Commit: e701bc50c81237a7415a177d9dc173ec0d8afecb - cammy (git)

A categorical programming language

Commit MetaInfo

• Revisión: e701bc50c81237a7415a177d9dc173ec0d8afecb (tree)
• Tiempo: 2021-11-13 14:38:30
• Autor: Corbin <cds@corb...>
• Commiter: Corbin

Log Message

cammy-run: Add lists.

Cambiar Resumen

• modified: cammy-run/main.py

Diferencia incremental

--- a/cammy-run/main.py
+++ b/cammy-run/main.py
@@ -42,6 +42,9 @@ class Element(object):
     def apply(self, y):
         raise TypeFail("not hom")
 
+    def fold(self, nil, cons):
+        raise TypeFail("not list")
+
 class T(Element):
     _immutable_ = True
 
@@ -111,6 +114,16 @@ class H(Element):
     def apply(self, y):
         return self._f.run(P(self._x, y))
 
+class Z(Element):
+    _immutable_ = True
+    def fold(self, nil, cons): return nil.run(T())
+
+class C(Element):
+    _immutable_ = True
+    def __init__(self, x, xs):
+        self._x = x
+        self._xs = xs
+    def fold(self, nil, cons): return cons.run(P(self._x, self._xs))
 
 class Arrow(object):
     _immutable_ = True
@@ -205,6 +218,21 @@ class PrimRec(Arrow):
             rv = self._f.run(rv)
         return rv
 
+class Nil(Arrow):
+    _immutable_ = True
+    def run(self, x): return Z()
+
+class Cons(Arrow):
+    _immutable_ = True
+    def run(self, x): return C(x.first(), x.second())
+
+class Fold(Arrow):
+    _immutable_ = True
+    def __init__(self, n, c):
+        self._n = n
+        self._c = c
+    def run(self, x): return x.fold(self._n, self._c)
+
 class FZero(Arrow):
     _immutable_ = True
     def run(self, x): return F(0.0)
@@ -306,6 +334,8 @@ unaryFunctors = {
     "either": Either(),
     "zero": Zero(),
     "succ": Succ(),
+    "nil": Nil(),
+    "cons": Cons(),
     "f-zero": FZero(),
     "f-one": FOne(),
     "f-pi": FPi(),
@@ -341,6 +371,8 @@ def buildCompound(name, args):
         return Uncurry(args[0])
     elif name == "pr" and len(args) == 2:
         return PrimRec(args[0], args[1])
+    elif name == "fold" and len(args) == 2:
+        return Fold(args[0], args[1])
     else:
         raise BuildProblem("Invalid compound functor: " + name)