| // Copyright 2009 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| /* |
| Package fmt implements formatted I/O with functions analogous |
| to C's printf. The format 'verbs' are derived from C's but |
| are simpler. |
| |
| The verbs: |
| |
| General: |
| %v the value in a default format. |
| when printing structs, the plus flag (%+v) adds field names |
| %#v a Go-syntax representation of the value |
| %T a Go-syntax representation of the type of the value |
| |
| Boolean: |
| %t the word true or false |
| Integer: |
| %b base 2 |
| %c the character represented by the corresponding Unicode code point |
| %d base 10 |
| %o base 8 |
| %x base 16, with lower-case letters for a-f |
| %X base 16, with upper-case letters for A-F |
| Floating-point: |
| %e scientific notation, e.g. -1234.456e+78 |
| %E scientific notation, e.g. -1234.456E+78 |
| %f decimal point but no exponent, e.g. 123.456 |
| %g whichever of %e or %f produces more compact output |
| %G whichever of %E or %f produces more compact output |
| String and slice of bytes: |
| %s the uninterpreted bytes of the string or slice |
| %q a double-quoted string safely escaped with Go syntax |
| %x base 16 notation with two characters per byte |
| Pointer: |
| %p base 16 notation, with leading 0x |
| |
| There is no 'u' flag. Integers are printed unsigned if they have unsigned type. |
| Similarly, there is no need to specify the size of the operand (int8, int64). |
| |
| For numeric values, the width and precision flags control |
| formatting; width sets the width of the field, precision the |
| number of places after the decimal, if appropriate. The |
| format %6.2f prints 123.45. |
| |
| Other flags: |
| + always print a sign for numeric values |
| - pad with spaces on the right rather than the left (left-justify the field) |
| # alternate format: add leading 0 for octal (%#o), 0x for hex (%#x); |
| suppress 0x for %p (%#p); |
| print a raw (backquoted) string if possible for %q (%#q) |
| ' ' (space) leave a space for elided sign in numbers (% d); |
| put spaces between bytes printing strings or slices in hex (% x) |
| 0 pad with leading zeros rather than spaces |
| |
| For each Printf-like function, there is also a Print function |
| that takes no format and is equivalent to saying %v for every |
| operand. Another variant Println inserts blanks between |
| operands and appends a newline. |
| |
| Regardless of the verb, if an operand is an interface value, |
| the internal concrete value is used, not the interface itself. |
| Thus: |
| var i interface{} = 23; |
| fmt.Printf("%v\n", i); |
| will print 23. |
| |
| If an operand implements interface Formatter, that interface |
| can be used for fine control of formatting. |
| |
| If an operand implements method String() string that method |
| will be used for %v, %s, or Print etc. |
| */ |
| package fmt |
| |
| |
| import ( |
| "bytes" |
| "io" |
| "os" |
| "reflect" |
| "utf8" |
| ) |
| |
| // Some constants in the form of bytes, to avoid string overhead. |
| // Needlessly fastidious, I suppose. |
| var ( |
| trueBytes = []byte{'t', 'r', 'u', 'e'} |
| falseBytes = []byte{'f', 'a', 'l', 's', 'e'} |
| commaSpaceBytes = []byte{',', ' '} |
| nilAngleBytes = []byte{'<', 'n', 'i', 'l', '>'} |
| nilParenBytes = []byte{'(', 'n', 'i', 'l', ')'} |
