rewrite the parser to produce an AST

Cargo.lock

@@ -23,6 +23,16 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "codespan-reporting"
+version = "0.11.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3538270d33cc669650c4b093848450d380def10c331d38c768e34cac80576e6e"
+dependencies = [
+ "termcolor",
+ "unicode-width",
+]
+
 [[package]]
 name = "cpufeatures"
 version = "0.2.9"
@@ -224,6 +234,15 @@ dependencies = [
  "unicode-ident",
 ]
 
+[[package]]
+name = "termcolor"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "be55cf8942feac5c765c2c993422806843c9a9a45d4d5c407ad6dd2ea95eb9b6"
+dependencies = [
+ "winapi-util",
+]
+
 [[package]]
 name = "thiserror"
 version = "1.0.47"
@@ -248,6 +267,7 @@ dependencies = [
 name = "treehouse-format"
 version = "0.1.0"
 dependencies = [
+ "log",
  "thiserror",
 ]
 
@@ -255,6 +275,7 @@ dependencies = [
 name = "treehouse-incubator"
 version = "0.1.0"
 dependencies = [
+ "codespan-reporting",
  "handlebars",
  "pulldown-cmark",
  "thiserror",
@@ -288,8 +309,45 @@ version = "1.0.11"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "301abaae475aa91687eb82514b328ab47a211a533026cb25fc3e519b86adfc3c"
 
+[[package]]
+name = "unicode-width"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c0edd1e5b14653f783770bce4a4dabb4a5108a5370a5f5d8cfe8710c361f6c8b"
+
 [[package]]
 name = "version_check"
 version = "0.9.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "49874b5167b65d7193b8aba1567f5c7d93d001cafc34600cee003eda787e483f"
+
+[[package]]
+name = "winapi"
+version = "0.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
+dependencies = [
+ "winapi-i686-pc-windows-gnu",
+ "winapi-x86_64-pc-windows-gnu",
+]
+
+[[package]]
+name = "winapi-i686-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
+
+[[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "70ec6ce85bb158151cae5e5c87f95a8e97d2c0c4b001223f33a334e3ce5de178"
+dependencies = [
+ "winapi",
+]
+
+[[package]]
+name = "winapi-x86_64-pc-windows-gnu"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"

Cargo.toml

@@ -3,4 +3,7 @@ members = ["crates/*"]
 resolver = "2"
 
 [workspace.dependencies]
+
+log = "0.4.20"
+
 treehouse-format = { path = "crates/treehouse-format" }

crates/treehouse-format/Cargo.toml

@@ -5,3 +5,4 @@ edition = "2021"
 
 [dependencies]
 thiserror = "1.0.47"
+log = { workspace = true }

crates/treehouse-format/src/ast.rs

@@ -0,0 +1,73 @@
+use std::ops::Range;
+
+use crate::{
+    pull::{BranchEvent, BranchKind, Parser},
+    ParseError, ParseErrorKind,
+};
+
+#[derive(Debug, Clone)]
+pub struct Roots {
+    pub branches: Vec<Branch>,
+}
+
+impl Roots {
+    pub fn parse(parser: &mut Parser) -> Result<Self, ParseError> {
+        let mut branches = vec![];
+        while let Some((branch, indent_level)) = Branch::parse_with_indent_level(parser)? {
+            if indent_level != 0 {
+                return Err(ParseErrorKind::RootIndentLevel.at(branch.kind_span));
+            }
+            branches.push(branch);
+        }
+        Ok(Self { branches })
+    }
+}
+
+#[derive(Debug, Clone)]
+pub struct Branch {
+    pub attributes: Range<usize>,
+    pub kind: BranchKind,
+    pub kind_span: Range<usize>,
+    pub content: Range<usize>,
+    pub children: Vec<Branch>,
+}
+
+impl From<BranchEvent> for Branch {
+    fn from(branch: BranchEvent) -> Self {
+        Self {
+            attributes: branch.attributes,
+            kind: branch.kind,
+            kind_span: branch.kind_span,
+            content: branch.content,
+            children: vec![],
+        }
+    }
+}
+
+impl Branch {
+    pub fn parse_with_indent_level(
+        parser: &mut Parser,
+    ) -> Result<Option<(Self, usize)>, ParseError> {
+        if let Some(branch_event) = parser.next_branch()? {
+            let own_indent_level = branch_event.indent_level;
+            let mut branch = Branch::from(branch_event);
+            let children_indent_level = parser.peek_indent_level();
+            if children_indent_level > own_indent_level {
+                while parser.peek_indent_level() == children_indent_level {
+                    if let Some(child) = Branch::parse(parser)? {
+                        branch.children.push(child);
+                    } else {
+                        break;
+                    }
+                }
+            }
+            Ok(Some((branch, own_indent_level)))
+        } else {
+            Ok(None)
+        }
+    }
+
+    pub fn parse(parser: &mut Parser) -> Result<Option<Self>, ParseError> {
+        Ok(Self::parse_with_indent_level(parser)?.map(|(branch, _)| branch))
+    }
+}

