Merge pull request #762 from ctheune/ctheune-floats

Implement floats

doc/manual/expressions/builtins.xml

@@ -32,7 +32,7 @@ available as <function>builtins.derivation</function>.</para>
   <varlistentry><term><function>builtins.add</function>
   <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
-    <listitem><para>Return the sum of the integers
+    <listitem><para>Return the sum of the numbers
     <replaceable>e1</replaceable> and
     <replaceable>e2</replaceable>.</para></listitem>
 
@@ -204,7 +204,7 @@ if builtins ? getEnv then builtins.getEnv "PATH" else ""</programlisting>
   <varlistentry><term><function>builtins.div</function>
   <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
-    <listitem><para>Return the quotient of the integers
+    <listitem><para>Return the quotient of the numbers
     <replaceable>e1</replaceable> and
     <replaceable>e2</replaceable>.</para></listitem>
 
@@ -620,12 +620,12 @@ x: x + 456</programlisting>
   <varlistentry><term><function>builtins.lessThan</function>
   <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
-    <listitem><para>Return <literal>true</literal> if the integer
-    <replaceable>e1</replaceable> is less than the integer
+    <listitem><para>Return <literal>true</literal> if the number
+    <replaceable>e1</replaceable> is less than the number
     <replaceable>e2</replaceable>, and <literal>false</literal>
     otherwise.  Evaluation aborts if either
     <replaceable>e1</replaceable> or <replaceable>e2</replaceable>
-    does not evaluate to an integer.</para></listitem>
+    does not evaluate to a number.</para></listitem>
 
   </varlistentry>
 
@@ -676,7 +676,7 @@ map (x: "foo" + x) [ "bar" "bla" "abc" ]</programlisting>
   <varlistentry><term><function>builtins.mul</function>
   <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
-    <listitem><para>Return the product of the integers
+    <listitem><para>Return the product of the numbers
     <replaceable>e1</replaceable> and
     <replaceable>e2</replaceable>.</para></listitem>
 
@@ -833,7 +833,7 @@ builtins.sort builtins.lessThan [ 483 249 526 147 42 77 ]
   <varlistentry><term><function>builtins.sub</function>
   <replaceable>e1</replaceable> <replaceable>e2</replaceable></term>
 
-    <listitem><para>Return the difference between the integers
+    <listitem><para>Return the difference between the numbers
     <replaceable>e1</replaceable> and
     <replaceable>e2</replaceable>.</para></listitem>
 
@@ -960,7 +960,7 @@ in foo</programlisting>
   <varlistentry><term><function>builtins.toJSON</function> <replaceable>e</replaceable></term>
 
     <listitem><para>Return a string containing a JSON representation
-    of <replaceable>e</replaceable>.  Strings, integers, booleans,
+    of <replaceable>e</replaceable>.  Strings, integers, floats, booleans,
     nulls and lists are mapped to their JSON equivalents.  Sets
     (except derivations) are represented as objects.  Derivations are
     translated to a JSON string containing the derivation’s output

doc/manual/expressions/derivations.xml

@@ -43,7 +43,7 @@ of which specify the inputs of the build.</para>
 
     <itemizedlist>
 
-      <listitem><para>Strings and integers are just passed
+      <listitem><para>Strings and numbers are just passed
       verbatim.</para></listitem>
 
       <listitem><para>A <emphasis>path</emphasis> (e.g.,

doc/manual/expressions/language-values.xml

@@ -140,8 +140,13 @@ stdenv.mkDerivation {
 
   </listitem>
 
-  <listitem><para><emphasis>Integers</emphasis>, e.g.,
-  <literal>123</literal>.</para></listitem>
+  <listitem><para>Numbers, which can be <emphasis>integers</emphasis> (like
+  <literal>123</literal>) or <emphasis>floating point</emphasis> (like
+  <literal>123.43</literal> or <literal>.27e13</literal>).</para>
+
+  <para>Numbers are type-compatible: pure integer operations will always
+  return integers, whereas any operation involving at least one floating point
+  number will have a floating point number as a result.</para></listitem>
 
   <listitem><para><emphasis>Paths</emphasis>, e.g.,
   <filename>/bin/sh</filename> or <filename>./builder.sh</filename>.

doc/manual/release-notes/rl-1.11.xml

@@ -121,6 +121,13 @@ $ diffoscope /nix/store/11a27shh6n2i…-zlib-1.2.8 /nix/store/11a27shh6n2i…-zl
     also improves performance.</para>
   </listitem>
 
+  <listitem>
+    <para>The Nix language now supports floating point numbers. They are
+    based on regular C++ <literal>float</literal> and compatible with
+    existing integers and number-related operations. Export and import to and
+    from JSON and XML works, too.
+  </para>
+  </listitem>
   <listitem>
     <para>All "chroot"-containing strings got renamed to "sandbox".
       In particular, some Nix options got renamed, but the old names