Add support for partials and path segments for Handlebars.

This introduces support for some missing features to the Handlebars lexer:
Partials and path segments. Partials mostly appeared to work before, but the
`>` in `{{> ... }}` would appear as a syntax error, as could other
components of the partial. This change introduces support for:

* Standard partials: `{{> partialName}}`
* Partials with parameters: `{{> partialName varname="value"}}`
* Ddynamic partials: `{{> (partialFunc)}}`
* Ddynamic partials with lookups: `{{> (lookup ../path "partialName")}}`
* Partial blocks: `{{> @partial-block}}`
* Inline partials: `{{#*inline}}..{{/inline}}`

It also introduces support for path segments, which can reference content in
the current context or in a parent context. For instance, `this.name`,
`this/name`, `./name`, `../name`, `this/name`, etc. These are all now tracked
as variables.

1 files changed, 388 insertions, 0 deletions

diff --git a/pygments/util.py b/pygments/util.py
new file mode 100644
index 00000000..7abcc5fd
--- /dev/null
+++ b/pygments/util.py
@@ -0,0 +1,388 @@
+# -*- coding: utf-8 -*-
+"""
+    pygments.util
+    ~~~~~~~~~~~~~
+
+    Utility functions.
+
+    :copyright: Copyright 2006-2015 by the Pygments team, see AUTHORS.
+    :license: BSD, see LICENSE for details.
+"""
+
+import re
+import sys
+
+
+split_path_re = re.compile(r'[/\\ ]')
+doctype_lookup_re = re.compile(r'''
+    (<\?.*?\?>)?\s*
+    <!DOCTYPE\s+(
+     [a-zA-Z_][a-zA-Z0-9]*
+     (?: \s+      # optional in HTML5
+     [a-zA-Z_][a-zA-Z0-9]*\s+
+     "[^"]*")?
+     )
+     [^>]*>
+''', re.DOTALL | re.MULTILINE | re.VERBOSE)
+tag_re = re.compile(r'<(.+?)(\s.*?)?>.*?</.+?>',
+                    re.UNICODE | re.IGNORECASE | re.DOTALL | re.MULTILINE)
+xml_decl_re = re.compile(r'\s*<\?xml[^>]*\?>', re.I)
+
+
+class ClassNotFound(ValueError):
+    """Raised if one of the lookup functions didn't find a matching class."""
+
+
+class OptionError(Exception):
+    pass
+
+
+def get_choice_opt(options, optname, allowed, default=None, normcase=False):
+    string = options.get(optname, default)
+    if normcase:
+        string = string.lower()
+    if string not in allowed:
+        raise OptionError('Value for option %s must be one of %s' %
+                          (optname, ', '.join(map(str, allowed))))
+    return string
+
+
+def get_bool_opt(options, optname, default=None):
+    string = options.get(optname, default)
+    if isinstance(string, bool):
+        return string
+    elif isinstance(string, int):
+        return bool(string)
+    elif not isinstance(string, string_types):
+        raise OptionError('Invalid type %r for option %s; use '
+                          '1/0, yes/no, true/false, on/off' % (
+                              string, optname))
+    elif string.lower() in ('1', 'yes', 'true', 'on'):
+        return True
+    elif string.lower() in ('0', 'no', 'false', 'off'):
+        return False
+    else:
+        raise OptionError('Invalid value %r for option %s; use '
+                          '1/0, yes/no, true/false, on/off' % (
+                              string, optname))
+
+
+def get_int_opt(options, optname, default=None):
+    string = options.get(optname, default)
+    try:
+        return int(string)
+    except TypeError:
+        raise OptionError('Invalid type %r for option %s; you '
+                          'must give an integer value' % (
+                              string, optname))
+    except ValueError:
+        raise OptionError('Invalid value %r for option %s; you '
+                          'must give an integer value' % (
+                              string, optname))
+
+
+def get_list_opt(options, optname, default=None):
+    val = options.get(optname, default)
+    if isinstance(val, string_types):
+        return val.split()
+    elif isinstance(val, (list, tuple)):
+        return list(val)
+    else:
+        raise OptionError('Invalid type %r for option %s; you '
+                          'must give a list value' % (
+                              val, optname))
+
+
+def docstring_headline(obj):
+    if not obj.__doc__:
+        return ''
+    res = []
+    for line in obj.__doc__.strip().splitlines():
+        if line.strip():
+            res.append(" " + line.strip())
+        else:
+            break
+    return ''.join(res).lstrip()
+
+
+def make_analysator(f):
+    """Return a static text analyser function that returns float values."""
