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v/vlib/cli/help.v

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module cli
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import term
import strings
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const (
base_indent_len = 2
min_description_indent_len = 20
spacing = 2
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)
fn help_flag(with_abbrev bool) Flag {
sabbrev := if with_abbrev { 'h' } else { '' }
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return Flag{
flag: .bool
name: 'help'
abbrev: sabbrev
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description: 'Prints help information.'
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}
}
fn help_cmd() Command {
return Command{
name: 'help'
usage: '<command>'
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description: 'Prints help information.'
execute: print_help_for_command
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}
}
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// print_help_for_command outputs the help message of `help_cmd`.
pub fn print_help_for_command(help_cmd Command) ! {
if help_cmd.args.len > 0 {
mut cmd := help_cmd.parent
for arg in help_cmd.args {
mut found := false
for sub_cmd in cmd.commands {
if sub_cmd.name == arg {
cmd = unsafe { &sub_cmd }
found = true
break
}
}
if !found {
args := help_cmd.args.join(' ')
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println('Invalid command: $args')
return
}
}
print(cmd.help_message())
} else {
if unsafe { help_cmd.parent != 0 } {
print(help_cmd.parent.help_message())
}
}
}
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// help_message returns a generated help message as a `string` for the `Command`.
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pub fn (cmd Command) help_message() string {
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mut help := ''
help += 'Usage: $cmd.full_name()'
if cmd.flags.len > 0 {
help += ' [flags]'
}
if cmd.commands.len > 0 {
help += ' [commands]'
}
if cmd.usage.len > 0 {
help += ' $cmd.usage'
} else {
for i in 0 .. cmd.required_args {
help += ' <arg$i>'
}
}
help += '\n'
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if cmd.description != '' {
help += '\n$cmd.description\n'
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}
mut abbrev_len := 0
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mut name_len := cli.min_description_indent_len
if cmd.posix_mode {
for flag in cmd.flags {
if flag.abbrev != '' {
abbrev_len = max(abbrev_len, flag.abbrev.len + cli.spacing + 1) // + 1 for '-' in front
}
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name_len = max(name_len, abbrev_len + flag.name.len + cli.spacing + 2) // + 2 for '--' in front
}
for command in cmd.commands {
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name_len = max(name_len, command.name.len + cli.spacing)
}
} else {
for flag in cmd.flags {
if flag.abbrev != '' {
abbrev_len = max(abbrev_len, flag.abbrev.len + cli.spacing + 1) // + 1 for '-' in front
}
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name_len = max(name_len, abbrev_len + flag.name.len + cli.spacing + 1) // + 1 for '-' in front
}
for command in cmd.commands {
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name_len = max(name_len, command.name.len + cli.spacing)
}
}
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if cmd.flags.len > 0 {
help += '\nFlags:\n'
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for flag in cmd.flags {
mut flag_name := ''
prefix := if cmd.posix_mode { '--' } else { '-' }
if flag.abbrev != '' {
abbrev_indent := ' '.repeat(abbrev_len - flag.abbrev.len - 1) // - 1 for '-' in front
flag_name = '-$flag.abbrev$abbrev_indent$prefix$flag.name'
} else {
abbrev_indent := ' '.repeat(abbrev_len)
flag_name = '$abbrev_indent$prefix$flag.name'
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}
mut required := ''
if flag.required {
required = ' (required)'
}
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base_indent := ' '.repeat(cli.base_indent_len)
description_indent := ' '.repeat(name_len - flag_name.len)
help += '$base_indent$flag_name$description_indent' +
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pretty_description(flag.description + required, cli.base_indent_len + name_len) +
'\n'
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}
}
if cmd.commands.len > 0 {
help += '\nCommands:\n'
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for command in cmd.commands {
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base_indent := ' '.repeat(cli.base_indent_len)
description_indent := ' '.repeat(name_len - command.name.len)
help += '$base_indent$command.name$description_indent' +
pretty_description(command.description, name_len) + '\n'
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}
}
return help
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}
// pretty_description resizes description text depending on terminal width.
// Essentially, smart wrap-around
fn pretty_description(s string, indent_len int) string {
width, _ := term.get_terminal_size()
// Don't prettify if the terminal is that small, it won't be pretty anyway.
if indent_len > width {
return s
}
indent := ' '.repeat(indent_len)
chars_per_line := width - indent_len
// Give us enough room, better a little bigger than smaller
mut acc := strings.new_builder(((s.len / chars_per_line) + 1) * (width + 1))
for k, line in s.split('\n') {
if k != 0 {
acc.write_string('\n$indent')
}
mut i := chars_per_line - 2
mut j := 0
for ; i < line.len; i += chars_per_line - 2 {
for line[i] != ` ` {
i--
}
// indent was already done the first iteration
if j != 0 {
acc.write_string(indent)
}
acc.writeln(line[j..i].trim_space())
j = i
}
// We need this even though it should never happen
if j != 0 {
acc.write_string(indent)
}
acc.write_string(line[j..].trim_space())
}
return acc.str()
}
fn max(a int, b int) int {
res := if a > b { a } else { b }
return res
}