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Diffstat (limited to 'python/pyyaml/examples/pygments-lexer/yaml.py')
| -rw-r--r-- | python/pyyaml/examples/pygments-lexer/yaml.py | 431 |
1 files changed, 431 insertions, 0 deletions
diff --git a/python/pyyaml/examples/pygments-lexer/yaml.py b/python/pyyaml/examples/pygments-lexer/yaml.py new file mode 100644 index 000000000..1ce9dac9e --- /dev/null +++ b/python/pyyaml/examples/pygments-lexer/yaml.py @@ -0,0 +1,431 @@ + +""" +yaml.py + +Lexer for YAML, a human-friendly data serialization language +(http://yaml.org/). + +Written by Kirill Simonov <xi@resolvent.net>. + +License: Whatever suitable for inclusion into the Pygments package. +""" + +from pygments.lexer import \ + ExtendedRegexLexer, LexerContext, include, bygroups +from pygments.token import \ + Text, Comment, Punctuation, Name, Literal + +__all__ = ['YAMLLexer'] + + +class YAMLLexerContext(LexerContext): + """Indentation context for the YAML lexer.""" + + def __init__(self, *args, **kwds): + super(YAMLLexerContext, self).__init__(*args, **kwds) + self.indent_stack = [] + self.indent = -1 + self.next_indent = 0 + self.block_scalar_indent = None + + +def something(TokenClass): + """Do not produce empty tokens.""" + def callback(lexer, match, context): + text = match.group() + if not text: + return + yield match.start(), TokenClass, text + context.pos = match.end() + return callback + +def reset_indent(TokenClass): + """Reset the indentation levels.""" + def callback(lexer, match, context): + text = match.group() + context.indent_stack = [] + context.indent = -1 + context.next_indent = 0 + context.block_scalar_indent = None + yield match.start(), TokenClass, text + context.pos = match.end() + return callback + +def save_indent(TokenClass, start=False): + """Save a possible indentation level.""" + def callback(lexer, match, context): + text = match.group() + extra = '' + if start: + context.next_indent = len(text) + if context.next_indent < context.indent: + while context.next_indent < context.indent: + context.indent = context.indent_stack.pop() + if context.next_indent > context.indent: + extra = text[context.indent:] + text = text[:context.indent] + else: + context.next_indent += len(text) + if text: + yield match.start(), TokenClass, text + if extra: + yield match.start()+len(text), TokenClass.Error, extra + context.pos = match.end() + return callback + +def set_indent(TokenClass, implicit=False): + """Set the previously saved indentation level.""" + def callback(lexer, match, context): + text = match.group() + if context.indent < context.next_indent: + context.indent_stack.append(context.indent) + context.indent = context.next_indent + if not implicit: + context.next_indent += len(text) + yield match.start(), TokenClass, text + context.pos = match.end() + return callback + +def set_block_scalar_indent(TokenClass): + """Set an explicit indentation level for a block scalar.""" + def callback(lexer, match, context): + text = match.group() + context.block_scalar_indent = None + if not text: + return + increment = match.group(1) + if increment: + current_indent = max(context.indent, 0) + increment = int(increment) + context.block_scalar_indent = current_indent + increment + if text: + yield match.start(), TokenClass, text + context.pos = match.end() + return callback + +def parse_block_scalar_empty_line(IndentTokenClass, ContentTokenClass): + """Process an empty line in a block scalar.""" + def callback(lexer, match, context): + text = match.group() + if (context.block_scalar_indent is None or + len(text) <= context.block_scalar_indent): + if text: + yield match.start(), IndentTokenClass, text + else: + indentation = text[:context.block_scalar_indent] + content = text[context.block_scalar_indent:] + yield match.start(), IndentTokenClass, indentation + yield (match.start()+context.block_scalar_indent, + ContentTokenClass, content) + context.pos = match.end() + return callback + +def parse_block_scalar_indent(TokenClass): + """Process indentation spaces in a block scalar.""" + def callback(lexer, match, context): + text = match.group() + if context.block_scalar_indent is None: + if len(text) <= max(context.indent, 0): + context.stack.pop() + context.stack.pop() + return + context.block_scalar_indent = len(text) + else: + if len(text) < context.block_scalar_indent: + context.stack.pop() + context.stack.pop() + return + if text: + yield match.start(), TokenClass, text + context.pos = match.end() + return callback + +def parse_plain_scalar_indent(TokenClass): + """Process indentation spaces in a plain scalar.""" + def callback(lexer, match, context): + text = match.group() + if len(text) <= context.indent: + context.stack.pop() + context.stack.pop() + return + if text: + yield match.start(), TokenClass, text + context.pos = match.end() + return callback + + +class YAMLLexer(ExtendedRegexLexer): + """Lexer for the YAML language.""" + + name = 'YAML' + aliases = ['yaml'] + filenames = ['*.yaml', '*.yml'] + mimetypes = ['text/x-yaml'] + + tokens = { + + # the root rules + 'root': [ + # ignored whitespaces + (r'[ ]+(?=#|$)', Text.Blank), + # line breaks + (r'\n+', Text.Break), + # a comment + (r'#[^\n]*', Comment.Single), + # the '%YAML' directive + (r'^%YAML(?=[ ]|$)', reset_indent(Name.Directive), + 'yaml-directive'), + # the %TAG directive + (r'^%TAG(?=[ ]|$)', reset_indent(Name.Directive), + 'tag-directive'), + # document start and document end indicators + (r'^(?:---|\.\.\.)(?=[ ]|$)', + reset_indent(Punctuation.Document), 'block-line'), + # indentation spaces + (r'[ ]*(?![ \t\n\r\f\v]|$)', + save_indent(Text.Indent, start=True), + ('block-line', 'indentation')), + ], + + # trailing whitespaces after directives or a block scalar indicator + 'ignored-line': [ + # ignored whitespaces + (r'[ ]+(?=#|$)', Text.Blank), + # a comment + (r'#[^\n]*', Comment.Single), + # line break + (r'\n', Text.Break, '#pop:2'), + ], + + # the %YAML directive + 'yaml-directive': [ + # the version number + (r'([ ]+)([0-9]+\.[0-9]+)', + bygroups(Text.Blank, Literal.Version), 'ignored-line'), + ], + + # the %YAG directive + 'tag-directive': [ + # a tag handle and the corresponding prefix + (r'([ ]+)(!|![0-9A-Za-z_-]*!)' + r'([ ]+)(!|!?[0-9A-Za-z;/?:@&=+$,_.!~*\'()\[\]%-]+)', + bygroups(Text.Blank, Name.Type, Text.Blank, Name.Type), + 'ignored-line'), + ], + + # block scalar indicators and indentation spaces + 'indentation': [ + # trailing whitespaces are ignored + (r'[ ]*$', something(Text.Blank), '#pop:2'), + # whitespaces preceeding block collection indicators + (r'[ ]+(?=[?:-](?:[ ]|$))', save_indent(Text.Indent)), + # block collection indicators + (r'[?:-](?=[ ]|$)', set_indent(Punctuation.Indicator)), + # the beginning a block line + (r'[ ]*', save_indent(Text.Indent), '#pop'), + ], + + # an indented line in the block context + 'block-line': [ + # the line end + (r'[ ]*(?=#|$)', something(Text.Blank), '#pop'), + # whitespaces separating tokens + (r'[ ]+', Text.Blank), + # tags, anchors and aliases, + include('descriptors'), + # block collections and scalars + include('block-nodes'), + # flow collections and quoted scalars + include('flow-nodes'), + # a plain scalar + (r'(?=[^ \t\n\r\f\v?:,\[\]{}#&*!|>\'"%@`-]|[?:-][^ \t\n\r\f\v])', + something(Literal.Scalar.Plain), + 'plain-scalar-in-block-context'), + ], + + # tags, anchors, aliases + 'descriptors' : [ + # a full-form tag + (r'!<[0-9A-Za-z;/?:@&=+$,_.!~*\'()\[\]%-]+>', Name.Type), + # a tag in the form '!', '!suffix' or '!handle!suffix' + (r'!(?:[0-9A-Za-z_-]+)?' + r'(?:![0-9A-Za-z;/?:@&=+$,_.!~*\'()\[\]%-]+)?', Name.Type), + # an anchor + (r'&[0-9A-Za-z_-]+', Name.Anchor), + # an alias + (r'\*[0-9A-Za-z_-]+', Name.Alias), + ], + + # block collections and scalars + 'block-nodes': [ + # implicit key + (r':(?=[ ]|$)', set_indent(Punctuation.Indicator, implicit=True)), + # literal and folded scalars + (r'[|>]', Punctuation.Indicator, + ('block-scalar-content', 'block-scalar-header')), + ], + + # flow collections and quoted scalars + 'flow-nodes': [ + # a flow sequence + (r'\[', Punctuation.Indicator, 'flow-sequence'), + # a flow mapping + (r'\{', Punctuation.Indicator, 'flow-mapping'), + # a single-quoted scalar + (r'\'', Literal.Scalar.Flow.Quote, 'single-quoted-scalar'), + # a double-quoted scalar + (r'\"', Literal.Scalar.Flow.Quote, 'double-quoted-scalar'), + ], + + # the content of a flow collection + 'flow-collection': [ + # whitespaces + (r'[ ]+', Text.Blank), + # line breaks + (r'\n+', Text.Break), + # a comment + (r'#[^\n]*', Comment.Single), + # simple indicators + (r'[?:,]', Punctuation.Indicator), + # tags, anchors and aliases + include('descriptors'), + # nested collections and quoted scalars + include('flow-nodes'), + # a plain scalar + (r'(?