Desugar body into last argument 🍩

10 files changed, 56 insertions, 79 deletions

diff --git a/src/func.rs b/src/func.rs
index 016770cb..abff559f 100644
--- a/src/func.rs
+++ b/src/func.rs
@@ -8,9 +8,7 @@ pub mod prelude {
     pub use crate::layout::Command::{self, *};
     pub use crate::style::*;
     pub use crate::syntax::expr::*;
-    pub use crate::syntax::parsing::{
-        parse, FuncArgs, FuncBody, FuncCall, FuncHeader, ParseState,
-    };
+    pub use crate::syntax::parsing::{parse, FuncArgs, FuncCall, ParseState};
     pub use crate::syntax::span::{Span, SpanVec, Spanned};
     pub use crate::syntax::tree::{DynamicNode, SyntaxNode, SyntaxTree};
     pub use crate::syntax::value::*;
@@ -55,10 +53,3 @@ pub fn drain_args(args: FuncArgs, f: &mut Feedback) {
         error!(@f, arg.span, "unexpected argument");
     }
 }
-
-/// Generate an error if there is function body even though none was expected.
-pub fn expect_no_body(body: FuncBody, f: &mut Feedback) {
-    if let Some(body) = body {
-        error!(@f, body.span, "unexpected body");
-    }
-}
diff --git a/src/library/align.rs b/src/library/align.rs
index 1ff07b89..115793b1 100644
--- a/src/library/align.rs
+++ b/src/library/align.rs
@@ -12,9 +12,9 @@ use super::*;
 /// There may not be two alignment specifications for the same axis.
 pub fn align(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
     let mut f = Feedback::new();
-    let mut args = call.header.args;
+    let mut args = call.args;
     let node = AlignNode {
-        body: call.body.map(|s| s.v),
+        content: args.pos.get::<SyntaxTree>(),
         aligns: args.pos.all::<Spanned<SpecAlign>>().collect(),
         h: args.key.get::<Spanned<SpecAlign>>("horizontal", &mut f),
         v: args.key.get::<Spanned<SpecAlign>>("vertical", &mut f),
@@ -25,7 +25,7 @@ pub fn align(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
 
 #[derive(Debug, Clone, PartialEq)]
 struct AlignNode {
-    body: Option<SyntaxTree>,
+    content: Option<SyntaxTree>,
     aligns: SpanVec<SpecAlign>,
     h: Option<Spanned<SpecAlign>>,
     v: Option<Spanned<SpecAlign>>,
@@ -64,9 +64,9 @@ impl Layout for AlignNode {
             }
         }
 
-        Pass::new(match &self.body {
-            Some(body) => {
-                let layouted = layout(body, ctx).await;
+        Pass::new(match &self.content {
+            Some(tree) => {
+                let layouted = layout(tree, ctx).await;
                 f.extend(layouted.feedback);
                 vec![AddMultiple(layouted.output)]
             }
diff --git a/src/library/boxed.rs b/src/library/boxed.rs
index 5191480f..3ca3ae44 100644
--- a/src/library/boxed.rs
+++ b/src/library/boxed.rs
@@ -8,9 +8,9 @@ use super::*;
 /// - `height`: The height of the box (length of relative to parent's height).
 pub fn boxed(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
     let mut f = Feedback::new();
-    let mut args = call.header.args;
+    let mut args = call.args;
     let node = BoxNode {
-        body: call.body.map(|s| s.v).unwrap_or(SyntaxTree::new()),
+        content: args.pos.get::<SyntaxTree>().unwrap_or(SyntaxTree::new()),
         width: args.key.get::<ScaleLength>("width", &mut f),
         height: args.key.get::<ScaleLength>("height", &mut f),
     };
@@ -20,7 +20,7 @@ pub fn boxed(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
 
 #[derive(Debug, Clone, PartialEq)]
 struct BoxNode {
-    body: SyntaxTree,
+    content: SyntaxTree,
     width: Option<ScaleLength>,
     height: Option<ScaleLength>,
 }
@@ -45,7 +45,7 @@ impl Layout for BoxNode {
             ctx.spaces[0].expansion.vertical = true;
         });
 
