Remove support for cons cells

hy/__init__.py

@@ -5,7 +5,7 @@ except ImportError:
     __version__ = 'unknown'
 
 
-from hy.models import HyExpression, HyInteger, HyKeyword, HyComplex, HyString, HyBytes, HySymbol, HyFloat, HyDict, HyList, HySet, HyCons  # NOQA
+from hy.models import HyExpression, HyInteger, HyKeyword, HyComplex, HyString, HyBytes, HySymbol, HyFloat, HyDict, HyList, HySet  # NOQA
 
 
 import hy.importer  # NOQA

hy/compiler.py

@@ -5,7 +5,7 @@
 
 from hy.models import (HyObject, HyExpression, HyKeyword, HyInteger, HyComplex,
                        HyString, HyBytes, HySymbol, HyFloat, HyList, HySet,
-                       HyDict, HyCons, wrap_value)
+                       HyDict, wrap_value)
 from hy.errors import HyCompileError, HyTypeError
 
 from hy.lex.parser import mangle
@@ -89,7 +89,7 @@ def builds(*types, **kwargs):
 
 
 def spoof_positions(obj):
-    if not isinstance(obj, HyObject) or isinstance(obj, HyCons):
+    if not isinstance(obj, HyObject):
         return
     if not hasattr(obj, "start_column"):
         obj.start_column = 0
@@ -719,24 +719,6 @@ class HyASTCompiler(object):
             return imports, HyExpression([HySymbol(name),
                                           contents]).replace(form), False
 
-        elif isinstance(form, HyCons):
-            ret = HyExpression([HySymbol(name)])
-            nimport, contents, splice = self._render_quoted_form(form.car,
-                                                                 level)
-            if splice:
-                raise HyTypeError(form, "Can't splice dotted lists yet")
-            imports.update(nimport)
-            ret.append(contents)
-
-            nimport, contents, splice = self._render_quoted_form(form.cdr,
-                                                                 level)
-            if splice:
-                raise HyTypeError(form, "Can't splice the cdr of a cons")
-            imports.update(nimport)
-            ret.append(contents)
-
-            return imports, ret.replace(form), False
-
         elif isinstance(form, HySymbol):
             return imports, HyExpression([HySymbol(name),
                                           HyString(form)]).replace(form), False
@@ -2131,10 +2113,6 @@ class HyASTCompiler(object):
                 if building == "eval_and_compile"
                 else Result())
 
-    @builds(HyCons)
-    def compile_cons(self, cons):
-        raise HyTypeError(cons, "Can't compile a top-level cons cell")
-
     @builds(HyInteger, HyFloat, HyComplex)
     def compile_numeric_literal(self, x, building):
         f = {HyInteger: long_type,

hy/contrib/walk.hy

@@ -18,9 +18,6 @@
     (outer (HyExpression (map inner form)))]
    [(instance? HyDict form)
     (HyDict (outer (HyExpression (map inner form))))]
-   [(cons? form)
-    (outer (cons (inner (first form))
-                 (inner (rest form))))]
    [(instance? list form)
     ((type form) (outer (HyExpression (map inner form))))]
    [(coll? form)

hy/core/language.hy

@@ -18,7 +18,7 @@
 (if-python2
   (import [collections :as cabc])
   (import [collections.abc :as cabc]))
-(import [hy.models [HyCons HySymbol HyKeyword]])
+(import [hy.models [HySymbol HyKeyword]])
 (import [hy.lex [LexException PrematureEndOfInput tokenize]])
 (import [hy.lex.parser [mangle unmangle]])
 (import [hy.compiler [HyASTCompiler spoof-positions]])
@@ -50,14 +50,6 @@
   (fn [&rest args &kwargs kwargs]
     (not (f #* args #** kwargs))))
 
-(defn cons [a b]
-  "Return a fresh cons cell with car = `a` and cdr = `b`."
-  (HyCons a b))
-
-(defn cons? [c]
-  "Check whether `c` is a cons cell."
-  (instance? HyCons c))
-
 (defn constantly [value]
   "Create a new function that always returns `value` regardless of its input."
   (fn [&rest args &kwargs kwargs]
@@ -294,7 +286,7 @@ Return series of accumulated sums (or other binary function results)."
 
 (defn juxt [f &rest fs]
   "Return a function applying each `fs` to args, collecting results in a list."
-  (setv fs (cons f fs))
+  (setv fs (+ (, f) fs))
   (fn [&rest args &kwargs kwargs]
     (list-comp (f #* args #** kwargs) [f fs])))
 
@@ -302,12 +294,6 @@ Return series of accumulated sums (or other binary function results)."
   "Return last item from `coll`."
   (get (tuple coll) -1))
 
-(defn list* [hd &rest tl]
-  "Return a chain of nested cons cells (dotted list) containing `hd` and `tl`."
-  (if (not tl)
-    hd
-    (cons hd (list* #* tl))))
-
 (defn macroexpand [form]
   "Return the full macro expansion of `form`."
   (import hy.macros)
@@ -488,11 +474,11 @@ Even objects with the __name__ magic will work."
 
