nushell/crates/nu-std/std/help.nu
Ian Manske 1038c64f80
Add sys subcommands (#12747)
# Description
Adds subcommands to `sys` corresponding to each column of the record
returned by `sys`. This is to alleviate the fact that `sys` now returns
a regular record, meaning that it must compute every column which might
take a noticeable amount of time. The subcommands, on the other hand,
only need to compute and return a subset of the data which should be
much faster. In fact, it should be as fast as before, since this is how
the lazy record worked (it would compute only each column as necessary).

I choose to add subcommands instead of having an optional cell-path
parameter on `sys`, since the cell-path parameter would:
- increase the code complexity (can access any value at any row or
nested column)
- prevents discovery with tab-completion
- hinders type checking and allows users to pass potentially invalid
columns

# User-Facing Changes
Deprecates `sys` in favor of the new `sys` subcommands.
2024-05-06 23:20:27 +00:00

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def error-fmt [] {
$"(ansi red)($in)(ansi reset)"
}
def throw-error [error: string, msg: string, span: record] {
error make {
msg: ($error | error-fmt)
label: {
text: $msg
span: $span
}
}
}
def module-not-found-error [span: record] {
throw-error "std::help::module_not_found" "module not found" $span
}
def alias-not-found-error [span: record] {
throw-error "std::help::alias_not_found" "alias not found" $span
}
def extern-not-found-error [span: record] {
throw-error "std::help::extern_not_found" "extern not found" $span
}
def operator-not-found-error [span: record] {
throw-error "std::help::operator_not_found" "operator not found" $span
}
def command-not-found-error [span: record] {
throw-error "std::help::command_not_found" "command not found" $span
}
def get-all-operators [] { return [
[type, operator, name, description, precedence];
[Assignment, =, Assign, "Assigns a value to a variable.", 10]
[Assignment, +=, PlusAssign, "Adds a value to a variable.", 10]
[Assignment, ++=, AppendAssign, "Appends a list or a value to a variable.", 10]
[Assignment, -=, MinusAssign, "Subtracts a value from a variable.", 10]
[Assignment, *=, MultiplyAssign, "Multiplies a variable by a value.", 10]
[Assignment, /=, DivideAssign, "Divides a variable by a value.", 10]
[Comparison, ==, Equal, "Checks if two values are equal.", 80]
[Comparison, !=, NotEqual, "Checks if two values are not equal.", 80]
[Comparison, <, LessThan, "Checks if a value is less than another.", 80]
[Comparison, <=, LessThanOrEqual, "Checks if a value is less than or equal to another.", 80]
[Comparison, >, GreaterThan, "Checks if a value is greater than another.", 80]
[Comparison, >=, GreaterThanOrEqual, "Checks if a value is greater than or equal to another.", 80]
[Comparison, =~, RegexMatch, "Checks if a value matches a regular expression.", 80]
[Comparison, !~, NotRegexMatch, "Checks if a value does not match a regular expression.", 80]
[Comparison, in, In, "Checks if a value is in a list or string.", 80]
[Comparison, not-in, NotIn, "Checks if a value is not in a list or string.", 80]
[Comparison, starts-with, StartsWith, "Checks if a string starts with another.", 80]
[Comparison, ends-with, EndsWith, "Checks if a string ends with another.", 80]
[Comparison, not, UnaryNot, "Negates a value or expression.", 0]
[Math, +, Plus, "Adds two values.", 90]
[Math, ++, Append, "Appends two lists or a list and a value.", 80]
[Math, -, Minus, "Subtracts two values.", 90]
[Math, *, Multiply, "Multiplies two values.", 95]
[Math, /, Divide, "Divides two values.", 95]
[Math, //, FloorDivision, "Divides two values and floors the result.", 95]
[Math, mod, Modulo, "Divides two values and returns the remainder.", 95]
[Math, **, "Pow ", "Raises one value to the power of another.", 100]
[Bitwise, bit-or, BitOr, "Performs a bitwise OR on two values.", 60]
[Bitwise, bit-xor, BitXor, "Performs a bitwise XOR on two values.", 70]
[Bitwise, bit-and, BitAnd, "Performs a bitwise AND on two values.", 75]
[Bitwise, bit-shl, ShiftLeft, "Shifts a value left by another.", 85]
[Bitwise, bit-shr, ShiftRight, "Shifts a value right by another.", 85]
[Boolean, and, And, "Checks if two values are true.", 50]
[Boolean, or, Or, "Checks if either value is true.", 40]
[Boolean, xor, Xor, "Checks if one value is true and the other is false.", 45]
]}
def "nu-complete list-aliases" [] {
scope aliases | select name usage | rename value description
}
def "nu-complete list-modules" [] {
scope modules | select name usage | rename value description
}
def "nu-complete list-operators" [] {
let completions = (
get-all-operators
| select name description
| rename value description
)
$completions
}
def "nu-complete list-commands" [] {
scope commands | select name usage | rename value description
}
def "nu-complete list-externs" [] {
scope commands | where is_extern | select name usage | rename value description
}
def build-help-header [
text: string
--no-newline (-n)
] {
let header = $"(ansi green)($text)(ansi reset):"
if $no_newline {
$header
} else {
$header ++ "\n"
}
}
def build-module-page [module: record] {
let usage = (if not ($module.usage? | is-empty) {[
$module.usage
""
]} else { [] })
let name = [
$"(build-help-header -n "Module") ($module.name)"
""
]
let commands = (if not ($module.commands? | is-empty) {[
(build-help-header -n "Exported commands")
$" (
$module.commands | each {|command|
$'($command) (char lparen)($module.name) ($command)(char rparen)'
}
| str join ', '
)"
""
]} else { [] })
let aliases = (if not ($module.aliases? | is-empty) {[
(build-help-header -n "Exported aliases")
$" ($module.aliases | str join ', ')"
""
]} else { [] })
let env_block = (if ($module.env_block? | is-empty) {[
$"This module (ansi cyan)does not export(ansi reset) environment."
]} else {[
$"This module (ansi cyan)exports(ansi reset) environment."
(view source $module.env_block)
]})
[$usage $name $commands $aliases $env_block] | flatten | str join "\n"
