Applications · Feb 2026
Knowledge Domains
CLN works wherever there's hierarchy + typed information. A
programming language has tags and attributes. A business process has steps and
decisions. An API has endpoints and responses. The structure is the same — only
the vocabulary changes.
01/Why CLN Works Across Domains
Principle
=
CLN captures the shape of
knowledge, not its vocabulary.
.
Universal elements CLN
expresses:
=
Definitions — what things are
(=)
.
Actions — what to do
(.)
!
Risks — what can go wrong
(!)
→
Results — what happens
(→)
*
Context — background info
(*)
→
Every domain has these elements — they just use
different names.
02/Domain Gallery
Interactive
*
Click any domain to see CLN example
HTML
Markup Language
Tags, attributes, semantic structure.
Perfect fit: each element has a role.
CSS
Styling Language
Properties, cascade, specificity.
Operators express inheritance rules.
HTTP
Protocol
Methods, status codes, headers. State
machine fits CLN naturally.
Architecture Decisions
Documentation
Context, decision, consequences.
Trade-offs expressed with + and -.
API Documentation
Technical Docs
Endpoints, parameters, responses.
Errors marked with ! naturally.
Design Patterns
Architecture
Intent, structure, when to use.
Pros/cons with + and -.
Git Workflow
Version Control
Branches, merges, conflicts. Warnings
for common mistakes.
Incident Response
Operations
Timeline, diagnosis, remediation.
Causality with → operator.
SQL
Query Language
Clauses, operators, performance.
Warnings for anti-patterns.
HTML in CLN
= HTML —
HyperText Markup Language
. Каждый
элемент = тег + атрибуты + содержимое
= Семантические
теги
.
<header> — шапка документа или секции
.
<nav> — навигация
.
<main> — основное содержимое (1 на страницу)
.
<article> — самодостаточный контент
! <div> и
<span> — несемантичны, использовать только когда
нет подходящего тега
→ семантика = лучше для
SEO + доступность + читаемость кода
CSS in CLN
= CSS —
Cascading Style Sheets
. три
принципа: каскад · специфичность · наследование
=
Специфичность (inline, id, class, tag)
. inline
style → (1,0,0,0) — максимум
. #id →
(0,1,0,0)
. .class →
(0,0,1,0)
. tag →
(0,0,0,1)
! !important — ломает
каскад, использовать только в крайнем случае
* побеждает: наибольший вес
слева направо в кортеже
HTTP in CLN
= HTTP
Methods
. GET —
получить ресурс (idempotent)
. POST —
создать ресурс
. PUT —
заменить ресурс (idempotent)
. PATCH —
частичное обновление
. DELETE —
удалить ресурс (idempotent)
= Status
Codes
+ 2xx —
успех
* 3xx —
редирект
- 4xx —
ошибка клиента
! 5xx —
ошибка сервера
Architecture Decision Record in
CLN
= ADR-001: Use
PostgreSQL for Primary Database
= Context
* Need
ACID compliance for financial transactions
* Team has
PostgreSQL expertise
= Decision
. Use
PostgreSQL as primary data store
+ Strong consistency
guarantees
+ Mature
ecosystem
+ JSON
support for flexibility
- Horizontal scaling
harder than NoSQL
- Schema
migrations require planning
~ Tension: Consistency vs.
Scale
→ Can migrate to Citus if
needed for horizontal scaling
API Documentation in CLN
= POST
/api/users
. Create a
new user
| Request Body
. email:
string (required)
. name:
string (required)
. role:
string (default: "user")
→ 201 Created
* Returns
created user object
! 400 Bad Request
* Missing
required field
* Invalid
email format
! 409 Conflict
* Email
already exists
Design Pattern in CLN
= Singleton
Pattern
= Intent
* Ensure a
class has only one instance
* Provide
global access point to it
= When to Use
. Logging
system
. Database
connection pool
.
Configuration manager
+ Controlled access to sole
instance
+ Avoids global variables
- Often used as
anti-pattern
- Makes unit testing
harder
! Hidden
dependencies in code
~ Tension: Convenience vs.
Testability
Git Workflow in CLN
= Git Flow —
Branching Strategy
. main — production-ready
code
! Never
commit directly to main
. develop — integration
branch
* Features
merge here first
. feature/* — new features
. Create
from: develop
→ Merge
back to: develop
. hotfix/* — urgent
production fixes
. Create
from: main
→ Merge
to: main AND develop
! Common Mistakes
-
Forgetting to pull before starting work
- Merge
without resolving conflicts
- Force
push to shared branches
Incident Response in CLN
= INC-001: API 500
Errors
@ severity:
P1
@ duration:
23 minutes
= Timeline
. 14:32 —
Alert triggered
. 14:35 —
First responder on-call
. 14:41 —
Root cause identified
. 14:58 —
Fix deployed
! Root Cause
= JWT secret
expired in production
→
Rotation job failed silently
. Fix
. Rotated
JWT secret manually
→ Service
restored
? Follow-ups
. Add alert
for rotation failures
. Update
runbook
SQL in CLN
= SELECT —
Retrieve data
. Clauses (in order)
. SELECT
columns
. FROM
table
. JOIN
table ON condition
. WHERE
filters
. GROUP BY
columns
. HAVING
aggregate_filter
. ORDER BY
columns
. LIMIT n
! Performance Anti-Patterns
- SELECT
* — fetches unnecessary columns
- N+1
queries — use JOIN instead
- LIKE
'%term%' — can't use index
- OR in
WHERE — may prevent index usage
→ Use EXPLAIN ANALYZE to
debug query plans
03/Domain Fit Quality
=
Not all domains fit CLN equally well.
*
CLN excels with structured,
hierarchical, typed information.
04/Domain Patterns
| Domain Type | Primary Operators | Example Structure |
|---|---|---|
| Languages / Tech | =
.
!
|
= Definition → . Elements → ! Caveats |
| Architecture | +
-
~
|
= Decision → + Pros / - Cons → ~ Trade-off |
| APIs | |
→
!
|
= Endpoint → | Request → → Response → ! Errors |
| Incidents | .
→
!
|
. Timeline → ! Cause → . Fix → ? Follow-up |
| Processes | .
?
→
|
. Step → ? Branch → → Result |
05/Limitations
Important
!
CLN does not work well
for:
-
Narrative prose — stories,
essays, emotional content
-
Dialogue — conversation lacks
single hierarchy
-
Highly visual content —
diagrams, layouts need their own medium
-
Ambiguous information — if you
can't classify it, CLN can't help
→
Use CLN for structure. Use
prose for story.
~
Tension: Structure makes things scannable, but
also strips nuance. Choose your trade-off.