 (setv EXPORTS
   '[*map accumulate butlast calling-module-name chain coll? combinations
-    comp complement compress cons cons? constantly count cycle dec distinct
+    comp complement compress constantly count cycle dec distinct
     disassemble drop drop-last drop-while empty? eval even? every? exec first
     filter flatten float? fraction gensym group-by identity inc input instance?
     integer integer? integer-char? interleave interpose islice iterable?
-    iterate iterator? juxt keyword keyword? last list* macroexpand
+    iterate iterator? juxt keyword keyword? last macroexpand
     macroexpand-1 mangle map merge-with multicombinations name neg? none? nth
     numeric? odd? partition permutations pos? product range read read-str
     remove repeat repeatedly rest reduce second some string string? symbol?

hy/lex/parser.py

@@ -11,9 +11,8 @@ import string, re, unicodedata
 from rply import ParserGenerator
 
 from hy._compat import PY3, str_type, isidentifier, UCS4
-from hy.models import (HyBytes, HyComplex, HyCons, HyDict, HyExpression,
+from hy.models import (HyBytes, HyComplex, HyDict, HyExpression, HyFloat,
-                       HyFloat, HyInteger, HyKeyword, HyList, HySet, HyString,
+                       HyInteger, HyKeyword, HyList, HySet, HyString, HySymbol)
-                       HySymbol)
 from .lexer import lexer
 from .exceptions import LexException, PrematureEndOfInput
 
@@ -151,28 +150,6 @@ def reject_spurious_dots(*items):
 @pg.production("paren : LPAREN list_contents RPAREN")
 @set_boundaries
 def paren(p):
-    cont = p[1]
-
-    # Dotted lists are expressions of the form
-    # (a b c . d)
-    # that evaluate to nested cons cells of the form
-    # (a . (b . (c . d)))
-    if len(cont) >= 3 and isinstance(cont[-2], HySymbol) and cont[-2] == ".":
-
-        reject_spurious_dots(cont[:-2], cont[-1:])
-
-        if len(cont) == 3:
-            # Two-item dotted list: return the cons cell directly
-            return HyCons(cont[0], cont[2])
-        else:
-            # Return a nested cons cell
-            return HyCons(cont[0], paren([p[0], cont[1:], p[2]]))
-
-    # Warn preemptively on a malformed dotted list.
-    # Only check for dots after the first item to allow for a potential
-    # attribute accessor shorthand
-    reject_spurious_dots(cont[1:])
-
     return HyExpression(p[1])
 
 

hy/models.py

@@ -334,101 +334,3 @@ class HySet(HyList):
     color = staticmethod(colored.red)
 
 _wrappers[set] = lambda s: HySet(wrap_value(x) for x in s)
-
-
-class HyCons(HyObject):
-    """
-    HyCons: a cons object.
-
-    Building a HyCons of something and a HyList really builds a HyList
-    """
-
-    __slots__ = ["car", "cdr"]
-
-    def __new__(cls, car, cdr):
-        if isinstance(cdr, list):
-
-            # Keep unquotes in the cdr of conses
-            if type(cdr) == HyExpression:
-                if len(cdr) > 0 and type(cdr[0]) == HySymbol:
-                    if cdr[0] in ("unquote", "unquote-splice"):
-                        return super(HyCons, cls).__new__(cls)
-
-            return cdr.__class__([wrap_value(car)] + cdr)
-
-        elif cdr is None:
-            return HyExpression([wrap_value(car)])
-
-        else:
-            return super(HyCons, cls).__new__(cls)
-
-    def __init__(self, car, cdr):
-        self.car = wrap_value(car)
-        self.cdr = wrap_value(cdr)
-
-    def __getitem__(self, n):
-        if n == 0:
-            return self.car
-        if n == slice(1, None):
-            return self.cdr
-
-        raise IndexError(
-            "Can only get the car ([0]) or the cdr ([1:]) of a HyCons")
-
-    def __setitem__(self, n, new):
-        if n == 0:
-            self.car = new
-            return
-        if n == slice(1, None):
-            self.cdr = new
-            return
-
-        raise IndexError(
-            "Can only set the car ([0]) or the cdr ([1:]) of a HyCons")
-
-    def __iter__(self):
-        yield self.car
-        try:
-            iterator = (i for i in self.cdr)
-        except TypeError:
-            if self.cdr is not None:
-                yield self.cdr
-                raise TypeError("Iteration on malformed cons")
-        else:
-            for i in iterator:
-                yield i
-
-    def replace(self, other):
-        if self.car is not None:
-            replace_hy_obj(self.car, other)
-        if self.cdr is not None:
-            replace_hy_obj(self.cdr, other)
-
-        HyObject.replace(self, other)
-
-    def __repr__(self):
-        if PRETTY:
-            return str(self)
-        else:
-            return "HyCons({}, {})".format(
-                repr(self.car), repr(self.cdr))
-
-    def __str__(self):
-        with pretty():
-            c = colored.yellow
-            lines = ['' + c("<HyCons (")]
-            while True:
-                lines.append("  " + repr_indent(self.car))
-                if not isinstance(self.cdr, HyCons):
-                    break
-                self = self.cdr
-            lines.append("{} {}{}".format(
-                c("."), repr_indent(self.cdr), c(")>")))
-            return '\n'.join(lines)
-
-    def __eq__(self, other):
-        return (
-            isinstance(other, self.__class__) and
-            self.car == other.car and
-            self.cdr == other.cdr
-        )