mirror of
https://github.com/vlang/v.git
synced 2023-08-10 21:13:21 +03:00
264 lines
6.7 KiB
Go
264 lines
6.7 KiB
Go
|
|
// module flag for command-line flag parsing
|
|
//
|
|
// - parsing flags like '--flag' or '--stuff=things' or '--things stuff'
|
|
// - handles bool, int, float and string args
|
|
// - is able to pring usage
|
|
// - handled unknown arguments as error
|
|
//
|
|
// Usage example:
|
|
//
|
|
// ```v
|
|
// module main
|
|
//
|
|
// import os
|
|
// import flag
|
|
//
|
|
// fn main() {
|
|
// mut fp := flag.new_flag_parser(os.args)
|
|
// fp.application('flag_example_tool')
|
|
// fp.version('v0.0.0')
|
|
// fp.description('This tool is only designed to show how the flag lib is working')
|
|
//
|
|
// fp.skip_executable()
|
|
//
|
|
// an_int := fp.int('an_int', 666, 'some int to define 666 is default')
|
|
// a_bool := fp.bool('a_bool', false, 'some \'real\' flag')
|
|
// a_float := fp.float('a_float', 1.0, 'also floats')
|
|
// a_string := fp.string('a_string', 'no text', 'finally, some text')
|
|
//
|
|
// additional_args := fp.finalize() or {
|
|
// eprintln(err)
|
|
// println(fp.usage())
|
|
// return
|
|
// }
|
|
//
|
|
// println('
|
|
// an_int: $an_int
|
|
// a_bool: $a_bool
|
|
// a_float: $a_float
|
|
// a_string: \'$a_string\'
|
|
// ')
|
|
// println(additional_args.join_lines())
|
|
// }
|
|
// ```
|
|
|
|
module flag
|
|
|
|
// data object storing informations about a defined flag
|
|
struct Flag {
|
|
pub:
|
|
name string // name as it appears on command line
|
|
usage string // help message
|
|
val_desc string // something like '<arg>' that appears in usage
|
|
}
|
|
|
|
//
|
|
struct FlagParser {
|
|
pub mut:
|
|
args []string // the arguments to be parsed
|
|
flags []Flag // registered flags
|
|
|
|
application_name string
|
|
application_version string
|
|
application_description string
|
|
}
|
|
|
|
// create a new flag set for parsing command line arguments
|
|
pub fn new_flag_parser(args []string) &FlagParser {
|
|
return &FlagParser{args:args}
|
|
}
|
|
|
|
// change the application name to be used in 'usage' output
|
|
pub fn (fs mut FlagParser) application(n string) {
|
|
fs.application_name = n
|
|
}
|
|
|
|
// change the application version to be used in 'usage' output
|
|
pub fn (fs mut FlagParser) version(n string) {
|
|
fs.application_version = n
|
|
}
|
|
|
|
// change the application version to be used in 'usage' output
|
|
pub fn (fs mut FlagParser) description(n string) {
|
|
fs.application_description = n
|
|
}
|
|
|
|
// in most cases you do not need the first argv for flag parsing
|
|
pub fn (fs mut FlagParser) skip_executable() {
|
|
fs.args.delete(0)
|
|
}
|
|
|
|
// private helper to register a flag
|
|
fn (fs mut FlagParser) add_flag(n, u, vd string) {
|
|
fs.flags << Flag{
|
|
name: n,
|
|
usage: u
|
|
val_desc: vd
|
|
}
|
|
}
|
|
|
|
// private: general parsing a single argument
|
|
// - search args for existance
|
|
// if true
|
|
// extract the defined value as string
|
|
// else
|
|
// return an (dummy) error -> argument is not defined
|
|
//
|
|
// - the name, usage are registered
|
|
// - found arguments and corresponding values are removed from args list
|
|
fn (fs mut FlagParser) parse_value(n string) ?string {
|
|
c := '--$n'
|
|
for i, a in fs.args {
|
|
if a == c {
|
|
if fs.args.len > i+1 && fs.args[i+1].left(2) != '--' {
|
|
val := fs.args[i+1]
|
|
fs.args.delete(i+1)
|
|
fs.args.delete(i)
|
|
return val
|
|
} else {
|
|
panic('Missing argument for \'$n\'')
|
|
}
|
|
} else if a.len > c.len && c == a.left(c.len) && a.substr(c.len, c.len+1) == '=' {
|
|
val := a.right(c.len+1)
|
|
fs.args.delete(i)
|
|
return val
|
|
}
|
|
}
|
|
