Remove stack from parser ♻

3 files changed, 103 insertions, 111 deletions

diff --git a/src/func.rs b/src/func.rs
index cbc2f58b..d85d7a18 100644
--- a/src/func.rs
+++ b/src/func.rs
@@ -3,37 +3,67 @@
 use std::any::Any;
 use std::collections::HashMap;
 use std::fmt::Debug;
+
 use crate::syntax::{Token, FuncHeader, Expression};
-use crate::parsing::ParseError;
+use crate::parsing::ParseResult;
 
 
 /// An optional iterator over the tokens of a function body.
 pub type BodyTokens<'a> = Option<Box<dyn Iterator<Item=Token<'a>> + 'a>>;
 
+/// Parser functions.
+pub type ParseFunc = dyn Fn(&FuncHeader, BodyTokens<'_>, &Scope)
+                         -> ParseResult<Box<dyn Function>>;
 
 /// Types that act as functions.
 ///
 /// These types have to be able to parse tokens into themselves and store the
 /// relevant information from the parsing to do their role in typesetting later.
 ///
-/// `FunctionRequirements` is automatically implemented for types which
-/// can be used as functions, that is they fulfill the bounds
-/// `Debug + PartialEq + 'static`.
-pub trait Function: FunctionRequirements + 'static {
+/// The trait `FunctionBounds` is automatically implemented for types which can be
+/// used as functions, that is they fulfill the bounds  `Debug + PartialEq + 'static`.
+pub trait Function: FunctionBounds {
     /// Parse the function.
     fn parse(header: &FuncHeader, tokens: BodyTokens<'_>, scope: &Scope)
-    -> Result<Self, ParseError> where Self: Sized;
+    -> ParseResult<Self> where Self: Sized;
 
     /// Execute the function and optionally yield a return value.
     fn typeset(&self, header: &FuncHeader) -> Option<Expression>;
 }
 
-/// A helper trait that describes requirements for types implement [`Function`].
+/// A map from identifiers to functions.
+pub struct Scope {
+    parsers: HashMap<String, Box<ParseFunc>>,
+}
+
+impl Scope {
+    /// Create a new empty scope.
+    pub fn new() -> Scope {
+        Scope { parsers: HashMap::new() }
+    }
+
+    /// Add a function type to the scope with a given name.
+    pub fn add<F: Function + 'static>(&mut self, name: &str) {
+        self.parsers.insert(
+            name.to_owned(),
+            Box::new(|header, tokens, scope| match F::parse(header, tokens, scope) {
+                Ok(func) => Ok(Box::new(func)),
+                Err(err) => Err(err),
+            })
+        );
+    }
+
+    /// Return the parser with the given name if there is one.
+    pub fn get_parser(&self, name: &str) -> Option<&ParseFunc> {
+        self.parsers.get(name).map(|x| &**x)
+    }
+}
+
+/// A helper trait that describes requirements for types that can implement [`Function`].
 ///
 /// Automatically implemented for all types which fulfill to the bounds
-/// `Debug + PartialEq + 'static`. There should be no need to implement this
-/// manually.
-pub trait FunctionRequirements: Debug {
+/// `Debug + PartialEq + 'static`. There should be no need to implement this manually.
+pub trait FunctionBounds: Debug {
     /// Cast self into `Any`.
     fn help_cast_as_any(&self) -> &dyn Any;
 
@@ -41,7 +71,7 @@ pub trait FunctionRequirements: Debug {
     fn help_eq(&self, other: &dyn Function) -> bool;
 }
 