crates/treehouse-format/src/lib.rs

@@ -1,40 +1,15 @@
 use std::ops::Range;
 
-#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub mod ast;
-pub enum BranchKind {
+pub mod pull;
-    /// Expanded by default.
-    Expanded,
-    /// Folded by default.
-    Collapsed,
-}
-
-impl BranchKind {
-    pub fn char(&self) -> char {
-        match self {
-            BranchKind::Expanded => '-',
-            BranchKind::Collapsed => '+',
-        }
-    }
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Branch {
-    pub indent_level: usize,
-    pub config: Range<usize>,
-    pub kind: BranchKind,
-    pub content: Range<usize>,
-}
-
-#[derive(Debug, Clone, PartialEq, Eq)]
-pub struct Parser<'a> {
-    pub input: &'a str,
-    pub position: usize,
-}
 
 #[derive(Debug, thiserror::Error, Clone, PartialEq, Eq)]
 pub enum ParseErrorKind {
     #[error("branch kind (`+` or `-`) expected")]
     BranchKindExpected,
+
+    #[error("root branches must not be indented")]
+    RootIndentLevel,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, thiserror::Error)]
@@ -44,70 +19,8 @@ pub struct ParseError {
     pub range: Range<usize>,
 }
 
-impl<'a> Parser<'a> {
+impl ParseErrorKind {
-    fn current(&self) -> Option<char> {
+    pub fn at(self, range: Range<usize>) -> ParseError {
-        self.input[self.position..].chars().next()
+        ParseError { kind: self, range }
-    }
-
-    fn advance(&mut self) {
-        self.position += self.current().map(|c| c.len_utf8()).unwrap_or(0);
-    }
-
-    fn eat_as_long_as(&mut self, c: char) -> usize {
-        let mut count = 0;
-        while self.current() == Some(c) {
-            count += 1;
-            self.advance();
-        }
-        count
-    }
-
-    fn eat_until(&mut self, c: char) {
-        while self.current() != Some(c) {
-            self.advance();
-        }
-        self.advance();
-    }
-
-    pub fn next_branch(&mut self) -> Result<Option<Branch>, ParseError> {
-        if self.current().is_none() {
-            return Ok(None);
-        }
-
-        let indent_level = self.eat_as_long_as(' ');
-
-        // TODO: Configs
-        let config_start = self.position;
-        let config_end = self.position;
-
-        let branch_kind_start = self.position;
-        let branch_kind = match self.current() {
-            Some('-') => BranchKind::Expanded,
-            Some('+') => BranchKind::Collapsed,
-            _ => {
-                return Err(ParseError {
-                    kind: ParseErrorKind::BranchKindExpected,
-                    range: branch_kind_start..branch_kind_start + 1,
-                })
-            }
-        };
-        self.advance();
-
-        let content_start = self.position;
-        loop {
-            self.eat_until('\n');
-            if let Some('\n') | None = self.current() {
-                self.advance();
-                break;
-            }
-        }
-        let content_end = self.position;
-
-        Ok(Some(Branch {
-            indent_level,
-            config: config_start..config_end,
-            kind: branch_kind,
-            content: content_start..content_end,
-        }))
     }
 }

