Commit 50139aa23245c7b6b6a5faff95f1a2c854051a38 | zig

author	Maks S <38307091+MadMax129@users.noreply.github.com> 2020-06-28 17:42:37-07:00
committer	Veikka Tuominen <git@vexu.eu> 2020-08-13 22:08:37+03:00
log	50139aa23245c7b6b6a5faff95f1a2c854051a38
tree	e3f24b26d5a1d929f74218907616e3cfd108211a
parent	6e0fb060109349b4fb7855c1587b6d9c396d926b
signature	Commit is signed but in an unrecognized format.

langref: explain why comptime_float cannot be divided by comptime_int

Co-authored-by: Andrew Kelley <andrew@ziglang.org>
Co-authored-by: Veikka Tuominen <git@vexu.eu>

1 files changed, 19 insertions(+), 3 deletions(-)

doc
- langref.html.in

doc/langref.html.in+19-3

 @@ -248,7 +248,7 @@ pub fn main() !void {
       </p>
       <p>
         Following the <code>hello.zig</code> Zig code sample, the {#link|Zig Build System#} is used
         to build an executable program from the <code>hello.zig</code> source code. Then, the
         <code>hello</code> program is executed showing its output <code>Hello, world!</code>. The
         lines beginning with <code>$</code> represent command line prompts and a command.
         Everything else is program output.
 @@ -293,7 +293,7 @@ pub fn main() !void {
       <p>
         In Zig, a function's block of statements and expressions are surrounded by <code>{</code> and
         <code>}</code> curly-braces. Inside of the <code>main</code> function are expressions that perform
         the task of outputting <code>Hello, world!</code> to standard output.
       </p>
       <p>
         First, a constant identifier, <code>stdout</code>, is initialized to represent standard output's
 @@ -5135,6 +5135,22 @@ test "float widening" {
     var c: f64 = b;
     var d: f128 = c;
     assert(d == a);
+}
+      {#code_end#}
+      {#header_close#}
+      {#header_open|Type Coercion: Coercion Float to Int#}
+      <p>
+      A compiler error is appropriate because this ambiguous expression leaves the compiler
+      two choices about the coercion.
+      <ul>
+        <li> Cast {#syntax#}54.0{#endsyntax#} to {#syntax#}comptime_int{#endsyntax#} resulting in {#syntax#}@as(comptime_int, 10){#endsyntax#}, which is casted to {#syntax#}@as(f32, 10){#endsyntax#}</li>
+        <li> Cast {#syntax#}5{#endsyntax#} to {#syntax#}comptime_float{#endsyntax#} resulting in {#syntax#}@as(comptime_float, 10.8){#endsyntax#}, which is casted to {#syntax#}@as(f32, 10.8){#endsyntax#}</li>
+      </ul>
+      </p>
+      {#code_begin|test_err#}
+// Compile time coercion of float to int
+test "implicit cast to comptime_int" {
+    var f: f32 = 54.0 / 5;
 }
       {#code_end#}
       {#header_close#}
 @@ -8179,7 +8195,7 @@ const expect = std.testing.expect;
 test "@src" {
     doTheTest();
 }
 fn doTheTest() void {
     const src = @src();