return error('parameter \'$n\' not found')
|
|
}
|
|
|
|
// special parsing for bool values
|
|
// see also: parse_value
|
|
//
|
|
// special: it is allowed to define bool flags without value
|
|
// -> '--flag' is parsed as true
|
|
// -> '--flag' is equal to '--flag=true'
|
|
fn (fs mut FlagParser) parse_bool_value(n string) ?string {
|
|
c := '--$n'
|
|
for i, a in fs.args {
|
|
if a == c {
|
|
if fs.args.len > i+1 && (fs.args[i+1] in ['true', 'false']) {
|
|
val := fs.args[i+1]
|
|
fs.args.delete(i+1)
|
|
fs.args.delete(i)
|
|
return val
|
|
} else {
|
|
val := 'true'
|
|
fs.args.delete(i)
|
|
return val
|
|
}
|
|
} else if a.len > c.len && c == a.left(c.len) && a.substr(c.len, c.len+1) == '=' {
|
|
val := a.right(c.len+1)
|
|
fs.args.delete(i)
|
|
return val
|
|
}
|
|
}
|
|
return error('parameter \'$n\' not found')
|
|
}
|
|
|
|
// defining and parsing a bool flag
|
|
// if defined
|
|
// the value is returned (true/false)
|
|
// else
|
|
// the default value is returned
|
|
//TODO error handling for invalid string to bool conversion
|
|
pub fn (fs mut FlagParser) bool(n string, v bool, u string) bool {
|
|
fs.add_flag(n, u, '')
|
|
parsed := fs.parse_bool_value(n) or {
|
|
return v
|
|
}
|
|
return parsed == 'true'
|
|
}
|
|
|
|
// defining and parsing an int flag
|
|
// if defined
|
|
// the value is returned (int)
|
|
// else
|
|
// the default value is returned
|
|
//TODO error handling for invalid string to int conversion
|
|
pub fn (fs mut FlagParser) int(n string, i int, u string) int {
|
|
fs.add_flag(n, u, '<int>')
|
|
parsed := fs.parse_value(n) or {
|
|
return i
|
|
}
|
|
return parsed.int()
|
|
}
|
|
|
|
// defining and parsing a flaot flag
|
|
// if defined
|
|
// the value is returned (float)
|
|
// else
|
|
// the default value is returned
|
|
//TODO error handling for invalid string to float conversion
|
|
pub fn (fs mut FlagParser) float(n string, f f32, u string) f32 {
|
|
fs.add_flag(n, u, '<float>')
|
|
parsed := fs.parse_value(n) or {
|
|
return f
|
|
}
|
|
return parsed.f32()
|
|
}
|
|
|
|
// defining and parsing a string flag
|
|
// if defined
|
|
// the value is returned (string)
|
|
// else
|
|
// the default value is returned
|
|
pub fn (fs mut FlagParser) string(n, v, u string) string {
|
|
fs.add_flag(n, u, '<arg>')
|
|
parsed := fs.parse_value(n) or {
|
|
return v
|
|
}
|
|
return parsed
|
|
}
|
|
|
|
const (
|
|
// used for formating usage message
|
|
SPACE = ' '
|
|
)
|
|
|
|
// collect all given information and
|
|
pub fn (fs FlagParser) usage() string {
|
|
mut use := '\n'
|
|
use += 'usage ${fs.application_name} [options] [ARGS]\n'
|
|
use += '\n'
|
|
|
|
if fs.flags.len > 0 {
|
|
use += 'options:\n'
|
|
for f in fs.flags {
|
|
flag_desc := ' --$f.name $f.val_desc'
|
|
space := if flag_desc.len > SPACE.len-2 {
|
|
'\n$SPACE'
|
|
} else {
|
|
SPACE.right(flag_desc.len)
|
|
}
|
|
use += '$flag_desc$space$f.usage\n'
|
|
}
|
|
}
|
|
|
|
use += '\n'
|
|
use += '$fs.application_name $fs.application_version\n'
|
|
if fs.application_description != '' {
|
|
use += '\n'
|
|
use += 'description:\n'
|
|
use += '$fs.application_description'
|
|
}
|
|
return use
|
|
}
|
|
|
|
// finalize argument parsing -> call after all arguments are defined
|
|
//
|
|
// all remaining arguments are returned in the same order they are defined on
|
|
// commandline
|
|
//
|
|
// if additional flag are found (things starting with '--') an error is returned
|
|
// error handling is up to the application developer
|
|
pub fn (fs FlagParser) finalize() ?[]string {
|
|
for a in fs.args {
|
|
if a.left(2) == '--' {
|
|
return error('Unknown argument \'${a.right(2)}\'')
|
|
}
|
|
}
|
|
return fs.args
|
|
}
|