Prettify peeking and rearrange syntax/parsing modules 🧶

1 files changed, 0 insertions, 726 deletions

diff --git a/src/parsing/mod.rs b/src/parsing/mod.rs
deleted file mode 100644
index 36920595..00000000
--- a/src/parsing/mod.rs
+++ /dev/null
@@ -1,726 +0,0 @@
-//! Parsing of source code into token streams and syntax trees.
-
-use std::collections::HashMap;
-
-use unicode_xid::UnicodeXID;
-
-use crate::func::{Function, Scope};
-use crate::size::Size;
-use crate::syntax::*;
-
-mod tokens;
-
-pub use tokens::{tokenize, Tokens};
-
-/// Parses source code into a syntax tree given a context.
-#[inline]
-pub fn parse(src: &str, ctx: ParseContext) -> ParseResult<SyntaxTree> {
-    Parser::new(src, ctx).parse()
-}
-
-/// The context for parsing.
-#[derive(Debug, Copy, Clone)]
-pub struct ParseContext<'a> {
-    /// The scope containing function definitions.
-    pub scope: &'a Scope,
-}
-
-/// Transforms token streams to syntax trees.
-#[derive(Debug)]
-struct Parser<'s> {
-    src: &'s str,
-    tokens: PeekableTokens<'s>,
-    state: ParserState,
-    ctx: ParseContext<'s>,
-    tree: SyntaxTree,
-}
-
-/// The state the parser is in.
-#[derive(Debug, Copy, Clone, Eq, PartialEq)]
-enum ParserState {
-    /// The base state of the parser.
-    Body,
-    /// We saw one newline already.
-    FirstNewline,
-    /// We wrote a newline.
-    WroteNewline,
-}
-
-impl<'s> Parser<'s> {
-    /// Create a new parser from the source and the context.
-    fn new(src: &'s str, ctx: ParseContext<'s>) -> Parser<'s> {
-        Parser {
-            src,
-            tokens: PeekableTokens::new(tokenize(src)),
-            state: ParserState::Body,
-            ctx,
-            tree: SyntaxTree::new(),
-        }
-    }
-
-    /// Parse the source into an abstract syntax tree.
-    fn parse(mut self) -> ParseResult<SyntaxTree> {
-        // Loop through all the tokens.
-        while self.tokens.peek().is_some() {
-            self.parse_white()?;
-            self.parse_body_part()?;
-        }
-
-        Ok(self.tree)
-    }
-
-    /// Parse the next part of the body.
-    fn parse_body_part(&mut self) -> ParseResult<()> {
-        if let Some(token) = self.tokens.peek() {
-            match token {
-                // Functions
-                Token::LeftBracket => self.parse_func()?,
-                Token::RightBracket => return Err(ParseError::new("unexpected closing bracket")),
-
-                // Modifiers
-                Token::Underscore => self.append_consumed(Node::ToggleItalics),
-                Token::Star => self.append_consumed(Node::ToggleBold),
-                Token::Backtick => self.append_consumed(Node::ToggleMonospace),
-
-                // Normal text
-                Token::Text(word) => self.append_consumed(Node::Text(word.to_owned())),
-
-                Token::Colon | Token::Equals => panic!("bad token for body: {:?}", token),
-
-                // The rest is handled elsewhere or should not happen, because `Tokens` does not
-                // yield colons or equals in the body, but their text equivalents instead.
-                _ => panic!("unexpected token: {:?}", token),
-            }
-        }
-        Ok(())
-    }
-
-    /// Parse a complete function from the current position.
-    fn parse_func(&mut self) -> ParseResult<()> {
-        // This should only be called if a left bracket was seen.
-        assert!(self.tokens.next() == Some(Token::LeftBracket));
-
-        let header = self.parse_func_header()?;
-        let body = self.parse_func_body(&header)?;
-
-        // Finally this function is parsed to the end.
-        self.append(Node::Func(FuncCall { header, body }));
-
-        Ok(self.switch(ParserState::Body))
-    }
-
-    /// Parse a function header.
-    fn parse_func_header(&mut self) -> ParseResult<FuncHeader> {
-        // The next token should be the name of the function.
