From 4a955d7e76e6116d1c80b82197827f1967ea6c80 Mon Sep 17 00:00:00 2001
From: Antoine Stevan <44101798+amtoine@users.noreply.github.com>
Date: Sun, 9 Apr 2023 19:00:20 +0200
Subject: [PATCH] stdlib: refactor into a multi-module library (#8815)

---
 .github/pull_request_template.md          |   2 +-
 .github/workflows/ci.yml                  |   2 +-
 crates/nu-std/examples.nu                 |  13 +
 crates/nu-std/lib/assert.nu               | 208 +++++++
 crates/nu-std/lib/dirs.nu                 |  83 +++
 crates/nu-std/{std.nu => lib/help.nu}     | 715 +---------------------
 crates/nu-std/lib/log.nu                  |  63 ++
 crates/nu-std/lib/mod.nu                  | 157 +++++
 crates/nu-std/lib/xml.nu                  | 206 +++++++
 crates/nu-std/src/lib.rs                  |  62 +-
 crates/nu-std/{tests.nu => tests/run.nu}  |   0
 crates/nu-std/{ => tests}/test_asserts.nu |   0
 crates/nu-std/{ => tests}/test_dirs.nu    |   0
 crates/nu-std/{ => tests}/test_logger.nu  |   7 -
 crates/nu-std/{ => tests}/test_std.nu     |   0
 crates/nu-std/{ => tests}/test_xml.nu     |   0
 toolkit.nu                                |   2 +-
 17 files changed, 774 insertions(+), 746 deletions(-)
 create mode 100644 crates/nu-std/examples.nu
 create mode 100644 crates/nu-std/lib/assert.nu
 create mode 100644 crates/nu-std/lib/dirs.nu
 rename crates/nu-std/{std.nu => lib/help.nu} (53%)
 create mode 100644 crates/nu-std/lib/log.nu
 create mode 100644 crates/nu-std/lib/mod.nu
 create mode 100644 crates/nu-std/lib/xml.nu
 rename crates/nu-std/{tests.nu => tests/run.nu} (100%)
 rename crates/nu-std/{ => tests}/test_asserts.nu (100%)
 rename crates/nu-std/{ => tests}/test_dirs.nu (100%)
 rename crates/nu-std/{ => tests}/test_logger.nu (83%)
 rename crates/nu-std/{ => tests}/test_std.nu (100%)
 rename crates/nu-std/{ => tests}/test_xml.nu (100%)

diff --git a/.github/pull_request_template.md b/.github/pull_request_template.md
index 12d4682006..30570ac96f 100644
--- a/.github/pull_request_template.md
+++ b/.github/pull_request_template.md
@@ -18,7 +18,7 @@ Make sure you've run and fixed any issues with these commands:
 - `cargo fmt --all -- --check` to check standard code formatting (`cargo fmt --all` applies these changes)
 - `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect` to check that you're using the standard code style
 - `cargo test --workspace` to check that all tests pass
-- `cargo run -- crates/nu-std/tests.nu` to run the tests for the standard library
+- `cargo run -- crates/nu-std/tests/run.nu` to run the tests for the standard library
 
 > **Note**
 > from `nushell` you can also use the `toolkit` as follows
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 3af32c7821..2016bc95ca 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -116,7 +116,7 @@ jobs:
         run: cargo install --path . --locked --no-default-features
 
       - name: Standard library tests
-        run: nu crates/nu-std/tests.nu
+        run: nu crates/nu-std/tests/run.nu
 
       - name: Setup Python
         uses: actions/setup-python@v4
diff --git a/crates/nu-std/examples.nu b/crates/nu-std/examples.nu
new file mode 100644
index 0000000000..b08fedfbbb
--- /dev/null
+++ b/crates/nu-std/examples.nu
@@ -0,0 +1,13 @@
+use std 'log debug'
+use std 'log info'
+use std 'log warning'
+use std 'log error'
+use std 'log critical'
+
+export def log [] {
+    log debug "Debug message"
+    log info "Info message"
+    log warning "Warning message"
+    log error "Error message"
+    log critical "Critical message"
+}
diff --git a/crates/nu-std/lib/assert.nu b/crates/nu-std/lib/assert.nu
new file mode 100644
index 0000000000..fee1bab62f
--- /dev/null
+++ b/crates/nu-std/lib/assert.nu
@@ -0,0 +1,208 @@
+# Universal assert command
+#
+# If the condition is not true, it generates an error.
