Support Unicode micro prefix symbols

src/unitpy/definitions/ledger.py

@@ -151,14 +151,15 @@ def add_derived_quantities():
 
 def add_with_prefix(entry: Entry):
     for pre in ledger.prefixes.values():
+        prefixed_abbrs = [abbr + entry.abbr for abbr in pre.abbr]
         ledger.add_unit(
             Entry(
                 label=pre.label + entry.label,
-                abbr=pre.abbr[0] + entry.abbr,
+                abbr=prefixed_abbrs[0],
                 base_unit=entry.base_unit,
                 multiplier=entry.multiplier,
                 prefix=pre,
-                additional_labels=get_additional_labels(pre.abbr, entry.additional_labels)
+                additional_labels=prefixed_abbrs[1:] + get_additional_labels(pre.abbr, entry.additional_labels)
             )
         )
 
@@ -208,4 +209,4 @@ def add_extra_quantities():
 add_extra_quantities()
 
 
-ledger.add_in_main_duplicates()
+ledger.add_in_main_duplicates()

src/unitpy/definitions/prefix.py

@@ -27,7 +27,7 @@ def __repr__(self):
     "femto": Prefix("femto", 1e-15, ("f",)),
     "pico": Prefix("pico", 1e-12, ("p",)),
     "nano": Prefix("nano", 1e-9, ("n",)),
-    "micro": Prefix("micro", 1e-6, ("u", "µ")),
+    "micro": Prefix("micro", 1e-6, ("u", "µ", "μ", "𝜇", "𝝁")),
     "milli": Prefix("milli", 1e-3, ("m",)),
     "centi": Prefix("centi", 1e-2, ("c",)),
     "deci": Prefix("deci", 1e-1, ("d",)),

src/unitpy/utils/parsing.py

@@ -151,7 +151,7 @@ def get_number(self) -> int | float | None:
         return None
 
     def get_unit(self) -> Unit | None:
-        match = re.match(r'[a-zA-Z_]+', self.expression[self.pos:])
+        match = re.match(r'[^+\-*/^()]+', self.expression[self.pos:])
         if match:
             value = self.expression[self.pos:self.pos + match.end()]
             if value in ledger:

tests/test_define_unit.py

@@ -71,4 +71,11 @@ def test_unit_prefix():
 def test_unit_prefix2():
     u = unitpy.Unit("kPa")
     assert u.abbr == "kPa"
-    assert u.multiplier == 1000
+    assert u.multiplier == 1000
+
+
+@pytest.mark.parametrize("micro_symbol", ["µ", "μ", "𝜇", "𝝁"])
+def test_unit_micro_prefix_symbols(micro_symbol):
+    u = unitpy.Unit(f"{micro_symbol}m")
+    assert u == unitpy.Unit("um")
+    assert u.multiplier == 1e-6

tests/test_parsing_unit.py

@@ -16,6 +16,10 @@
     ["ns", {ledger.get_entry("ns"): 1}],
     ["mK", {ledger.get_entry("mK"): 1}],
     ["Gg", {ledger.get_entry("Gg"): 1}],
+    ["µm", {ledger.get_entry("um"): 1}],
+    ["μm", {ledger.get_entry("um"): 1}],
+    ["𝜇m", {ledger.get_entry("um"): 1}],
+    ["𝝁m", {ledger.get_entry("um"): 1}],
 
     # division
     ["g/ml", {ledger.get_entry("g"): 1, ledger.get_entry("ml"): -1}],