}
# Show help on nushell modules.
#
# When requesting help for a single module, its commands and aliases will be highlighted if they
# are also available in the current scope. Commands/aliases that were imported under a different name
# (such as with a prefix after `use some-module`) will be highlighted in parentheses.
#
# Examples:
# > let us define some example modules to play with
# > ```nushell
# > # my foo module
# > module foo {
# > def bar [] { "foo::bar" }
# > export def baz [] { "foo::baz" }
# >
# > export-env {
# > $env.FOO = "foo::FOO"
# > }
# > }
# >
# > # my bar module
# > module bar {
# > def bar [] { "bar::bar" }
# > export def baz [] { "bar::baz" }
# >
# > export-env {
# > $env.BAR = "bar::BAR"
# > }
# > }
# >
# > # my baz module
# > module baz {
# > def foo [] { "baz::foo" }
# > export def bar [] { "baz::bar" }
# >
# > export-env {
# > $env.BAZ = "baz::BAZ"
# > }
# > }
# > ```
#
# show all aliases
# > help modules
# ╭───┬──────┬──────────┬────────────────┬──────────────┬───────────────╮
# │ # │ name │ commands │ aliases │ env_block │ usage │
# ├───┼──────┼──────────┼────────────────┼──────────────┼───────────────┤
# │ 0 │ bar │ [baz] │ [list 0 items] │ <Block 1331> │ my bar module │
# │ 1 │ baz │ [bar] │ [list 0 items] │ <Block 1335> │ my baz module │
# │ 2 │ foo │ [baz] │ [list 0 items] │ <Block 1327> │ my foo module │
# ╰───┴──────┴──────────┴────────────────┴──────────────┴───────────────╯
#
# search for string in module names
# > help modules --find ba
# ╭───┬──────┬─────────────┬────────────────┬──────────────┬───────────────╮
# │ # │ name │ commands │ aliases │ env_block │ usage │
# ├───┼──────┼─────────────┼────────────────┼──────────────┼───────────────┤
# │ 0 │ bar │ ╭───┬─────╮ │ [list 0 items] │ <Block 1331> │ my bar module │
# │ │ │ │ 0 │ baz │ │ │ │ │
# │ │ │ ╰───┴─────╯ │ │ │ │
# │ 1 │ baz │ ╭───┬─────╮ │ [list 0 items] │ <Block 1335> │ my baz module │
# │ │ │ │ 0 │ bar │ │ │ │ │
# │ │ │ ╰───┴─────╯ │ │ │ │
# ╰───┴──────┴─────────────┴────────────────┴──────────────┴───────────────╯
#
# search help for single module
# > help modules foo
# my foo module
#
# Module: foo
#
# Exported commands:
# baz [foo baz]
#
# This module exports environment.
# {
# $env.FOO = "foo::FOO"
# }
#
# search for a module that does not exist
# > help modules "does not exist"
# Error:
# × std::help::module_not_found
# ╭─[entry #21:1:1]
# 1 │ help modules "does not exist"
# · ────────┬───────
# · ╰── module not found
# ╰────
export def modules [
...module: string@"nu-complete list-modules" # the name of module to get help on
--find (-f): string # string to find in module names
] {
let modules = (scope modules)
if not ($find | is-empty) {
$modules | find $find --columns [name usage]
} else if not ($module | is-empty) {
let found_module = ($modules | where name == ($module | str join " "))
if ($found_module | is-empty) {
module-not-found-error (metadata $module | get span)
}
build-module-page ($found_module | get 0)
} else {
$modules
}
}
def build-alias-page [alias: record] {
let usage = (if not ($alias.usage? | is-empty) {[
$alias.usage
""
]} else { [] })
let rest = [
(build-help-header -n "Alias")
$" ($alias.name)"
""
(build-help-header -n "Expansion")
$" ($alias.expansion)"
]
[$usage $rest] | flatten | str join "\n"
}
# Show help on nushell aliases.
#
# Examples:
# > let us define a bunch of aliases
# > ```nushell
# > # my foo alias
# > alias foo = echo "this is foo"
# >
# > # my bar alias
# > alias bar = echo "this is bar"
# >
# > # my baz alias
# > alias baz = echo "this is baz"
# >
# > # a multiline alias
# > alias multi = echo "this
# > is
# > a
# > multiline
# > string"
# > ```
#
# show all aliases
# > help aliases
# ╭───┬───────┬────────────────────┬───────────────────╮
# │ # │ name │ expansion │ usage │
# ├───┼───────┼────────────────────┼───────────────────┤
# │ 0 │ bar │ echo "this is bar" │ my bar alias │
# │ 1 │ baz │ echo "this is baz" │ my baz alias │
# │ 2 │ foo │ echo "this is foo" │ my foo alias │
# │ 3 │ multi │ echo "this │ a multiline alias │
# │ │ │ is │ │
# │ │ │ a │ │
# │ │ │ multiline │ │
# │ │ │ string" │ │
# ╰───┴───────┴────────────────────┴───────────────────╯
#
# search for string in alias names
# > help aliases --find ba
# ╭───┬──────┬────────────────────┬──────────────╮
# │ # │ name │ expansion │ usage │
# ├───┼──────┼────────────────────┼──────────────┤
# │ 0 │ bar │ echo "this is bar" │ my bar alias │
# │ 1 │ baz │ echo "this is baz" │ my baz alias │
# ╰───┴──────┴────────────────────┴──────────────╯
#
# search help for single alias
# > help aliases multi
# a multiline alias
#
# Alias: multi
#
# Expansion:
# echo "this
# is
# a
# multiline
# string"
#
# search for an alias that does not exist
# > help aliases "does not exist"
# Error:
# × std::help::alias_not_found
# ╭─[entry #21:1:1]
# 1 │ help aliases "does not exist"
# · ────────┬───────
# · ╰── alias not found
# ╰────
export def aliases [
...alias: string@"nu-complete list-aliases" # the name of alias to get help on
--find (-f): string # string to find in alias names
] {
let aliases = (scope aliases | sort-by name)
if not ($find | is-empty) {
$aliases | find $find --columns [name usage]
} else if not ($alias | is-empty) {
let found_alias = ($aliases | where name == ($alias | str join " "))
if ($found_alias | is-empty) {
alias-not-found-error (metadata $alias | get span)
}
build-alias-page ($found_alias | get 0)
} else {
$aliases
}
}
def build-extern-page [extern: record] {
let usage = (if not ($extern.usage? | is-empty) {[
$extern.usage
""
]} else { [] })
let rest = [
(build-help-header -n "Extern")
$" ($extern.name)"
]
[$usage $rest] | flatten | str join "\n"
