From b0a30ee84ef3c6e9505a8f872a260db373fdb641 Mon Sep 17 00:00:00 2001
From: Vivien Maisonneuve <v.maisonneuve@gmail.com>
Date: Thu, 26 Jun 2014 14:36:50 +0200
Subject: [PATCH 1/1] Improve Expression.fromstring(), Domain.fromstring()
---
pypol/domains.py | 29 +++++++++++++++++++----------
pypol/linexprs.py | 5 ++++-
2 files changed, 23 insertions(+), 11 deletions(-)
diff --git a/pypol/domains.py b/pypol/domains.py
index 20493fa..9bb403e 100644
--- a/pypol/domains.py
+++ b/pypol/domains.py
@@ -287,25 +287,34 @@ class Domain:
return Polyhedron(equalities, inequalities)
raise SyntaxError('invalid syntax')
+ _RE_BRACES = re.compile(r'^\{\s*|\s*\}$')
+ _RE_EQ = re.compile(r'([^<=>])=([^<=>])')
+ _RE_AND = re.compile(r'\band\b|,|&&|/\\|â§|â©')
+ _RE_OR = re.compile(r'\bor\b|;|\|\||\\/|â¨|âª')
+ _RE_NOT = re.compile(r'\bnot\b|!|¬')
+ _RE_NUM_VAR = Expression._RE_NUM_VAR
+ _RE_OPERATORS = re.compile(r'(&|\||~)')
+
@classmethod
def fromstring(cls, string):
- # remove brackets
- string = re.sub(r'^\{\s*|\s*\}$', '', string)
+ # remove curly brackets
+ string = cls._RE_BRACES.sub(r'', string)
# replace '=' by '=='
- string = re.sub(r'([^<=>])=([^<=>])', r'\1==\2', string)
+ string = cls._RE_EQ.sub(r'\1==\2', string)
# replace 'and', 'or', 'not'
- string = re.sub(r'\band\b|,|&&|/\\|â§|â©', r' & ', string)
- string = re.sub(r'\bor\b|;|\|\||\\/|â¨|âª', r' | ', string)
- string = re.sub(r'\bnot\b|!|¬', r' ~', string)
- tokens = re.split(r'(&|\||~)', string)
+ string = cls._RE_AND.sub(r' & ', string)
+ string = cls._RE_OR.sub(r' | ', string)
+ string = cls._RE_NOT.sub(r' ~', string)
+ # add implicit multiplication operators, e.g. '5x' -> '5*x'
+ string = cls._RE_NUM_VAR.sub(r'\1*\2', string)
+ # add parentheses to force precedence
+ tokens = cls._RE_OPERATORS.split(string)
for i, token in enumerate(tokens):
if i % 2 == 0:
- # add implicit multiplication operators, e.g. '5x' -> '5*x'
- token = re.sub(r'(\d+|\))\s*([^\W\d_]\w*|\()', r'\1*\2', token)
token = '({})'.format(token)
tokens[i] = token
string = ''.join(tokens)
- tree = ast.parse(string)
+ tree = ast.parse(string, 'eval')
return cls._fromast(tree)
def __repr__(self):
diff --git a/pypol/linexprs.py b/pypol/linexprs.py
index 0db7edd..9ab5c86 100644
--- a/pypol/linexprs.py
+++ b/pypol/linexprs.py
@@ -252,9 +252,12 @@ class Expression:
return left / right
raise SyntaxError('invalid syntax')
+ _RE_NUM_VAR = re.compile(r'(\d+|\))\s*([^\W\d_]\w*|\()')
+
@classmethod
def fromstring(cls, string):
- string = re.sub(r'(\d+|\))\s*([^\W\d_]\w*|\()', r'\1*\2', string)
+ # add implicit multiplication operators, e.g. '5x' -> '5*x'
+ string = cls._RE_NUM_VAR.sub(r'\1*\2', string)
tree = ast.parse(string, 'eval')
return cls._fromast(tree)
--
2.20.1