Created
May 25, 2020 12:13
-
-
Save zengxs/172f202adb532c6aadfb4bba6079bd73 to your computer and use it in GitHub Desktop.
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
#!/usr/bin/env python3 | |
### | |
# START pandocfilters.py | |
### | |
# Author: John MacFarlane <jgm@berkeley.edu> | |
# Copyright: (C) 2013 John MacFarlane | |
# License: BSD3 | |
""" | |
Functions to aid writing python scripts that process the pandoc | |
AST serialized as JSON. | |
""" | |
import codecs | |
import hashlib | |
import io | |
import json | |
import os | |
import sys | |
# some utility-functions: make it easier to create your own filters | |
def get_filename4code(module, content, ext=None): | |
"""Generate filename based on content | |
The function ensures that the (temporary) directory exists, so that the | |
file can be written. | |
Example: | |
filename = get_filename4code("myfilter", code) | |
""" | |
imagedir = module + "-images" | |
fn = hashlib.sha1(content.encode(sys.getfilesystemencoding())).hexdigest() | |
try: | |
os.mkdir(imagedir) | |
sys.stderr.write('Created directory ' + imagedir + '\n') | |
except OSError: | |
pass | |
if ext: | |
fn += "." + ext | |
return os.path.join(imagedir, fn) | |
def get_value(kv, key, value = None): | |
"""get value from the keyvalues (options)""" | |
res = [] | |
for k, v in kv: | |
if k == key: | |
value = v | |
else: | |
res.append([k, v]) | |
return value, res | |
def get_caption(kv): | |
"""get caption from the keyvalues (options) | |
Example: | |
if key == 'CodeBlock': | |
[[ident, classes, keyvals], code] = value | |
caption, typef, keyvals = get_caption(keyvals) | |
... | |
return Para([Image([ident, [], keyvals], caption, [filename, typef])]) | |
""" | |
caption = [] | |
typef = "" | |
value, res = get_value(kv, u"caption") | |
if value is not None: | |
caption = [Str(value)] | |
typef = "fig:" | |
return caption, typef, res | |
def get_extension(format, default, **alternates): | |
"""get the extension for the result, needs a default and some specialisations | |
Example: | |
filetype = get_extension(format, "png", html="svg", latex="eps") | |
""" | |
try: | |
return alternates[format] | |
except KeyError: | |
return default | |
# end of utilities | |
def walk(x, action, format, meta): | |
"""Walk a tree, applying an action to every object. | |
Returns a modified tree. An action is a function of the form | |
`action(key, value, format, meta)`, where: | |
* `key` is the type of the pandoc object (e.g. 'Str', 'Para') `value` is | |
* the contents of the object (e.g. a string for 'Str', a list of | |
inline elements for 'Para') | |
* `format` is the target output format (as supplied by the | |
`format` argument of `walk`) | |
* `meta` is the document's metadata | |
The return of an action is either: | |
* `None`: this means that the object should remain unchanged | |
* a pandoc object: this will replace the original object | |
* a list of pandoc objects: these will replace the original object; the | |
list is merged with the neighbors of the orignal objects (spliced into | |
the list the original object belongs to); returning an empty list deletes | |
the object | |
""" | |
if isinstance(x, list): | |
array = [] | |
for item in x: | |
if isinstance(item, dict) and 't' in item: | |
res = action(item['t'], | |
item['c'] if 'c' in item else None, format, meta) | |
if res is None: | |
array.append(walk(item, action, format, meta)) | |
elif isinstance(res, list): | |
for z in res: | |
array.append(walk(z, action, format, meta)) | |
else: | |
array.append(walk(res, action, format, meta)) | |
else: | |
array.append(walk(item, action, format, meta)) | |
return array | |
elif isinstance(x, dict): | |
for k in x: | |
x[k] = walk(x[k], action, format, meta) | |
return x | |
else: | |
return x | |
def toJSONFilter(action): | |
"""Like `toJSONFilters`, but takes a single action as argument. | |
""" | |
toJSONFilters([action]) | |
def toJSONFilters(actions): | |
"""Generate a JSON-to-JSON filter from stdin to stdout | |
The filter: | |
* reads a JSON-formatted pandoc document from stdin | |
* transforms it by walking the tree and performing the actions | |
* returns a new JSON-formatted pandoc document to stdout | |
The argument `actions` is a list of functions of the form | |
`action(key, value, format, meta)`, as described in more | |
detail under `walk`. | |
This function calls `applyJSONFilters`, with the `format` | |
argument provided by the first command-line argument, | |
if present. (Pandoc sets this by default when calling | |
