From 1b61f4b25bcab91eaa248368e9e4af8be61b5f68 Mon Sep 17 00:00:00 2001
From: rvcas <x@rvcas.dev>
Date: Sun, 2 Oct 2022 18:16:19 -0400
Subject: [PATCH] feat: field access

---
 crates/lang/src/parser.rs       | 66 ++++++++++++++++++++++++++++++++-
 crates/lang/src/tests/parser.rs | 34 +++++++++++++++++
 2 files changed, 98 insertions(+), 2 deletions(-)

diff --git a/crates/lang/src/parser.rs b/crates/lang/src/parser.rs
index a5b9663f..2e6bca86 100644
--- a/crates/lang/src/parser.rs
+++ b/crates/lang/src/parser.rs
@@ -2,12 +2,22 @@ use chumsky::prelude::*;
 use vec1::Vec1;
 
 use crate::{
-    ast::{self, BinOp, TodoKind},
+    ast::{self, BinOp, Span, TodoKind},
     error::ParseError,
     expr,
     token::Token,
 };
 
+// Parsing a function call into the appropriate structure
+#[derive(Debug)]
+pub enum ParserArg {
+    Arg(Box<ast::CallArg<expr::UntypedExpr>>),
+    Hole {
+        location: Span,
+        label: Option<String>,
+    },
+}
+
 pub fn module_parser(
     kind: ast::ModuleKind,
 ) -> impl Parser<Token, ast::UntypedModule, Error = ParseError> {
@@ -453,13 +463,65 @@ pub fn expr_parser(
             assert_parser,
         ));
 
+        enum Chain {
+            FieldAccess(String, Span),
+            RecordUpdate,
+            Call(Vec<ParserArg>, Span),
+        }
+
+        let field_access_parser = just(Token::Dot)
+            .ignore_then(select! {
+                Token::Name { name } => name,
+                Token::UpName { name } => name
+            })
+            .map_with_span(Chain::FieldAccess);
+
+        let call_parser = choice((
+            select! { Token::Name { name } => name }
+                .then_ignore(just(Token::Colon))
+                .or_not()
+                .then(r.clone())
+                .map_with_span(|(label, value), span| {
+                    ParserArg::Arg(Box::new(ast::CallArg {
+                        label,
+                        location: span,
+                        value,
+                    }))
+                }),
+            select! { Token::Name { name } => name }
+                .then_ignore(just(Token::Colon))
+                .or_not()
+                .then_ignore(select! {Token::DiscardName {name} => name })
+                .map_with_span(|label, span| ParserArg::Hole {
+                    location: span,
+                    label,
+                }),
+        ))
+        .separated_by(just(Token::Comma))
+        .delimited_by(just(Token::LeftParen), just(Token::RightParen))
+        .map_with_span(Chain::Call);
+
+        let chain = choice((field_access_parser, call_parser));
+
+        let chained = expr_unit_parser
+            .then(chain.repeated())
+            .foldl(|e, chain| match chain {
+                Chain::FieldAccess(label, span) => expr::UntypedExpr::FieldAccess {
+                    location: e.location().union(span),
+                    label,
+                    container: Box::new(e),
+                },
+                _ => todo!(),
+            });
+
+        // Negate
         let op = just(Token::Bang);
 
         let unary = op
             .ignored()
             .map_with_span(|_, span| span)
             .repeated()
-            .then(expr_unit_parser)
+            .then(chained)
             .foldr(|span, value| expr::UntypedExpr::Negate {
                 location: span.union(value.location()),
                 value: Box::new(value),
diff --git a/crates/lang/src/tests/parser.rs b/crates/lang/src/tests/parser.rs
index 09db6f0c..5ab777e9 100644
--- a/crates/lang/src/tests/parser.rs
+++ b/crates/lang/src/tests/parser.rs
@@ -77,6 +77,10 @@ fn module() {
             }
 
             fn run() {}
+
+            fn name(user: User) {
+                user.name
+            }
         "#;
     let len = code.chars().count();
 
@@ -725,6 +729,36 @@ fn module() {
                     return_annotation: None,
                     return_type: (),
                 },
+                ast::UntypedDefinition::Fn {
+                    arguments: vec![ast::Arg {
+                        arg_name: ast::ArgName::Named {
+                            name: "user".to_string(),
+                            location: Span::new(SrcId::empty(), 1425..1429),
+                        },
+                        location: Span::new(SrcId::empty(), 1425..1435),
+                        annotation: Some(ast::Annotation::Constructor {
+                            location: Span::new(SrcId::empty(), 1431..1435),
+                            module: None,
+                            name: "User".to_string(),
+                            arguments: vec![],
+                        },),
+                        tipo: (),
+                    },],
+                    body: expr::UntypedExpr::FieldAccess {
+                        location: Span::new(SrcId::empty(), 1455..1464),
+                        label: "name".to_string(),
+                        container: Box::new(expr::UntypedExpr::Var {
+                            location: Span::new(SrcId::empty(), 1455..1459),
+                            name: "user".to_string(),
+                        }),
+                    },
+                    doc: None,
+                    location: Span::new(SrcId::empty(), 1417..1478),
+                    name: "name".to_string(),
+                    public: false,
+                    return_annotation: None,
+                    return_type: (),
+                },
             ]
         },
     );