-        self.skip_white();
-        let name = match self.tokens.next() {
-            Some(Token::Text(word)) => {
-                if is_identifier(word) {
-                    Ok(word.to_owned())
-                } else {
-                    Err(ParseError::new(format!("invalid identifier: '{}'", word)))
-                }
-            }
-            _ => Err(ParseError::new("expected identifier")),
-        }?;
-
-        let mut header = FuncHeader {
-            name,
-            args: vec![],
-            kwargs: HashMap::new(),
-        };
-
-        self.skip_white();
-
-        // Check for arguments
-        match self.tokens.next() {
-            Some(Token::RightBracket) => {}
-            Some(Token::Colon) => {
-                let (args, kwargs) = self.parse_func_args()?;
-                header.args = args;
-                header.kwargs = kwargs;
-            }
-            _ => {
-                return Err(ParseError::new(
-                    "expected function arguments or closing bracket",
-                ))
-            }
-        }
-
-        // Store the header information of the function invocation.
-        Ok(header)
-    }
-
-    /// Parse the arguments to a function.
-    fn parse_func_args(&mut self) -> ParseResult<(Vec<Expression>, HashMap<String, Expression>)> {
-        let mut args = Vec::new();
-        let kwargs = HashMap::new();
-
-        let mut comma = false;
-        loop {
-            self.skip_white();
-
-            match self.tokens.peek() {
-                Some(Token::Text(_)) | Some(Token::Quoted(_)) if !comma => {
-                    args.push(self.parse_expression()?);
-                    comma = true;
-                }
-
-                Some(Token::Comma) if comma => {
-                    self.advance();
-                    comma = false
-                }
-                Some(Token::RightBracket) => {
-                    self.advance();
-                    break;
-                }
-
-                _ if comma => return Err(ParseError::new("expected comma or closing bracket")),
-                _ => return Err(ParseError::new("expected closing bracket")),
-            }
-        }
-
-        Ok((args, kwargs))
-    }
-
-    /// Parse an expression.
-    fn parse_expression(&mut self) -> ParseResult<Expression> {
-        Ok(match self.tokens.next() {
-            Some(Token::Quoted(text)) => Expression::Str(text.to_owned()),
-            Some(Token::Text(text)) => {
-                if let Ok(b) = text.parse::<bool>() {
-                    Expression::Bool(b)
-                } else if let Ok(num) = text.parse::<f64>() {
-                    Expression::Number(num)
-                } else if let Ok(size) = text.parse::<Size>() {
-                    Expression::Size(size)
-                } else {
-                    Expression::Ident(text.to_owned())
-                }
-            }
-            _ => return Err(ParseError::new("expected expression")),
-        })
-    }
-
-    /// Parse the body of a function.
-    fn parse_func_body(&mut self, header: &FuncHeader) -> ParseResult<Box<dyn Function>> {
-        // Whether the function has a body.
-        let has_body = self.tokens.peek() == Some(Token::LeftBracket);
-        if has_body {
-            self.advance();
-        }
-
-        // Now we want to parse this function dynamically.
-        let parser = self
-            .ctx
-            .scope
-            .get_parser(&header.name)
-            .ok_or_else(|| ParseError::new(format!("unknown function: '{}'", &header.name)))?;
-
-        // Do the parsing dependent on whether the function has a body.
-        Ok(if has_body {
-            // Find out the string which makes the body of this function.
-            let (start, end) = self
-                .tokens
-                .current_index()
-                .and_then(|index| {
-                    find_closing_bracket(&self.src[index..]).map(|end| (index, index + end))
-                })
-                .ok_or_else(|| ParseError::new("expected closing bracket"))?;
-
-            // Parse the body.
-            let body_string = &self.src[start..end];
-            let body = parser(&header, Some(body_string), self.ctx)?;
-
-            // Skip to the end of the function in the token stream.
-            self.tokens.goto(end);
-
-            // Now the body should be closed.
-            assert!(self.tokens.next() == Some(Token::RightBracket));
-
-            body
-        } else {
-            parser(&header, None, self.ctx)?
-        })
-    }
-
-    /// Parse whitespace (as long as there is any) and skip over comments.