}
# Show help on nushell externs.
export def externs [
...extern: string@"nu-complete list-externs" # the name of extern to get help on
--find (-f): string # string to find in extern names
] {
let externs = (
scope commands
| where is_extern
| select name module_name usage
| sort-by name
| str trim
)
if not ($find | is-empty) {
$externs | find $find --columns [name usage]
} else if not ($extern | is-empty) {
let found_extern = ($externs | where name == ($extern | str join " "))
if ($found_extern | is-empty) {
extern-not-found-error (metadata $extern | get span)
}
build-extern-page ($found_extern | get 0)
} else {
$externs
}
}
def build-operator-page [operator: record] {
[
(build-help-header -n "Description")
$" ($operator.description)"
""
(build-help-header -n "Operator")
$" ($operator.name) (char lparen)(ansi cyan_bold)($operator.operator)(ansi reset)(char rparen)"
(build-help-header -n "Type")
$" ($operator.type)"
(build-help-header -n "Precedence")
$" ($operator.precedence)"
] | str join "\n"
}
# Show help on nushell operators.
#
# Examples:
# search for string in operators names
# > help operators --find Bit
# ╭───┬─────────┬──────────┬────────┬───────────────────────────────────────┬────────────╮
# │ # │ type │ operator │ name │ description │ precedence │
# ├───┼─────────┼──────────┼────────┼───────────────────────────────────────┼────────────┤
# │ 0 │ Bitwise │ bit-and │ BitAnd │ Performs a bitwise AND on two values. │ 75 │
# │ 1 │ Bitwise │ bit-or │ BitOr │ Performs a bitwise OR on two values. │ 60 │
# │ 2 │ Bitwise │ bit-xor │ BitXor │ Performs a bitwise XOR on two values. │ 70 │
# ╰───┴─────────┴──────────┴────────┴───────────────────────────────────────┴────────────╯
#
# search help for single operator
# > help operators NotRegexMatch
# Description:
# Checks if a value does not match a regular expression.
#
# Operator: NotRegexMatch (!~)
# Type: Comparison
# Precedence: 80
#
# search for an operator that does not exist
# > help operator "does not exist"
# Error:
# × std::help::operator_not_found
# ╭─[entry #21:1:1]
# 1 │ help operator "does not exist"
# · ────────┬───────
# · ╰── operator not found
# ╰────
export def operators [
...operator: string@"nu-complete list-operators" # the name of operator to get help on
--find (-f): string # string to find in operator names
] {
let operators = (get-all-operators)
if not ($find | is-empty) {
$operators | find $find --columns [type name]
} else if not ($operator | is-empty) {
let found_operator = ($operators | where name == ($operator | str join " "))
if ($found_operator | is-empty) {
operator-not-found-error (metadata $operator | get span)
}
build-operator-page ($found_operator | get 0)
} else {
$operators
}
}
def build-command-page [command: record] {
let usage = (if not ($command.usage? | is-empty) {[
$command.usage
]} else { [] })
let extra_usage = (if not ($command.extra_usage? | is-empty) {[
""
$command.extra_usage
]} else { [] })
let search_terms = (if not ($command.search_terms? | is-empty) {[
""
$"(build-help-header -n 'Search terms') ($command.search_terms)"
]} else { [] })
let module = (if not ($command.module_name? | is-empty) {[
""
$"(build-help-header -n 'Module') ($command.module_name)"
]} else { [] })
let category = (if not ($command.category? | is-empty) {[
""
$"(build-help-header -n 'Category') ($command.category)"
]} else { [] })
let this = ([
""
"This command:"
] | append (
if ($command.creates_scope) {
$"- (ansi cyan)does create(ansi reset) a scope."