+    def text_analyse(text):
+        try:
+            rv = f(text)
+        except Exception:
+            return 0.0
+        if not rv:
+            return 0.0
+        try:
+            return min(1.0, max(0.0, float(rv)))
+        except (ValueError, TypeError):
+            return 0.0
+    text_analyse.__doc__ = f.__doc__
+    return staticmethod(text_analyse)
+
+
+def shebang_matches(text, regex):
+    r"""Check if the given regular expression matches the last part of the
+    shebang if one exists.
+
+        >>> from pygments.util import shebang_matches
+        >>> shebang_matches('#!/usr/bin/env python', r'python(2\.\d)?')
+        True
+        >>> shebang_matches('#!/usr/bin/python2.4', r'python(2\.\d)?')
+        True
+        >>> shebang_matches('#!/usr/bin/python-ruby', r'python(2\.\d)?')
+        False
+        >>> shebang_matches('#!/usr/bin/python/ruby', r'python(2\.\d)?')
+        False
+        >>> shebang_matches('#!/usr/bin/startsomethingwith python',
+        ...                 r'python(2\.\d)?')
+        True
+
+    It also checks for common windows executable file extensions::
+
+        >>> shebang_matches('#!C:\\Python2.4\\Python.exe', r'python(2\.\d)?')
+        True
+
+    Parameters (``'-f'`` or ``'--foo'`` are ignored so ``'perl'`` does
+    the same as ``'perl -e'``)
+
+    Note that this method automatically searches the whole string (eg:
+    the regular expression is wrapped in ``'^$'``)
+    """
+    index = text.find('\n')
+    if index >= 0:
+        first_line = text[:index].lower()
+    else:
+        first_line = text.lower()
+    if first_line.startswith('#!'):
+        try:
+            found = [x for x in split_path_re.split(first_line[2:].strip())
+                     if x and not x.startswith('-')][-1]
+        except IndexError:
+            return False
+        regex = re.compile(r'^%s(\.(exe|cmd|bat|bin))?$' % regex, re.IGNORECASE)
+        if regex.search(found) is not None:
+            return True
+    return False
+
+
+def doctype_matches(text, regex):
+    """Check if the doctype matches a regular expression (if present).
+
+    Note that this method only checks the first part of a DOCTYPE.
+    eg: 'html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"'
+    """
+    m = doctype_lookup_re.match(text)
+    if m is None:
+        return False
+    doctype = m.group(2)
+    return re.compile(regex, re.I).match(doctype.strip()) is not None
+
+
+def html_doctype_matches(text):
+    """Check if the file looks like it has a html doctype."""
+    return doctype_matches(text, r'html')
+
+
+_looks_like_xml_cache = {}
+
+
+def looks_like_xml(text):
+    """Check if a doctype exists or if we have some tags."""
+    if xml_decl_re.match(text):
+        return True
+    key = hash(text)
+    try:
+        return _looks_like_xml_cache[key]
+    except KeyError:
+        m = doctype_lookup_re.match(text)
+        if m is not None:
+            return True
+        rv = tag_re.search(text[:1000]) is not None
+        _looks_like_xml_cache[key] = rv
+        return rv
+
+
+# Python narrow build compatibility
+
+def _surrogatepair(c):
+    # Given a unicode character code
+    # with length greater than 16 bits,
+    # return the two 16 bit surrogate pair.
+    # From example D28 of:
+    # http://www.unicode.org/book/ch03.pdf
+    return (0xd7c0 + (c >> 10), (0xdc00 + (c & 0x3ff)))
+
+
+def unirange(a, b):
+    """Returns a regular expression string to match the given non-BMP range."""
+    if b < a:
+        raise ValueError("Bad character range")
+    if a < 0x10000 or b < 0x10000:
+        raise ValueError("unirange is only defined for non-BMP ranges")
+
+    if sys.maxunicode > 0xffff:
+        # wide build
+        return u'[%s-%s]' % (unichr(a), unichr(b))
+    else:
+        # narrow build stores surrogates, and the 're' module handles them
+        # (incorrectly) as characters.  Since there is still ordering among
+        # these characters, expand the range to one that it understands.  Some
+        # background in http://bugs.python.org/issue3665 and
+        # http://bugs.python.org/issue12749
+        #
+        # Additionally, the lower constants are using unichr rather than
+        # literals because jython [which uses the wide path] can't load this
+        # file if they are literals.
+        ah, al = _surrogatepair(a)
+        bh, bl = _surrogatepair(b)
+        if ah == bh:
+            return u'(?:%s[%s-%s])' % (unichr(ah), unichr(al), unichr(bl))