| nilBytes = []byte{'n', 'i', 'l'} |
| mapBytes = []byte{'m', 'a', 'p', '['} |
| missingBytes = []byte{'m', 'i', 's', 's', 'i', 'n', 'g'} |
| extraBytes = []byte{'?', '(', 'e', 'x', 't', 'r', 'a', ' '} |
| ) |
| |
| // State represents the printer state passed to custom formatters. |
| // It provides access to the io.Writer interface plus information about |
| // the flags and options for the operand's format specifier. |
| type State interface { |
| // Write is the function to call to emit formatted output to be printed. |
| Write(b []byte) (ret int, err os.Error) |
| // Width returns the value of the width option and whether it has been set. |
| Width() (wid int, ok bool) |
| // Precision returns the value of the precision option and whether it has been set. |
| Precision() (prec int, ok bool) |
| |
| // Flag returns whether the flag c, a character, has been set. |
| Flag(int) bool |
| } |
| |
| // Formatter is the interface implemented by values with a custom formatter. |
| // The implementation of Format may call Sprintf or Fprintf(f) etc. |
| // to generate its output. |
| type Formatter interface { |
| Format(f State, c int) |
| } |
| |
| // Stringer is implemented by any value that has a String method(), |
| // which defines the ``native'' format for that value. |
| // The String method is used to print values passed as an operand |
| // to a %s or %v format or to an unformatted printer such as Print. |
| type Stringer interface { |
| String() string |
| } |
| |
| // GoStringer is implemented by any value that has a GoString() method, |
| // which defines the Go syntax for that value. |
| // The GoString method is used to print values passed as an operand |
| // to a %#v format. |
| type GoStringer interface { |
| GoString() string |
| } |
| |
| const allocSize = 32 |
| |
| type pp struct { |
| n int |
| buf bytes.Buffer |
| runeBuf [utf8.UTFMax]byte |
| fmt fmt |
| } |
| |
| // A leaky bucket of reusable pp structures. |
| var ppFree = make(chan *pp, 100) |
| |
| // Allocate a new pp struct. Probably can grab the previous one from ppFree. |
| func newPrinter() *pp { |
| p, ok := <-ppFree |
| if !ok { |
| p = new(pp) |
| } |
| p.fmt.init(&p.buf) |
| return p |
| } |
| |
| // Save used pp structs in ppFree; avoids an allocation per invocation. |
| func (p *pp) free() { |
| // Don't hold on to pp structs with large buffers. |
| if cap(p.buf.Bytes()) > 1024 { |
| return |
| } |
| p.buf.Reset() |
| _ = ppFree <- p |
| } |
| |
| func (p *pp) Width() (wid int, ok bool) { return p.fmt.wid, p.fmt.widPresent } |
| |
| func (p *pp) Precision() (prec int, ok bool) { return p.fmt.prec, p.fmt.precPresent } |
| |
| func (p *pp) 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 *pp) add(c int) { |
| if c < utf8.RuneSelf { |
| p.buf.WriteByte(byte(c)) |
| } else { |
| w := utf8.EncodeRune(c, &p.runeBuf) |
| p.buf.Write(p.runeBuf[0:w]) |
| } |
| } |
| |
| // Implement Write so we can call Fprintf on a pp (through State), for |
| // recursive use in custom verbs. |
| func (p *pp) Write(b []byte) (ret int, err os.Error) { |
| return p.buf.Write(b) |
| } |
| |
| // These routines end in 'f' and take a format string. |
| |
| // Fprintf formats according to a format specifier and writes to w. |
| func Fprintf(w io.Writer, format string, a ...) (n int, error os.Error) { |