-impl<T> FunctionRequirements for T where T: Debug + PartialEq + 'static {
+impl<T> FunctionBounds for T where T: Debug + PartialEq + 'static {
     fn help_cast_as_any(&self) -> &dyn Any {
         self
     }
@@ -60,34 +90,3 @@ impl PartialEq for dyn Function {
         self.help_eq(other)
     }
 }
-
-/// A map from identifiers to functions.
-pub struct Scope {
-    parsers: HashMap<String, Box<dyn Fn(&FuncHeader, BodyTokens<'_>, &Scope)
-                                     -> Result<Box<dyn Function>, ParseError>>>,
-}
-
-impl Scope {
-    /// Create a new empty scope.
-    pub fn new() -> Scope {
-        Scope { parsers: HashMap::new() }
-    }
-
-    /// Add a function type to the scope with a given name.
-    pub fn add<F: Function + 'static>(&mut self, name: &str) {
-        self.parsers.insert(
-            name.to_owned(),
-            Box::new(|header, tokens, scope| match F::parse(header, tokens, scope) {
-                Ok(func) => Ok(Box::new(func)),
-                Err(err) => Err(err),
-            })
-        );
-    }
-
-    /// Return the parser with the given name if there is one.
-    pub fn get_parser(&self, name: &str)
-        -> Option<&dyn Fn(&FuncHeader, BodyTokens<'_>, &Scope)
-            -> Result<Box<dyn Function>, ParseError>> {
-        self.parsers.get(name).map(|x| &**x)
-    }
-}
diff --git a/src/parsing.rs b/src/parsing.rs
index 7c4d6041..ebcdeef4 100644
--- a/src/parsing.rs
+++ b/src/parsing.rs
@@ -5,11 +5,13 @@ use std::fmt;
 use std::iter::Peekable;
 use std::mem::swap;
 use std::ops::Deref;
-use unicode_segmentation::{UnicodeSegmentation, UWordBounds};
+
 use crate::syntax::*;
 use crate::func::{Scope, BodyTokens};
 use crate::utility::{Splinor, Spline, Splined, StrExt};
 
+use unicode_segmentation::{UnicodeSegmentation, UWordBounds};
+
 
 /// An iterator over the tokens of source code.
 #[derive(Clone)]
@@ -211,7 +213,6 @@ pub struct Parser<'s, T> where T: Iterator<Item=Token<'s>> {
     tokens: Peekable<T>,
     scope: ParserScope<'s>,
     state: ParserState,
-    stack: Vec<FuncInvocation>,
     tree: SyntaxTree,
 }
 
@@ -228,23 +229,6 @@ enum ParserState {
     Function,
 }
 
-/// An owned or shared scope.
-enum ParserScope<'s> {
-    Owned(Scope),
-    Shared(&'s Scope)
-}
-
-impl Deref for ParserScope<'_> {
-    type Target = Scope;
-
-    fn deref(&self) -> &Scope {
-        match self {
-            ParserScope::Owned(scope) => &scope,
-            ParserScope::Shared(scope) => scope,
-        }
-    }
-}
-
 impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
     /// Create a new parser from a type that emits results of tokens.
     pub fn new(tokens: T) -> Parser<'s, T> {
@@ -262,7 +246,6 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
             tokens: tokens.peekable(),
             scope,
             state: ParserState::Body,
-            stack: vec![],
             tree: SyntaxTree::new(),
         }
     }
@@ -310,11 +293,7 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
                     // Functions
                     Token::LeftBracket => self.switch_consumed(PS::Function),
                     Token::RightBracket => {
-                        self.advance();
-                        match self.stack.pop() {
-                            Some(func) => self.append(Node::Func(func)),
-                            None => return Err(ParseError::new("unexpected closing bracket")),
-                        }
+                        return Err(ParseError::new("unexpected closing bracket"));
                     },
 
                     // Modifiers
@@ -366,20 +345,18 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
                     let body = if let Some(parser) = self.scope.get_parser(&name) {
                         parser(&header, borrow_tokens, &self.scope)?
                     } else {
-                        let message = format!("unknown function: '{}'", &name);
-                        return Err(ParseError::new(message));
+                        return Err(ParseError::new(format!("unknown function: '{}'", &name)));
                     };
 
                     // Expect the closing bracket if it had a body.
                     if let Some(tokens) = tokens {
-                        println!("lulz");
                         if tokens.unexpected_end {
                             return Err(ParseError::new("expected closing bracket"));
                         }
                     }
 
                     // Finally this function is parsed to the end.
-                    self.append(Node::Func(FuncInvocation {
+                    self.append(Node::Func(FuncCall {
                         header,
                         body,
                     }));
@@ -390,10 +367,6 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
             }
         }
 