} else {
$"- (ansi cyan)does not create(ansi reset) a scope."
}
) | append (
if ($command.is_builtin) {
$"- (ansi cyan)is(ansi reset) a built-in command."
} else {
$"- (ansi cyan)is not(ansi reset) a built-in command."
}
) | append (
if ($command.is_sub) {
$"- (ansi cyan)is(ansi reset) a subcommand."
} else {
$"- (ansi cyan)is not(ansi reset) a subcommand."
}
) | append (
if ($command.is_plugin) {
$"- (ansi cyan)is part(ansi reset) of a plugin."
} else {
$"- (ansi cyan)is not part(ansi reset) of a plugin."
}
) | append (
if ($command.is_custom) {
$"- (ansi cyan)is(ansi reset) a custom command."
} else {
$"- (ansi cyan)is not(ansi reset) a custom command."
}
) | append (
if ($command.is_keyword) {
$"- (ansi cyan)is(ansi reset) a keyword."
} else {
$"- (ansi cyan)is not(ansi reset) a keyword."
}
))
let signatures = ($command.signatures | transpose | get column1)
let cli_usage = (if not ($signatures | is-empty) {
let parameters = ($signatures | get 0 | where parameter_type != input and parameter_type != output)
let positionals = ($parameters | where parameter_type == positional and parameter_type != rest)
let flags = ($parameters | where parameter_type != positional and parameter_type != rest)
[
""
(build-help-header -n "Usage")
([
$" > ($command.name) "
(if not ($flags | is-empty) { "{flags} " } else "")
($positionals | each {|param|
$"<($param.parameter_name)> "
})
] | flatten | str join "")
""
]
} else { [] })
let subcommands = (scope commands | where name =~ $"^($command.name) " | select name usage)
let subcommands = (if not ($subcommands | is-empty) {[
(build-help-header "Subcommands")
($subcommands | each {|subcommand |
$" (ansi teal)($subcommand.name)(ansi reset) - ($subcommand.usage)"
} | str join "\n")
]} else { [] })
let rest = (if not ($signatures | is-empty) {
let parameters = ($signatures | get 0 | where parameter_type != input and parameter_type != output)
let positionals = ($parameters | where parameter_type == positional and parameter_type != rest)
let flags = ($parameters | where parameter_type != positional and parameter_type != rest)
let is_rest = (not ($parameters | where parameter_type == rest | is-empty))
([
""
(build-help-header "Flags")
($flags | each {|flag|
[
" ",
(if ($flag.short_flag | is-empty) { "" } else {
$"-(ansi teal)($flag.short_flag)(ansi reset), "
}),
(if ($flag.parameter_name | is-empty) { "" } else {
$"--(ansi teal)($flag.parameter_name)(ansi reset)"
}),
(if ($flag.syntax_shape | is-empty) { "" } else {
$": <(ansi light_blue)($flag.syntax_shape)(ansi reset)>"
}),
(if ($flag.description | is-empty) { "" } else {
$" - ($flag.description)"
}),
(if ($flag.parameter_default | is-empty) { "" } else {
$" \(default: ($flag.parameter_default)\)"
}),
] | str join ""
} | str join "\n")
$" (ansi teal)-h(ansi reset), --(ansi teal)help(ansi reset) - Display the help message for this command"
""
(build-help-header "Signatures")
($signatures | each {|signature|
let input = ($signature | where parameter_type == input | get 0)
let output = ($signature | where parameter_type == output | get 0)
([
$" <($input.syntax_shape)> | ($command.name)"
($positionals | each {|positional|
$" <($positional.syntax_shape)>"
})
$" -> <($output.syntax_shape)>"
] | str join "")
} | str join "\n")
(if (not ($positionals | is-empty)) or $is_rest {[
""
(build-help-header "Parameters")
($positionals | each {|positional|
([
" ",
$"(ansi teal)($positional.parameter_name)(ansi reset)",
(if ($positional.syntax_shape | is-empty) { "" } else {
$": <(ansi light_blue)($positional.syntax_shape)(ansi reset)>"
}),
(if ($positional.description | is-empty) { "" } else {
$" ($positional.description)"
}),
(if ($positional.parameter_default | is-empty) { "" } else {
$" \(optional, default: ($positional.parameter_default)\)"
})
] | str join "")
} | str join "\n")
(if $is_rest {
let rest = ($parameters | where parameter_type == rest | get 0)
$" ...(ansi teal)rest(ansi reset): <(ansi light_blue)($rest.syntax_shape)(ansi reset)> ($rest.description)"
})
]} else { [] })
] | flatten)
} else { [] })
let examples = (if not ($command.examples | is-empty) {[
""
(build-help-header -n "Examples")
($command.examples | each {|example| [
$" ($example.description)"
$" > ($example.example | nu-highlight)"
(if not ($example.result | is-empty) {
$example.result
| table
| to text
| if ($example.result | describe) == "binary" { str join } else { lines }
| each {|line|
$" ($line)"
}
| str join "\n"
})
""
] | str join "\n"})
] | flatten} else { [] })
[
$usage
$extra_usage
$search_terms
$module
$category
$this
$cli_usage
$subcommands
$rest
$examples
] | flatten | str join "\n"
