New code to guess types

relational/rtypes.py

@@ -23,98 +23,47 @@
 import datetime
 import keyword
 import re
-from typing import Union
+from typing import Union, Set, Any, Callable
+
 
 RELATION_NAME_REGEXP = re.compile(r'^[_a-z][_a-z0-9]*$', re.IGNORECASE)
-
-
-class Rstring(str):
-
-    '''String subclass with some custom methods'''
-
-    int_regexp = re.compile(r'^[\+\-]{0,1}[0-9]+$')
-    float_regexp = re.compile(r'^[\+\-]{0,1}[0-9]+(\.([0-9])+)?$')
-    date_regexp = re.compile(
+_date_regexp = re.compile(
         r'^([0-9]{1,4})(\\|-|/)([0-9]{1,2})(\\|-|/)([0-9]{1,2})$'
     )
+CastValue = Union[str, int, float, 'Rdate']
+
+
+def guess_type(value: str) -> Set[Callable[[Any], Any]]:
+    r: Set[Callable[[Any], Any]] = {str}
+    if _date_regexp.match(value) is not None:
+        r.add(Rdate)
 
-    def autocast(self) -> Union[int, float, 'Rdate', 'Rstring']:
-        '''
-        Returns the automatic cast for this
-        value.
-        '''
     try:
-            return self._autocast
-        except:
+        int(value)
+        r.add(int)
+    except ValueError:
         pass
 
-        self._autocast = self #  type: Union[int, float, 'Rdate', 'Rstring']
-        if len(self) > 0:
-            if self.isInt():
-                self._autocast = int(self)
-            elif self.isFloat():
-                self._autocast = float(self)
-            elif self.isDate():
-                self._autocast = Rdate(self)
-        return self._autocast
-
-    def isInt(self) -> bool:
-        '''Returns true if the string represents an int number
-        it only considers as int numbers the strings matching
-        the following regexp:
-        r'^[\+\-]{0,1}[0-9]+$'
-        '''
-        return Rstring.int_regexp.match(self) is not None
-
-    def isFloat(self) -> bool:
-        '''Returns true if the string represents a float number
-        it only considers as float numbers, the strings matching
-        the following regexp:
-            r'^[\+\-]{0,1}[0-9]+(\.([0-9])+)?$'
-        '''
-        return Rstring.float_regexp.match(self) is not None
-
-    def isDate(self) -> bool:
-        '''Returns true if the string represents a date,
-        in the format YYYY-MM-DD. as separators '-' , '\', '/' are allowed.
-        As side-effect, the date object will be stored for future usage, so
-        no more parsings are needed
-        '''
     try:
-            return self._isdate #  type: ignore
-        except:
+        float(value)
+        r.add(float)
+    except ValueError:
         pass
-
-        r = Rstring.date_regexp.match(self)
-        if r is None:
-            self._isdate = False
-            self._date = None
-            return False
-
-        try:  # Any of the following operations can generate an exception, if it happens, we aren't dealing with a date
-            year = int(r.group(1))
-            month = int(r.group(3))
-            day = int(r.group(5))
-            d = datetime.date(year, month, day)
-            self._isdate = True
-            self._date = d
-            return True
-        except:
-            self._isdate = False
-            self._date = None
-            return False
-
-    def getDate(self):
-        '''Returns the datetime.date object or None'''
-        try:
-            return self._date
-        except:
-            self.isDate()
-            return self._date
+    return r
 
 
-class Rdate (object):
+def cast(value: str, guesses: Set) -> CastValue:
+    if int in guesses:
+        return int(value)
+    if Rdate in guesses:
+        print(repr(value), guesses)
+        return Rdate(value)
+    if float in guesses:
+        return float(value)
+    return value
 
+
+class Rdate(datetime.date):
     '''Represents a date'''
 
     def __init__(self, date):