filters.) | |
""" | |
try: | |
input_stream = io.TextIOWrapper(sys.stdin.buffer, encoding='utf-8') | |
except AttributeError: | |
# Python 2 does not have sys.stdin.buffer. | |
# REF: https://stackoverflow.com/questions/2467928/python-unicodeencode | |
input_stream = codecs.getreader("utf-8")(sys.stdin) | |
source = input_stream.read() | |
if len(sys.argv) > 1: | |
format = sys.argv[1] | |
else: | |
format = "" | |
sys.stdout.write(applyJSONFilters(actions, source, format)) | |
def applyJSONFilters(actions, source, format=""): | |
"""Walk through JSON structure and apply filters | |
This: | |
* reads a JSON-formatted pandoc document from a source string | |
* transforms it by walking the tree and performing the actions | |
* returns a new JSON-formatted pandoc document as a string | |
The `actions` argument is a list of functions (see `walk` | |
for a full description). | |
The argument `source` is a string encoded JSON object. | |
The argument `format` is a string describing the output format. | |
Returns a the new JSON-formatted pandoc document. | |
""" | |
doc = json.loads(source) | |
if 'meta' in doc: | |
meta = doc['meta'] | |
elif doc[0]: # old API | |
meta = doc[0]['unMeta'] | |
else: | |
meta = {} | |
altered = doc | |
for action in actions: | |
altered = walk(altered, action, format, meta) | |
return json.dumps(altered) | |
def stringify(x): | |
"""Walks the tree x and returns concatenated string content, | |
leaving out all formatting. | |
""" | |
result = [] | |
def go(key, val, format, meta): | |
if key in ['Str', 'MetaString']: | |
result.append(val) | |
elif key == 'Code': | |
result.append(val[1]) | |
elif key == 'Math': | |
result.append(val[1]) | |
elif key == 'LineBreak': | |
result.append(" ") | |
elif key == 'SoftBreak': | |
result.append(" ") | |
elif key == 'Space': | |
result.append(" ") | |
walk(x, go, "", {}) | |
return ''.join(result) | |
def attributes(attrs): | |
"""Returns an attribute list, constructed from the | |
dictionary attrs. | |
""" | |
attrs = attrs or {} | |
ident = attrs.get("id", "") | |
classes = attrs.get("classes", []) | |
keyvals = [[x, attrs[x]] for x in attrs if (x != "classes" and x != "id")] | |
return [ident, classes, keyvals] | |
def elt(eltType, numargs): | |
def fun(*args): | |
lenargs = len(args) | |
if lenargs != numargs: | |
raise ValueError(eltType + ' expects ' + str(numargs) + | |
' arguments, but given ' + str(lenargs)) | |
if numargs == 0: | |
xs = [] | |
elif len(args) == 1: | |
xs = args[0] | |
else: | |
xs = list(args) | |
return {'t': eltType, 'c': xs} | |
return fun | |
# Constructors for block elements | |
Plain = elt('Plain', 1) | |
Para = elt('Para', 1) | |
CodeBlock = elt('CodeBlock', 2) | |
RawBlock = elt('RawBlock', 2) | |
BlockQuote = elt('BlockQuote', 1) | |
OrderedList = elt('OrderedList', 2) | |
BulletList = elt('BulletList', 1) | |
DefinitionList = elt('DefinitionList', 1) | |
Header = elt('Header', 3) | |
HorizontalRule = elt('HorizontalRule', 0) | |
Table = elt('Table', 5) | |
Div = elt('Div', 2) | |
Null = elt('Null', 0) | |
# Constructors for inline elements | |
Str = elt('Str', 1) | |
Emph = elt('Emph', 1) | |
Strong = elt('Strong', 1) | |
Strikeout = elt('Strikeout', 1) | |
Superscript = elt('Superscript', 1) | |
Subscript = elt('Subscript', 1) | |
SmallCaps = elt('SmallCaps', 1) | |
Quoted = elt('Quoted', 2) | |
Cite = elt('Cite', 2) | |
Code = elt('Code', 2) | |
Space = elt('Space', 0) | |
LineBreak = elt('LineBreak', 0) | |
Math = elt('Math', 2) | |
RawInline = elt('RawInline', 2) | |
Link = elt('Link', 3) | |
Image = elt('Image', 3) | |
Note = elt('Note', 1) | |
SoftBreak = elt('SoftBreak', 0) | |
Span = elt('Span', 2) | |
### | |
# END pandocfilters.py | |
### | |
from functools import wraps | |
def for_html(func): | |
@wraps(func) | |
def wrapper(*args): | |
to_fmt = args[2] | |
if to_fmt in ['html', 'html4', 'html5']: | |
return func(*args) | |
return wrapper | |
def for_key(key): | |
def decorator(func): | |
@wraps(func) | |
def wrapper(*args): | |
input_key = args[0] | |
if input_key == key: | |
return func(*args) | |
return wrapper | |
return decorator | |
@for_html | |
@for_key('Header') | |
def header_filter(key, value, to_fmt, meta): | |
[level, [ident, klass, kvs], contents] = value | |
klass.append('remarkup-header') | |
contents.insert(0, RawInline('html', f'<a name="{ident}"></a>')) | |
return Header(level, [ident, klass, kvs], contents) | |
if __name__ == "__main__": | |
toJSONFilters([ | |
header_filter, | |
]) |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment