part-find-requirements: wip

1 files changed, 22 insertions, 4 deletions

diff --git a/src/ee/__init__.py b/src/ee/__init__.py
index 2ba113e..06c5aab 100644
--- a/src/ee/__init__.py
+++ b/src/ee/__init__.py
@@ -1,5 +1,6 @@
 import re
 from functools import total_ordering
+from typing import Optional
 
 import math
 
@@ -52,8 +53,10 @@ class EeVal(object):
         'P': 15,
         'E': 18,
     }
+    keys = "".join(exponents.keys())
+    units = "|".join(units)
     r = re.compile(
-        "([0-9]+\\.[0-9]+|\\.?[0-9]+|[0-9]+\\.?) *([" + "".join(exponents.keys()) + "]?) *(" + "|".join(units) + "?)")
+        "([0-9]+(?:\\.[0-9]*)?(?:e-?[0-9]+)|[0-9]+\\.[0-9]+|\\.?[0-9]+|[0-9]+\\.?) *([" + keys + "]?) *(" + units + "?)")
 
     def __init__(self, s=None, value=None, exp=None, unit=None):
         # This is where I regret having a string in the API at once.
@@ -66,7 +69,14 @@ class EeVal(object):
             (self._value, self._exp, self._unit) = (value, exp, unit)
 
     @staticmethod
-    def parse(s) -> "EeVal":
+    def try_parse(s, expected_unit=None) -> Optional["EeVal"]:
+        try:
+            return EeVal.parse(s, expected_unit)
+        except EeException:
+            return None
+
+    @staticmethod
+    def parse(s, expected_unit=None) -> "EeVal":
         m = EeVal.r.match(s)
         if not m:
             raise EeException("Could not parse value: " + str(s))
@@ -79,10 +89,18 @@ class EeVal(object):
             e = math.ceil(math.log10(value))
             exp = exp + e
             value = value * math.pow(10, -e)
-        return EeVal(None, value=float(value), exp=exp, unit=unit if len(unit) > 0 else None)
+
+        unit = unit if len(unit) > 0 else None
+        if expected_unit is not None:
+            if unit is None:
+                unit = expected_unit
+            elif unit != expected_unit:
+                raise EeException("Bad unit when parsing, expected {}, got {}".format(expected_unit, unit))
+
+        return EeVal(None, value=float(value), exp=exp, unit=unit)
 
     @property
-    def value(self):
+    def value(self) -> float:
         return self.__float__()
 
     @property