-        // if !self.stack.is_empty() {
-        //     return Err(ParseError::new("expected closing bracket"));
-        // }
-
         Ok(self.tree)
     }
 
@@ -402,13 +375,9 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
         self.tokens.next();
     }
 
-    /// Append a node to the top-of-stack function or the main tree itself.
+    /// Append a node to the tree.
     fn append(&mut self, node: Node) {
         self.tree.nodes.push(node);
-        // match self.stack.last_mut() {
-        //     Some(func) => func.body.as_mut().unwrap(),
-        //     None => &mut self.tree,
-        // }.nodes.push(node);
     }
 
     /// Advance and return the given node.
@@ -422,7 +391,10 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
     }
 
     /// Advance and append a space if there is not one already.
-    fn append_space_consumed(&mut self) { self.advance(); self.append_space(); }
+    fn append_space_consumed(&mut self) {
+        self.advance();
+        self.append_space();
+    }
 
     /// Switch the state.
     fn switch(&mut self, state: ParserState) {
@@ -430,15 +402,14 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
     }
 
     /// Advance and switch the state.
-    fn switch_consumed(&mut self, state: ParserState) { self.advance(); self.state = state; }
+    fn switch_consumed(&mut self, state: ParserState) {
+        self.advance();
+        self.state = state;
+    }
 
-    /// The last appended node of the top-of-stack function or of the main tree.
+    /// The last appended node of the tree.
     fn last(&self) -> Option<&Node> {
         self.tree.nodes.last()
-        // match self.stack.last() {
-        //     Some(func) => func.body.as_ref().unwrap(),
-        //     None => &self.tree,
-        // }.nodes.last()
     }
 
     /// Skip tokens until the condition is met.
@@ -452,6 +423,23 @@ impl<'s, T> Parser<'s, T> where T: Iterator<Item=Token<'s>> {
     }
 }
 
+/// An owned or shared scope.
+enum ParserScope<'s> {
+    Owned(Scope),
+    Shared(&'s Scope)
+}
+
+impl Deref for ParserScope<'_> {
+    type Target = Scope;
+
+    fn deref(&self) -> &Scope {
+        match self {
+            ParserScope::Owned(scope) => &scope,
+            ParserScope::Shared(scope) => scope,
+        }
+    }
+}
+
 /// A token iterator that that stops after the first unbalanced right paren.
 pub struct FuncTokens<'s, T> where T: Iterator<Item=Token<'s>> {
     tokens: T,
@@ -505,9 +493,11 @@ impl ParseError {
     }
 }
 
+/// The result type for parsing.
+pub type ParseResult<T> = Result<T, ParseError>;
+
 error_type! {
     err: ParseError,
-    res: ParseResult,
     show: f => f.write_str(&err.message),
 }
 
@@ -623,6 +613,7 @@ mod token_tests {
     }
 }
 
+
 #[cfg(test)]
 mod parse_tests {
     use super::*;
@@ -653,7 +644,8 @@ mod parse_tests {
     struct BodylessFn;
 
     impl Function for BodylessFn {
-        fn parse(_: &FuncHeader, tokens: BodyTokens<'_>, _: &Scope) -> ParseResult<Self> where Self: Sized {
+        fn parse(_: &FuncHeader, tokens: BodyTokens<'_>, _: &Scope)
+        -> ParseResult<Self> where Self: Sized {
             if tokens.is_none() {
                 Ok(BodylessFn)
             } else {
@@ -672,7 +664,7 @@ mod parse_tests {
             func!(@$name, Box::new(TreeFn($tree)))
         };
         (@$name:expr, $body:expr) => {
-            FuncInvocation {
+            FuncCall {
                 header: FuncHeader {
                     name: Ident::new($name).unwrap(),
                     args: vec![],
@@ -707,7 +699,7 @@ mod parse_tests {
         assert_eq!(Parser::new(Tokens::new(src)).parse().unwrap_err().message, err);
     }
 
