Add two new Integer builtins

5 files changed, 20 insertions, 0 deletions

diff --git a/dhall/src/semantics/phase/normalize.rs b/dhall/src/semantics/phase/normalize.rs
index 6258ae8..5a0f566 100644
--- a/dhall/src/semantics/phase/normalize.rs
+++ b/dhall/src/semantics/phase/normalize.rs
@@ -1,4 +1,5 @@
 use std::collections::HashMap;
+use std::convert::TryInto;
 
 use crate::semantics::core::value::Value;
 use crate::semantics::core::value::ValueKind;
@@ -141,6 +142,16 @@ pub(crate) fn apply_builtin(
             }
             _ => Ret::DoneAsIs,
         },
+        (IntegerNegate, [n]) => match &*n.as_whnf() {
+            IntegerLit(n) => Ret::ValueKind(IntegerLit(-n)),
+            _ => Ret::DoneAsIs,
+        },
+        (IntegerClamp, [n]) => match &*n.as_whnf() {
+            IntegerLit(n) => {
+                Ret::ValueKind(NaturalLit((*n).try_into().unwrap_or(0)))
+            }
+            _ => Ret::DoneAsIs,
+        },
         (DoubleShow, [n]) => {
             match &*n.as_whnf() {
                 DoubleLit(n) => Ret::ValueKind(TextLit(vec![
diff --git a/dhall/src/semantics/phase/typecheck.rs b/dhall/src/semantics/phase/typecheck.rs
index c9834e1..7ea4951 100644
--- a/dhall/src/semantics/phase/typecheck.rs
+++ b/dhall/src/semantics/phase/typecheck.rs
@@ -235,6 +235,9 @@ fn type_of_builtin<E>(b: Builtin) -> Expr<E> {
 
         IntegerToDouble => make_type!(Integer -> Double),
         IntegerShow => make_type!(Integer -> Text),
+        IntegerNegate => make_type!(Integer -> Integer),
+        IntegerClamp => make_type!(Integer -> Natural),
+
         DoubleShow => make_type!(Double -> Text),
         TextShow => make_type!(Text -> Text),
 
diff --git a/dhall/src/syntax/ast/expr.rs b/dhall/src/syntax/ast/expr.rs
index fe49448..68cb524 100644
--- a/dhall/src/syntax/ast/expr.rs
+++ b/dhall/src/syntax/ast/expr.rs
@@ -79,6 +79,8 @@ pub enum Builtin {
     NaturalSubtract,
     IntegerToDouble,
     IntegerShow,
+    IntegerNegate,
+    IntegerClamp,
     DoubleShow,
     ListBuild,
     ListFold,
diff --git a/dhall/src/syntax/text/parser.rs b/dhall/src/syntax/text/parser.rs
index fe34aee..d9e5c3b 100644
--- a/dhall/src/syntax/text/parser.rs
+++ b/dhall/src/syntax/text/parser.rs
@@ -57,6 +57,8 @@ impl crate::syntax::Builtin {
             "Natural/subtract" => Some(NaturalSubtract),
             "Integer/toDouble" => Some(IntegerToDouble),
             "Integer/show" => Some(IntegerShow),
+            "Integer/negate" => Some(IntegerNegate),
+            "Integer/clamp" => Some(IntegerClamp),
             "Double/show" => Some(DoubleShow),
             "List/build" => Some(ListBuild),
             "List/fold" => Some(ListFold),
diff --git a/dhall/src/syntax/text/printer.rs b/dhall/src/syntax/text/printer.rs
index 626ab1c..96f4c2a 100644
--- a/dhall/src/syntax/text/printer.rs
+++ b/dhall/src/syntax/text/printer.rs
@@ -468,6 +468,8 @@ impl Display for Builtin {
             NaturalShow => "Natural/show",
             NaturalSubtract => "Natural/subtract",
             IntegerToDouble => "Integer/toDouble",
+            IntegerNegate => "Integer/negate",
+            IntegerClamp => "Integer/clamp",
             IntegerShow => "Integer/show",
             DoubleShow => "Double/show",
             ListBuild => "List/build",