mirror of
https://github.com/vlang/v.git
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443 lines
13 KiB
V
443 lines
13 KiB
V
module flag
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// data object storing information about a defined flag
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pub struct Flag {
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pub:
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name string // name as it appears on command line
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abbr byte // shortcut
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usage string // help message
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val_desc string // something like '<arg>' that appears in usage,
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// and also the default value, when the flag is not given
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}
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pub fn (f Flag) str() string {
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return ''
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+' flag:\n'
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+' name: $f.name\n'
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+' abbr: $f.abbr\n'
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+' usag: $f.usage\n'
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+' desc: $f.val_desc'
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}
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pub fn (af []Flag) str() string {
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mut res := []string{}
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res << '\n []Flag = ['
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for f in af {
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res << f.str()
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}
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res << ' ]'
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return res.join('\n')
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}
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//
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pub struct FlagParser {
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pub mut:
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args []string // the arguments to be parsed
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max_free_args int
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flags []Flag // registered flags
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application_name string
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application_version string
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application_description string
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min_free_args int
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args_description string
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}
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pub const (
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// used for formating usage message
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space = ' '
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underline = '-----------------------------------------------'
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max_args_number = 4048
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)
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// create a new flag set for parsing command line arguments
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// TODO use INT_MAX some how
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pub fn new_flag_parser(args []string) &FlagParser {
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return &FlagParser{args: args.clone(), max_free_args: max_args_number}
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}
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// change the application name to be used in 'usage' output
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pub fn (mut fs FlagParser) application(name string) {
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fs.application_name = name
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}
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// change the application version to be used in 'usage' output
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pub fn (mut fs FlagParser) version(vers string) {
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fs.application_version = vers
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}
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// change the application version to be used in 'usage' output
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pub fn (mut fs FlagParser) description(desc string) {
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fs.application_description = desc
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}
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// in most cases you do not need the first argv for flag parsing
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pub fn (mut fs FlagParser) skip_executable() {
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fs.args.delete(0)
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}
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// private helper to register a flag
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fn (mut fs FlagParser) add_flag(name string, abbr byte, usage string, desc string) {
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fs.flags << Flag{
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name: name,
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abbr: abbr,
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usage: usage,
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val_desc: desc
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}
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}
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// private: general parsing a single argument
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// - search args for existence
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// if true
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// extract the defined value as string
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// else
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// return an (dummy) error -> argument is not defined
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//
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// - the name, usage are registered
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// - found arguments and corresponding values are removed from args list
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fn (mut fs FlagParser) parse_value(longhand string, shorthand byte) []string {
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full := '--$longhand'
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mut found_entries := []string{}
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mut to_delete := []int{}
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mut should_skip_one := false
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for i, arg in fs.args {
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if should_skip_one {
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should_skip_one = false
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continue
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}
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if arg == '--' {
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//End of input. We're done here.
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break
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}
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if arg[0] != `-` {
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continue
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}
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if (arg.len == 2 && arg[0] == `-` && arg[1] == shorthand ) || arg == full {
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if i+1 >= fs.args.len {
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panic("Missing argument for '$longhand'")
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}
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nextarg := fs.args[i+1]
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if nextarg.len > 2 && nextarg[..2] == '--' {
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//It could be end of input (--) or another argument (--abc).
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//Both are invalid so die.
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panic("Missing argument for '$longhand'")
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}
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found_entries << fs.args[i+1]
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to_delete << i
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to_delete << i+1
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should_skip_one = true
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continue
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}
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if arg.len > full.len+1 && arg[..full.len+1] == '$full=' {
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found_entries << arg[full.len+1..]
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to_delete << i
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continue
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}
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}
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for i, del in to_delete {
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//i entrys are deleted so it's shifted left i times.
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fs.args.delete(del - i)
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}
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return found_entries
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}
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// special parsing for bool values
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// see also: parse_value
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//
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// special: it is allowed to define bool flags without value
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// -> '--flag' is parsed as true
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// -> '--flag' is equal to '--flag=true'
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fn (mut fs FlagParser) parse_bool_value(longhand string, shorthand byte) ?string {
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full := '--$longhand'
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for i, arg in fs.args {
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if arg == '--' {
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//End of input. We're done.
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break
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}
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if arg.len == 0 {
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continue
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}
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if arg[0] != `-` {
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continue
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}
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if ( arg.len == 2 && arg[0] == `-` && arg[1] == shorthand ) || arg == full {
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if fs.args.len > i+1 && (fs.args[i+1] in ['true', 'false']) {
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val := fs.args[i+1]
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fs.args.delete(i+1)
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fs.args.delete(i)
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return val
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} else {
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fs.args.delete(i)
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return 'true'
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}
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}
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if arg.len > full.len+1 && arg[..full.len+1] == '$full=' {
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// Flag abc=true
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val := arg[full.len+1..]
