Merge branch 'feat/cheddar-extensions'

This commit is contained in:
Vincent Ambo 2020-02-09 12:07:10 +00:00
commit 14b5447aac
2 changed files with 120 additions and 36 deletions

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@ -24,6 +24,9 @@ Twitter][].
challenges, before I ran out of interest
* `tools/blog_cli` contains my tool for writing new blog posts and storing them
in the DNS zone
* `tools/cheddar` contains a source code and Markdown rendering tool
that is integrated with my cgit instance to render files in various
views
* `ops/kms_pass.nix` is a tiny tool that emulates the user-interface of `pass`,
but actually uses Google Cloud KMS for secret decryption
* `ops/kontemplate` contains my Kubernetes resource templating tool (with which
@ -34,6 +37,9 @@ Twitter][].
* `nix/buildGo` implements a Nix library that can build Go software in the style
of Bazel's `rules_go`. Go programs in this repository are built using this
library.
* `nix/buildLisp` implements a Nix library that can build Common Lisp
software. Currently only SBCL is supported. Lisp programs in this
repository are built using this library.
* `tools/emacs-pkgs` contains various Emacs libraries that my Emacs setup uses,
for example:
* `dottime.el` provides [dottime][] in the Emacs modeline

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@ -1,6 +1,8 @@
use comrak::nodes::{AstNode, NodeValue, NodeHtmlBlock};
use comrak::arena_tree::Node;
use comrak::nodes::{Ast, AstNode, NodeValue, NodeCodeBlock, NodeHtmlBlock};
use comrak::{Arena, parse_document, format_html, ComrakOptions};
use lazy_static::lazy_static;
use std::cell::RefCell;
use std::env;
use std::ffi::OsStr;
use std::io::BufRead;
@ -104,9 +106,94 @@ fn iter_nodes<'a, F>(node: &'a AstNode<'a>, f: &F) where F : Fn(&'a AstNode<'a>)
// Instead, try finding a syntax match by comparing case insensitively (for
// ASCII characters, anyways).
fn find_syntax_case_insensitive(info: &str) -> Option<&'static SyntaxReference> {
// TODO(tazjin): memoize this lookup
SYNTAXES.syntaxes().iter().rev().find(|&s| info.eq_ignore_ascii_case(&s.name))
}
// Replaces code-block inside of a Markdown AST with HTML blocks rendered by
// syntect. This enables static (i.e. no JavaScript) syntax highlighting, even
// of complex languages.
fn highlight_code_block(code_block: &NodeCodeBlock) -> NodeValue {
let theme = &THEMES.themes["InspiredGitHub"];
let info = String::from_utf8_lossy(&code_block.info);
let syntax = find_syntax_case_insensitive(&info)
.or_else(|| SYNTAXES.find_syntax_by_extension(&info))
.unwrap_or_else(|| SYNTAXES.find_syntax_plain_text());
let code = String::from_utf8_lossy(&code_block.literal);
let rendered = {
// Write the block preamble manually to get exactly the
// desired layout:
let mut hl = HighlightLines::new(syntax, theme);
let mut buf = BLOCK_PRE.to_string();
for line in LinesWithEndings::from(&code) {
let regions = hl.highlight(line, &SYNTAXES);
append_highlighted_html_for_styled_line(
&regions[..], IncludeBackground::No, &mut buf,
);
}
buf.push_str("</pre>");
buf
};
let block = NodeHtmlBlock {
block_type: 1, // It's unclear what behaviour is toggled by this
literal: rendered.into_bytes(),
};
NodeValue::HtmlBlock(block)
}
// Supported callout elements (which each have their own distinct rendering):
enum Callout {
Todo,
Warning,
Question,
Tip,
}
// Determine whether the first child of the supplied node contains a text that
// should cause a callout section to be rendered.
fn has_callout<'a>(node: &Node<'a, RefCell<Ast>>) -> Option<Callout> {
match node.first_child().map(|c| c.data.borrow()) {
Some(child) => match &child.value {
NodeValue::Text(text) => {
if text.starts_with("TODO".as_bytes()) {
return Some(Callout::Todo)
} else if text.starts_with("WARNING".as_bytes()) {
return Some(Callout::Warning)
} else if text.starts_with("QUESTION".as_bytes()) {
return Some(Callout::Question)
} else if text.starts_with("TIP".as_bytes()) {
return Some(Callout::Tip)
}
return None
},
_ => return None,
},
_ => return None,
}
}
fn format_callout_paragraph(callout: Callout) -> NodeValue {
let class = match callout {
Callout::Todo => "cheddar-todo",
Callout::Warning => "cheddar-warning",
Callout::Question => "cheddar-question",
Callout::Tip => "cheddar-tip",
};
NodeValue::HtmlBlock(NodeHtmlBlock {
block_type: 1,
literal: format!("<p class=\"cheddar-callout {}\">", class).into_bytes(),
})
}
fn format_markdown() {
let document = {
let mut buffer = String::new();
@ -119,47 +206,38 @@ fn format_markdown() {
let arena = Arena::new();
let root = parse_document(&arena, &document, &MD_OPTS);
// This node must exist with a lifetime greater than that of the parsed AST
// in case that callouts are encountered (otherwise insertion into the tree
// is not possible).
let p_close = Node::new(RefCell::new(Ast {
start_line: 0, // TODO(tazjin): hrmm
content: vec![],
open: false,
last_line_blank: false,
value: NodeValue::HtmlBlock(NodeHtmlBlock {
block_type: 1,
literal: "</p>".as_bytes().to_vec(),
}),
}));
// Syntax highlighting is implemented by traversing the arena and
// replacing all code blocks with HTML blocks rendered by syntect.
iter_nodes(root, &|node| {
let mut ast = node.data.borrow_mut();
match &ast.value {
NodeValue::CodeBlock(code_block) => {
let theme = &THEMES.themes["InspiredGitHub"];
let info = String::from_utf8_lossy(&code_block.info);
let syntax = find_syntax_case_insensitive(&info)
.or_else(|| SYNTAXES.find_syntax_by_extension(&info))
.unwrap_or_else(|| SYNTAXES.find_syntax_plain_text());
let code = String::from_utf8_lossy(&code_block.literal);
let rendered = {
// Write the block preamble manually to get exactly the
// desired layout:
let mut hl = HighlightLines::new(syntax, theme);
let mut buf = BLOCK_PRE.to_string();
for line in LinesWithEndings::from(&code) {
let regions = hl.highlight(line, &SYNTAXES);
append_highlighted_html_for_styled_line(
&regions[..], IncludeBackground::No, &mut buf,
);
}
buf.push_str("</pre>");
buf
};
let block = NodeHtmlBlock {
block_type: 1, // It's unclear what behaviour is toggled by this
literal: rendered.into_bytes(),
};
ast.value = NodeValue::HtmlBlock(block);
let new = match &ast.value {
NodeValue::CodeBlock(code) => Some(highlight_code_block(code)),
NodeValue::Paragraph => if let Some(callout) = has_callout(node) {
node.insert_after(&p_close);
Some(format_callout_paragraph(callout))
} else {
None
},
_ => (),
_ => None,
};
if let Some(new_value) = new {
ast.value = new_value
}
});
format_html(root, &MD_OPTS, &mut io::stdout())