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std.fmt.format: handle non-pointer struct/union/enum

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Also adds support for printing structs via reflection.
The case when structs have pointers to themselves is not
handled yet.

closes #1380
This commit is contained in:
Andrew Kelley 2018-08-20 16:04:03 -04:00
parent b8ce8f219c
commit 820bf054ea
1 changed files with 50 additions and 31 deletions
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81
std/fmt/index.zig
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@ -146,6 +146,40 @@ pub fn formatType(
builtin.TypeId.Promise => {
return format(context, Errors, output, "promise@{x}", @ptrToInt(value));
},
builtin.TypeId.Enum, builtin.TypeId.Union, builtin.TypeId.Struct => {
const has_cust_fmt = comptime cf: {
const info = @typeInfo(T);
const defs = switch (info) {
builtin.TypeId.Struct => |s| s.defs,
builtin.TypeId.Union => |u| u.defs,
builtin.TypeId.Enum => |e| e.defs,
else => unreachable,
};
for (defs) |def| {
if (mem.eql(u8, def.name, "format")) {
break :cf true;
}
}
break :cf false;
};
if (has_cust_fmt) return value.format(fmt, context, Errors, output);
try output(context, @typeName(T));
comptime var field_i = 0;
inline while (field_i < @memberCount(T)) : (field_i += 1) {
if (field_i == 0) {
try output(context, "{ .");
} else {
try output(context, ", .");
}
try output(context, @memberName(T, field_i));
try output(context, " = ");
try formatType(@field(value, @memberName(T, field_i)), "", context, Errors, output);
}
try output(context, " }");
return;
},
builtin.TypeId.Pointer => |ptr_info| switch (ptr_info.size) {
builtin.TypeInfo.Pointer.Size.One => switch (@typeInfo(ptr_info.child)) {
builtin.TypeId.Array => |info| {
@ -155,25 +189,7 @@ pub fn formatType(
return format(context, Errors, output, "{}@{x}", @typeName(T.Child), @ptrToInt(value));
},
builtin.TypeId.Enum, builtin.TypeId.Union, builtin.TypeId.Struct => {
const has_cust_fmt = comptime cf: {
const info = @typeInfo(T.Child);
const defs = switch (info) {
builtin.TypeId.Struct => |s| s.defs,
builtin.TypeId.Union => |u| u.defs,
builtin.TypeId.Enum => |e| e.defs,
else => unreachable,
};
for (defs) |def| {
if (mem.eql(u8, def.name, "format")) {
break :cf true;
}
}
break :cf false;
};
if (has_cust_fmt) return value.format(fmt, context, Errors, output);
return format(context, Errors, output, "{}@{x}", @typeName(T.Child), @ptrToInt(value));
return formatType(value.*, fmt, context, Errors, output);
},
else => return format(context, Errors, output, "{}@{x}", @typeName(T.Child), @ptrToInt(value)),
},
@ -911,14 +927,12 @@ test "fmt.format" {
try testFmt("file size: 63MiB\n", "file size: {Bi}\n", usize(63 * 1024 * 1024));
try testFmt("file size: 66.06MB\n", "file size: {B2}\n", usize(63 * 1024 * 1024));
{
// Dummy field because of https://github.com/ziglang/zig/issues/557.
const Struct = struct {
unused: u8,
field: u8,
};
var buf1: [32]u8 = undefined;
const value = Struct{ .unused = 42 };
const result = try bufPrint(buf1[0..], "pointer: {}\n", &value);
assert(mem.startsWith(u8, result, "pointer: Struct@"));
const value = Struct{ .field = 42 };
try testFmt("struct: Struct{ .field = 42 }\n", "struct: {}\n", value);
try testFmt("struct: Struct{ .field = 42 }\n", "struct: {}\n", &value);
}
{
var buf1: [32]u8 = undefined;
@ -941,6 +955,7 @@ test "fmt.format" {
{
// This fails on release due to a minor rounding difference.
// --release-fast outputs 9.999960000000001e-40 vs. the expected.
// TODO fix this, it should be the same in Debug and ReleaseFast
if (builtin.mode == builtin.Mode.Debug) {
var buf1: [32]u8 = undefined;
const value: f64 = 9.999960e-40;
@ -1133,23 +1148,23 @@ test "fmt.format" {
y: f32,
pub fn format(
self: *SelfType,
self: SelfType,
comptime fmt: []const u8,
context: var,
comptime Errors: type,
output: fn (@typeOf(context), []const u8) Errors!void,
) Errors!void {
if (fmt.len > 0) {
if (fmt.len > 1) unreachable;
switch (fmt[0]) {
switch (fmt.len) {
0 => return std.fmt.format(context, Errors, output, "({.3},{.3})", self.x, self.y),
1 => switch (fmt[0]) {
//point format
'p' => return std.fmt.format(context, Errors, output, "({.3},{.3})", self.x, self.y),
//dimension format
'd' => return std.fmt.format(context, Errors, output, "{.3}x{.3}", self.x, self.y),
else => unreachable,
}
},
else => unreachable,
}
return std.fmt.format(context, Errors, output, "({.3},{.3})", self.x, self.y);
}
};
@ -1160,6 +1175,10 @@ test "fmt.format" {
};
try testFmt("point: (10.200,2.220)\n", "point: {}\n", &value);
try testFmt("dim: 10.200x2.220\n", "dim: {d}\n", &value);
// same thing but not passing a pointer
try testFmt("point: (10.200,2.220)\n", "point: {}\n", value);
try testFmt("dim: 10.200x2.220\n", "dim: {d}\n", value);
}
}