crates/treehouse-format/src/pull.rs

@@ -0,0 +1,107 @@
+use std::ops::Range;
+
+use crate::{ParseError, ParseErrorKind};
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum BranchKind {
+    /// Expanded by default.
+    Expanded,
+    /// Folded by default.
+    Collapsed,
+}
+
+impl BranchKind {
+    pub fn char(&self) -> char {
+        match self {
+            BranchKind::Expanded => '-',
+            BranchKind::Collapsed => '+',
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct BranchEvent {
+    pub indent_level: usize,
+    pub attributes: Range<usize>,
+    pub kind: BranchKind,
+    pub kind_span: Range<usize>,
+    pub content: Range<usize>,
+}
+
+#[derive(Debug, Clone, PartialEq, Eq)]
+pub struct Parser<'a> {
+    pub input: &'a str,
+    pub position: usize,
+}
+
+impl<'a> Parser<'a> {
+    fn current(&self) -> Option<char> {
+        self.input[self.position..].chars().next()
+    }
+
+    fn advance(&mut self) {
+        self.position += self.current().map(|c| c.len_utf8()).unwrap_or(0);
+    }
+
+    fn eat_as_long_as(&mut self, c: char) -> usize {
+        let mut count = 0;
+        while self.current() == Some(c) {
+            count += 1;
+            self.advance();
+        }
+        count
+    }
+
+    fn eat_until(&mut self, c: char) {
+        while self.current() != Some(c) {
+            self.advance();
+        }
+        self.advance();
+    }
+
+    pub fn peek_indent_level(&mut self) -> usize {
+        let position = self.position;
+        let indent_level = self.eat_as_long_as(' ');
+        self.position = position;
+        indent_level
+    }
+
+    pub fn next_branch(&mut self) -> Result<Option<BranchEvent>, ParseError> {
+        if self.current().is_none() {
+            return Ok(None);
+        }
+
+        let indent_level = self.eat_as_long_as(' ');
+
+        // TODO: Configs
+        let config_start = self.position;
+        let config_end = self.position;
+
+        let kind_start = self.position;
+        let kind = match self.current() {
+            Some('-') => BranchKind::Expanded,
+            Some('+') => BranchKind::Collapsed,
+            _ => return Err(ParseErrorKind::BranchKindExpected.at(kind_start..kind_start + 1)),
+        };
+        self.advance();
+        let kind_end = self.position;
+
+        let content_start = self.position;
+        loop {
+            self.eat_until('\n');
+            if let Some('\n') | None = self.current() {
+                self.advance();
+                break;
+            }
+        }
+        let content_end = self.position;
+
+        Ok(Some(BranchEvent {
+            indent_level,
+            attributes: config_start..config_end,
+            kind,
+            kind_span: kind_start..kind_end,
+            content: content_start..content_end,
+        }))
+    }
+}

crates/treehouse-incubator/Cargo.toml

@@ -4,6 +4,7 @@ version = "0.1.0"
 edition = "2021"
 
 [dependencies]
+codespan-reporting = "0.11.1"
 handlebars = "4.3.7"
 pulldown-cmark = { version = "0.9.3", default-features = false }
 thiserror = "1.0.47"

crates/treehouse-incubator/src/main.rs

@@ -1,6 +1,12 @@
-use tree_html::HtmlGenerator;
+use codespan_reporting::{
-
+    diagnostic::{Diagnostic, Label, LabelStyle, Severity},
-mod tree_html;
+    files::SimpleFile,
+    term::termcolor::{ColorChoice, StandardStream},
+};
+use treehouse_format::{
+    ast::{Branch, Roots},
+    pull::Parser,
+};
 
 #[derive(Debug, thiserror::Error)]
 enum Error {
@@ -11,35 +17,82 @@ enum Error {
     Parse(#[from] treehouse_format::ParseError),
 }
 