+        else:
+            buf = []
+            buf.append(u'%s[%s-%s]' %
+                       (unichr(ah), unichr(al),
+                        ah == bh and unichr(bl) or unichr(0xdfff)))
+            if ah - bh > 1:
+                buf.append(u'[%s-%s][%s-%s]' %
+                           unichr(ah+1), unichr(bh-1), unichr(0xdc00), unichr(0xdfff))
+            if ah != bh:
+                buf.append(u'%s[%s-%s]' %
+                           (unichr(bh), unichr(0xdc00), unichr(bl)))
+
+            return u'(?:' + u'|'.join(buf) + u')'
+
+
+def format_lines(var_name, seq, raw=False, indent_level=0):
+    """Formats a sequence of strings for output."""
+    lines = []
+    base_indent = ' ' * indent_level * 4
+    inner_indent = ' ' * (indent_level + 1) * 4
+    lines.append(base_indent + var_name + ' = (')
+    if raw:
+        # These should be preformatted reprs of, say, tuples.
+        for i in seq:
+            lines.append(inner_indent + i + ',')
+    else:
+        for i in seq:
+            # Force use of single quotes
+            r = repr(i + '"')
+            lines.append(inner_indent + r[:-2] + r[-1] + ',')
+    lines.append(base_indent + ')')
+    return '\n'.join(lines)
+
+
+def duplicates_removed(it, already_seen=()):
+    """
+    Returns a list with duplicates removed from the iterable `it`.
+
+    Order is preserved.
+    """
+    lst = []
+    seen = set()
+    for i in it:
+        if i in seen or i in already_seen:
+            continue
+        lst.append(i)
+        seen.add(i)
+    return lst
+
+
+class Future(object):
+    """Generic class to defer some work.
+
+    Handled specially in RegexLexerMeta, to support regex string construction at
+    first use.
+    """
+    def get(self):
+        raise NotImplementedError
+
+
+def guess_decode(text):
+    """Decode *text* with guessed encoding.
+
+    First try UTF-8; this should fail for non-UTF-8 encodings.
+    Then try the preferred locale encoding.
+    Fall back to latin-1, which always works.
+    """
+    try:
+        text = text.decode('utf-8')
+        return text, 'utf-8'
+    except UnicodeDecodeError:
+        try:
+            import locale
+            prefencoding = locale.getpreferredencoding()
+            text = text.decode()
+            return text, prefencoding
+        except (UnicodeDecodeError, LookupError):
+            text = text.decode('latin1')
+            return text, 'latin1'
+
+
+def guess_decode_from_terminal(text, term):
+    """Decode *text* coming from terminal *term*.
+
+    First try the terminal encoding, if given.
+    Then try UTF-8.  Then try the preferred locale encoding.
+    Fall back to latin-1, which always works.
+    """
+    if getattr(term, 'encoding', None):
+        try:
+            text = text.decode(term.encoding)
+        except UnicodeDecodeError:
+            pass
+        else:
+            return text, term.encoding
+    return guess_decode(text)
+
+
+def terminal_encoding(term):
+    """Return our best guess of encoding for the given *term*."""
+    if getattr(term, 'encoding', None):
+        return term.encoding
+    import locale
+    return locale.getpreferredencoding()
+
+
+# Python 2/3 compatibility
+
+if sys.version_info < (3, 0):
+    unichr = unichr
+    xrange = xrange
+    string_types = (str, unicode)
+    text_type = unicode
+    u_prefix = 'u'
+    iteritems = dict.iteritems
+    itervalues = dict.itervalues
+    import StringIO
+    import cStringIO
+    # unfortunately, io.StringIO in Python 2 doesn't accept str at all
+    StringIO = StringIO.StringIO
+    BytesIO = cStringIO.StringIO
+else:
+    unichr = chr
+    xrange = range
+    string_types = (str,)
+    text_type = str
+    u_prefix = ''
+    iteritems = dict.items
+    itervalues = dict.values
+    from io import StringIO, BytesIO, TextIOWrapper
+
+    class UnclosingTextIOWrapper(TextIOWrapper):
+        # Don't close underlying buffer on destruction.
+        def close(self):
+            self.flush()
+
+
+def add_metaclass(metaclass):
+    """Class decorator for creating a class with a metaclass."""
+    def wrapper(cls):
+        orig_vars = cls.__dict__.copy()
+        orig_vars.pop('__dict__', None)
+        orig_vars.pop('__weakref__', None)
+        for slots_var in orig_vars.get('__slots__', ()):
+            orig_vars.pop(slots_var)
+        return metaclass(cls.__name__, cls.__bases__, orig_vars)
+    return wrapper