
+++ b/bu4/parsing/extensions/extension.py
@@ -0,0 +1,23 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.abstractparser import AbstractParser
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+
+__all__ = ('Extension',)
+
+
+class Extension:
+    code: int
+
+    def __init_subclass__(cls, /, code: int = None, **kwargs):
+        super().__init_subclass__(**kwargs)
+        if code is None:
+            raise TypeError
+        cls.code = code
+
+    def __init__(self, parser: AbstractParser):
+        self.parser = parser
+
+    def apply(self, state: PSAfter) -> ParseState:
+        raise NotImplementedError
diff --git a/bu4/parsing/extensions/xcall.py b/bu4/parsing/extensions/xcall.py
new file mode 100644
index 0000000..503ae20
--- /dev/null
+++ b/bu4/parsing/extensions/xcall.py
@@ -0,0 +1,15 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_CALL
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+from bu4.parsing.states.pscall import pscall
+
+__all__ = ('XCall',)
+
+
+class XCall(Extension, code=CODE_CALL):
+    def apply(self, state: PSAfter) -> ParseState:
+        state.state = pscall()
+        return state
diff --git a/bu4/parsing/extensions/xmake.py b/bu4/parsing/extensions/xmake.py
new file mode 100644
index 0000000..4afe2d9
--- /dev/null
+++ b/bu4/parsing/extensions/xmake.py
@@ -0,0 +1,25 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_MAKE
+from bu4.parsing.constructs.plambda import PLambda
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+from bu4.parsing.states.psfinal import PSFinal
+from bu4.parsing.states.psread import PSRead
+
+__all__ = ('XMake',)
+
+from bu4.parsing.targets.pslambda import PSLambda
+
+
+class XMake(Extension, code=CODE_MAKE):
+    def apply(self, state: PSAfter) -> ParseState:
+        name = self.parser.parse_name()
+        state.state = PSAfter(
+            PSRead(),
+            PSLambda(
+                lambda value: PSFinal(PLambda(name, value))
+            )
+        )
+        return state
diff --git a/bu4/parsing/extensions/xname.py b/bu4/parsing/extensions/xname.py
new file mode 100644
index 0000000..c9cf95a
--- /dev/null
+++ b/bu4/parsing/extensions/xname.py
@@ -0,0 +1,16 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_NAME
+from bu4.parsing.constructs.pname import PName
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+from bu4.parsing.states.psfinal import PSFinal
+
+__all__ = ('XName',)
+
+
+class XName(Extension, code=CODE_NAME):
+    def apply(self, state: PSAfter) -> ParseState:
+        state.state = PSFinal(PName(self.parser.parse_name()))
+        return state
diff --git a/bu4/parsing/extensions/xnull.py b/bu4/parsing/extensions/xnull.py
new file mode 100644
index 0000000..2120359
--- /dev/null
+++ b/bu4/parsing/extensions/xnull.py
@@ -0,0 +1,16 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_NULL
+from bu4.parsing.constructs.pnull import PNull
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+from bu4.parsing.states.psfinal import PSFinal
+
+__all__ = ('XNull',)
+
+
+class XNull(Extension, code=CODE_NULL):
+    def apply(self, state: PSAfter) -> ParseState:
+        state.state = PSFinal(PNull())
+        return state
diff --git a/bu4/parsing/extensions/xqopn.py b/bu4/parsing/extensions/xqopn.py
new file mode 100644
index 0000000..87e5fbb
--- /dev/null
+++ b/bu4/parsing/extensions/xqopn.py
@@ -0,0 +1,16 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_QOPN, CODE_QCLS
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+from bu4.parsing.targets.pschain import PSChain
+from bu4.parsing.targets.psendswith import PSEndsWith
+
+__all__ = ('XQopn',)
+
+
+class XQopn(Extension, code=CODE_QOPN):
+    def apply(self, state: PSAfter) -> ParseState:
+        state.target = PSChain(PSEndsWith(self.parser, CODE_QCLS, 'quot expected'), state.target)
+        return state
diff --git a/bu4/parsing/extensions/xquot.py b/bu4/parsing/extensions/xquot.py
new file mode 100644
index 0000000..ae40053
--- /dev/null
+++ b/bu4/parsing/extensions/xquot.py
@@ -0,0 +1,16 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_QUOT
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+from bu4.parsing.targets.pschain import PSChain
+from bu4.parsing.targets.psendswith import PSEndsWith
+
+__all__ = ('XQuot',)
+
+
+class XQuot(Extension, code=CODE_QUOT):
+    def apply(self, state: PSAfter) -> ParseState:
+        state.target = PSChain(PSEndsWith(self.parser, CODE_QUOT, 'quot expected'), state.target)
+        return state
diff --git a/bu4/parsing/extensions/xskip.py b/bu4/parsing/extensions/xskip.py
new file mode 100644
index 0000000..997fca9
--- /dev/null
+++ b/bu4/parsing/extensions/xskip.py
@@ -0,0 +1,13 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.codes import CODE_SKIP
+from bu4.parsing.extensions.extension import Extension
+from bu4.parsing.states.parsestate import ParseState
+from bu4.parsing.states.psafter import PSAfter
+
+__all__ = ('XSkip',)
+
+
+class XSkip(Extension, code=CODE_SKIP):
+    def apply(self, state: PSAfter) -> ParseState:
+        return state
diff --git a/bu4/parsing/parser.py b/bu4/parsing/parser.py
index 3b519a3..a26f3c5 100644
--- a/bu4/parsing/parser.py
+++ b/bu4/parsing/parser.py
@@ -1,34 +1,35 @@
 #  Copyright (c) PARRRATE T&V 2021. All rights reserved.
 
