from typing import List, Optional, Sequence
from markdown_it import MarkdownIt
from markdown_it.rules_block import StateBlock
from markdown_it.rules_core import StateCore
from markdown_it.rules_inline import StateInline
from markdown_it.token import Token
from mdit_py_plugins.utils import is_code_block
from .parse import ParseError, parse
[docs]def attrs_plugin(
md: MarkdownIt,
*,
after: Sequence[str] = ("image", "code_inline", "link_close", "span_close"),
spans: bool = False,
span_after: str = "link",
) -> None:
"""Parse inline attributes that immediately follow certain inline elements::
{#id .a b=c}
This syntax is inspired by
`Djot spans
<https://htmlpreview.github.io/?https://github.com/jgm/djot/blob/master/doc/syntax.html#inline-attributes>`_.
Inside the curly braces, the following syntax is possible:
- `.foo` specifies foo as a class.
Multiple classes may be given in this way; they will be combined.
- `#foo` specifies foo as an identifier.
An element may have only one identifier;
if multiple identifiers are given, the last one is used.
- `key="value"` or `key=value` specifies a key-value attribute.
Quotes are not needed when the value consists entirely of
ASCII alphanumeric characters or `_` or `:` or `-`.
Backslash escapes may be used inside quoted values.
- `%` begins a comment, which ends with the next `%` or the end of the attribute (`}`).
Multiple attribute blocks are merged.
:param md: The MarkdownIt instance to modify.
:param after: The names of inline elements after which attributes may be specified.
This plugin does not support attributes after emphasis, strikethrough or text elements,
which all require post-parse processing.
:param spans: If True, also parse attributes after spans of text, encapsulated by `[]`.
Note Markdown link references take precedence over this syntax.
:param span_after: The name of an inline rule after which spans may be specified.
"""
def _attr_inline_rule(state: StateInline, silent: bool) -> bool:
if state.pending or not state.tokens:
return False
token = state.tokens[-1]
if token.type not in after:
return False
try:
new_pos, attrs = parse(state.src[state.pos :])
except ParseError:
return False
token_index = _find_opening(state.tokens, len(state.tokens) - 1)
if token_index is None:
return False
state.pos += new_pos + 1
if not silent:
attr_token = state.tokens[token_index]
if "class" in attrs and "class" in token.attrs:
attrs["class"] = f"{attr_token.attrs['class']} {attrs['class']}"
attr_token.attrs.update(attrs)
return True
if spans:
md.inline.ruler.after(span_after, "span", _span_rule)
if after:
md.inline.ruler.push("attr", _attr_inline_rule)
[docs]def attrs_block_plugin(md: MarkdownIt) -> None:
"""Parse block attributes.
Block attributes are attributes on a single line, with no other content.
They attach the specified attributes to the block below them::
{.a #b c=1}
A paragraph, that will be assigned the class ``a`` and the identifier ``b``.
Attributes can be stacked, with classes accumulating and lower attributes overriding higher::
{#a .a c=1}
{#b .b c=2}
A paragraph, that will be assigned the class ``a b c``, and the identifier ``b``.
This syntax is inspired by Djot block attributes.
"""
md.block.ruler.before("fence", "attr", _attr_block_rule)
md.core.ruler.after("block", "attr", _attr_resolve_block_rule)
def _find_opening(tokens: List[Token], index: int) -> Optional[int]:
"""Find the opening token index, if the token is closing."""
if tokens[index].nesting != -1:
return index
level = 0
while index >= 0:
level += tokens[index].nesting
if level == 0:
return index
index -= 1
return None
def _span_rule(state: StateInline, silent: bool) -> bool:
if state.src[state.pos] != "[":
return False
maximum = state.posMax
labelStart = state.pos + 1
labelEnd = state.md.helpers.parseLinkLabel(state, state.pos, False)
# parser failed to find ']', so it's not a valid span
if labelEnd < 0:
return False
pos = labelEnd + 1
# check not at end of inline
if pos >= maximum:
return False
try:
new_pos, attrs = parse(state.src[pos:])
except ParseError:
return False
pos += new_pos + 1
if not silent:
state.pos = labelStart
state.posMax = labelEnd
token = state.push("span_open", "span", 1)
token.attrs = attrs # type: ignore
state.md.inline.tokenize(state)
token = state.push("span_close", "span", -1)
state.pos = pos
state.posMax = maximum
return True
def _attr_block_rule(
state: StateBlock, startLine: int, endLine: int, silent: bool
) -> bool:
"""Find a block of attributes.
The block must be a single line that begins with a `{`, after three or less spaces,
and end with a `}` followed by any number if spaces.
"""
if is_code_block(state, startLine):
return False
pos = state.bMarks[startLine] + state.tShift[startLine]
maximum = state.eMarks[startLine]
# if it doesn't start with a {, it's not an attribute block
if state.src[pos] != "{":
return False
# find first non-space character from the right
while maximum > pos and state.src[maximum - 1] in (" ", "\t"):
maximum -= 1
# if it doesn't end with a }, it's not an attribute block
if maximum <= pos:
return False
if state.src[maximum - 1] != "}":
return False
try:
new_pos, attrs = parse(state.src[pos:maximum])
except ParseError:
return False
# if the block was resolved earlier than expected, it's not an attribute block
# TODO this was not working in some instances, so I disabled it
# if (maximum - 1) != new_pos:
# return False
if silent:
return True
token = state.push("attrs_block", "", 0)
token.attrs = attrs # type: ignore
token.map = [startLine, startLine + 1]
state.line = startLine + 1
return True
def _attr_resolve_block_rule(state: StateCore) -> None:
"""Find attribute block then move its attributes to the next block."""
i = 0
len_tokens = len(state.tokens)
while i < len_tokens:
if state.tokens[i].type != "attrs_block":
i += 1
continue
if i + 1 < len_tokens:
next_token = state.tokens[i + 1]
# classes are appended
if "class" in state.tokens[i].attrs and "class" in next_token.attrs:
state.tokens[i].attrs[
"class"
] = f"{state.tokens[i].attrs['class']} {next_token.attrs['class']}"
if next_token.type == "attrs_block":
# subsequent attribute blocks take precedence, when merging
for key, value in state.tokens[i].attrs.items():
if key == "class" or key not in next_token.attrs:
next_token.attrs[key] = value
else:
# attribute block takes precedence over attributes in other blocks
next_token.attrs.update(state.tokens[i].attrs)
state.tokens.pop(i)
len_tokens -= 1