patterns

from corio import patterns

patterns is a regex-driven transformation utility for structured rewrite rules.

Main types:

• Key: serializable pattern key with named capture support
• Item: source/target rule pair
• Transformer: compiles many rules into one expression and applies one-pass or recursive rewrite

Install:

pip install "corio[patterns]" --upgrade

Why Use It

Use this when dictionary-style lookups are not enough and you need:

• regex capture groups
• templated target rewrites
• recursive transforms with loop detection

Real-world Pattern (generalized)

In DNS tooling, repos use:

• Key subclasses (name, records)
• Item rules mapping a source key to transformed key or sentinel value
• Transformer.get(key) to select upstream behavior or blocklist output

Example

from dataclasses import dataclass
from corio import patterns


@dataclass
class HostKey(patterns.Key):
    FILLS = {"sub": r"[a-z0-9-]+"}
    host: str


rules = [
    patterns.Item(source=HostKey(host=r"{sub}\.example\.com"), target=HostKey(host=r"edge-{sub}.example.net")),
]

tx = patterns.Transformer(items=rules, default=None)

If recursive mode is enabled and rules loop, RewriteCircularLoopError is raised.