Dynamically increase decimal places till displayed result is non-zero #…

…38

CHANGELOG.md

@@ -3,6 +3,13 @@ Changelog
 =========
 
 
+### [3.5][v3.5] ###
+
+Released 2018-01-12
+
+- Add `DYNAMIC_DECIMALS` setting to expand the number of decimal places until the displayed result is non-zero.
+
+
 ### [3.4][v3.4] ###
 
 Released 2017-12-27
@@ -160,4 +167,5 @@ Released 2014-08-09.
 [v3.3]: https://github.com/deanishe/alfred-convert/releases/tag/v3.3
 [v3.3.1]: https://github.com/deanishe/alfred-convert/releases/tag/v3.3.1
 [v3.4]: https://github.com/deanishe/alfred-convert/releases/tag/v3.4
+[v3.5]: https://github.com/deanishe/alfred-convert/releases/tag/v3.5
 [openx]: https://openexchangerates.org/

README.md

@@ -90,14 +90,15 @@ The workflow is configured via the configuration sheet (`[𝒙]`) in Alfred Pref
 
 Basic configuration is performed in the configuration sheet:
 
-|         Option        |                                                 Meaning                                                  |
-|-----------------------|----------------------------------------------------------------------------------------------------------|
-| `APP_KEY`             | API key for [openexchangerates.org][openx].                                                              |
-| `COPY_UNIT`           | Include unit when copying conversion result. Any value but `0` or empty turns this option on.            |
-| `DECIMAL_PLACES`      | Number of decimal places to show in results.                                                             |
-| `DECIMAL_SEPARATOR`   | Character to separate whole numbers and decimal fractions. Used for parsing input and generating output. |
-| `THOUSANDS_SEPARATOR` | Character to delimit thousands Used for parsing input and generating output.                             |
-| `UPDATE_INTERVAL`     | How often (in minutes) to update currency exchange rates.                                                |
+|         Option        |                                                                    Meaning                                                                    |
+|-----------------------|-----------------------------------------------------------------------------------------------------------------------------------------------|
+| `APP_KEY`             | API key for [openexchangerates.org][openx].                                                                                                   |
+| `COPY_UNIT`           | Include unit when copying conversion result. Any value but `0` or empty turns this option on.                                                 |
+| `DECIMAL_PLACES`      | Number of decimal places to show in results.                                                                                                  |
+| `DECIMAL_SEPARATOR`   | Character to separate whole numbers and decimal fractions. Used for parsing input and generating output.                                      |
+| `DYNAMIC_DECIMALS`    | Dynamically increase the number of decimal places (up to 10) so that the result is non-zero. Any value but `0` or empty turns this option on. |
+| `THOUSANDS_SEPARATOR` | Character to delimit thousands Used for parsing input and generating output.                                                                  |
+| `UPDATE_INTERVAL`     | How often (in minutes) to update currency exchange rates.                                                                                     |
 
 
 #### Active currencies ####
@@ -155,6 +156,8 @@ See [CHANGELOG][changelog] for more information.
 
 |     Release     |      Date      |
 |-----------------|----------------|
+| [3.5][v3.5]     | 2018-01-12     |
+| [3.4][v3.4]     | 2017-12-26     |
 | [3.3.1][v3.3.1] | 2017-11-21     |
 | [3.3][v3.3]     | 2017-11-20     |
 | [3.2.2][v3.2.2] | 2017-11-07     |
@@ -214,6 +217,8 @@ All other code/media are released under the [MIT Licence][mit].
 [v3.2.2]: https://github.com/deanishe/alfred-convert/releases/tag/v3.2.2
 [v3.3]: https://github.com/deanishe/alfred-convert/releases/tag/v3.3
 [v3.3.1]: https://github.com/deanishe/alfred-convert/releases/tag/v3.3.1
+[v3.4]: https://github.com/deanishe/alfred-convert/releases/tag/v3.4
+[v3.5]: https://github.com/deanishe/alfred-convert/releases/tag/v3.5
 [cryptocompare]: https://www.cryptocompare.com/
 [openx]: https://openexchangerates.org/
 [openx-free]: https://openexchangerates.org/signup/free

src/config.py

@@ -26,8 +26,10 @@
 DECIMAL_SEPARATOR = os.getenv('DECIMAL_SEPARATOR') or '.'
 THOUSANDS_SEPARATOR = os.getenv('THOUSANDS_SEPARATOR') or ''
 
+DYNAMIC_DECIMALS = os.getenv('DYNAMIC_DECIMALS', '') not in ('', '0')
 COPY_UNIT = os.getenv('COPY_UNIT', '') not in ('', '0')
 