-        layout(&self.body, ctx).await.map(|out| {
+        layout(&self.content, ctx).await.map(|out| {
             let layout = out.into_iter().next().unwrap();
             vec![Add(layout)]
         })
diff --git a/src/library/font.rs b/src/library/font.rs
index 356acc58..d445a246 100644
--- a/src/library/font.rs
+++ b/src/library/font.rs
@@ -20,10 +20,10 @@ use super::*;
 ///   ```
 pub fn font(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
     let mut f = Feedback::new();
-    let mut args = call.header.args;
+    let mut args = call.args;
 
     let node = FontNode {
-        body: call.body.map(|s| s.v),
+        content: args.pos.get::<SyntaxTree>(),
         size: args.pos.get::<ScaleLength>(),
         style: args.key.get::<FontStyle>("style", &mut f),
         weight: args.key.get::<FontWeight>("weight", &mut f),
@@ -53,7 +53,7 @@ pub fn font(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
 
 #[derive(Debug, Clone, PartialEq)]
 struct FontNode {
-    body: Option<SyntaxTree>,
+    content: Option<SyntaxTree>,
     size: Option<ScaleLength>,
     style: Option<FontStyle>,
     weight: Option<FontWeight>,
@@ -91,7 +91,7 @@ impl Layout for FontNode {
 
         text.fallback.flatten();
 
-        Pass::okay(match &self.body {
+        Pass::okay(match &self.content {
             Some(tree) => vec![
                 SetTextStyle(text),
                 LayoutSyntaxTree(tree),
diff --git a/src/library/page.rs b/src/library/page.rs
index 0a018994..b47749ea 100644
--- a/src/library/page.rs
+++ b/src/library/page.rs
@@ -18,8 +18,7 @@ use super::*;
 /// - `flip`: Flips custom or paper-defined width and height (boolean).
 pub fn page(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
     let mut f = Feedback::new();
-    let mut args = call.header.args;
-    expect_no_body(call.body, &mut f);
+    let mut args = call.args;
     let node = PageNode {
         paper: args.pos.get::<Paper>(),
         width: args.key.get::<Length>("width", &mut f),
@@ -79,7 +78,7 @@ impl Layout for PageNode {
 /// `pagebreak`: Ends the current page.
 pub fn pagebreak(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
     let mut f = Feedback::new();
-    drain_args(call.header.args, &mut f);
+    drain_args(call.args, &mut f);
     Pass::node(PageBreakNode, f)
 }
 
diff --git a/src/library/spacing.rs b/src/library/spacing.rs
index 14c6135a..ad30a122 100644
--- a/src/library/spacing.rs
+++ b/src/library/spacing.rs
@@ -20,12 +20,11 @@ pub fn v(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
 
 fn spacing(call: FuncCall, axis: SpecAxis) -> Pass<SyntaxNode> {
     let mut f = Feedback::new();
-    let mut args = call.header.args;
-    expect_no_body(call.body, &mut f);
+    let mut args = call.args;
     let node = SpacingNode {
         spacing: args.pos.expect::<ScaleLength>(&mut f)
             .map(|s| (axis, s))
-            .or_missing(call.header.name.span, "spacing", &mut f),
+            .or_missing(call.name.span, "spacing", &mut f),
     };
     drain_args(args, &mut f);
     Pass::node(node, f)
diff --git a/src/library/val.rs b/src/library/val.rs
index bbbeb1d1..6e83571a 100644
--- a/src/library/val.rs
+++ b/src/library/val.rs
@@ -5,21 +5,22 @@ use super::*;
 /// This is also the fallback function, which is used when a function name
 /// cannot be resolved.
 pub fn val(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
+    let mut args = call.args;
     let node = ValNode {
-        body: call.body.map(|s| s.v),
+        content: args.pos.get::<SyntaxTree>(),
     };
     Pass::node(node, Feedback::new())
 }
 
 #[derive(Debug, Clone, PartialEq)]
 struct ValNode {
-    body: Option<SyntaxTree>,
+    content: Option<SyntaxTree>,
 }
 
