styled-text 0.1.2

Flexible library to convert a text with custom markup to html (or anything else).

styled-text (Python version)

The Python version of the styled-text library. Designed for custom markup transformations.

This library is for anyone who wants to create styled text like markdown, but with total flexibility to create their own rules.

Installation

pip install styled-text

Usage

import re

from text_styler import TextStyler, TextStylerRegexRule, TextStylerRule, html_tag

# Let's style this text:
text = "_Welcome_ to _<~my library~>*styled-text*_ version 0.0.1"

# Create the rules (only need to do this once)
style_rules = [
    TextStylerRule(start="*", transform=html_tag("strong")),
    TextStylerRule(start="_", transform=html_tag("em")),
    TextStylerRule(start="<~", transform=html_tag("del"), end="~>"),
    TextStylerRegexRule(
        regex=re.compile(r"(\d+\.\d+\.\d+)"),
        replace=r"<span style='color: red'>\1</span>",
    ),
]

# Create the styler:
styler = TextStyler(style_rules)

# Process text
html = styler.process_text(text)

# `html` looks like this now:
# <em>Welcome</em> to <em><del>my library</del><strong>styled-text</strong></em> version <span style='color: red'>0.0.1</span>

Examples

Simple bold

TextStylerRule(
  start='*',
  transform=html_tag("strong")
)

Input: My *bolded* text
Output (raw): My <strong>bolded</strong> text
Output (visual): My bolded text

Nested bold/italic

TextStylerRule(
  start='*',
  transform=html_tag("strong")
),
TextStylerRule(
  start='_',
  transform=html_tag("em")
)

Input: My *bolded and _italicized_ text*
Output (raw): My <strong>bolded and <em>italicized</em> text</strong>
Output (visual): My bolded and italicized text

Input: Three *asterisks* matches* eagerly
Output (raw): Three <strong>asterisks</strong> matches* eagerly
Output (visual): Three asterisks matches* eagerly

Input: Overlapping * tags _ also * matches _ eagerly
Output (raw): Overlapping <strong> tags _ also </strong> matches _ eagerly
Output (visual): Overlapping tags _ also matches _ eagerly

Nested / Conflicting Tags

Here we show two things:

1. start can be multiple characters (~~ for strikethrough)
2. one rule can be a subset of another, and it still works as expected (~ for subscript)

TextStylerRule(
  start="~",
  transform=html_tag("sub")
),
TextStylerRule(
  start="~~",
  transform=html_tag("del")
)

Input: H\~\~\~3\~\~2\~O
Output (raw): H<sub><del>3</del>2</sub>O
Output (visual): H₃₂O

Input: A \~\~\~[sic]\~tyop\~\~ typo is...
Output (raw): H<del><sub>[sic]<sub>tyop</del> typo is...
Output (visual): H_[sic]tyop typo is...

Regexes

Regexes are the best way to built a complex replacement strategy, like if you need to parse the inner text into pieces, or use the inner text multiple times, such as in this example, where the matched url is used both as the property href and as the link text:

TextStylerRegexRule(
  regex=re.compile(r"https://www.[^\.]+.com),
  replace=r"<a href='\\g<0>'>\\g<0></a>"
)

Input: My link https://www.google.com
Output (raw): My link <a href='https://www.google.com'>https://www.google.com</a>
Output (visual): My link https://www.google.com

However, regexes are matched like literal strings, meaning that any styling within them is not matched by any other rules.
For example, even if we included the rule from asterisks to <strong> that we've used before, it will not use it to match within our regex:

Input: My link https://www.*google*.com
Output (raw): My link <a href='https://www.*google*.com'>https://www.*google*.com</a>
Output (visual): My link https://www.*google*.com

Preserving the special characters

By default, the special characters are removed from the output, but they can be preserved on the inside or on the outside:

TextStylerRule(
  start='*',
  transform=html_tag("strong"),
  consume_start=ConsumptionStyle.OUTSIDE,
  consume_end=ConsumptionStyle.OUTSIDE,
),
TextStylerRule(
  start='_',
  transform=html_tag("em")
  consume_start=ConsumptionStyle.INSIDE,
  consume_end=ConsumptionStyle.INSIDE,
)

Input: My *bolded* text, my _italicized_ text
Output (raw): My <strong>*bolded*</strong> text, my _<em>italicized</em>_ text
Output (visual): My *bolded* text, my _italicized_ text

Disallowing self-nesting

By default, a rule nesting within itself is allowed, but this can be disabled in two ways:

1. Completely disallowed, at any depth
2. A direct parent-child is disallowed, but grandparent-grandchild (or more distant) is allowed

TextStylerRule(
  start='*',
  transform=html_tag("strong"),
  allow_inner=InnerStyle.DISALLOW_DIRECT,
),
TextStylerRule(
  start='^',
  transform=html_tag("sup")
  allow_inner=InnerStyle.DISALLOW_ANCESTOR,
),
TextStylerRule(
  start='~',
  transform=html_tag("sub")
  allow_inner=InnerStyle.DISALLOW_DIRECT,
)

Input: Subscript ~cannot exist ~directly~ within subscript, but *can exist ~within~ the bolded* region~
Output (raw): Subscript <sub>cannot exist ~directly~ within subscript, but <strong>can exist <sub>within</sub> the bolded</strong> region</sub>
Output (visual): Subscript _{cannot exist ~directly~ within subscript, but can exist within the bolded region}`

Input: Superscript ^of multiple depths is ^disallowed^, *even if we ^wrap^ it in a bolded* region^
Output (raw): Superscript <sup>of multiple depths is ^disallowed^, <strong>even if we ^wrap^ it in a bolded</strong> region</sup>
Output (visual): Superscript ^{of multiple depths is ^disallowed^, even if we ^wrap^ it in a bolded region}

Reference

To use the library, just set up a list of "rules", create a TextStyler object, then call process_text.

Class / Function	Parameter	Type	Default	Description
TextStyler	rules	list	Required	A list of TextStylerRule or TextStylerRegexRule objects.
TextStylerRegexRule	regex	str	Required	The regular expression pattern to match.
	replace	str	Required	The replacement string (supports regex capture groups like \1).
TextStylerRule	start	str	Required	The marker string that begins the rule.
	transform	Callable[str, str]	Required	"Function to process inner content (e.g., html_tag)."
	end	str	start	The marker string that terminates the rule.
	consume_start	ConsumptionType	REPLACE	"Determines if start is included in output (INSIDE, OUTSIDE, REPLACE)."
	consume_end	ConsumptionType	REPLACE	"Determines if end is included in output (INSIDE, OUTSIDE, REPLACE)."
	allow_inner	InnerStyle	ALLOW	"Determines if self-nesting is allowed (ALLOW, DISALLOW_DIRECT, DISALLOW_ANCESTOR)."
html_tag	name	str	Required	The HTML tag name (e.g., "strong").
	attrs	dict	{}	Optional HTML attributes (e.g., {"class": "my-css-class"}).