 from io import BytesIO
+from typing import Iterable, Type
 
 from bu4.parsing.abstractparser import AbstractParser
-from bu4.parsing.codes import *
 from bu4.parsing.constructs.parsed import Parsed
-from bu4.parsing.constructs.plambda import PLambda
-from bu4.parsing.constructs.pname import PName
-from bu4.parsing.constructs.pnull import PNull
+from bu4.parsing.extensions.extension import Extension
 from bu4.parsing.states.parsestate import ParseState
 from bu4.parsing.states.psafter import PSAfter
-from bu4.parsing.states.pscall import pscall
 from bu4.parsing.states.psfinal import PSFinal
 from bu4.parsing.states.psread import PSRead
 from bu4.parsing.targets.pschain import PSChain
-from bu4.parsing.targets.psendswith import PSEndsWith
 from bu4.parsing.targets.pslambda import PSLambda
 
 __all__ = ('Parser',)
 
 
 class Parser(AbstractParser):
-    def __init__(self, source: bytes):
+    def __init__(self, source: bytes, extensions: Iterable[Type[Extension]]):
         self.__source = BytesIO(source)
+        self.__extensions: dict[int, Extension] = {}
+        for extension in extensions:
+            if extension.code in self.__extensions:
+                raise ValueError('code overload')
+            self.__extensions[extension.code] = extension(self)
 
     def read(self) -> int:
         bytes_ = self.__source.read(1)
         return bytes_[0] if bytes_ else 0
 
-    def _parse_name(self) -> bytes:
+    def parse_name(self) -> bytes:
         s = BytesIO()
         while True:
             c = self.read()
@@ -37,29 +38,11 @@ class Parser(AbstractParser):
             s.write(bytes([c]))
 
     def _state_read(self, state: PSAfter) -> ParseState:
-        c = self.read()
-        if c == CODE_NULL:
-            state.state = PSFinal(PNull())
-        elif c == CODE_CALL:
-            state.state = pscall()
-        elif c == CODE_MAKE:
-            name = self._parse_name()
-            state.state = PSAfter(
-                PSRead(),
-                PSLambda(
-                    lambda value: PSFinal(PLambda(name, value))
-                )
-            )
-        elif c == CODE_NAME:
-            state.state = PSFinal(PName(self._parse_name()))
-        elif c == CODE_SKIP:
-            pass
-        elif c == CODE_QUOT:
-            state.target = PSChain(PSEndsWith(self, CODE_QUOT, "quot expected"), state.target)
-        elif c == CODE_QOPN:
-            state.target = PSChain(PSEndsWith(self, CODE_QCLS, "qcls expected"), state.target)
-        else:
-            raise ValueError(f"unknown control: {hex(c)}")
+        code = self.read()
+        extension = self.__extensions.get(code)
+        if extension is None:
+            raise ValueError(f'unknown control: {hex(code)}')
+        state = extension.apply(state)
         return state
 
     def _state_next(self, state: PSAfter) -> ParseState:
diff --git a/bu4/parsing/toolchain/parse.py b/bu4/parsing/toolchain/parse.py
index e2ce877..0f60b3e 100644
--- a/bu4/parsing/toolchain/parse.py
+++ b/bu4/parsing/toolchain/parse.py
@@ -1,10 +1,16 @@
 #  Copyright (c) PARRRATE T&V 2021. All rights reserved.
 
+from typing import Iterable, Type
+
 from bu4.parsing.constructs.parsed import Parsed
+from bu4.parsing.extensions.extension import Extension
 from bu4.parsing.parser import Parser
 
 __all__ = ('parse',)
 
 
-def parse(source: bytes) -> Parsed:
-    return Parser(source).parse()
+def parse(source: bytes, extensions: Iterable[Type[Extension]]) -> Parsed:
+    return Parser(
+        source,
+        extensions
+    ).parse()
diff --git a/bu4/parsing/toolchain/stdext.py b/bu4/parsing/toolchain/stdext.py
new file mode 100644
index 0000000..6342008
--- /dev/null
+++ b/bu4/parsing/toolchain/stdext.py
@@ -0,0 +1,21 @@
+#  Copyright (c) PARRRATE T&V 2021. All rights reserved.
+
+from bu4.parsing.extensions.xcall import XCall
+from bu4.parsing.extensions.xmake import XMake
+from bu4.parsing.extensions.xname import XName
+from bu4.parsing.extensions.xnull import XNull
+from bu4.parsing.extensions.xqopn import XQopn
+from bu4.parsing.extensions.xquot import XQuot
+from bu4.parsing.extensions.xskip import XSkip
+
+__all__ = ('standard_extension',)
+
+standard_extension = (
+    XNull,
+    XCall,
+    XMake,
+    XName,
+    XSkip,
+    XQuot,
+    XQopn,
+)
diff --git a/bu4/synced.py b/bu4/synced.py
index 2ecb827..b402005 100644
--- a/bu4/synced.py
+++ b/bu4/synced.py
@@ -4,6 +4,7 @@ from bu4.evaluation.constructs.evalue import EValue
 from bu4.evaluation.sync import sync
 from bu4.linking.evaluable_from_parsed import evaluable_from_parsed
 from bu4.parsing.toolchain.parse import parse
+from bu4.parsing.toolchain.stdext import standard_extension
 from bu4.parsing.toolchain.transply import transply
 
 __all__ = ('synced',)
@@ -11,6 +12,6 @@ __all__ = ('synced',)
 
 def synced(source: str) -> EValue:
     bsource = transply(source)
-    parsed = parse(bsource)
+    parsed = parse(bsource, standard_extension)
     evaluable = evaluable_from_parsed({}, parsed)
     return sync(evaluable)
diff --git a/manual/extensions.md b/manual/extensions.md
new file mode 100644
index 0000000..2ab5143
--- /dev/null
+++ b/manual/extensions.md
@@ -0,0 +1,26 @@
+Application (essential):
+* Call
+
+Abstraction:
+* Lambda
+* Name
+
+Common:
+* Null (=exception/undefined)
+* Quot
+* Qopn-Qcls
+* Skip
+
+Special:
+* Namespaces (E- inputs)
+* String literals (=exceptions)
+* Trace/probes
+* Classes (named lambda constructs)
+* Methods (statically typed, optionally explicitly)
+* Factories (statically typed, optionally explicitly)
+* Await/after constructs with callbacks (and mutability/io quasimonads)
+* Speculative execution (anychronousity and multithreading)
+* Index-based linking (more static)
+* Hashes (v13 extension)
+* Bitstring call protocol (v13 extension)
+* Evaluable to parsed