| v := reflect.NewValue(a).(*reflect.StructValue) |
| p := newPrinter() |
| p.doprintf(format, v) |
| n64, error := p.buf.WriteTo(w) |
| p.free() |
| return int(n64), error |
| } |
| |
| // Printf formats according to a format specifier and writes to standard output. |
| func Printf(format string, v ...) (n int, errno os.Error) { |
| n, errno = Fprintf(os.Stdout, format, v) |
| return n, errno |
| } |
| |
| // Sprintf formats according to a format specifier and returns the resulting string. |
| func Sprintf(format string, a ...) string { |
| v := reflect.NewValue(a).(*reflect.StructValue) |
| p := newPrinter() |
| p.doprintf(format, v) |
| s := p.buf.String() |
| p.free() |
| return s |
| } |
| |
| // These routines do not take a format string |
| |
| // Fprint formats using the default formats for its operands and writes to w. |
| // Spaces are added between operands when neither is a string. |
| func Fprint(w io.Writer, a ...) (n int, error os.Error) { |
| v := reflect.NewValue(a).(*reflect.StructValue) |
| p := newPrinter() |
| p.doprint(v, false, false) |
| n64, error := p.buf.WriteTo(w) |
| p.free() |
| return int(n64), error |
| } |
| |
| // Print formats using the default formats for its operands and writes to standard output. |
| // Spaces are added between operands when neither is a string. |
| func Print(v ...) (n int, errno os.Error) { |
| n, errno = Fprint(os.Stdout, v) |
| return n, errno |
| } |
| |
| // Sprint formats using the default formats for its operands and returns the resulting string. |
| // Spaces are added between operands when neither is a string. |
| func Sprint(a ...) string { |
| v := reflect.NewValue(a).(*reflect.StructValue) |
| p := newPrinter() |
| p.doprint(v, false, false) |
| s := p.buf.String() |
| p.free() |
| return s |
| } |
| |
| // These routines end in 'ln', do not take a format string, |
| // always add spaces between operands, and add a newline |
| // after the last operand. |
| |
| // Fprintln formats using the default formats for its operands and writes to w. |
| // Spaces are always added between operands and a newline is appended. |
| func Fprintln(w io.Writer, a ...) (n int, error os.Error) { |
| v := reflect.NewValue(a).(*reflect.StructValue) |
| p := newPrinter() |
| p.doprint(v, true, true) |
| n64, error := p.buf.WriteTo(w) |
| p.free() |
| return int(n64), error |
| } |
| |
| // Println formats using the default formats for its operands and writes to standard output. |
| // Spaces are always added between operands and a newline is appended. |
| func Println(v ...) (n int, errno os.Error) { |
| n, errno = Fprintln(os.Stdout, v) |
| return n, errno |
| } |
| |
| // Sprintln formats using the default formats for its operands and returns the resulting string. |
| // Spaces are always added between operands and a newline is appended. |
| func Sprintln(a ...) string { |
| v := reflect.NewValue(a).(*reflect.StructValue) |
| p := newPrinter() |
| p.doprint(v, true, true) |
| s := p.buf.String() |
| p.free() |
| return s |
| } |
| |
| |
| // Get the i'th arg of the struct value. |
| // If the arg itself is an interface, return a value for |
| // the thing inside the interface, not the interface itself. |
| func getField(v *reflect.StructValue, i int) reflect.Value { |
| val := v.Field(i) |