-    fn parse_white(&mut self) -> ParseResult<()> {
-        while let Some(token) = self.tokens.peek() {
-            match self.state {
-                ParserState::FirstNewline => match token {
-                    Token::Newline => {
-                        self.append_consumed(Node::Newline);
-                        self.switch(ParserState::WroteNewline);
-                    }
-                    Token::Space => self.append_space_consumed(),
-                    _ => {
-                        self.append_space();
-                        self.switch(ParserState::Body);
-                    }
-                },
-                ParserState::WroteNewline => match token {
-                    Token::Newline | Token::Space => self.append_space_consumed(),
-                    _ => self.switch(ParserState::Body),
-                },
-                ParserState::Body => match token {
-                    // Whitespace
-                    Token::Space => self.append_space_consumed(),
-                    Token::Newline => {
-                        self.advance();
-                        self.switch(ParserState::FirstNewline);
-                    }
-
-                    // Comments
-                    Token::LineComment(_) | Token::BlockComment(_) => self.advance(),
-                    Token::StarSlash => {
-                        return Err(ParseError::new("unexpected end of block comment"));
-                    }
-
-                    // Anything else skips out of the function.
-                    _ => break,
-                },
-            }
-        }
-
-        Ok(())
-    }
-
-    /// Skip over whitespace and comments.
-    fn skip_white(&mut self) {
-        while let Some(token) = self.tokens.peek() {
-            match token {
-                Token::Space | Token::Newline | Token::LineComment(_) | Token::BlockComment(_) => {
-                    self.advance()
-                }
-                _ => break,
-            }
-        }
-    }
-
-    /// Advance the iterator by one step.
-    fn advance(&mut self) {
-        self.tokens.next();
-    }
-
-    /// Switch the state.
-    fn switch(&mut self, state: ParserState) {
-        self.state = state;
-    }
-
-    /// Append a node to the tree.
-    fn append(&mut self, node: Node) {
-        self.tree.nodes.push(node);
-    }
-
-    /// Append a space if there is not one already.
-    fn append_space(&mut self) {
-        if self.tree.nodes.last() != Some(&Node::Space) {
-            self.append(Node::Space);
-        }
-    }
-
-    /// Advance and return the given node.
-    fn append_consumed(&mut self, node: Node) {
-        self.advance();
-        self.append(node);
-    }
-
-    /// Advance and append a space if there is not one already.
-    fn append_space_consumed(&mut self) {
-        self.advance();
-        self.append_space();
-    }
-}
-
-/// Find the index of the first unbalanced and unescaped closing bracket.
-fn find_closing_bracket(src: &str) -> Option<usize> {
-    let mut parens = 0;
-    let mut escaped = false;
-    for (index, c) in src.char_indices() {
-        match c {
-            '\\' => {
-                escaped = !escaped;
-                continue;
-            }
-            ']' if !escaped && parens == 0 => return Some(index),
-            '[' if !escaped => parens += 1,
-            ']' if !escaped => parens -= 1,
-            _ => {}
-        }
-        escaped = false;
-    }
-    None
-}
-
-/// A peekable iterator for tokens which allows access to the original iterator
-/// inside this module (which is needed by the parser).
-#[derive(Debug, Clone)]
-struct PeekableTokens<'s> {
-    tokens: Tokens<'s>,
-    peeked: Option<Option<Token<'s>>>,
-}
-
-impl<'s> PeekableTokens<'s> {
-    /// Create a new iterator from a string.
-    fn new(tokens: Tokens<'s>) -> PeekableTokens<'s> {
-        PeekableTokens {
-            tokens,
-            peeked: None,
-        }
-    }
-
-    /// Peek at the next element.
-    fn peek(&mut self) -> Option<Token<'s>> {
-        let iter = &mut self.tokens;
-        *self.peeked.get_or_insert_with(|| iter.next())
-    }
-
-    /// The index of the first character of the next token in the source string.
-    fn current_index(&mut self) -> Option<usize> {
-        self.tokens.chars.current_index()
-    }
-
-    /// Go to a new position in the underlying string.
