Merge pull request #131 from Nadrieril/hir

Decouple main expression types

2 files changed, 37 insertions, 31 deletions

diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index 8d571c0..f3ebd2b 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -5,23 +5,20 @@ use std::rc::Rc;
 
 use pest_consume::{match_nodes, Parser};
 
-use crate::syntax;
 use crate::syntax::map::{DupTreeMap, DupTreeSet};
 use crate::syntax::ExprKind::*;
+use crate::syntax::LitKind::*;
 use crate::syntax::{
-    Double, FilePath, FilePrefix, Hash, ImportLocation, ImportMode, Integer,
-    InterpolatedText, InterpolatedTextContents, Label, NaiveDouble, Natural,
-    Scheme, Span, URL, V,
+    Double, Expr, FilePath, FilePrefix, Hash, ImportLocation, ImportMode,
+    Integer, InterpolatedText, InterpolatedTextContents, Label, NaiveDouble,
+    Natural, Scheme, Span, UnspannedExpr, URL, V,
 };
-use crate::Normalized;
 
 // This file consumes the parse tree generated by pest and turns it into
 // our own AST. All those custom macros should eventually moved into
 // their own crate because they are quite general and useful. For now they
 // are here and hopefully you can figure out how they work.
 
-type Expr = syntax::Expr<Normalized>;
-type UnspannedExpr = syntax::UnspannedExpr<Normalized>;
 type ParsedText = InterpolatedText<Expr>;
 type ParsedTextContents = InterpolatedTextContents<Expr>;
 type ParseInput<'input> = pest_consume::Node<'input, Rule, Rc<str>>;
@@ -348,8 +345,8 @@ impl DhallParser {
         let e = match crate::syntax::Builtin::parse(s) {
             Some(b) => Builtin(b),
             None => match s {
-                "True" => BoolLit(true),
-                "False" => BoolLit(false),
+                "True" => Lit(Bool(true)),
+                "False" => Lit(Bool(false)),
                 "Type" => Const(crate::syntax::Const::Type),
                 "Kind" => Const(crate::syntax::Const::Kind),
                 "Sort" => Const(crate::syntax::Const::Sort),
@@ -837,9 +834,9 @@ impl DhallParser {
     #[alias(expression, shortcut = true)]
     fn primitive_expression(input: ParseInput) -> ParseResult<Expr> {
         Ok(match_nodes!(input.children();
-            [double_literal(n)] => spanned(input, DoubleLit(n)),
-            [natural_literal(n)] => spanned(input, NaturalLit(n)),
-            [integer_literal(n)] => spanned(input, IntegerLit(n)),
+            [double_literal(n)] => spanned(input, Lit(Double(n))),
+            [natural_literal(n)] => spanned(input, Lit(Natural(n))),
+            [integer_literal(n)] => spanned(input, Lit(Integer(n))),
             [double_quote_literal(s)] => spanned(input, TextLit(s)),
             [single_quote_literal(s)] => spanned(input, TextLit(s)),
             [record_type_or_literal(e)] => spanned(input, e),
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 06dd70f..8891d41 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -19,17 +19,17 @@ enum PrintPhase {
 // Wraps an Expr with a phase, so that phase selection can be done separate from the actual
 // printing.
 #[derive(Clone)]
-struct PhasedExpr<'a, E>(&'a Expr<E>, PrintPhase);
+struct PhasedExpr<'a>(&'a Expr, PrintPhase);
 
-impl<'a, E: Display + Clone> PhasedExpr<'a, E> {
-    fn phase(self, phase: PrintPhase) -> PhasedExpr<'a, E> {
+impl<'a> PhasedExpr<'a> {
+    fn phase(self, phase: PrintPhase) -> PhasedExpr<'a> {
         PhasedExpr(self.0, phase)
     }
 }
 
-impl<E: Display + Clone> UnspannedExpr<E> {
+impl UnspannedExpr {
     // Annotate subexpressions with the appropriate phase, defaulting to Base
-    fn annotate_with_phases<'a>(&'a self) -> ExprKind<PhasedExpr<'a, E>, E> {
+    fn annotate_with_phases<'a>(&'a self) -> ExprKind<PhasedExpr<'a>> {
         use crate::syntax::ExprKind::*;
         use PrintPhase::*;
         let with_base = self.map_ref(|e| PhasedExpr(e, Base));
@@ -134,7 +134,7 @@ where
 }
 
 /// Generic instance that delegates to subexpressions
-impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
+impl<SE: Display + Clone> Display for ExprKind<SE> {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         use crate::syntax::ExprKind::*;
         match self {
@@ -196,15 +196,7 @@ impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
             Var(a) => a.fmt(f)?,
             Const(k) => k.fmt(f)?,
             Builtin(v) => v.fmt(f)?,
-            BoolLit(true) => f.write_str("True")?,
-            BoolLit(false) => f.write_str("False")?,
-            NaturalLit(a) => a.fmt(f)?,
-            IntegerLit(a) if *a >= 0 => {
-                f.write_str("+")?;
-                a.fmt(f)?;
-            }
-            IntegerLit(a) => a.fmt(f)?,
-            DoubleLit(a) => a.fmt(f)?,
+            Lit(a) => a.fmt(f)?,
             TextLit(a) => a.fmt(f)?,
             RecordType(a) if a.is_empty() => f.write_str("{}")?,
             RecordType(a) => fmt_list("{ ", ", ", " }", a, f, |(k, t), f| {
@@ -232,19 +224,36 @@ impl<SE: Display + Clone, E: Display> Display for ExprKind<SE, E> {
                 write!(f, "{}::{}", a, b)?;
             }
             Import(a) => a.fmt(f)?,
-            Embed(a) => a.fmt(f)?,
         }
         Ok(())
     }
 }
 
-impl<E: Display + Clone> Display for Expr<E> {
+impl Display for Expr {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        self.kind().fmt_phase(f, PrintPhase::Base)
+    }
+}
+
+impl Display for LitKind {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        self.as_ref().fmt_phase(f, PrintPhase::Base)
+        use LitKind::*;
+        match self {
+            Bool(true) => f.write_str("True")?,
+            Bool(false) => f.write_str("False")?,
+            Natural(a) => a.fmt(f)?,
+            Integer(a) if *a >= 0 => {
+                f.write_str("+")?;
+                a.fmt(f)?;
+            }
+            Integer(a) => a.fmt(f)?,
+            Double(a) => a.fmt(f)?,
+        }
+        Ok(())
     }
 }
 
-impl<'a, E: Display + Clone> Display for PhasedExpr<'a, E> {
+impl<'a> Display for PhasedExpr<'a> {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
         self.0.as_ref().fmt_phase(f, self.1)
     }