| if i, ok := val.(*reflect.InterfaceValue); ok { |
| if inter := i.Interface(); inter != nil { |
| return reflect.NewValue(inter) |
| } |
| } |
| return val |
| } |
| |
| // Getters for the fields of the argument structure. |
| |
| func getBool(v reflect.Value) (val bool, ok bool) { |
| if b, ok := v.(*reflect.BoolValue); ok { |
| return b.Get(), true |
| } |
| return |
| } |
| |
| func getInt(v reflect.Value) (val int64, signed, ok bool) { |
| switch v := v.(type) { |
| case *reflect.IntValue: |
| return int64(v.Get()), true, true |
| case *reflect.Int8Value: |
| return int64(v.Get()), true, true |
| case *reflect.Int16Value: |
| return int64(v.Get()), true, true |
| case *reflect.Int32Value: |
| return int64(v.Get()), true, true |
| case *reflect.Int64Value: |
| return int64(v.Get()), true, true |
| case *reflect.UintValue: |
| return int64(v.Get()), false, true |
| case *reflect.Uint8Value: |
| return int64(v.Get()), false, true |
| case *reflect.Uint16Value: |
| return int64(v.Get()), false, true |
| case *reflect.Uint32Value: |
| return int64(v.Get()), false, true |
| case *reflect.Uint64Value: |
| return int64(v.Get()), false, true |
| case *reflect.UintptrValue: |
| return int64(v.Get()), false, true |
| } |
| return |
| } |
| |
| func getString(v reflect.Value) (val string, ok bool) { |
| if v, ok := v.(*reflect.StringValue); ok { |
| return v.Get(), true |
| } |
| if bytes, ok := v.Interface().([]byte); ok { |
| return string(bytes), true |
| } |
| return |
| } |
| |
| func getFloat32(v reflect.Value) (val float32, ok bool) { |
| switch v := v.(type) { |
| case *reflect.Float32Value: |
| return float32(v.Get()), true |
| case *reflect.FloatValue: |
| if v.Type().Size()*8 == 32 { |
| return float32(v.Get()), true |
| } |
| } |
| return |
| } |
| |
| func getFloat64(v reflect.Value) (val float64, ok bool) { |
| switch v := v.(type) { |
| case *reflect.FloatValue: |
| if v.Type().Size()*8 == 64 { |
| return float64(v.Get()), true |
| } |
| case *reflect.Float64Value: |
| return float64(v.Get()), true |
| } |
| return |
| } |
| |
| // Convert ASCII to integer. n is 0 (and got is false) if no number present. |
| |
| func parsenum(s string, start, end int) (n int, got bool, newi int) { |
| if start >= end { |
| return 0, false, end |
| } |
| isnum := false |
| num := 0 |
| for '0' <= s[start] && s[start] <= '9' { |
| num = num*10 + int(s[start]-'0') |
| start++ |
| isnum = true |
| } |
| return num, isnum, start |
| } |
| |
| type uintptrGetter interface { |
| Get() uintptr |
| } |
| |
| func (p *pp) printField(field reflect.Value, plus, sharp bool, depth int) (was_string bool) { |
| inter := field.Interface() |
| if inter != nil { |
| switch { |
| default: |
| if stringer, ok := inter.(Stringer); ok { |
| p.buf.WriteString(stringer.String()) |
| return false // this value is not a string |
| } |
| case sharp: |
| if stringer, ok := inter.(GoStringer); ok { |
| p.buf.WriteString(stringer.GoString()) |
| return false // this value is not a string |
| } |
| } |
| } |
| BigSwitch: |
| switch f := field.(type) { |
| case *reflect.BoolValue: |
| p.fmt.fmt_boolean(f.Get()) |
| case *reflect.Float32Value: |
| p.fmt.fmt_g32(f.Get()) |
| case *reflect.Float64Value: |
| p.fmt.fmt_g64(f.Get()) |
| case *reflect.FloatValue: |