-    fn goto(&mut self, index: usize) {
-        self.tokens.chars.goto(index);
-        self.peeked = None;
-    }
-}
-
-impl<'s> Iterator for PeekableTokens<'s> {
-    type Item = Token<'s>;
-
-    fn next(&mut self) -> Option<Token<'s>> {
-        match self.peeked.take() {
-            Some(value) => value,
-            None => self.tokens.next(),
-        }
-    }
-}
-
-/// Whether this word is a valid unicode identifier.
-fn is_identifier(string: &str) -> bool {
-    let mut chars = string.chars();
-
-    match chars.next() {
-        Some(c) if c != '.' && !UnicodeXID::is_xid_start(c) => return false,
-        None => return false,
-        _ => (),
-    }
-
-    while let Some(c) = chars.next() {
-        if c != '.' && !UnicodeXID::is_xid_continue(c) {
-            return false;
-        }
-    }
-
-    true
-}
-
-/// The error type for parsing.
-pub struct ParseError(String);
-
-/// The result type for parsing.
-pub type ParseResult<T> = Result<T, ParseError>;
-
-impl ParseError {
-    /// Create a new parse error with a message.
-    pub fn new<S: Into<String>>(message: S) -> ParseError {
-        ParseError(message.into())
-    }
-}
-
-error_type! {
-    err: ParseError,
-    show: f => f.write_str(&err.0),
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use crate::func::{CommandList, Function, Scope};
-    use crate::layout::{LayoutContext, LayoutResult};
-    use funcs::*;
-    use Node::{Func as F, Newline as N, Space as S};
-
-    /// Two test functions, one which parses it's body as another syntax tree
-    /// and another one which does not expect a body.
-    mod funcs {
-        use super::*;
-
-        /// A testing function which just parses it's body into a syntax tree.
-        #[derive(Debug, PartialEq)]
-        pub struct TreeFn(pub SyntaxTree);
-
-        impl Function for TreeFn {
-            fn parse(_: &FuncHeader, body: Option<&str>, ctx: ParseContext) -> ParseResult<Self>
-            where Self: Sized {
-                if let Some(src) = body {
-                    parse(src, ctx).map(|tree| TreeFn(tree))
-                } else {
-                    Err(ParseError::new("expected body for tree fn"))
-                }
-            }
-
-            fn layout(&self, _: LayoutContext) -> LayoutResult<CommandList> {
-                Ok(CommandList::new())
-            }
-        }
-
-        /// A testing function without a body.
-        #[derive(Debug, PartialEq)]
-        pub struct BodylessFn;
-
-        impl Function for BodylessFn {
-            fn parse(_: &FuncHeader, body: Option<&str>, _: ParseContext) -> ParseResult<Self>
-            where Self: Sized {
-                if body.is_none() {
-                    Ok(BodylessFn)
-                } else {
-                    Err(ParseError::new("unexpected body for bodyless fn"))
-                }
-            }
-
-            fn layout(&self, _: LayoutContext) -> LayoutResult<CommandList> {
-                Ok(CommandList::new())
-            }
-        }
-    }
-
-    /// Test if the source code parses into the syntax tree.
-    fn test(src: &str, tree: SyntaxTree) {
-        let ctx = ParseContext {
-            scope: &Scope::new(),
-        };
-        assert_eq!(parse(src, ctx).unwrap(), tree);
-    }
-
-    /// Test with a scope containing function definitions.
-    fn test_scoped(scope: &Scope, src: &str, tree: SyntaxTree) {
-        let ctx = ParseContext { scope };
-        assert_eq!(parse(src, ctx).unwrap(), tree);
-    }
-
-    /// Test if the source parses into the error.
-    fn test_err(src: &str, err: &str) {
-        let ctx = ParseContext {
-            scope: &Scope::new(),
-        };
-        assert_eq!(parse(src, ctx).unwrap_err().to_string(), err);
-    }
-
-    /// Test with a scope if the source parses into the error.
-    fn test_err_scoped(scope: &Scope, src: &str, err: &str) {
-        let ctx = ParseContext { scope };
-        assert_eq!(parse(src, ctx).unwrap_err().to_string(), err);
-    }
-
-    /// Create a text node.