 #[async_trait(?Send)]
 impl Layout for ValNode {
     async fn layout<'a>(&'a self, _: LayoutContext<'_>) -> Pass<Commands<'a>> {
-        Pass::okay(match &self.body {
+        Pass::okay(match &self.content {
             Some(tree) => vec![LayoutSyntaxTree(tree)],
             None => vec![],
         })
diff --git a/src/syntax/parsing.rs b/src/syntax/parsing.rs
index 502f4de1..2980cce2 100644
--- a/src/syntax/parsing.rs
+++ b/src/syntax/parsing.rs
@@ -16,21 +16,10 @@ pub type CallParser = dyn Fn(FuncCall, &ParseState) -> Pass<SyntaxNode>;
 /// An invocation of a function.
 #[derive(Debug, Clone, PartialEq)]
 pub struct FuncCall {
-    pub header: FuncHeader,
-    pub body: FuncBody,
-}
-
-/// The parsed header of a function (everything in the first set of brackets).
-#[derive(Debug, Clone, PartialEq)]
-pub struct FuncHeader {
     pub name: Spanned<Ident>,
     pub args: FuncArgs,
 }
 
-/// The body of a function as a raw spanned string containing what's inside of
-/// the brackets.
-pub type FuncBody = Option<Spanned<SyntaxTree>>;
-
 /// The positional and keyword arguments passed to a function.
 #[derive(Debug, Default, Clone, PartialEq)]
 pub struct FuncArgs {
@@ -166,8 +155,8 @@ impl<'s> FuncParser<'s> {
     }
 
     fn parse(mut self) -> Pass<SyntaxNode> {
-        let (parser, header) = if let Some(header) = self.parse_func_header() {
-            let name = header.name.v.as_str();
+        let (parser, mut call) = if let Some(call) = self.parse_func_call() {
+            let name = call.name.v.as_str();
             let (parser, deco) = match self.state.scope.get_parser(name) {
                 // The function exists in the scope.
                 Some(parser) => (parser, Decoration::ResolvedFunc),
@@ -177,32 +166,34 @@ impl<'s> FuncParser<'s> {
                 // the content of the function is not totally dropped (on a best
                 // effort basis).
                 None => {
-                    error!(@self.feedback, header.name.span, "unknown function");
+                    error!(@self.feedback, call.name.span, "unknown function");
                     let parser = self.state.scope.get_fallback_parser();
                     (parser, Decoration::UnresolvedFunc)
                 }
             };
 
-            self.feedback.decorations.push(Spanned::new(deco, header.name.span));
-            (parser, header)
+            self.feedback.decorations.push(Spanned::new(deco, call.name.span));
+            (parser, call)
         } else {
-            // Parse the body with the fallback parser even when the header is
+            // Parse the call with the fallback parser even when the header is
             // completely unparsable.
             let parser = self.state.scope.get_fallback_parser();
-            let header = FuncHeader {
+            let call = FuncCall {
                 name: Spanned::new(Ident(String::new()), Span::ZERO),
                 args: FuncArgs::new(),
             };
-            (parser, header)
+            (parser, call)
         };
 
-        let body = self.body.map(|body| body.map(|src| {
-            let parsed = parse(src, body.span.start, &self.state);
-            self.feedback.extend(parsed.feedback);
-            parsed.output
-        }));
+        if let Some(body) = self.body {
+            let tree = body.map(|src| {
+                let parsed = parse(src, body.span.start, &self.state);
+                self.feedback.extend(parsed.feedback);
+                Expr::Tree(parsed.output)
+            });
 
-        let call = FuncCall { header, body };
+            call.args.pos.push(tree);
+        }
 
         let parsed = parser(call, self.state);
         self.feedback.extend(parsed.feedback);
@@ -210,7 +201,7 @@ impl<'s> FuncParser<'s> {
         Pass::new(parsed.output, self.feedback)
     }
 
-    fn parse_func_header(&mut self) -> Option<FuncHeader> {
+    fn parse_func_call(&mut self) -> Option<FuncCall> {
         let after_bracket = self.pos();
 
         self.skip_white();
@@ -229,7 +220,7 @@ impl<'s> FuncParser<'s> {
             None => FuncArgs::new(),
         };
 