| if field.Type().Size()*8 == 32 { |
| p.fmt.fmt_g32(float32(f.Get())) |
| } else { |
| p.fmt.fmt_g64(float64(f.Get())) |
| } |
| case *reflect.StringValue: |
| if sharp { |
| p.fmt.fmt_q(f.Get()) |
| } else { |
| p.fmt.fmt_s(f.Get()) |
| was_string = true |
| } |
| case *reflect.MapValue: |
| if sharp { |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte('{') |
| } else { |
| p.buf.Write(mapBytes) |
| } |
| keys := f.Keys() |
| for i, key := range keys { |
| if i > 0 { |
| if sharp { |
| p.buf.Write(commaSpaceBytes) |
| } else { |
| p.buf.WriteByte(' ') |
| } |
| } |
| p.printField(key, plus, sharp, depth+1) |
| p.buf.WriteByte(':') |
| p.printField(f.Elem(key), plus, sharp, depth+1) |
| } |
| if sharp { |
| p.buf.WriteByte('}') |
| } else { |
| p.buf.WriteByte(']') |
| } |
| case *reflect.StructValue: |
| if sharp { |
| p.buf.WriteString(field.Type().String()) |
| } |
| p.add('{') |
| v := f |
| t := v.Type().(*reflect.StructType) |
| p.fmt.clearflags() // clear flags for p.printField |
| for i := 0; i < v.NumField(); i++ { |
| if i > 0 { |
| if sharp { |
| p.buf.Write(commaSpaceBytes) |
| } else { |
| p.buf.WriteByte(' ') |
| } |
| } |
| if plus || sharp { |
| if f := t.Field(i); f.Name != "" { |
| p.buf.WriteString(f.Name) |
| p.buf.WriteByte(':') |
| } |
| } |
| p.printField(getField(v, i), plus, sharp, depth+1) |
| } |
| p.buf.WriteByte('}') |
| case *reflect.InterfaceValue: |
| value := f.Elem() |
| if value == nil { |
| if sharp { |
| p.buf.WriteString(field.Type().String()) |
| p.buf.Write(nilParenBytes) |
| } else { |
| p.buf.Write(nilAngleBytes) |
| } |
| } else { |
| return p.printField(value, plus, sharp, depth+1) |
| } |
| case reflect.ArrayOrSliceValue: |
| if sharp { |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte('{') |
| } else { |
| p.buf.WriteByte('[') |
| } |
| for i := 0; i < f.Len(); i++ { |
| if i > 0 { |
| if sharp { |
| p.buf.Write(commaSpaceBytes) |
| } else { |
| p.buf.WriteByte(' ') |
| } |
| } |
| p.printField(f.Elem(i), plus, sharp, depth+1) |
| } |
| if sharp { |
| p.buf.WriteByte('}') |
| } else { |
| p.buf.WriteByte(']') |
| } |
| case *reflect.PtrValue: |
| v := f.Get() |
| // pointer to array or slice or struct? ok at top level |
| // but not embedded (avoid loops) |
| if v != 0 && depth == 0 { |
| switch a := f.Elem().(type) { |
| case reflect.ArrayOrSliceValue: |
| p.buf.WriteByte('&') |
| p.printField(a, plus, sharp, depth+1) |
| break BigSwitch |
| case *reflect.StructValue: |
| p.buf.WriteByte('&') |
| p.printField(a, plus, sharp, depth+1) |
| break BigSwitch |
| } |
| } |
| if sharp { |
| p.buf.WriteByte('(') |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte(')') |
| p.buf.WriteByte('(') |
| if v == 0 { |
| p.buf.Write(nilBytes) |
| } else { |
| p.fmt.sharp = true |
| p.fmt.fmt_ux64(uint64(v)) |
| } |
| p.buf.WriteByte(')') |
| break |
| } |
| if v == 0 { |
| p.buf.Write(nilAngleBytes) |
| break |
| } |
| p.fmt.sharp = true // turn 0x on |
| p.fmt.fmt_ux64(uint64(v)) |
| case uintptrGetter: |
| v := f.Get() |
| if sharp { |
| p.buf.WriteByte('(') |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte(')') |
| p.buf.WriteByte('(') |
| if v == 0 { |
| p.buf.Write(nilBytes) |
| } else { |
| p.fmt.sharp = true |
| p.fmt.fmt_ux64(uint64(v)) |
| } |
| p.buf.WriteByte(')') |
| } else { |