+#
+# # Example
+#
+# ```nushell
+# >_ assert (3 == 3)
+# >_ assert (42 == 3)
+# Error:
+#   × Assertion failed: 
+#     ╭─[myscript.nu:11:1]
+#  11 │ assert (3 == 3)
+#  12 │ assert (42 == 3)
+#     ·         ───┬────
+#     ·            ╰── It is not true.
+#  13 │
+#     ╰────
+# ```
+#
+# The --error-label flag can be used if you want to create a custom assert command:
+# ```
+# def "assert even" [number: int] {
+#     assert ($number mod 2 == 0) --error-label {
+#         start: (metadata $number).span.start,
+#         end: (metadata $number).span.end,
+#         text: $"($number) is not an even number",
+#     }
+# }
+# ```
+export def main [
+    condition: bool, # Condition, which should be true 
+    message?: string, # Optional error message
+    --error-label: record # Label for `error make` if you want to create a custom assert
+] {
+    if $condition { return }
+    let span = (metadata $condition).span
+    error make {
+        msg: ($message | default "Assertion failed."),
+        label: ($error_label | default {
+            text: "It is not true.",
+            start: (metadata $condition).span.start,
+            end: (metadata $condition).span.end
+        })
+    }
+}
+
+# Assert that executing the code generates an error
+#
+# For more documentation see the assert command
+# 
+# # Examples
+#
+# > assert error {|| missing_command} # passes
+# > assert error {|| 12} # fails
+export def "assert error" [
+    code: closure,
+    message?: string
+] {
+    let error_raised = (try { do $code; false } catch { true })
+    main ($error_raised) $message --error-label {
+        start: (metadata $code).span.start
+        end: (metadata $code).span.end
+        text: $"There were no error during code execution: (view source $code)"
+    }
+}
+
+# Skip the current test case
+#
+# # Examples
+#
+# if $condition { assert skip }
+export def "assert skip" [] {
+    error make {msg: "ASSERT:SKIP"}
+}
+
+
+# Assert $left == $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+# 
+# > assert equal 1 1 # passes
+# > assert equal (0.1 + 0.2) 0.3
+# > assert equal 1 2 # fails
+export def "assert equal" [left: any, right: any, message?: string] {
+    main ($left == $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"They are not equal. Left = ($left). Right = ($right)."
+    }
+}
+
+# Assert $left != $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert not equal 1 2 # passes
+# > assert not equal 1 "apple" # passes
+# > assert not equal 7 7 # fails
+export def "assert not equal" [left: any, right: any, message?: string] {
+    main ($left != $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"They both are ($left)."