-    #[allow(non_snake_case)]
-    fn T(s: &str) -> Node {
-        Node::Text(s.to_owned())
-    }
-
-    /// Shortcut macro to create a syntax tree. Is `vec`-like and the elements
-    /// are the nodes.
-    macro_rules! tree {
-        ($($x:expr),*) => (
-            SyntaxTree { nodes: vec![$($x),*] }
-        );
-        ($($x:expr,)*) => (tree![$($x),*])
-    }
-
-    /// Shortcut macro to create a function.
-    macro_rules! func {
-        (name => $name:expr, body => None $(,)*) => {
-            func!(@$name, Box::new(BodylessFn))
-        };
-        (name => $name:expr, body => $tree:expr $(,)*) => {
-            func!(@$name, Box::new(TreeFn($tree)))
-        };
-        (@$name:expr, $body:expr) => {
-            FuncCall {
-                header: FuncHeader {
-                    name: $name.to_string(),
-                    args: vec![],
-                    kwargs: HashMap::new(),
-                },
-                body: $body,
-            }
-        }
-    }
-
-    /// Parse the basic cases.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_base() {
-        test("", tree! []);
-        test("Hello World!", tree! [ T("Hello"), S, T("World!") ]);
-    }
-
-    /// Test whether newlines generate the correct whitespace.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_newlines_whitespace() {
-        test("Hello\nWorld", tree! [ T("Hello"), S, T("World") ]);
-        test("Hello \n World", tree! [ T("Hello"), S, T("World") ]);
-        test("Hello\n\nWorld", tree! [ T("Hello"), N, T("World") ]);
-        test("Hello \n\nWorld", tree! [ T("Hello"), S, N, T("World") ]);
-        test("Hello\n\n  World", tree! [ T("Hello"), N, S, T("World") ]);
-        test("Hello \n \n \n  World", tree! [ T("Hello"), S, N, S, T("World") ]);
-        test("Hello\n \n\n  World", tree! [ T("Hello"), S, N, S, T("World") ]);
-    }
-
-    /// Parse things dealing with functions.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_functions() {
-        let mut scope = Scope::new();
-        scope.add::<BodylessFn>("test");
-        scope.add::<BodylessFn>("end");
-        scope.add::<TreeFn>("modifier");
-        scope.add::<TreeFn>("func");
-
-        test_scoped(&scope,"[test]", tree! [ F(func! { name => "test", body => None }) ]);
-        test_scoped(&scope,"[ test]", tree! [ F(func! { name => "test", body => None }) ]);
-        test_scoped(&scope, "This is an [modifier][example] of a function invocation.", tree! [
-            T("This"), S, T("is"), S, T("an"), S,
-            F(func! { name => "modifier", body => tree! [ T("example") ] }), S,
-            T("of"), S, T("a"), S, T("function"), S, T("invocation.")
-        ]);
-        test_scoped(&scope, "[func][Hello][modifier][Here][end]",  tree! [
-            F(func! { name => "func", body => tree! [ T("Hello") ] }),
-            F(func! { name => "modifier", body => tree! [ T("Here") ] }),
-            F(func! { name => "end", body => None }),
-        ]);
-        test_scoped(&scope, "[func][]", tree! [ F(func! { name => "func", body => tree! [] }) ]);
-        test_scoped(&scope, "[modifier][[func][call]] outside", tree! [
-            F(func! {
-                name => "modifier",
-                body => tree! [ F(func! { name => "func", body => tree! [ T("call") ] }) ],
-            }),
-            S, T("outside")
-        ]);
-
-    }
-
-    /// Parse functions with arguments.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_function_args() {
-        use Expression::{Number as N, Size as Z, Bool as B};
-
-        #[allow(non_snake_case)]
-        fn S(string: &str) -> Expression { Expression::Str(string.to_owned()) }
-        #[allow(non_snake_case)]
-        fn I(string: &str) -> Expression { Expression::Ident(string.to_owned()) }
-
-        fn func(name: &str, args: Vec<Expression>) -> SyntaxTree {
-            tree! [
-                F(FuncCall {
-                    header: FuncHeader {
-                        name: name.to_string(),
