From e9f55783091fb1d5c07059be865d9d1fb02d3bfa Mon Sep 17 00:00:00 2001
From: Nadrieril
Date: Tue, 5 Mar 2019 22:30:34 +0100
Subject: Parse doubles

---
 dhall/src/parser.rs                    | 16 ++++++++++++++++
 dhall_parser/build.rs                  | 10 ++++++++--
 dhall_parser/src/dhall.abnf            | 10 +++++++++-
 dhall_parser/src/dhall.pest.visibility |  2 +-
 4 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/dhall/src/parser.rs b/dhall/src/parser.rs
index 57af7b8..7bdc085 100644
--- a/dhall/src/parser.rs
+++ b/dhall/src/parser.rs
@@ -562,6 +562,18 @@ rule!(single_quote_literal<String>;
     }
 );
 
+rule!(double_literal_raw<f64>;
+    raw_pair!(pair) => {
+        pair.as_str().trim()
+            .parse()
+            .map_err(|e: std::num::ParseFloatError| custom_parse_error(&pair, format!("{}", e)))?
+    }
+);
+
+rule!(minus_infinity_literal<()>; children!() => ());
+rule!(plus_infinity_literal<()>; children!() => ());
+rule!(NaN_raw<()>; children!() => ());
+
 rule!(natural_literal_raw<usize>;
     raw_pair!(pair) => {
         pair.as_str().trim()
@@ -677,6 +689,10 @@ rule!(selector_expression_raw<BoxExpr<'a>>;
 );
 
 rule!(literal_expression_raw<BoxExpr<'a>>;
+    children!(n: double_literal_raw) => bx(Expr::DoubleLit(n)),
+    children!(n: minus_infinity_literal) => bx(Expr::DoubleLit(std::f64::NEG_INFINITY)),
+    children!(n: plus_infinity_literal) => bx(Expr::DoubleLit(std::f64::INFINITY)),
+    children!(n: NaN_raw) => bx(Expr::DoubleLit(std::f64::NAN)),
     children!(n: natural_literal_raw) => bx(Expr::NaturalLit(n)),
     children!(n: integer_literal_raw) => bx(Expr::IntegerLit(n)),
     children!(s: double_quote_literal) => bx(Expr::TextLit(s)),
diff --git a/dhall_parser/build.rs b/dhall_parser/build.rs
index 3ca36b5..743aa2d 100644
--- a/dhall_parser/build.rs
+++ b/dhall_parser/build.rs
@@ -38,8 +38,14 @@ fn main() -> std::io::Result<()> {
     let mut file = File::create(pest_path)?;
     writeln!(&mut file, "// AUTO-GENERATED FILE. See build.rs.")?;
     writeln!(&mut file, "{}", abnf_to_pest(&data, &rule_settings)?)?;
-    writeln!(&mut file, "keyword_raw = _{{ let_raw | in_raw | if_raw | then_raw | else_raw }}")?;
-    writeln!(&mut file, "final_expression = {{ SOI ~ complete_expression ~ EOI }}")?;
+    writeln!(&mut file, "keyword_raw = _{{
+        let_raw | in_raw | if_raw | then_raw
+            | else_raw | Infinity_raw | NaN_raw
+    }}")?;
+    writeln!(
+        &mut file,
+        "final_expression = {{ SOI ~ complete_expression ~ EOI }}"
+    )?;
 
     Ok(())
 }
diff --git a/dhall_parser/src/dhall.abnf b/dhall_parser/src/dhall.abnf
index e311aa6..76af24b 100644
--- a/dhall_parser/src/dhall.abnf
+++ b/dhall_parser/src/dhall.abnf
@@ -279,6 +279,7 @@ Optional-raw          = %x4f.70.74.69.6f.6e.61.6c
 Text-raw              = %x54.65.78.74
 List-raw              = %x4c.69.73.74
 Infinity-raw          = %x49.6e.66.69.6e.69.74.79
+NaN-raw               = %x4e.61.4e
 
 ; Whitespaced rules for reserved words, to be used when matching expressions
 if       = if-raw           nonempty-whitespace
@@ -648,7 +649,11 @@ literal-expression-raw =
     / integer-literal-raw
     
     ; "-Infinity"
-    / "-" Infinity-raw
+    / minus-infinity-literal
+    ; "Infinity"
+    / plus-infinity-literal
+    ; "NaN"
+    / NaN-raw
     
     ; '"ABC"'
     / text-literal-raw
@@ -657,6 +662,9 @@ literal-expression-raw =
     ; "x@2"
     / identifier-raw
 
+minus-infinity-literal = "-" Infinity-raw
+plus-infinity-literal = Infinity-raw
+
 ; "{ foo = 1      , bar = True }"
 ; "{ foo : Integer, bar : Bool }"
 record-type-or-literal =
diff --git a/dhall_parser/src/dhall.pest.visibility b/dhall_parser/src/dhall.pest.visibility
index b3a2660..08171b3 100644
--- a/dhall_parser/src/dhall.pest.visibility
+++ b/dhall_parser/src/dhall.pest.visibility
@@ -37,7 +37,7 @@ single_quote_literal
 # Optional_raw
 # Text_raw
 # List_raw
-Infinity_raw
+# Infinity_raw
 # if_
 # then
 # else_
-- 
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