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fs.args.delete(i)
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return val
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}
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if arg.len > 1 && arg[0] == `-` && arg[1] != `-` && arg.index_byte(shorthand) != -1 {
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// -abc is equivalent to -a -b -c
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return 'true'
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}
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}
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return error("parameter '$longhand' not found")
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}
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// bool_opt returns an optional that returns the value associated with the flag.
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// In the situation that the flag was not provided, it returns null.
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pub fn (mut fs FlagParser) bool_opt(name string, abbr byte, usage string) ?bool {
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fs.add_flag(name, abbr, usage, '<bool>')
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parsed := fs.parse_bool_value(name, abbr) or {
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return error("parameter '$name' not provided")
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}
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return parsed == 'true'
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}
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// defining and parsing a bool flag
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// if defined
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// the value is returned (true/false)
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// else
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// the default value is returned
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// version with abbr
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//TODO error handling for invalid string to bool conversion
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pub fn (mut fs FlagParser) bool(name string, abbr byte, bdefault bool, usage string) bool {
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value := fs.bool_opt(name, abbr, usage) or {
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return bdefault
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}
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return value
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}
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// int_multi returns all instances of values associated with the flags provided
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// In the case that none were found, it returns an empty array.
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pub fn (mut fs FlagParser) int_multi(name string, abbr byte, usage string) []int {
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fs.add_flag(name, abbr, usage, '<multiple ints>')
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parsed := fs.parse_value(name, abbr)
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mut value := []int{}
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for val in parsed {
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value << val.int()
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}
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return value
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}
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// int_opt returns an optional that returns the value associated with the flag.
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// In the situation that the flag was not provided, it returns null.
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pub fn (mut fs FlagParser) int_opt(name string, abbr byte, usage string) ?int {
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fs.add_flag(name, abbr, usage, '<int>')
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parsed := fs.parse_value(name, abbr)
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if parsed.len == 0 {
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return error("parameter '$name' not provided")
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}
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return parsed[0].int()
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}
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// defining and parsing an int flag
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// if defined
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// the value is returned (int)
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// else
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// the default value is returned
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// version with abbr
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//TODO error handling for invalid string to int conversion
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pub fn (mut fs FlagParser) int(name string, abbr byte, idefault int, usage string) int {
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value := fs.int_opt(name, abbr, usage) or {
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return idefault
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}
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return value
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}
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// float_multi returns all instances of values associated with the flags provided
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// In the case that none were found, it returns an empty array.
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pub fn (mut fs FlagParser) float_multi(name string, abbr byte, usage string) []f64 {
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fs.add_flag(name, abbr, usage, '<multiple floats>')
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parsed := fs.parse_value(name, abbr)
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mut value := []f64{}
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for val in parsed {
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value << val.f64()
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}
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return value
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}
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// float_opt returns an optional that returns the value associated with the flag.
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// In the situation that the flag was not provided, it returns null.
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pub fn (mut fs FlagParser) float_opt(name string, abbr byte, usage string) ?f64 {
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fs.add_flag(name, abbr, usage, '<float>')
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parsed := fs.parse_value(name, abbr)
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if parsed.len == 0 {
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return error("parameter '$name' not provided")
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}
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return parsed[0].f64()
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}
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// defining and parsing a float flag
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// if defined
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// the value is returned (float)
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// else
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// the default value is returned
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// version with abbr
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//TODO error handling for invalid string to float conversion
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pub fn (mut fs FlagParser) float(name string, abbr byte, fdefault f64, usage string) f64 {
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value := fs.float_opt(name, abbr, usage) or {
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return fdefault
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}
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return value
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}
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// string_multi returns all instances of values associated with the flags provided
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// In the case that none were found, it returns an empty array.
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pub fn (mut fs FlagParser) string_multi(name string, abbr byte, usage string) []string {
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fs.add_flag(name, abbr, usage, '<multiple strings>')
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return fs.parse_value(name, abbr)
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}
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// string_opt returns an optional that returns the value associated with the flag.
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// In the situation that the flag was not provided, it returns null.