-                        args,
-                        kwargs: HashMap::new(),
-                    },
-                    body: Box::new(BodylessFn)
-                })
-            ]
-        }
-
-        let mut scope = Scope::new();
-        scope.add::<BodylessFn>("align");
-
-        test_scoped(&scope, "[align: left]", func("align", vec![I("left")]));
-        test_scoped(&scope, "[align: left,right]", func("align", vec![I("left"), I("right")]));
-        test_scoped(&scope, "[align: left, right]", func("align", vec![I("left"), I("right")]));
-        test_scoped(&scope, "[align: \"hello\"]", func("align", vec![S("hello")]));
-        test_scoped(&scope, r#"[align: "hello\"world"]"#, func("align", vec![S(r#"hello\"world"#)]));
-        test_scoped(&scope, "[align: 12]", func("align", vec![N(12.0)]));
-        test_scoped(&scope, "[align: 17.53pt]", func("align", vec![Z(Size::pt(17.53))]));
-        test_scoped(&scope, "[align: 2.4in]", func("align", vec![Z(Size::inches(2.4))]));
-        test_scoped(&scope, "[align: true, 10mm, left, \"hi, there\"]",
-            func("align", vec![B(true), Z(Size::mm(10.0)), I("left"), S("hi, there")]));
-    }
-
-    /// Parse comments (line and block).
-    #[test]
-    #[rustfmt::skip]
-    fn parse_comments() {
-        let mut scope = Scope::new();
-        scope.add::<BodylessFn>("test");
-        scope.add::<TreeFn>("func");
-
-        test_scoped(&scope, "Text\n// Comment\n More text",
-            tree! [ T("Text"), S, T("More"), S, T("text") ]);
-        test_scoped(&scope, "[test/*world*/]",
-            tree! [ F(func! { name => "test", body => None }) ]);
-        test_scoped(&scope, "[test/*]*/]",
-            tree! [ F(func! { name => "test", body => None }) ]);
-    }
-
-    /// Test if escaped, but unbalanced parens are correctly parsed.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_unbalanced_body_parens() {
-        let mut scope = Scope::new();
-        scope.add::<TreeFn>("code");
-
-        test_scoped(&scope, r"My [code][Close \]] end", tree! [
-            T("My"), S, F(func! {
-                name => "code",
-                body => tree! [ T("Close"), S, T("]") ]
-            }), S, T("end")
-        ]);
-        test_scoped(&scope, r"My [code][\[ Open] end", tree! [
-            T("My"), S, F(func! {
-                name => "code",
-                body => tree! [ T("["), S, T("Open") ]
-            }), S, T("end")
-        ]);
-        test_scoped(&scope, r"My [code][Open \]  and  \[ close]end", tree! [
-            T("My"), S, F(func! {
-                name => "code",
-                body => tree! [ T("Open"), S, T("]"), S, T("and"), S, T("["), S, T("close") ]
-            }), T("end")
-        ]);
-    }
-
-    /// Tests if the parser handles non-ASCII stuff correctly.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_unicode() {
-        let mut scope = Scope::new();
-        scope.add::<BodylessFn>("func");
-        scope.add::<TreeFn>("bold");
-
-        test_scoped(&scope, "[func] ⺐.", tree! [
-            F(func! {
-                name => "func",
-                body => None,
-            }),
-            S, T("⺐.")
-        ]);
-        test_scoped(&scope, "[bold][Hello 🌍!]", tree! [
-            F(func! {
-                name => "bold",
-                body => tree! [ T("Hello"), S, T("🌍!") ],
-            })
-        ]);
-    }
-
-    /// Tests whether errors get reported correctly.
-    #[test]
-    #[rustfmt::skip]
-    fn parse_errors() {
-        let mut scope = Scope::new();
-        scope.add::<TreeFn>("hello");
-
-        test_err("No functions here]", "unexpected closing bracket");
-        test_err_scoped(&scope, "[hello][world", "expected closing bracket");
-        test_err("[hello world", "expected function arguments or closing bracket");
-        test_err("[ no-name][Why?]", "invalid identifier: 'no-name'");
-        test_err("Hello */", "unexpected end of block comment");
-    }
-}