| p.fmt.sharp = true // turn 0x on |
| p.fmt.fmt_ux64(uint64(f.Get())) |
| } |
| default: |
| v, signed, ok := getInt(field) |
| if ok { |
| if signed { |
| p.fmt.fmt_d64(v) |
| } else { |
| if sharp { |
| p.fmt.sharp = true // turn on 0x |
| p.fmt.fmt_ux64(uint64(v)) |
| } else { |
| p.fmt.fmt_ud64(uint64(v)) |
| } |
| } |
| break |
| } |
| p.buf.WriteByte('?') |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte('?') |
| } |
| return was_string |
| } |
| |
| func (p *pp) doprintf(format string, v *reflect.StructValue) { |
| end := len(format) - 1 |
| fieldnum := 0 // we process one field per non-trivial format |
| for i := 0; i <= end; { |
| c, w := utf8.DecodeRuneInString(format[i:]) |
| if c != '%' || i == end { |
| if w == 1 { |
| p.buf.WriteByte(byte(c)) |
| } else { |
| p.buf.WriteString(format[i : i+w]) |
| } |
| i += w |
| continue |
| } |
| i++ |
| // flags and widths |
| p.fmt.clearflags() |
| F: for ; i < end; i++ { |
| switch format[i] { |
| case '#': |
| p.fmt.sharp = true |
| case '0': |
| p.fmt.zero = true |
| case '+': |
| p.fmt.plus = true |
| case '-': |
| p.fmt.minus = true |
| case ' ': |
| p.fmt.space = true |
| default: |
| break F |
| } |
| } |
| // do we have 20 (width)? |
| p.fmt.wid, p.fmt.widPresent, i = parsenum(format, i, end) |
| // do we have .20 (precision)? |
| if i < end && format[i] == '.' { |
| p.fmt.prec, p.fmt.precPresent, i = parsenum(format, i+1, end) |
| } |
| c, w = utf8.DecodeRuneInString(format[i:]) |
| i += w |
| // percent is special - absorbs no operand |
| if c == '%' { |
| p.buf.WriteByte('%') // TODO: should we bother with width & prec? |
| continue |
| } |
| if fieldnum >= v.NumField() { // out of operands |
| p.buf.WriteByte('%') |
| p.add(c) |
| p.buf.Write(missingBytes) |
| continue |
| } |
| field := getField(v, fieldnum) |
| fieldnum++ |
| |
| // Try formatter except for %T, |
| // which is special and handled internally. |
| inter := field.Interface() |
| if inter != nil && c != 'T' { |
| if formatter, ok := inter.(Formatter); ok { |
| formatter.Format(p, c) |
| continue |
| } |
| } |
| |
| switch c { |
| // bool |
| case 't': |
| if v, ok := getBool(field); ok { |
| if v { |
| p.buf.Write(trueBytes) |
| } else { |
| p.buf.Write(falseBytes) |
| } |
| } else { |
| goto badtype |
| } |
| |
| // int |
| case 'b': |
| if v, _, ok := getInt(field); ok { |
| p.fmt.fmt_b64(uint64(v)) // always unsigned |
| } else if v, ok := getFloat32(field); ok { |
| p.fmt.fmt_fb32(v) |
| } else if v, ok := getFloat64(field); ok { |
| p.fmt.fmt_fb64(v) |
| } else { |
| goto badtype |
| } |
| case 'c': |
| if v, _, ok := getInt(field); ok { |
| p.fmt.fmt_c(int(v)) |
| } else { |
| goto badtype |
| } |
| case 'd': |
| if v, signed, ok := getInt(field); ok { |
| if signed { |
| p.fmt.fmt_d64(v) |
| } else { |
| p.fmt.fmt_ud64(uint64(v)) |
| } |
| } else { |
| goto badtype |
| } |
| case 'o': |
| if v, signed, ok := getInt(field); ok { |
| if signed { |
| p.fmt.fmt_o64(v) |
| } else { |
| p.fmt.fmt_uo64(uint64(v)) |
| } |
| } else { |
| goto badtype |
| } |
| case 'x': |
| if v, signed, ok := getInt(field); ok { |
| if signed { |
| p.fmt.fmt_x64(v) |
| } else { |
| p.fmt.fmt_ux64(uint64(v)) |
| } |
| } else if v, ok := getString(field); ok { |
| p.fmt.fmt_sx(v) |
| } else { |
| goto badtype |
| } |
| case 'X': |
