view source for debug

Command Type

built-in

Signature

> view source {flags} (item)

Flags

• --dependencies, -d: Also show every custom command the item calls, transitively, and every constant those bodies read.

Parameters

• item: Name or block to view.

Input/output types:

Examples

View the source of a code block.

> let abc = {|| echo 'hi' }; view source $abc
{|| echo 'hi' }

View the source of a custom command.

> def hi [] { echo 'Hi!' }; view source hi
def hi [] { echo 'Hi!' }

View the source of a custom command, which participates in the caller environment.

> def --env foo [] { $env.BAR = 'BAZ' }; view source foo
def --env foo [] { $env.BAR = 'BAZ' }

View the source of a custom command with flags.

> def --wrapped --env foo [...rest: string] { print $rest }; view source foo
def --env --wrapped foo [ ...rest: string] { print $rest }

View the source of a custom command with flags and arguments.

> def test [a?:any --b:int ...rest:string] { echo 'test' }; view source test
def test [ a?: any --b: int ...rest: string] { echo 'test' }

View the source of a module.

> module mod-foo { export-env { $env.FOO_ENV = 'BAZ' } }; view source mod-foo
 export-env { $env.FOO_ENV = 'BAZ' }

View the source of an alias.

> alias hello = echo hi; view source hello
echo hi

View a command together with the commands it calls.

> def helper [] { 42 }; def caller [] { helper }; view source caller --dependencies
def caller [] { helper }

def helper [] { 42 }

View the file where a definition lives via metadata.

> view source some_command | metadata

Notes

The def header is rebuilt from the signature instead of being quoted from the source, so export and attributes are lost. That holds with or without --dependencies.

--dependencies applies to a custom command; on an alias, a module, a closure or a block id it does nothing. It follows only the calls the parser can see, so a closure written inside the body is followed even when it is run through a variable, but one that arrives as an argument is not. And a command built on a large module can pull in a lot of output.

A constant is rebuilt the same way, as const <name> = <value>, because only the name is recorded with a source span. So the value is the one the command actually reads: an expression such as path self shows up already resolved, and an explicit type annotation is lost. $nu and the record bound by use <module> are left out — neither is written as a const anywhere.