print field names on struct members.

also don't concatenate strings next
to each other in the struct,
like p.doprint does.

expose additional print flags to formatters

R=r
DELTA=128  (111 added, 11 deleted, 6 changed)
OCL=20991
CL=21018

src/lib/fmt/fmt_test.go

@@ -6,6 +6,7 @@ package fmt
 
 import (
 	"fmt";
+	"io";
 	"syscall";
 	"testing";
 )
@@ -163,3 +164,77 @@ export func TestSprintf(t *testing.T) {
 	}
 }
 
+type FlagPrinter struct { }
+func (*FlagPrinter) Format(f fmt.Formatter, c int) {
+	s := "%";
+	for i := 0; i < 128; i++ {
+		if f.Flag(i) {
+			s += string(i);
+		}
+	}
+	if w, ok := f.Width(); ok {
+		s += fmt.sprintf("%d", w);
+	}
+	if p, ok := f.Precision(); ok {
+		s += fmt.sprintf(".%d", p);
+	}
+	s += string(c);
+	io.WriteString(f, "["+s+"]");
+}
+
+type FlagTest struct {
+	in string;
+	out string;
+}
+
+var flagtests = []FlagTest {
+	FlagTest{ "%a", "[%a]" },
+	FlagTest{ "%-a", "[%-a]" },
+	FlagTest{ "%+a", "[%+a]" },
+	FlagTest{ "%#a", "[%#a]" },
+	FlagTest{ "% a", "[% a]" },
+	FlagTest{ "%0a", "[%0a]" },
+	FlagTest{ "%1.2a", "[%1.2a]" },
+	FlagTest{ "%-1.2a", "[%-1.2a]" },
+	FlagTest{ "%+1.2a", "[%+1.2a]" },
+	FlagTest{ "%-+1.2a", "[%+-1.2a]" },
+	FlagTest{ "%-+1.2abc", "[%+-1.2a]bc" },
+	FlagTest{ "%-1.2abc", "[%-1.2a]bc" },
+}
+
+export func TestFlagParser(t *testing.T) {
+	var flagprinter FlagPrinter;
+	for i := 0; i < len(flagtests); i++ {
+		tt := flagtests[i];
+		s := fmt.sprintf(tt.in, &flagprinter);
+		if s != tt.out {
+			t.Errorf("sprintf(%q, &flagprinter) => %q, want %q", tt.in, s, tt.out);
+		}
+	}
+}
+
+export func TestStructPrinter(t *testing.T) {
+	var s struct {
+		a string;
+		b string;
+		c int;
+	};
+	s.a = "abc";
+	s.b = "def";
+	s.c = 123;
+	type Test struct {
+		fmt string;
+		out string;
+	}
+	var tests = []Test {
+		Test{ "%v", "{abc def 123}" },
+		Test{ "%+v", "{a=abc b=def c=123}" },
+	};
+	for i := 0; i < len(tests); i++ {
+		tt := tests[i];
+		out := fmt.sprintf(tt.fmt, s);
+		if out != tt.out {
+			t.Errorf("sprintf(%q, &s) = %q, want %q", tt.fmt, out, tt.out);
+		}
+	}
+}

src/lib/fmt/format.go

@@ -50,7 +50,9 @@ export type Fmt struct {
 }
 
 func (f *Fmt) clearflags() {
+	f.wid = 0;
 	f.wid_present = false;
+	f.prec = 0;
 	f.prec_present = false;
 	f.minus = false;
 	f.plus = false;

src/lib/fmt/print.go

@@ -23,6 +23,9 @@ export type Formatter interface {
 	Write(b *[]byte) (ret int, err *os.Error);
 	Width()	(wid int, ok bool);
 	Precision()	(prec int, ok bool);
+
+	// flags
+	Flag(int)	bool;
 }
 
 type Format interface {
@@ -40,10 +43,6 @@ type P struct {
 	n	int;
 	buf	*[]byte;
 	fmt	*Fmt;
-	wid	int;
-	wid_ok	bool;
-	prec	int;
-	prec_ok	bool;
 }
 
 func Printer() *P {
@@ -53,11 +52,27 @@ func Printer() *P {
 }
 
 func (p *P) Width() (wid int, ok bool) {
-	return p.wid, p.wid_ok
+	return p.fmt.wid, p.fmt.wid_present
 }
 
 func (p *P) Precision() (prec int, ok bool) {
-	return p.prec, p.prec_ok
+	return p.fmt.prec, p.fmt.prec_present
+}
+
+func (p *P) Flag(b int) bool {
+	switch b {
+	case '-':
+		return p.fmt.minus;
+	case '+':
+		return p.fmt.plus;
+	case '#':
+		return p.fmt.sharp;
+	case ' ':
+		return p.fmt.space;
+	case '0':
+		return p.fmt.zero;
+	}
+	return false
 }
 
 func (p *P) ensure(n int) {
@@ -369,7 +384,21 @@ func (p *P) printField(field reflect.Value) (was_string bool) {
 		}
 	case reflect.StructKind:
 		p.add('{');
-		p.doprint(field, true, false);
+		v := field.(reflect.StructValue);
+		t := v.Type().(reflect.StructType);
+		donames := p.fmt.plus;	// first p.printField clears flag
+		for i := 0; i < v.Len();  i++ {
+			if i > 0 {
+				p.add(' ')
+			}
+			if donames {
+				if name, typ, tag, off := t.Field(i); name != "" {
+					p.addstr(name);
+					p.add('=');
+				}
+			}
+			p.printField(getField(v, i));
+		}
 		p.add('}');
 	case reflect.InterfaceKind:
 		inter := field.(reflect.InterfaceValue).Get();
@@ -398,7 +427,8 @@ func (p *P) doprintf(format string, v reflect.StructValue) {
 			continue;
 		}
 		i++;
-		// flags
+		// flags and widths
+		p.fmt.clearflags();
 		F: for ; i < end; i++ {
 			switch format[i] {
 			case '#':
@@ -416,11 +446,10 @@ func (p *P) doprintf(format string, v reflect.StructValue) {
 			}
 		}
 		// do we have 20 (width)?
-		p.wid, p.wid_ok, i = parsenum(format, i, end);
+		p.fmt.wid, p.fmt.wid_present, i = parsenum(format, i, end);
-		p.prec_ok = false;
 		// do we have .20 (precision)?
 		if i < end && format[i] == '.' {
-			p.prec, p.prec_ok, i = parsenum(format, i+1, end);
+			p.fmt.prec, p.fmt.prec_present, i = parsenum(format, i+1, end);
 		}
 		c, w = sys.stringtorune(format, i);
 		i += w;
@@ -445,12 +474,6 @@ func (p *P) doprintf(format string, v reflect.StructValue) {
 			}
 		}
 		s := "";
-		if p.wid_ok {
-			p.fmt.w(p.wid);
-		}
-		if p.prec_ok {
-			p.fmt.p(p.prec);
-		}
 		switch c {
 			// bool
 			case 't':