+    }
+}
+
+# Assert $left <= $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert less or equal 1 2 # passes
+# > assert less or equal 1 1 # passes
+# > assert less or equal 1 0 # fails
+export def "assert less or equal" [left: any, right: any, message?: string] {
+    main ($left <= $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"Left: ($left), Right: ($right)"
+    }
+}
+
+# Assert $left < $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert less 1 2 # passes
+# > assert less 1 1 # fails
+export def "assert less" [left: any, right: any, message?: string] {
+    main ($left < $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"Left: ($left), Right: ($right)"
+    }
+}
+
+# Assert $left > $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert greater 2 1 # passes
+# > assert greater 2 2 # fails
+export def "assert greater" [left: any, right: any, message?: string] {
+    main ($left > $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"Left: ($left), Right: ($right)"
+    }
+}
+
+# Assert $left >= $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert greater or equal 2 1 # passes
+# > assert greater or equal 2 2 # passes
+# > assert greater or equal 1 2 # fails
+export def "assert greater or equal" [left: any, right: any, message?: string] {
+    main ($left >= $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"Left: ($left), Right: ($right)"
+    }
+}
+
+# Assert length of $left is $right
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert length [0, 0] 2 # passes
+# > assert length [0] 3 # fails
+export def "assert length" [left: list, right: int, message?: string] {
+    main (($left | length) == $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"Length of ($left) is ($left | length), not ($right)"
+    }
+}
+
+# Assert that ($left | str contains $right)
+#
+# For more documentation see the assert command
+#
+# # Examples
+#
+# > assert str contains "arst" "rs" # passes
+# > assert str contains "arst" "k" # fails
+export def "assert str contains" [left: string, right: string, message?: string] {
+    main ($left | str contains $right) $message --error-label {
+        start: (metadata $left).span.start
+        end: (metadata $right).span.end
+        text: $"'($left)' does not contain '($right)'."
+    }
+}
diff --git a/crates/nu-std/lib/dirs.nu b/crates/nu-std/lib/dirs.nu
new file mode 100644
index 0000000000..d2e9664461
--- /dev/null
+++ b/crates/nu-std/lib/dirs.nu
@@ -0,0 +1,83 @@
+# Maintain a list of working directories and navigates them
+
+# the directory stack
+export-env {
+    let-env DIRS_POSITION = 0
+    let-env DIRS_LIST = [($env.PWD | path expand)]
+}
+
+# Add one or more directories to the list.
+# PWD becomes first of the newly added directories.
+export def-env "dirs add" [
+    ...paths: string    # directory or directories to add to working list
+    ] {
+        mut abspaths = []
+        for p in $paths {
+            let exp = ($p | path expand)
+            if ($exp | path type) != 'dir' {
+                let span = (metadata $p).span
+                error make {msg: "not a directory", label: {text: "not a directory", start: $span.start, end: $span.end } }
+            }
+        $abspaths = ($abspaths | append $exp)
+
+        }
+        let-env DIRS_LIST = ($env.DIRS_LIST | insert ($env.DIRS_POSITION + 1) $abspaths | flatten)
+        let-env DIRS_POSITION = $env.DIRS_POSITION + 1
+
+    _fetch 0
+}
+
+# Advance to the next directory in the list or wrap to beginning.
+export def-env "dirs next" [
+    N:int = 1   # number of positions to move.
+] {
+    _fetch $N    
+}
+
+# Back up to the previous directory or wrap to the end.
+export def-env "dirs prev" [
+    N:int = 1   # number of positions to move.
+] {
+    _fetch (-1 * $N)    
+}
+
+# Drop the current directory from the list, if it's not the only one.
+# PWD becomes the next working directory
+export def-env "dirs drop" [] {
+    if ($env.DIRS_LIST | length) > 1 {
+        let-env DIRS_LIST = (
+            ($env.DIRS_LIST | take $env.DIRS_POSITION) 
+            | append ($env.DIRS_LIST | skip ($env.DIRS_POSITION + 1))
+        )
+    }
+
+    _fetch 0
+}
+
+# Display current working directories.
+export def-env "dirs show" [] {
+    mut out = []
+    for $p in ($env.DIRS_LIST | enumerate) {
+        $out = ($out | append [
+            [active, path]; 
+            [($p.index == $env.DIRS_POSITION), $p.item]
+        ])
+    }
+
+    $out
+}
+
+# fetch item helper
+def-env  _fetch [
+    offset: int,    # signed change to position
+] {
+    # nushell 'mod' operator is really 'remainder', can return negative values.
