diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/lib/Makefile | 2 | ||||
| -rw-r--r-- | src/lib/flag.go | 54 |
2 files changed, 46 insertions, 10 deletions
diff --git a/src/lib/Makefile b/src/lib/Makefile index 089c328f5..39dce2b90 100644 --- a/src/lib/Makefile +++ b/src/lib/Makefile @@ -96,7 +96,7 @@ test: test.files bignum.6: fmt.dirinstall bufio.6: io.dirinstall os.dirinstall exec.6: os.dirinstall -flag.6: fmt.dirinstall +flag.6: fmt.dirinstall os.dirinstall strconv.dirinstall log.6: fmt.dirinstall io.dirinstall os.dirinstall time.dirinstall once.6: sync.dirinstall strings.6: utf8.install diff --git a/src/lib/flag.go b/src/lib/flag.go index 164b9c5ba..f8e31ca68 100644 --- a/src/lib/flag.go +++ b/src/lib/flag.go @@ -2,8 +2,6 @@ // Use of this source code is governed by a BSD-style // license that can be found in the LICENSE file. -package flag - /* * Flags * @@ -41,9 +39,11 @@ package flag * Integer flags accept 1234, 0664, 0x1234 and may be negative. * Boolean flags may be 1, 0, t, f, true, false, TRUE, FALSE, True, False. */ +package flag import ( "fmt"; + "os"; "strconv" ) @@ -186,13 +186,14 @@ func (s *stringValue) String() string { return fmt.Sprintf("%s", *s.p) } -// -- FlagValue interface +// FlagValue is the interface to the dynamic value stored in a flag. +// (The default value is represented as a string.) type FlagValue interface { String() string; set(string) bool; } -// -- Flag structure +// A Flag represents the state of a flag. type Flag struct { Name string; // name as it appears on command line Usage string; // help message @@ -208,20 +209,21 @@ type allFlags struct { var flags *allFlags = &allFlags{make(map[string] *Flag), make(map[string] *Flag), 1} -// Visit all flags, including those defined but not set. +// VisitAll visits the flags, calling fn for each. It visits all flags, even those not set. func VisitAll(fn func(*Flag)) { for k, f := range flags.formal { fn(f) } } -// Visit only those flags that have been set +// Visit visits the flags, calling fn for each. It visits only those flags that have been set. func Visit(fn func(*Flag)) { for k, f := range flags.actual { fn(f) } } +// Lookup returns the Flag structure of the named flag, returning nil if none exists. func Lookup(name string) *Flag { f, ok := flags.formal[name]; if !ok { @@ -230,6 +232,8 @@ func Lookup(name string) *Flag { return f } +// Set sets the value of tne named flag. It returns true if the set succeeded; false if +// there is no such flag defined. func Set(name, value string) bool { f, ok := flags.formal[name]; if !ok { @@ -243,6 +247,7 @@ func Set(name, value string) bool { return true; } +// PrintDefaults prints to standard error the default values of all defined flags. func PrintDefaults() { VisitAll(func(f *Flag) { format := " -%s=%s: %s\n"; @@ -250,15 +255,17 @@ func PrintDefaults() { // put quotes on the value format = " -%s=%q: %s\n"; } - fmt.Printf(format, f.Name, f.DefValue, f.Usage); + fmt.Fprintf(os.Stderr, format, f.Name, f.DefValue, f.Usage); }) } +// Usage prints to standard error a default usage message documenting all defined flags and +// then calls sys.Exit(1). func Usage() { if len(sys.Args) > 0 { - print("Usage of ", sys.Args[0], ": \n"); + fmt.Fprintf(os.Stderr, "Usage of ", sys.Args[0], ": \n"); } else { - print("Usage: \n"); + fmt.Fprintf(os.Stderr, "Usage: \n"); } PrintDefaults(); sys.Exit(1); @@ -268,6 +275,8 @@ func NFlag() int { return len(flags.actual) } +// Arg returns the i'th command-line argument. Arg(0) is the first remaining argument +// after flags have been processed. func Arg(i int) string { i += flags.first_arg; if i < 0 || i >= len(sys.Args) { @@ -276,6 +285,7 @@ func Arg(i int) string { return sys.Args[i] } +// NArg is the number of arguments remaining after flags have been processed. func NArg() int { return len(sys.Args) - flags.first_arg } @@ -291,60 +301,84 @@ func add(name string, value FlagValue, usage string) { flags.formal[name] = f; } +// BoolVar defines a bool flag with specified name, default value, and usage string. +// The argument p points to a bool variable in which to store the value of the flag. func BoolVar(p *bool, name string, value bool, usage string) { add(name, newBoolValue(value, p), usage); } +// Bool defines a bool flag with specified name, default value, and usage string. +// The return value is the address of a bool variable that stores the value of the flag. func Bool(name string, value bool, usage string) *bool { p := new(bool); BoolVar(p, name, value, usage); return p; } +// IntVar defines an int flag with specified name, default value, and usage string. +// The argument p points to an int variable in which to store the value of the flag. func IntVar(p *int, name string, value int, usage string) { add(name, newIntValue(value, p), usage); } +// Int defines an int flag with specified name, default value, and usage string. +// The return value is the address of an int variable that stores the value of the flag. func Int(name string, value int, usage string) *int { p := new(int); IntVar(p, name, value, usage); return p; } +// Int64Var defines an int64 flag with specified name, default value, and usage string. +// The argument p points to an int64 variable in which to store the value of the flag. func Int64Var(p *int64, name string, value int64, usage string) { add(name, newInt64Value(value, p), usage); } +// Int64 defines an int64 flag with specified name, default value, and usage string. +// The return value is the address of an int64 variable that stores the value of the flag. func Int64(name string, value int64, usage string) *int64 { p := new(int64); Int64Var(p, name, value, usage); return p; } +// UintVar defines a uint flag with specified name, default value, and usage string. +// The argument p points to a uint variable in which to store the value of the flag. func UintVar(p *uint, name string, value uint, usage string) { add(name, newUintValue(value, p), usage); } +// Uint defines a uint flag with specified name, default value, and usage string. +// The return value is the address of a uint variable that stores the value of the flag. func Uint(name string, value uint, usage string) *uint { p := new(uint); UintVar(p, name, value, usage); return p; } +// Uint64Var defines a uint64 flag with specified name, default value, and usage string. +// The argument p points to a uint64 variable in which to store the value of the flag. func Uint64Var(p *uint64, name string, value uint64, usage string) { add(name, newUint64Value(value, p), usage); } +// Uint64 defines a uint64 flag with specified name, default value, and usage string. +// The return value is the address of a uint64 variable that stores the value of the flag. func Uint64(name string, value uint64, usage string) *uint64 { p := new(uint64); Uint64Var(p, name, value, usage); return p; } +// StringVar defines a string flag with specified name, default value, and usage string. +// The argument p points to a string variable in which to store the value of the flag. func StringVar(p *string, name, value string, usage string) { add(name, newStringValue(value, p), usage); } +// String defines a string flag with specified name, default value, and usage string. +// The return value is the address of a string variable that stores the value of the flag. func String(name, value string, usage string) *string { p := new(string); StringVar(p, name, value, usage); @@ -430,6 +464,8 @@ func (f *allFlags) parseOne(index int) (ok bool, next int) return true, index + 1 } +// Parse parses the command-line flags. Must be called after all flags are defined +// and before any are accessed by the program. func Parse() { for i := 1; i < len(sys.Args); { ok, next := flags.parseOne(i); |