Agent Skills: FenCore Library

FenCore Library

FenCore is a pure logic library for WoW addons - no UI dependencies, just utility functions.

Design Philosophy

• Pure Functions: No side effects, predictable outputs
• No UI Dependencies: Works in any layer of your addon
• Testable: All functions can be unit tested without WoW
• Documented: Every function has clear input/output contracts

MCP Tools

| Task | MCP Tool | |------|----------| | List All Functions | fencore.catalog() | | Search Functions | fencore.search(query="clamp") | | Get Function Details | fencore.info(domain="Math", function="Clamp") |

Domains

FenCore organizes functions by domain:

| Domain | Purpose | Examples | |--------|---------|----------| | Math | Numeric operations | Clamp, Round, Lerp, InRange | | Table | Table manipulation | Copy, Merge, Filter, Map | | String | String utilities | Split, Trim, StartsWith, Format | | Color | Color manipulation | HexToRGB, RGBToHex, Lighten, Darken | | Time | Time formatting | FormatDuration, FormatTime, ParseDuration | | Environment | WoW detection | IsRetail, IsClassic, GetExpansion |

Usage Pattern

local FenCore = LibStub("FenCore")

-- Access by domain
local Math = FenCore.Math
local result = Math.Clamp(value, 0, 100)

-- Or direct access
local clamped = FenCore.Math.Clamp(value, 0, 100)

Common Functions

Math

FenCore.Math.Clamp(value, min, max)     -- Constrain value to range
FenCore.Math.Round(value, decimals)      -- Round to decimal places
FenCore.Math.Lerp(a, b, t)              -- Linear interpolation
FenCore.Math.InRange(value, min, max)   -- Check if value in range

Table

FenCore.Table.Copy(tbl)                 -- Shallow copy
FenCore.Table.DeepCopy(tbl)             -- Deep copy
FenCore.Table.Merge(base, override)     -- Merge tables
FenCore.Table.Filter(tbl, predicate)    -- Filter by function
FenCore.Table.Map(tbl, transform)       -- Transform values

Environment

FenCore.Environment.IsRetail()          -- true if retail client
FenCore.Environment.IsClassic()         -- true if classic client
FenCore.Environment.GetExpansion()      -- "TWW", "Classic", etc.
FenCore.Environment.GetBuildInfo()      -- version, build, date

Best Practices

1. Use for Core layer - FenCore belongs in your addon's pure logic layer
2. Don't wrap unnecessarily - Call FenCore directly, don't create wrappers
3. Check domain first - Use fencore.search to find existing functions before writing your own
4. Prefer pure functions - If you need state, that belongs in Bridge layer