--- a/calc.py Sun Apr 19 20:04:05 2015 +0300
+++ b/calc.py Sun Apr 19 20:49:43 2015 +0300
@@ -204,31 +204,47 @@
Symbols += Tokens
Symbols = sorted (Symbols, key=lambda x: len (x), reverse=True)
-ContainsHex = False
+PreferredBase = 10
def parse_number (expr):
"""Tries to parse a number from the expression. Returns (value, length) on success."""
- global ContainsHex
+ global PreferredBase
i = 0
value = None
+ base = 10
# Possibly it's hexadecimal
if expr[0:2].lower() == '0x':
- ContainsHex = True
+ base = PreferredBase = 0x10
+ digits = string.hexdigits
+ digitname = 'hexit'
+ i = 2
+ elif expr[0:2].lower() == '0b':
+ base = PreferredBase = 0b10
+ digits = ['0', '1']
+ digitname = 'bit'
i = 2
- value = ''
- while i < len (expr) and expr[i] in string.hexdigits:
- value += expr[i]
+ if base != 10:
+ # Skip leading zeroes
+ while i < len (expr) and expr[i] == '0':
+ i += 1
+
+ startingIndex = i
+ while i < len (expr) and expr[i] in digits:
i += 1
if i < len(expr) and expr[i] == '.':
- raise ValueError ('hexadecimal floating point numbers are not supported')
+ raise ValueError ('non-decimal floating point numbers are not supported')
- if not value:
- raise ValueError ('not a valid hexadecimal number: %s' % expr[0:i+1])
+ if i == startingIndex:
+ if i < len (expr):
+ raise ValueError ('not a valid %s "%s" in %s' % (digitname, expr[i], expr[0:i+1]))
+ else:
+ raise ValueError ('end of expression encountered while parsing '
+ 'base-%d literal' % base)
- return (complex (int (expr[2:i], 16), 0), i)
+ return (complex (int (expr[startingIndex:i], base), 0), i)
if expr[0] == 'i':
# Special case, we just have 'i' -- need special handling here because otherwise this would
@@ -263,8 +279,8 @@
return None
def tokenize (expr):
- global ContainsHex
- ContainsHex = False
+ global PreferredBase
+ PreferredBase = 10
expr = re.sub ('\s+', '', expr.strip())
i=0
tokens = []
@@ -480,6 +496,29 @@
def repr_number (x):
"""Returns a string representation for a real number"""
+ if math.fabs (x - math.floor(x)) < epsilon and PreferredBase != 10:
+ digits='0123456789abcdef'
+ assert PreferredBase <= len (digits), '''preferred base %d is too large''' % PreferredBase
+
+ divisor = PreferredBase
+ rep = ''
+ x = int (x)
+ runaway = 0
+
+ while x > 0:
+ runaway += 1
+ if runaway > 8:
+ raise ValueError('runaway triggered')
+
+ i = (x % divisor) / (divisor / PreferredBase)
+ x -= i * (divisor / PreferredBase)
+ rep += digits[i]
+ divisor *= PreferredBase
+
+ rep += 'x' if PreferredBase == 16 else 'b'
+ rep += '0'
+ return rep[::-1]
+
rep = '%.10f' % x
if '.' in rep:
@@ -489,8 +528,7 @@
if rep[-1] == '.':
rep = rep[:-1]
- if '.' not in rep and ContainsHex:
- rep = '0x%X' % int (x)
+
return rep
