F2PY G3: Impl. pattern tools for expression parsing.

1 files changed, 119 insertions, 0 deletions

diff --git a/numpy/f2py/lib/parser/pattern_tools.py b/numpy/f2py/lib/parser/pattern_tools.py
new file mode 100644
index 000000000..9cd4b5a1c
--- /dev/null
+++ b/numpy/f2py/lib/parser/pattern_tools.py
@@ -0,0 +1,119 @@
+
+import re
+
+class Pattern:
+    """
+    p1 | p2    -> <p1> | <p2>
+    p1 + p2    -> <p1> <p2>
+    p1 & p2    -> <p1><p2>
+    ~p1        -> [ <p1> ]
+    ~~p1       -> [ <p1> ]...
+    ~~~p1      -> <p1> [ <p1> ]...
+    ~~~~p1     -> <p1> [ <p1> ]...
+    abs(p1)    -> whole string match of <p1>
+    p1.named(name) -> match of <p1> has name
+    p1.match(string) -> return string match with <p1>
+    """
+    _special_symbol_map = {'.': '[.]',
+                           '*': '[*]',
+                           '+': '[+]',
+                           '|': '[|]',
+                           '(': r'\(',
+                           ')': r'\)',
+                           }
+
+    def __init__(self, label, pattern, optional=0):
+        self.label = label
+        self.pattern = pattern
+        self.optional = optional
+        return
+
+    def match(self, string):
+        if hasattr(self, '_compiled_match'):
+            return self._compiled.match(string)
+        self._compiled = compiled = re.compile(self.pattern)
+        return compiled.match(string)
+
+    def __abs__(self):
+        return Pattern(self.label, r'\A' + self.pattern+ r'\Z')
+
+    def __repr__(self):
+        return '%s(%r, %r)' % (self.__class__.__name__, self.label, self.pattern)
+
+    def __or__(self, other):
+        label = '( %s OR %s )' % (self.label, other.label)
+        pattern = '(%s|%s)' % (self.pattern, other.pattern)
+        return Pattern(label, pattern)
+
+    def __and__(self, other):
+        if isinstance(other, Pattern):
+            label = '%s%s' % (self.label, other.label)
+            pattern = self.pattern + other.pattern
+        else:
+            assert isinstance(other,str),`other`
+            label = '%s%s' % (self.label, other)
+            pattern = self.pattern + other
+        return Pattern(label, pattern)
+
+    def __rand__(self, other):
+        assert isinstance(other,str),`other`
+        label = '%s%s' % (other, self.label)
+        pattern = other + self.pattern
+        return Pattern(label, pattern)
+
+    def __invert__(self):
+        if self.optional:
+            if self.optional==1:
+                return Pattern(self.label + '...', self.pattern[:-1] + '*', 2)
+            if self.optional==2:
+                return Pattern('%s %s' % (self.label[1:-4].strip(), self.label), self.pattern[:-1] + '+', 3)
+            return self
+        label = '[ %s ]' % (self.label)
+        pattern = '(%s)?' % (self.pattern)
+        return Pattern(label, pattern, 1)
+
+    def __add__(self, other):
+        if isinstance(other, Pattern):
+            label = '%s %s' % (self.label, other.label)
+            pattern = self.pattern + r'\s*' + other.pattern
+        else:
+            assert isinstance(other,str),`other`
+            label = '%s %s' % (self.label, other)
+            other = self._special_symbol_map.get(other, other)
+            pattern = self.pattern + r'\s*' + other
+        return Pattern(label, pattern)
+
+    def __radd__(self, other):
+        assert isinstance(other,str),`other`
+        label = '%s %s' % (other, self.label)
+        other = self._special_symbol_map.get(other, other)
+        pattern = other + r'\s*' + self.pattern
+        return Pattern(label, pattern)
+
+    def named(self, name = None):
+        if name is None:
+            label = self.label
+            assert label[0]+label[-1]=='<>' and ' ' not in label,`label`
+        else:
+            label = '<%s>' % (name)
+        pattern = '(?P%s%s)' % (label.replace('-','_'), self.pattern)
+        return Pattern(label, pattern)
+
+name = Pattern('<name>', r'[a-z]\w*')
+digit_string = Pattern('<digit-string>',r'\d+')
+sign = Pattern('<sign>',r'[+-]')
+exponent_letter = Pattern('<exponent-letter>',r'[ED]')
+
+kind_param = digit_string | name
+signed_digit_string = ~sign + digit_string
+int_literal_constant = digit_string + ~('_' + kind_param)
+signed_int_literal_constant = ~sign + int_literal_constant
+
+exponent = signed_digit_string
+significand = digit_string + '.' + ~digit_string | '.' + digit_string
+real_literal_constant = significand + ~(exponent_letter + exponent) + ~ ('_' + kind_param) | \
+                        digit_string + exponent_letter + exponent + ~ ('_' + kind_param)
+signed_real_literal_constant = ~sign + real_literal_constant
+
+
+print signed_real_literal_constant