=[^ \t\n\r\f\v?:,\[\]{}#&*!|>\'"%@`])', + something(Literal.Scalar.Plain), + 'plain-scalar-in-flow-context'), + ], + + # a flow sequence indicated by '[' and ']' + 'flow-sequence': [ + # include flow collection rules + include('flow-collection'), + # the closing indicator + (r'\]', Punctuation.Indicator, '#pop'), + ], + + # a flow mapping indicated by '{' and '}' + 'flow-mapping': [ + # include flow collection rules + include('flow-collection'), + # the closing indicator + (r'\}', Punctuation.Indicator, '#pop'), + ], + + # block scalar lines + 'block-scalar-content': [ + # line break + (r'\n', Text.Break), + # empty line + (r'^[ ]+$', + parse_block_scalar_empty_line(Text.Indent, + Literal.Scalar.Block)), + # indentation spaces (we may leave the state here) + (r'^[ ]*', parse_block_scalar_indent(Text.Indent)), + # line content + (r'[^\n\r\f\v]+', Literal.Scalar.Block), + ], + + # the content of a literal or folded scalar + 'block-scalar-header': [ + # indentation indicator followed by chomping flag + (r'([1-9])?[+-]?(?=[ ]|$)', + set_block_scalar_indent(Punctuation.Indicator), + 'ignored-line'), + # chomping flag followed by indentation indicator + (r'[+-]?([1-9])?(?=[ ]|$)', + set_block_scalar_indent(Punctuation.Indicator), + 'ignored-line'), + ], + + # ignored and regular whitespaces in quoted scalars + 'quoted-scalar-whitespaces': [ + # leading and trailing whitespaces are ignored + (r'^[ ]+|[ ]+$', Text.Blank), + # line breaks are ignored + (r'\n+', Text.Break), + # other whitespaces are a part of the value + (r'[ ]+', Literal.Scalar.Flow), + ], + + # single-quoted scalars + 'single-quoted-scalar': [ + # include whitespace and line break rules + include('quoted-scalar-whitespaces'), + # escaping of the quote character + (r'\'\'', Literal.Scalar.Flow.Escape), + # regular non-whitespace characters + (r'[^ \t\n\r\f\v\']+', Literal.Scalar.Flow), + # the closing quote + (r'\'', Literal.Scalar.Flow.Quote, '#pop'), + ], + + # double-quoted scalars + 'double-quoted-scalar': [ + # include whitespace and line break rules + include('quoted-scalar-whitespaces'), + # escaping of special characters + (r'\\[0abt\tn\nvfre "\\N_LP]', Literal.Scalar.Flow.Escape), + # escape codes + (r'\\(?:x[0-9A-Fa-f]{2}|u[0-9A-Fa-f]{4}|U[0-9A-Fa-f]{8})', + Literal.Scalar.Flow.Escape), + # regular non-whitespace characters + (r'[^ \t\n\r\f\v\"\\]+', Literal.Scalar.Flow), + # the closing quote + (r'"', Literal.Scalar.Flow.Quote, '#pop'), + ], + + # the beginning of a new line while scanning a plain scalar + 'plain-scalar-in-block-context-new-line': [ + # empty lines + (r'^[ ]+$', Text.Blank), + # line breaks + (r'\n+', Text.Break), + # document start and document end indicators + (r'^(?=---|\.\.\.)', something(Punctuation.Document), '#pop:3'), + # indentation spaces (we may leave the block line state here) + (r'^[ ]*', parse_plain_scalar_indent(Text.Indent), '#pop'), + ], + + # a plain scalar in the block context + 'plain-scalar-in-block-context': [ + # the scalar ends with the ':' indicator + (r'[ ]*(?=:[ ]|:$)', something(Text.Blank), '#pop'), + # the scalar ends with whitespaces followed by a comment + (r'[ ]+(?=#)', Text.Blank, '#pop'), + # trailing whitespaces are ignored + (r'[ ]+$', Text.Blank), + # line breaks are ignored + (r'\n+', Text.Break, 'plain-scalar-in-block-context-new-line'), + # other whitespaces are a part of the value + (r'[ ]+', Literal.Scalar.Plain), + # regular non-whitespace characters + (r'(?::(?![ \t\n\r\f\v])|[^ \t\n\r\f\v:])+', + Literal.Scalar.Plain), + ], + + # a plain scalar is the flow context + 'plain-scalar-in-flow-context': [ + # the scalar ends with an indicator character + (r'[ ]*(?=[,:?\[\]{}])', something(Text.Blank), '#pop'), + # the scalar ends with a comment + (r'[ ]+(?=#)', Text.Blank, '#pop'), + # leading and trailing whitespaces are ignored + (r'^[ ]+|[ ]+$', Text.Blank), + # line breaks are ignored + (r'\n+', Text.Break), + # other whitespaces are a part of the value + (r'[ ]+', Literal.Scalar.Plain), + # regular non-whitespace characters + (r'[^ \t\n\r\f\v,:?\[\]{}]+', Literal.Scalar.Plain), + ], + + } + + def get_tokens_unprocessed(self, text=None, context=None): + if context is None: + context = YAMLLexerContext(text, 0) + return super(YAMLLexer, self).get_tokens_unprocessed(text, context) + + |