+
 # ----------------------------------------------------------------------
 # Currency settings
 # ----------------------------------------------------------------------

src/convert.py

@@ -31,6 +31,7 @@
     DECIMAL_PLACES,
     DECIMAL_SEPARATOR,
     DEFAULT_SETTINGS,
+    DYNAMIC_DECIMALS,
     HELP_URL,
     ICON_UPDATE,
     NOKEY_FILENAME,
@@ -153,19 +154,63 @@ class Formatter(object):
     """
 
     def __init__(self, decimal_places=2, decimal_separator='.',
-                 thousands_separator=''):
+                 thousands_separator='', dynamic_decimals=True):
         """Create a new `Formatter`."""
         self.decimal_places = decimal_places
         self.decimal_separator = decimal_separator
         self.thousands_separator = thousands_separator
+        self.dynamic_decimals = dynamic_decimals
+
+    def _decimal_places(self, n):
+        """Calculate the number of decimal places the result should have.
+
+        If :attr:`dynamic_decimals` is `True`, increase the number of
+        decimal places until the result is non-zero.
+
+        Args:
+            n (float): Number that will be formatted.
+
+        Returns:
+            int: Number of decimal places for result.
+        """
+        log.debug('DYNAMIC_DECIMALS are %s',
+                  ('off', 'on')[self.dynamic_decimals])
+
+        if not self.dynamic_decimals:
+            return self.decimal_places
+
+        m = max(self.decimal_places, 10) + 1
+        p = self.decimal_places
+        while p < m:
+            e = 10 ** p
+            i = n * e
+            # log.debug('n=%f, e=%d, i=%f, p=%d', n, e, i, p)
+            if n * e >= 10:
+                break
+
+            p += 1
+
+        # Remove trailing zeroes
+        s = str(i)
+        if '.' not in s:  # not a fraction
+            return p
+
+        s = s.split('.')[-1]
+        # log.debug('s=%s, p=%d', s, p)
+        while s.endswith('0'):
+            s = s[:-1]
+            p -= 1
+            # log.debug('s=%s, p=%d', s, p)
+
+        return p
 
     def formatted(self, n, unit=None):
         """Format number with thousands and decimal separators."""
         sep = u''
         if self.thousands_separator:
             sep = u','
 
-        fmt = u'{{:0{}.{:d}f}}'.format(sep, self.decimal_places)
+        fmt = u'{{:0{}.{:d}f}}'.format(sep, self._decimal_places(n))
         num = fmt.format(n)
         # log.debug('n=%r, fmt=%r, num=%r', n, fmt, num)
         num = num.replace(',', '||comma||')
@@ -436,27 +481,6 @@ def parse_units(self, query, qty=1):
         return from_unit, to_unit
 
 
-def format_number(n):
-    """Format a floating point number with thousands/decimal separators.
-
-    Args:
-        n (float): Number to format
-
-    """
-    sep = ''
-    if THOUSANDS_SEPARATOR:
-        sep = ','
-
-    fmt = '{{:0{}.{:d}f}}'.format(sep, DECIMAL_PLACES)
-    num = fmt.format(n)
-    # log.debug('n=%r, fmt=%r, num=%r', n, fmt, num)
-    num = num.replace(',', '||comma||')
-    num = num.replace('.', '||point||')
-    num = num.replace('||comma||', THOUSANDS_SEPARATOR)
-    num = num.replace('||point||', DECIMAL_SEPARATOR)
-    return num
-
-
 def register_units():
     """Add built-in and user units to unit registry."""
     # Add custom units from workflow and user data
@@ -541,7 +565,8 @@ def convert(query):
                     valid=False, icon=ICON_WARNING)
 
     else:  # Show results
-        f = Formatter(DECIMAL_PLACES, DECIMAL_SEPARATOR, THOUSANDS_SEPARATOR)
+        f = Formatter(DECIMAL_PLACES, DECIMAL_SEPARATOR, THOUSANDS_SEPARATOR,
+                      DYNAMIC_DECIMALS)
         wf.setvar('query', query)
         for conv in results:
             value = copytext = f.formatted(conv.to_number, conv.to_unit)

src/info.plist

@@ -503,6 +503,8 @@ DECIMAL_PLACES is the number of decimal places to show in conversion results.
 
 DECIMAL_SEPARATOR is the character used to separate whole numbers from decimal fraction when parsing and outputting numbers.
 
+DYNAMIC_DECIMALS is whether to dynamically increase the number of decimal places shown until the result is non-zero. Set to 0 or empty to turn off.
+
 THOUSANDS_SEPARATOR is the character used to separate thousands when parsing and outputting numbers.
 
 UPDATE_INTERVAL is the number of minutes between exchange rate updates.</string>
@@ -627,6 +629,8 @@ UPDATE_INTERVAL is the number of minutes between exchange rate updates.</string>
 		<string>2</string>
 		<key>DECIMAL_SEPARATOR</key>
 		<string>.</string>
+		<key>DYNAMIC_DECIMALS</key>
+		<string>1</string>
 		<key>THOUSANDS_SEPARATOR</key>
 		<string>,</string>
 		<key>UPDATE_INTERVAL</key>
@@ -637,7 +641,7 @@ UPDATE_INTERVAL is the number of minutes between exchange rate updates.</string>
 		<string>APP_KEY</string>
 	</array>
 	<key>version</key>
-	<string>3.4</string>
+	<string>3.5</string>
 	<key>webaddress</key>
 	<string></string>
 </dict>