按自定义字段对Hakyll项目列表进行排序

---
title: My Project
date: 2022-01-01
author: John Doe
custom_field: 5
---

This is my project description.

import Hakyll

main :: IO ()
main = hakyll $ do
    -- 读取项目列表
    match "projects/*.md" $ do
        route $ setExtension "html"
        compile pandocCompiler

    -- 获取项目列表的元数据
    projects <- fmap (sortByField "custom_field") . recentFirst =<< loadAll "projects/*.md"

    -- 生成项目列表页面
    create ["projects.html"] $ do
        route idRoute
        compile $ do
            let context = listField "projects" defaultContext (return projects)
            makeItem ""
                >>= loadAndApplyTemplate "templates/projects.html" context
                >>= loadAndApplyTemplate "templates/default.html" defaultContext
                >>= relativizeUrls