-        Some(FuncHeader { name, args })
+        Some(FuncCall { name, args })
     }
 
     fn parse_func_args(&mut self) -> FuncArgs {
@@ -790,13 +781,13 @@ mod tests {
                     value: Z($value),
                 })));)*)?
             )?
-            SyntaxNode::boxed(DebugNode {
-                header: FuncHeader {
+            SyntaxNode::boxed(DebugNode(
+                FuncCall {
                     name: span_item!($name).map(|s| Ident(s.to_string())),
                     args,
                 },
-                body: func!(@body $($($body)*)?),
-            })
+                func!(@body $($($body)*)?),
+            ))
         }};
         (@body [$($body:tt)*]) => { Some(span_vec![$($body)*].0) };
         (@body) => { None };
diff --git a/src/syntax/test.rs b/src/syntax/test.rs
index 2ea5dde3..97fecebc 100644
--- a/src/syntax/test.rs
+++ b/src/syntax/test.rs
@@ -3,10 +3,10 @@ use std::fmt::Debug;
 use crate::func::prelude::*;
 use super::decoration::Decoration;
 use super::expr::{Expr, Ident, NamedTuple, Object, Pair, Tuple};
-use super::parsing::{FuncArg, FuncArgs, FuncHeader};
+use super::parsing::{FuncArg, FuncArgs};
 use super::span::Spanned;
 use super::tokens::Token;
-use super::tree::{DynamicNode, SyntaxNode, SyntaxTree};
+use super::tree::{DynamicNode, SyntaxNode};
 
 pub fn check<T>(src: &str, exp: T, found: T, cmp_spans: bool)
 where
@@ -58,19 +58,13 @@ macro_rules! span_item {
     };
 }
 
-pub fn debug_func(call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
-    let node = DebugNode {
-        header: call.header,
-        body: call.body.map(|s| s.v),
-    };
-    Pass::node(node, Feedback::new())
+pub fn debug_func(mut call: FuncCall, _: &ParseState) -> Pass<SyntaxNode> {
+    let tree = call.args.pos.get::<SyntaxTree>();
+    Pass::node(DebugNode(call, tree), Feedback::new())
 }
 
 #[derive(Debug, Clone, PartialEq)]
-pub struct DebugNode {
-    pub header: FuncHeader,
-    pub body: Option<SyntaxTree>,
-}
+pub struct DebugNode(pub FuncCall, pub Option<SyntaxTree>);
 
 #[async_trait(?Send)]
 impl Layout for DebugNode {
@@ -102,12 +96,12 @@ impl SpanlessEq for SyntaxNode {
 
 impl SpanlessEq for DebugNode {
     fn spanless_eq(&self, other: &Self) -> bool {
-        self.header.spanless_eq(&other.header)
-            && self.body.spanless_eq(&other.body)
+        self.0.spanless_eq(&other.0)
+            && self.1.spanless_eq(&other.1)
     }
 }
 
-impl SpanlessEq for FuncHeader {
+impl SpanlessEq for FuncCall {
     fn spanless_eq(&self, other: &Self) -> bool {
         self.name.spanless_eq(&other.name)
             && self.args.spanless_eq(&other.args)
diff --git a/src/syntax/value.rs b/src/syntax/value.rs
index c523ff93..aa5049e0 100644
--- a/src/syntax/value.rs
+++ b/src/syntax/value.rs
@@ -8,6 +8,7 @@ use crate::paper::Paper;
 use crate::Feedback;
 use super::expr::*;
 use super::span::Spanned;
+use super::tree::SyntaxTree;
 
 /// Value types are used to extract values from functions, tuples and
 /// objects. They represent the value part of an argument.
@@ -58,6 +59,7 @@ match_value!(String, "string",     Expr::Str(s)    => s);
 match_value!(bool,   "bool",       Expr::Bool(b)   => b);
 match_value!(f64,    "number",     Expr::Number(n) => n);
 match_value!(Length, "length",     Expr::Length(l) => l);
+match_value!(SyntaxTree, "tree",   Expr::Tree(t)   => t);
 match_value!(Tuple,  "tuple",      Expr::Tuple(t)  => t);
 match_value!(Object, "object",     Expr::Object(o) => o);
 match_value!(ScaleLength, "number or length",