bookshelf-doc/DocGen4/ToHtmlFormat.lean

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/-
Copyright (c) 2021 Wojciech Nawrocki. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Wojciech Nawrocki, Sebastian Ullrich, Henrik Böving
-/
import Lean.Data.Json
import Lean.Parser
/-! This module defines:
- a representation of HTML trees
- together with a JSX-like DSL for writing them
- and widget support for visualizing any type as HTML. -/
namespace DocGen4
open Lean
inductive Html where
-- TODO(WN): it's nameless for shorter JSON; re-add names when we have deriving strategies for From/ToJson
-- element (tag : String) (flatten : Bool) (attrs : Array HtmlAttribute) (children : Array Html)
| element : String → Bool → Array (String × String) → Array Html → Html
| text : String → Html
deriving Repr, BEq, Inhabited, FromJson, ToJson
instance : Coe String Html :=
⟨Html.text⟩
namespace Html
def attributesToString (attrs : Array (String × String)) :String :=
attrs.foldl (λ acc (k, v) => acc ++ " " ++ k ++ "=\"" ++ v ++ "\"") ""
-- TODO: Termination proof
partial def toStringAux : Html → String
| element tag false attrs #[text s] => s!"<{tag}{attributesToString attrs}>{s}</{tag}>\n"
| element tag false attrs #[child] => s!"<{tag}{attributesToString attrs}>\n{child.toStringAux}</{tag}>\n"
| element tag false attrs children => s!"<{tag}{attributesToString attrs}>\n{children.foldl (· ++ toStringAux ·) ""}</{tag}>\n"
| element tag true attrs children => s!"<{tag}{attributesToString attrs}>{children.foldl (· ++ toStringAux ·) ""}</{tag}>"
| text s => s
def toString (html : Html) : String :=
html.toStringAux.trimRight
instance : ToString Html :=
⟨toString⟩
end Html
namespace Jsx
open Parser PrettyPrinter
declare_syntax_cat jsxElement
declare_syntax_cat jsxChild
2021-12-17 14:59:33 +00:00
def jsxAttrVal : Parser := strLit <|> group ("{" >> termParser >> "}")
def jsxAttr : Parser := ident >> "=" >> jsxAttrVal
-- JSXTextCharacter : SourceCharacter but not one of {, <, > or }
def jsxText : Parser :=
withAntiquot (mkAntiquot "jsxText" `jsxText) {
fn := fun c s =>
let startPos := s.pos
let s := takeWhile1Fn (not ∘ "[{<>}]$".contains) "expected JSX text" c s
mkNodeToken `jsxText startPos c s }
@[combinatorFormatter DocGen4.Jsx.jsxText] def jsxText.formatter : Formatter := pure ()
@[combinatorParenthesizer DocGen4.Jsx.jsxText] def jsxText.parenthesizer : Parenthesizer := pure ()
scoped syntax "<" ident jsxAttr* "/>" : jsxElement
scoped syntax "<" ident jsxAttr* ">" jsxChild* "</" ident ">" : jsxElement
scoped syntax jsxText : jsxChild
scoped syntax "{" term "}" : jsxChild
scoped syntax "[" term "]" : jsxChild
scoped syntax jsxElement : jsxChild
scoped syntax:max jsxElement : term
macro_rules
| `(<$n $[$ns = $vs]* />) =>
let ns := ns.map (quote <| toString ·.getId)
let vs := vs.map fun
| `(jsxAttrVal| $s:strLit) => s
| `(jsxAttrVal| { $t:term }) => t
| _ => unreachable!
`(Html.element $(quote <| toString n.getId) false #[ $[($ns, $vs)],* ] #[])
| `(<$n $[$ns = $vs]* >$cs*</$m>) =>
if n.getId == m.getId then do
let ns := ns.map (quote <| toString ·.getId)
let vs := vs.map fun
| `(jsxAttrVal| $s:strLit) => s
| `(jsxAttrVal| { $t:term }) => t
| _ => unreachable!
let cs ← cs.mapM fun
| `(jsxChild|$t:jsxText) => `(#[Html.text $(quote t[0].getAtomVal!)])
-- TODO(WN): elab as list of children if type is `t Html` where `Foldable t`
| `(jsxChild|{$t}) => `(#[$t])
| `(jsxChild|[$t]) => `($t)
| `(jsxChild|$e:jsxElement) => `(#[$e:jsxElement])
| _ => unreachable!
let tag := toString n.getId
`(Html.element $(quote tag) false #[ $[($ns, $vs)],* ] (Array.foldl Array.append #[] #[ $[$cs],* ]))
else Macro.throwError ("expected </" ++ toString n.getId ++ ">")
end Jsx
/-- A type which implements `ToHtmlFormat` will be visualized
as the resulting HTML in editors which support it. -/
class ToHtmlFormat (α : Type u) where
formatHtml : α → Html
end DocGen4