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pub fn (mut fs FlagParser) string_opt(name string, abbr byte, usage string) ?string {
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fs.add_flag(name, abbr, usage, '<string>')
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parsed := fs.parse_value(name, abbr)
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if parsed.len == 0 {
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return error("parameter '$name' not provided")
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}
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return parsed[0]
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}
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// defining and parsing a string flag
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// if defined
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// the value is returned (string)
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// else
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// the default value is returned
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// version with abbr
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pub fn (mut fs FlagParser) string(name string, abbr byte, sdefault string, usage string) string {
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value := fs.string_opt(name, abbr, usage) or {
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return sdefault
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}
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return value
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}
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pub fn (mut fs FlagParser) limit_free_args_to_at_least(n int) {
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if n > max_args_number {
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panic('flag.limit_free_args_to_at_least expect n to be smaller than $max_args_number')
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}
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if n <= 0 {
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panic('flag.limit_free_args_to_at_least expect n to be a positive number')
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}
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fs.min_free_args = n
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}
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pub fn (mut fs FlagParser) limit_free_args_to_exactly(n int) {
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if n > max_args_number {
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panic('flag.limit_free_args_to_exactly expect n to be smaller than $max_args_number')
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}
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if n < 0 {
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panic('flag.limit_free_args_to_exactly expect n to be a non negative number')
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}
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fs.min_free_args = n
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fs.max_free_args = n
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}
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// this will cause an error in finalize() if free args are out of range
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// (min, ..., max)
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pub fn (mut fs FlagParser) limit_free_args(min, max int) {
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if min > max {
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panic('flag.limit_free_args expect min < max, got $min >= $max')
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}
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fs.min_free_args = min
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fs.max_free_args = max
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}
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pub fn (mut fs FlagParser) arguments_description(description string){
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fs.args_description = description
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}
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// collect all given information and
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pub fn (fs FlagParser) usage() string {
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positive_min_arg := ( fs.min_free_args > 0 )
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positive_max_arg := ( fs.max_free_args > 0 && fs.max_free_args != max_args_number )
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no_arguments := ( fs.min_free_args == 0 && fs.max_free_args == 0 )
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mut adesc := if fs.args_description.len > 0 { fs.args_description } else { '[ARGS]' }
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if no_arguments { adesc = '' }
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mut use := ''
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if fs.application_version != '' {
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use += '$fs.application_name $fs.application_version\n'
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use += '$underline\n'
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}
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use += 'Usage: ${fs.application_name} [options] $adesc\n'
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use += '\n'
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if fs.application_description != '' {
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use += 'Description:\n'
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use += '$fs.application_description'
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use += '\n\n'
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}
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// show a message about the [ARGS]:
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if positive_min_arg || positive_max_arg || no_arguments {
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if no_arguments {
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use += 'This application does not expect any arguments\n\n'
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goto end_of_arguments_handling
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}
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mut s:= []string{}
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if positive_min_arg { s << 'at least $fs.min_free_args' }
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if positive_max_arg { s << 'at most $fs.max_free_args' }
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if positive_min_arg && positive_max_arg && fs.min_free_args == fs.max_free_args {
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s = ['exactly $fs.min_free_args']
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}
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sargs := s.join(' and ')
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use += 'The arguments should be $sargs in number.\n\n'
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}
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end_of_arguments_handling:
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if fs.flags.len > 0 {
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use += 'Options:\n'
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for f in fs.flags {
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mut onames := []string{}
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if f.abbr != 0 {
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onames << '-${f.abbr.str()}'
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}
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if f.name != '' {
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if !f.val_desc.contains('<bool>') {
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onames << '--${f.name} $f.val_desc'
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}else{
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onames << '--${f.name}'
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}
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}
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option_names := ' ' + onames.join(', ')
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mut xspace := ''
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if option_names.len > space.len-2 {
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xspace = '\n${space}'
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} else {
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xspace = space[option_names.len..]
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}
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use += '${option_names}${xspace}${f.usage}\n'
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}
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}
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return use
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}
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// finalize argument parsing -> call after all arguments are defined
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//
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// all remaining arguments are returned in the same order they are defined on
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// command line
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//
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// if additional flag are found (things starting with '--') an error is returned
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// error handling is up to the application developer
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pub fn (fs FlagParser) finalize() ?[]string {
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for a in fs.args {
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if a.len >= 2 && a[..2] == '--' {
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return error('Unknown argument \'${a[2..]}\'')
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}
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}
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if fs.args.len < fs.min_free_args && fs.min_free_args > 0 {
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return error('Expected at least ${fs.min_free_args} arguments, but given $fs.args.len')
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}
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if fs.args.len > fs.max_free_args && fs.max_free_args > 0 {
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return error('Expected at most ${fs.max_free_args} arguments, but given $fs.args.len')
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}
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if fs.args.len > 0 && fs.max_free_args == 0 && fs.min_free_args == 0 {
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return error('Expected no arguments, but given $fs.args.len')
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}
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return fs.args
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}
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