scripts: Simplified csv.py's func/uop/bop/top helpers

Now that I know my way around the weirdness that is Python's class
scope, this just required another function indirection to capture the
class-level dicts correctly.

I was considering using the __subclasses__ trick, but it seems like that
would actually be more complicated here.

scripts/csv.py

@@ -541,20 +541,18 @@ class CsvExpr:
             return fields[self.a]
 
     # func expr helper
+    def func(funcs):
         def func(name, args="a"):
             def func(f):
                 f._func = name
                 f._fargs = args
+                funcs[f._func] = f
                 return f
             return func
+        return func
 
-    class Funcs:
+    funcs = {}
-        @ft.cache
+    func = func(funcs)
-        def __get__(self, _, cls):
-            return {x._func: x
-                    for x in cls.__dict__.values()
-                    if hasattr(x, '_func')}
-    funcs = Funcs()
 
     # type exprs
     @func('int', 'a')
@@ -881,19 +879,17 @@ class CsvExpr:
                 return CsvInt(0)
 
     # unary expr helper
+    def uop(uops):
         def uop(op):
             def uop(f):
                 f._uop = op
+                uops[f._uop] = f
                 return f
             return uop
+        return uop
 
-    class UOps:
+    uops = {}
-        @ft.cache
+    uop = uop(uops)
-        def __get__(self, _, cls):
-            return {x._uop: x
-                    for x in cls.__dict__.values()
-                    if hasattr(x, '_uop')}
-    uops = UOps()
 
     # unary ops
     @uop('+')
@@ -921,28 +917,20 @@ class CsvExpr:
                 return CsvInt(1)
 
     # binary expr help
+    def bop(bops, bprecs):
         def bop(op, prec):
             def bop(f):
                 f._bop = op
                 f._bprec = prec
+                bops[f._bop] = f
+                bprecs[f._bop] = f._bprec
                 return f
             return bop
+        return bop
 
-    class BOps:
+    bops = {}
-        @ft.cache
+    bprecs = {}
-        def __get__(self, _, cls):
+    bop = bop(bops, bprecs)
-            return {x._bop: x
-                    for x in cls.__dict__.values()
-                    if hasattr(x, '_bop')}
-    bops = BOps()
-
-    class BPrecs:
-        @ft.cache
-        def __get__(self, _, cls):
-            return {x._bop: x._bprec
-                    for x in cls.__dict__.values()
-                    if hasattr(x, '_bop')}
-    bprecs = BPrecs()
 
     # binary ops
     @bop('*', 10)
@@ -1052,28 +1040,20 @@ class CsvExpr:
                 return self.b.eval(fields)
 
     # ternary expr help
+    def top(tops, tprecs):
         def top(op_a, op_b, prec):
             def top(f):
                 f._top = (op_a, op_b)
                 f._tprec = prec
+                tops[f._top] = f
+                tprecs[f._top] = f._tprec
                 return f
             return top
+        return top
 
-    class TOps:
+    tops = {}
-        @ft.cache
+    tprecs = {}
-        def __get__(self, _, cls):
+    top = top(tops, tprecs)
-            return {x._top: x
-                    for x in cls.__dict__.values()
-                    if hasattr(x, '_top')}
-    tops = TOps()
-
-    class TPrecs:
-        @ft.cache
-        def __get__(self, _, cls):
-            return {x._top: x._tprec
-                    for x in cls.__dict__.values()
-                    if hasattr(x, '_top')}
-    tprecs = TPrecs()
 
     # ternary ops
     @top('?', ':', 1)