The Challenge
FLIN needed a complete UI component library. Not "import from npm" -- compiled directly into the binary. When you write <Button> in FLIN, the component exists because the compiler knows it, not because you installed a package.
The scope: 180 components across 14 categories. Buttons, inputs, modals, charts, data tables, navigation, layout, typography, feedback, e-commerce templates, and more.
The Architecture: Three-Level Component Hierarchy
FLIN components follow a strict hierarchy:
- HTML native (lowercase) --
<div>,<input>,<button>-- standard HTML elements - FLIN built-in (PascalCase) --
<Button>,<Modal>,<DataTable>-- compiled into the binary - Developer custom -- User-defined components in their own codebase
Built-in components use PHF (perfect hash function) for O(1) lookup at compile time. No runtime scanning, no registration.
The Phased Rollout
| Phase | Category | Components |
|---|---|---|
| 1-3 | Basic | Button, Input, Textarea, Select, Switch, Checkbox, Radio |
| 4-6 | Display | Card, Badge, Avatar, Tag, Stat, Timeline, Comment |
| 7-9 | Feedback | Toast, Modal, Alert, Popconfirm, Progress, Skeleton |
| 10-11 | Advanced Forms | DatePicker, RichTextEditor, ImageUpload, ColorPicker |
| 12-14 | Templates | ProductCard, CartItem, PricingToggle, ChatBubble, Dashboard |
Parallel AI Agents in Action
Session 282b used 5 Claude agents working simultaneously to create 40 showcase pages with zero conflicts. Each agent owned a category, produced isolated files, and the results merged cleanly.
This is the manual agent methodology in practice: Thales assigns work boundaries, each agent executes within its scope, results are reviewed at the gate before merge.
The Design Token System
Every component inherits from a single token system:
- Colours -- CSS custom properties with light/dark mode support
- Typography -- Font scale from xs to 4xl
- Spacing -- Consistent gap/padding scale
- Shadows -- Three elevation levels
- Motion -- Duration and easing curves for transitions
Change a token, every component updates. No "find and replace across 180 files."
The Result
180 components. 148 showcase pages. Compiled into the binary. Zero npm dependencies. Zero build step. One command: flin dev.
A developer using FLIN gets a complete enterprise UI library on day one, without installing anything.