}
# Show help on commands.
export def commands [
...command: string@"nu-complete list-commands" # the name of command to get help on
--find (-f): string # string to find in command names and usage
] {
let commands = (scope commands | where not is_extern | reject is_extern | sort-by name)
if not ($find | is-empty) {
# TODO: impl find for external commands
$commands | find $find --columns [name usage search_terms] | select name category usage signatures search_terms
} else if not ($command | is-empty) {
let target_command = ($command | str join " ")
let found_command = ($commands | where name == $target_command)
if ($found_command | is-empty) {
try {
print $"(ansi default_italic)Help pages from external command ($target_command | pretty-cmd):(ansi reset)"
^($env.NU_HELPER? | default "man") $target_command
} catch {
command-not-found-error (metadata $command | get span)
}
}
build-command-page ($found_command | get 0)
} else {
$commands | select name category usage signatures search_terms
}
}
def pretty-cmd [] {
let cmd = $in
$"(ansi default_dimmed)(ansi default_italic)($cmd)(ansi reset)"
}
# Display help information about different parts of Nushell.
#
# `help word` searches for "word" in commands, aliases and modules, in that order.
#
# Examples:
# show help for single command, alias, or module
# > help match
#
# show help for single sub-command, alias, or module
# > help str join
#
# search for string in command names, usage and search terms
# > help --find char
export def main [
...item: string # the name of the help item to get help on
--find (-f): string # string to find in help items names and usage
] {
if ($item | is-empty) and ($find | is-empty) {
print $"Welcome to Nushell.
Here are some tips to help you get started.
* ('help -h' | pretty-cmd) or ('help help' | pretty-cmd) - show available ('help' | pretty-cmd) subcommands and examples
* ('help commands' | pretty-cmd) - list all available commands
* ('help <name>' | pretty-cmd) - display help about a particular command, alias, or module
* ('help --find <text to search>' | pretty-cmd) - search through all help commands table
Nushell works on the idea of a "(ansi default_italic)pipeline(ansi reset)". Pipelines are commands connected with the '|' character.
Each stage in the pipeline works together to load, parse, and display information to you.
(ansi green)Examples(ansi reset):
List the files in the current directory, sorted by size
> ('ls | sort-by size' | nu-highlight)
Get the current system host name
> ('sys host | get hostname' | nu-highlight)
Get the processes on your system actively using CPU
> ('ps | where cpu > 0' | nu-highlight)
You can also learn more at (ansi default_italic)(ansi light_cyan_underline)https://www.nushell.sh/book/(ansi reset)"
return
}
let target_item = ($item | str join " ")
let commands = (try { commands $target_item --find $find })
if not ($commands | is-empty) { return $commands }
let aliases = (try { aliases $target_item --find $find })
if not ($aliases | is-empty) { return $aliases }
let modules = (try { modules $target_item --find $find })
if not ($modules | is-empty) { return $modules }
let span = (metadata $item | get span)
error make {
msg: ("std::help::item_not_found" | error-fmt)
label: {
text: "item not found"
span: $span
}
}
}