-    /// Test if the source parses into the error.
+    /// Test with a scope if the source parses into the error.
     fn test_err_scoped(scope: &Scope, src: &str, err: &str) {
         assert_eq!(Parser::with_scope(scope, Tokens::new(src)).parse().unwrap_err().message, err);
     }
@@ -735,10 +727,10 @@ mod parse_tests {
     #[test]
     fn parse_functions() {
         let mut scope = Scope::new();
-        let tree_fns = ["modifier", "func", "links", "bodyempty", "nested"];
-        let bodyless_fns = ["test", "end"];
-        for func in &bodyless_fns { scope.add::<BodylessFn>(func); }
-        for func in &tree_fns { scope.add::<TreeFn>(func); }
+        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, "This is an [modifier][example] of a function invocation.", tree! [
@@ -746,13 +738,13 @@ mod parse_tests {
             F(func! { name => "modifier", body => tree! [ W("example") ] }), S,
             W("of"), S, W("a"), S, W("function"), S, W("invocation"), W(".")
         ]);
-        test_scoped(&scope, "[func][Hello][links][Here][end]",  tree! [
+        test_scoped(&scope, "[func][Hello][modifier][Here][end]",  tree! [
             F(func! {
                 name => "func",
                 body => tree! [ W("Hello") ],
             }),
             F(func! {
-                name => "links",
+                name => "modifier",
                 body => tree! [ W("Here") ],
             }),
             F(func! {
@@ -760,15 +752,15 @@ mod parse_tests {
                 body => None,
             }),
         ]);
-        test_scoped(&scope, "[bodyempty][]", tree! [
+        test_scoped(&scope, "[func][]", tree! [
             F(func! {
-                name => "bodyempty",
+                name => "func",
                 body => tree! [],
             })
         ]);
-        test_scoped(&scope, "[nested][[func][call]] outside", tree! [
+        test_scoped(&scope, "[modifier][[func][call]] outside", tree! [
             F(func! {
-                name => "nested",
+                name => "modifier",
                 body => tree! [
                     F(func! {
                         name => "func",
@@ -784,19 +776,19 @@ mod parse_tests {
     #[test]
     fn parse_unicode() {
         let mut scope = Scope::new();
-        scope.add::<BodylessFn>("lib_parse");
-        scope.add::<TreeFn>("func123");
+        scope.add::<BodylessFn>("func");
+        scope.add::<TreeFn>("bold");
 
-        test_scoped(&scope, "[lib_parse] ⺐.", tree! [
+        test_scoped(&scope, "[func] ⺐.", tree! [
             F(func! {
-                name => "lib_parse",
+                name => "func",
                 body => None,
             }),
             S, W("⺐"), W(".")
         ]);
-        test_scoped(&scope, "[func123][Hello 🌍!]", tree! [
+        test_scoped(&scope, "[bold][Hello 🌍!]", tree! [
             F(func! {
-                name => "func123",
+                name => "bold",
                 body => tree! [ W("Hello"), S, W("🌍"), W("!") ],
             })
         ]);
diff --git a/src/syntax.rs b/src/syntax.rs
index dd83b4a3..8d248ab7 100644
--- a/src/syntax.rs
+++ b/src/syntax.rs
@@ -3,6 +3,7 @@
 use std::collections::HashMap;
 use std::fmt::{self, Display, Formatter};
 use std::ops::Deref;
+
 use crate::func::Function;
 use crate::utility::StrExt;
 
@@ -68,18 +69,18 @@ pub enum Node {
     /// A literal word.
     Word(String),
     /// A function invocation.
-    Func(FuncInvocation),
+    Func(FuncCall),
 }
 
 /// A complete function invocation consisting of header and body.
 #[derive(Debug)]
-pub struct FuncInvocation {
+pub struct FuncCall {
     pub header: FuncHeader,
     pub body: Box<dyn Function>,
 }
 
-impl PartialEq for FuncInvocation {
-    fn eq(&self, other: &FuncInvocation) -> bool {
+impl PartialEq for FuncCall {
+    fn eq(&self, other: &FuncCall) -> bool {
         (self.header == other.header) && (&self.body == &other.body)
     }
 }