Resolve #19: add curry-friendly thin wrapper unpythonic.it.map.

Technologicat · Technologicat · commit 1aa6f9dfd15a · 2019-08-20T23:35:46.000+03:00
diff --git a/unpythonic/it.py b/unpythonic/it.py
@@ -10,7 +10,7 @@
 ``itertools`` recipes.
 """
 
-__all__ = ["rev", "map_longest",
+__all__ = ["rev", "map", "map_longest",
            "rmap", "rzip", "rmap_longest", "rzip_longest",
            "mapr", "zipr", "mapr_longest", "zipr_longest",
            "flatmap",
@@ -27,6 +27,7 @@
            "window", "chunked",
            "within", "fixpoint"]
 
+from builtins import map as stdlib_map
 from operator import itemgetter
 from itertools import tee, islice, zip_longest, starmap, chain, filterfalse, groupby, takewhile
 from collections import deque
@@ -51,6 +52,22 @@ def rev(iterable):
     except TypeError:
         return reversed(tuple(iterable))
 
+def map(function, iterable0, *iterables):
+    """Curry-friendly map.
+
+    Thin wrapper around Python's builtin ``map``, making it mandatory to
+    provide at least one iterable, so we may say things such as::
+
+        from unpythonic import map, curry
+        oneplus = lambda x: 1 + x  # noqa: E731
+
+        add_one = curry(map, oneplus)
+
+        assert tuple(add_one(range(5))) == tuple(range(1, 6))
+
+    """
+    return stdlib_map(function, iterable0, *iterables)
+
 # When completing an existing set of functions (map, zip, zip_longest),
 # consistency wins over curry-friendliness.
 def map_longest(func, *iterables, fillvalue=None):
diff --git a/unpythonic/test/test_it.py b/unpythonic/test/test_it.py
@@ -6,7 +6,7 @@
 from collections import deque
 from math import cos, sqrt
 
-from ..it import mapr, rmap, zipr, rzip, \
+from ..it import map, mapr, rmap, zipr, rzip, \
                  map_longest, mapr_longest, rmap_longest, \
                  zip_longest, zipr_longest, rzip_longest, \
                  first, second, nth, last, lastn, \
@@ -21,7 +21,7 @@
                  window, chunked, \
                  within, fixpoint
 
-from ..fun import composel, identity
+from ..fun import composel, identity, curry
 from ..gmemo import imemoize, gmemoize
 from ..mathseq import s
 from ..misc import Popper, ulp
@@ -31,9 +31,15 @@ def noneadd(a, b):
         if all(x is not None for x in (a, b)):
             return a + b
 
+    # Our map is a thin wrapper that makes it mandatory to provide at least one iterable,
+    # so we can easily curry it with just the function to be applied.
+    oneplus = lambda x: 1 + x  # noqa: E731
+    add_one = curry(map, oneplus)
+    assert tuple(add_one(range(5))) == tuple(range(1, 6))
+
     # Adding the missing batteries to the algebra of map and zip.
     # Note Python's (and Racket's) map is like Haskell's zipWith, but for n inputs.
-    assert tuple(map(add, (1, 2), (3, 4))) == (4, 6)  # builtin
+    assert tuple(map(add, (1, 2), (3, 4))) == (4, 6)  # builtin (or ours, doesn't matter)
     assert tuple(mapr(add, (1, 2), (3, 4))) == (6, 4)
     assert tuple(rmap(add, (1, 2), (3, 4))) == (6, 4)
     assert tuple(zip((1, 2, 3), (4, 5, 6), (7, 8))) == ((1, 4, 7), (2, 5, 8))  # builtin
