From af6c171eb4afcdc02f66a01884572b5a55eba072 Mon Sep 17 00:00:00 2001
From: Joscha <joscha@plugh.de>
Date: Tue, 22 Nov 2022 09:44:29 +0100
Subject: [PATCH] Desugar table constructors

---
 src/desugar.rs              |  1 +
 src/desugar/basic.rs        | 22 ++++++++++++++-
 src/desugar/expr.rs         |  6 ++--
 src/desugar/table_constr.rs | 55 +++++++++++++++++++++++++++++++++++++
 4 files changed, 80 insertions(+), 4 deletions(-)
 create mode 100644 src/desugar/table_constr.rs

diff --git a/src/desugar.rs b/src/desugar.rs
index 7402709..db66687 100644
--- a/src/desugar.rs
+++ b/src/desugar.rs
@@ -4,4 +4,5 @@ mod expr;
 mod field;
 mod lit;
 mod program;
+mod table_constr;
 mod var;
diff --git a/src/desugar/basic.rs b/src/desugar/basic.rs
index 156445f..55526cf 100644
--- a/src/desugar/basic.rs
+++ b/src/desugar/basic.rs
@@ -1,4 +1,4 @@
-use crate::ast::BoundedSeparated;
+use crate::ast::{BoundedSeparated, Space};
 
 impl<E> BoundedSeparated<E> {
     pub fn desugar(self, desugar_elem: impl Fn(E) -> (E, bool)) -> (Self, bool) {
@@ -21,4 +21,24 @@ impl<E> BoundedSeparated<E> {
         };
         (new, desugared)
     }
+
+    pub fn remove_map<E1, E2>(
+        self,
+        f: impl Fn(E) -> Result<E1, E2>,
+    ) -> (BoundedSeparated<E1>, Vec<(Space, E2, Space)>) {
+        let mut kept = vec![];
+        let mut removed = vec![];
+        for (s0, elem, s1) in self.elems {
+            match f(elem) {
+                Ok(elem) => kept.push((s0, elem, s1)),
+                Err(elem) => removed.push((s0, elem, s1)),
+            }
+        }
+        let new = BoundedSeparated {
+            elems: kept,
+            trailing: self.trailing,
+            span: self.span,
+        };
+        (new, removed)
+    }
 }
diff --git a/src/desugar/expr.rs b/src/desugar/expr.rs
index 0c8e569..5f7cb02 100644
--- a/src/desugar/expr.rs
+++ b/src/desugar/expr.rs
@@ -11,10 +11,10 @@ impl Expr {
             Self::Call(call) => call.desugar(),
             Self::Field(field) => field.desugar(),
             Self::Var(var) => var.desugar(),
+            Self::TableConstr(constr) => constr.desugar(),
 
-            Self::TableConstr(constr) => (Self::TableConstr(constr), false), // TODO Implement
-            Self::TableDestr(destr) => (Self::TableDestr(destr), false),     // TODO Implement
-            Self::FuncDef(def) => (Self::FuncDef(def), false),               // TODO Implement
+            Self::TableDestr(destr) => (Self::TableDestr(destr), false), // TODO Implement
+            Self::FuncDef(def) => (Self::FuncDef(def), false),           // TODO Implement
 
             Self::Paren {
                 s0,
diff --git a/src/desugar/table_constr.rs b/src/desugar/table_constr.rs
new file mode 100644
index 0000000..aa37214
--- /dev/null
+++ b/src/desugar/table_constr.rs
@@ -0,0 +1,55 @@
+use crate::ast::{
+    BoundedSeparated, Expr, Field, Ident, Line, Lit, Space, TableConstr, TableConstrElem, TableLit,
+    TableLitElem,
+};
+use crate::span::HasSpan;
+
+impl TableConstr {
+    pub fn desugar(self) -> (Expr, bool) {
+        let span = self.span();
+
+        let (elems, setters) = self.0.remove_map(|e| match e {
+            TableConstrElem::Lit(lit) => Ok(lit),
+            TableConstrElem::Indexed {
+                s0,
+                index,
+                s1,
+                s2,
+                s3,
+                value,
+                span,
+            } => Err((s0, index, s1, s2, s3, value, span)),
+        });
+
+        let raw_elem = TableLitElem::Named {
+            name: Ident::new("raw", span),
+            s0: Space::empty(span),
+            s1: Space::empty(span),
+            value: Box::new(Expr::Lit(Lit::Table(TableLit(elems)))),
+            span,
+        };
+        let mut expr = Expr::Lit(Lit::Table(TableLit(BoundedSeparated {
+            elems: vec![(Space::empty(span), raw_elem, Space::empty(span))],
+            trailing: None,
+            span,
+        })));
+
+        // `sl [ s0 index s1 ] s2 = s3 value sr`
+        // -> `expr s0 [ s1 index s2 ] s3 = s4 s5 value`
+        for (s0, (s1, index, s2, s3, s4, value, span), s5) in setters {
+            expr = Expr::Field(Field::Assign {
+                expr: Box::new(expr),
+                s0,
+                s1,
+                index,
+                s2,
+                s3,
+                s4: s4.then_line(Line::Empty).then(s5),
+                value,
+                span,
+            });
+        }
+
+        (expr, true)
+    }
+}