-fn main() -> Result<(), Box<dyn std::error::Error>> {
+fn print_branch(branch: &Branch, source: &str) {
-    let _ = std::fs::remove_dir_all("target/site");
+    fn inner(branch: &Branch, source: &str, indent_level: usize) {
-    std::fs::create_dir_all("target/site")?;
+        for _ in 0..indent_level {
-
-    let root_file = std::fs::read_to_string("content/tree/root.tree")?;
-
-    let mut parser = treehouse_format::Parser {
-        input: &root_file,
-        position: 0,
-    };
-    let mut generator = HtmlGenerator::default();
-    while let Some(branch) = parser.next_branch()? {
-        for _ in 0..branch.indent_level {
             print!("  ");
         }
         println!(
             "{} {:?}",
             branch.kind.char(),
-            &root_file[branch.content.clone()]
+            &source[branch.content.clone()]
         );
-        generator.add(&root_file, &branch);
+        for child in &branch.children {
+            inner(child, source, indent_level + 1);
         }
-    std::fs::write(
+    }
-        "target/site/index.html",
+    inner(branch, source, 0);
-        format!(
+}
-            "<!DOCTYPE html><html><head></head><body>{}</body></html>",
+
-            generator.finish()
+fn main() -> Result<(), Box<dyn std::error::Error>> {
-        ),
+    let _ = std::fs::remove_dir_all("target/site");
-    )?;
+    std::fs::create_dir_all("target/site")?;
+
+    let root_file = std::fs::read_to_string("content/tree/root.tree")?;
+    let parse_result = Roots::parse(&mut Parser {
+        input: &root_file,
+        position: 0,
+    });
+
+    match parse_result {
+        Ok(roots) => {
+            for root in &roots.branches {
+                print_branch(root, &root_file);
+            }
+        }
+        Err(error) => {
+            let writer = StandardStream::stderr(ColorChoice::Auto);
+            let config = codespan_reporting::term::Config::default();
+            let files = SimpleFile::new("root.tree", &root_file);
+            let diagnostic = Diagnostic {
+                severity: Severity::Error,
+                code: None,
+                message: error.kind.to_string(),
+                labels: vec![Label {
+                    style: LabelStyle::Primary,
+                    file_id: (),
+                    range: error.range,
+                    message: String::new(),
+                }],
+                notes: vec![],
+            };
+            codespan_reporting::term::emit(&mut writer.lock(), &config, &files, &diagnostic)?;
+        }
+    }
+
+    // let mut parser = treehouse_format::Parser {
+    //     input: &root_file,
+    //     position: 0,
+    // };
+    // let mut generator = HtmlGenerator::default();
+    // while let Some(branch) = parser.next_branch()? {
+    //     for _ in 0..branch.indent_level {
+    //         print!(" ");
+    //     }
+    //     println!(
+    //         "{} {:?}",
+    //         branch.kind.char(),
+    //         &root_file[branch.content.clone()]
+    //     );
+    //     generator.add(&root_file, &branch);
+    // }
+    // std::fs::write(
+    //     "target/site/index.html",
+    //     format!(
+    //         "<!DOCTYPE html><html><head></head><body>{}</body></html>",
+    //         generator.finish()
+    //     ),
+    // )?;
 
     Ok(())
 }

crates/treehouse-incubator/src/tree_html.rs

@@ -1,30 +0,0 @@
-use treehouse_format::Branch;
-
-#[derive(Debug, Clone, Default)]
-pub struct HtmlGenerator {
-    buffer: String,
-    indent_level_stack: Vec<usize>,
-}
-
-impl HtmlGenerator {
-    pub fn add(&mut self, source: &str, branch: &Branch) {
-        if Some(&branch.indent_level) > self.indent_level_stack.last() {
-            self.indent_level_stack.push(branch.indent_level);
-            self.buffer.push_str("<ul>");
-        }
-        while Some(&branch.indent_level) < self.indent_level_stack.last() {
-            self.indent_level_stack.pop();
-            self.buffer.push_str("</ul>");
-        }
-        self.buffer.push_str("<li>");
-        self.buffer.push_str(&source[branch.content.clone()]);
-        self.buffer.push_str("</li>");
-    }
-
-    pub fn finish(mut self) -> String {
-        for _ in self.indent_level_stack.drain(..) {
-            self.buffer.push_str("</ul>");
-        }
-        self.buffer
-    }
-}

static/index.hbs

@@ -1,13 +0,0 @@
-<!DOCTYPE html>
-
-<html>
-
-<head>
-    <title>{{ config.treehouse.title }}</title>
-</head>
-
-<body>
-    {{ tree }}
-</body>
-
-</html>

template/index.hbs

@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+
+<html>
+
+<head>
+    <title>{{ config.user.title }}</title>
+    <link rel="stylesheet" href="{{ local 'static/main.css' }}">
+</head>
+
+<body>
+    {{{ tree }}}
+</body>
+
+</html>

treehouse.toml

@@ -1,3 +1,5 @@
-[treehouse]
+# User settings go here. These are (string, string) key-value pairs.
+# They are available under `config.user`.
+[user]
 title = "treehouse"
 author = "liquidex"