| if v, signed, ok := getInt(field); ok { |
| if signed { |
| p.fmt.fmt_X64(v) |
| } else { |
| p.fmt.fmt_uX64(uint64(v)) |
| } |
| } else if v, ok := getString(field); ok { |
| p.fmt.fmt_sX(v) |
| } else { |
| goto badtype |
| } |
| |
| // float |
| case 'e': |
| if v, ok := getFloat32(field); ok { |
| p.fmt.fmt_e32(v) |
| } else if v, ok := getFloat64(field); ok { |
| p.fmt.fmt_e64(v) |
| } else { |
| goto badtype |
| } |
| case 'E': |
| if v, ok := getFloat32(field); ok { |
| p.fmt.fmt_E32(v) |
| } else if v, ok := getFloat64(field); ok { |
| p.fmt.fmt_E64(v) |
| } else { |
| goto badtype |
| } |
| case 'f': |
| if v, ok := getFloat32(field); ok { |
| p.fmt.fmt_f32(v) |
| } else if v, ok := getFloat64(field); ok { |
| p.fmt.fmt_f64(v) |
| } else { |
| goto badtype |
| } |
| case 'g': |
| if v, ok := getFloat32(field); ok { |
| p.fmt.fmt_g32(v) |
| } else if v, ok := getFloat64(field); ok { |
| p.fmt.fmt_g64(v) |
| } else { |
| goto badtype |
| } |
| case 'G': |
| if v, ok := getFloat32(field); ok { |
| p.fmt.fmt_G32(v) |
| } else if v, ok := getFloat64(field); ok { |
| p.fmt.fmt_G64(v) |
| } else { |
| goto badtype |
| } |
| |
| // string |
| case 's': |
| if inter != nil { |
| // if object implements String, use the result. |
| if stringer, ok := inter.(Stringer); ok { |
| p.fmt.fmt_s(stringer.String()) |
| break |
| } |
| } |
| if v, ok := getString(field); ok { |
| p.fmt.fmt_s(v) |
| } else { |
| goto badtype |
| } |
| case 'q': |
| if v, ok := getString(field); ok { |
| p.fmt.fmt_q(v) |
| } else { |
| goto badtype |
| } |
| |
| // pointer, including addresses of reference types. |
| case 'p': |
| switch v := field.(type) { |
| case *reflect.PtrValue: |
| p.fmt.fmt_s("0x") |
| p.fmt.fmt_uX64(uint64(v.Get())) |
| case *reflect.ChanValue, *reflect.MapValue, *reflect.SliceValue: |
| p.fmt.fmt_s("0x") |
| p.fmt.fmt_uX64(uint64(field.Addr())) |
| default: |
| goto badtype |
| } |
| |
| // arbitrary value; do your best |
| case 'v': |
| plus, sharp := p.fmt.plus, p.fmt.sharp |
| p.fmt.plus = false |
| p.fmt.sharp = false |
| p.printField(field, plus, sharp, 0) |
| |
| // the value's type |
| case 'T': |
| p.buf.WriteString(field.Type().String()) |
| |
| default: |
| badtype: |
| p.buf.WriteByte('%') |
| p.add(c) |
| p.buf.WriteByte('(') |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte('=') |
| p.printField(field, false, false, 0) |
| p.buf.WriteByte(')') |
| } |
| } |
| if fieldnum < v.NumField() { |
| p.buf.Write(extraBytes) |
| for ; fieldnum < v.NumField(); fieldnum++ { |
| field := getField(v, fieldnum) |
| p.buf.WriteString(field.Type().String()) |
| p.buf.WriteByte('=') |
| p.printField(field, false, false, 0) |
| if fieldnum+1 < v.NumField() { |
| p.buf.Write(commaSpaceBytes) |
| } |
| } |
| p.buf.WriteByte(')') |
| } |
| } |
| |
| func (p *pp) doprint(v *reflect.StructValue, addspace, addnewline bool) { |
| prev_string := false |
| for fieldnum := 0; fieldnum < v.NumField(); fieldnum++ { |
| // always add spaces if we're doing println |
| field := getField(v, fieldnum) |
| if fieldnum > 0 { |
| _, is_string := field.(*reflect.StringValue) |
| if addspace || !is_string && !prev_string { |
| p.buf.WriteByte(' ') |
| } |
| } |
| prev_string = p.printField(field, false, false, 0) |
| } |
| if addnewline { |
| p.buf.WriteByte('\n') |
| } |
| } |