From 802efbca25cb92d8567761361b6513fd57e05578 Mon Sep 17 00:00:00 2001
From: metamuffin <metamuffin@disroot.org>
Date: Tue, 30 Aug 2022 16:54:57 +0200
Subject: basic syntax highlighting

---
 code/src/main.rs                     |  1 +
 code/src/markdown.rs                 | 10 +++++++---
 code/src/syntax_highlight/grammar.rs |  6 ++++++
 code/src/syntax_highlight/mod.rs     | 29 +++++++++++++++++++++++++++++
 code/src/syntax_highlight/theme.rs   |  6 ++++++
 5 files changed, 49 insertions(+), 3 deletions(-)
 create mode 100644 code/src/syntax_highlight/grammar.rs
 create mode 100644 code/src/syntax_highlight/mod.rs
 create mode 100644 code/src/syntax_highlight/theme.rs

(limited to 'code/src')

diff --git a/code/src/main.rs b/code/src/main.rs
index 0bd0169..c20d137 100644
--- a/code/src/main.rs
+++ b/code/src/main.rs
@@ -1,6 +1,7 @@
 pub mod atom;
 pub mod html;
 pub mod markdown;
+pub mod syntax_highlight;
 
 use atom::generate_atom;
 use clap::{Parser, Subcommand};
diff --git a/code/src/markdown.rs b/code/src/markdown.rs
index 5d98f83..22934c5 100644
--- a/code/src/markdown.rs
+++ b/code/src/markdown.rs
@@ -1,5 +1,6 @@
 use markdown::{Block, ListItem, Span};
 
+use crate::syntax_highlight::syntax_highlight;
 
 pub fn span_to_html(ss: Vec<Span>) -> String {
     let mut out = String::new();
@@ -28,8 +29,12 @@ pub fn blocks_to_html(blocks: Vec<Block>) -> String {
             }
             Block::Paragraph(p) => format!("<p>{}</p>", span_to_html(p)),
             Block::Blockquote(q) => format!("<quote>{}</quote>", blocks_to_html(q)),
-            Block::CodeBlock(_syntax, content) => {
-                format!("<pre>{}</pre>", escape(&content)) // TODO syntax highlighting
+            Block::CodeBlock(syntax, content) => {
+                if let Some(s) = &syntax {
+                    format!("<pre>{}</pre>", syntax_highlight(s, &content))
+                } else {
+                    format!("<pre>{}</pre>", escape(&content))
+                }
             }
             Block::OrderedList(els, _) => format!(
                 "<ol>{}</ol>",
@@ -74,4 +79,3 @@ pub fn escape(text: &str) -> String {
         .replace("'", "&#8217;")
         .replace("\"", "&quot;")
 }
-
diff --git a/code/src/syntax_highlight/grammar.rs b/code/src/syntax_highlight/grammar.rs
new file mode 100644
index 0000000..95417ab
--- /dev/null
+++ b/code/src/syntax_highlight/grammar.rs
@@ -0,0 +1,6 @@
+pub fn grammar_for(syntax: &str) -> &'static [(&'static [&'static str], &'static str)] {
+    match syntax {
+        "rs" => &[(&["fn", "pub", "async"], "keyword")],
+        _ => unreachable!(),
+    }
+}
diff --git a/code/src/syntax_highlight/mod.rs b/code/src/syntax_highlight/mod.rs
new file mode 100644
index 0000000..688b010
--- /dev/null
+++ b/code/src/syntax_highlight/mod.rs
@@ -0,0 +1,29 @@
+pub mod grammar;
+pub mod theme;
+
+use crate::{markdown::escape, syntax_highlight::theme::theme};
+use grammar::grammar_for;
+use synoptic::{Highlighter, Token};
+
+pub fn syntax_highlight(lang: &str, source: &str) -> String {
+    let mut h = Highlighter::new();
+    for (regex, kind) in grammar_for(lang) {
+        h.join(regex, kind).unwrap();
+    }
+    let highlighting = h.run(source);
+    let mut out = String::new();
+
+    for (_c, row) in highlighting.iter().enumerate() {
+        eprintln!("{row:?}");
+        for tok in row {
+            match tok {
+                Token::Start(kind) => out += &format!("<span style=\"color:{}\">", theme(kind)),
+                Token::Text(text) => out += &escape(text),
+                Token::End(_kind) => out += "</span>",
+            }
+        }
+        out += "\n"
+    }
+    eprintln!("{out:?}");
+    out
+}
diff --git a/code/src/syntax_highlight/theme.rs b/code/src/syntax_highlight/theme.rs
new file mode 100644
index 0000000..40434ad
--- /dev/null
+++ b/code/src/syntax_highlight/theme.rs
@@ -0,0 +1,6 @@
+pub fn theme(kind: &str) -> &'static str {
+    match kind {
+        "keyword" => "#9999ff",
+        _ => "#ff00ff",
+    }
+}
-- 
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