+    # see: https://stackoverflow.com/questions/13683563/whats-the-difference-between-mod-and-remainder    
+    let pos = ($env.DIRS_POSITION 
+                + $offset 
+                + ($env.DIRS_LIST | length)
+            ) mod ($env.DIRS_LIST | length)
+    let-env DIRS_POSITION = $pos
+
+    cd ($env.DIRS_LIST | get $pos )
+}
diff --git a/crates/nu-std/std.nu b/crates/nu-std/lib/help.nu
similarity index 53%
rename from crates/nu-std/std.nu
rename to crates/nu-std/lib/help.nu
index c2dbda3fcb..f7fa8b39d8 100644
--- a/crates/nu-std/std.nu
+++ b/crates/nu-std/lib/help.nu
@@ -1,716 +1,3 @@
-# std.nu, `used` to load all standard library components
-
-# Universal assert command
-#
-# If the condition is not true, it generates an error.
-#
-# # Example
-#
-# ```nushell
-# >_ assert (3 == 3)
-# >_ assert (42 == 3)
-# Error:
-#   × Assertion failed: 
-#     ╭─[myscript.nu:11:1]
-#  11 │ assert (3 == 3)
-#  12 │ assert (42 == 3)
-#     ·         ───┬────
-#     ·            ╰── It is not true.
-#  13 │
-#     ╰────
-# ```
-#
-# The --error-label flag can be used if you want to create a custom assert command:
-# ```
-# def "assert even" [number: int] {
-#     assert ($number mod 2 == 0) --error-label {
-#         start: (metadata $number).span.start,
-#         end: (metadata $number).span.end,
-#         text: $"($number) is not an even number",
-#     }
-# }
-# ```
-export def assert [
-    condition: bool, # Condition, which should be true 
-    message?: string, # Optional error message
-    --error-label: record # Label for `error make` if you want to create a custom assert
-] {
-    if $condition { return }
-    let span = (metadata $condition).span
-    error make {
-        msg: ($message | default "Assertion failed."),
-        label: ($error_label | default {
-            text: "It is not true.",
-            start: (metadata $condition).span.start,
-            end: (metadata $condition).span.end
-        })
-    }
-}
-
-# Assert that executing the code generates an error
-#
-# For more documentation see the assert command
-# 
-# # Examples
-#
-# > assert error {|| missing_command} # passes
-# > assert error {|| 12} # fails
-export def "assert error" [
-    code: closure,
-    message?: string
-] {
-    let error_raised = (try { do $code; false } catch { true })
-    assert ($error_raised) $message --error-label {
-        start: (metadata $code).span.start
-        end: (metadata $code).span.end
-        text: $"There were no error during code execution: (view source $code)"
-    }
-}
-
-# Skip the current test case
-#
-# # Examples
-#
-# if $condition { assert skip }
-export def "assert skip" [] {
-    error make {msg: "ASSERT:SKIP"}
-}
-
-
-# Assert $left == $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-# 
-# > assert equal 1 1 # passes
-# > assert equal (0.1 + 0.2) 0.3
-# > assert equal 1 2 # fails
-export def "assert equal" [left: any, right: any, message?: string] {
-    assert ($left == $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"They are not equal. Left = ($left). Right = ($right)."
-    }
-}
-
-# Assert $left != $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert not equal 1 2 # passes
-# > assert not equal 1 "apple" # passes
-# > assert not equal 7 7 # fails
-export def "assert not equal" [left: any, right: any, message?: string] {
-    assert ($left != $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"They both are ($left)."
-    }
-}
-
-# Assert $left <= $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert less or equal 1 2 # passes
-# > assert less or equal 1 1 # passes
-# > assert less or equal 1 0 # fails
-export def "assert less or equal" [left: any, right: any, message?: string] {
-    assert ($left <= $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"Left: ($left), Right: ($right)"
-    }
-}
-
-# Assert $left < $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert less 1 2 # passes
-# > assert less 1 1 # fails
-export def "assert less" [left: any, right: any, message?: string] {
-    assert ($left < $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"Left: ($left), Right: ($right)"
-    }
-}
-
-# Assert $left > $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert greater 2 1 # passes
-# > assert greater 2 2 # fails
-export def "assert greater" [left: any, right: any, message?: string] {
-    assert ($left > $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"Left: ($left), Right: ($right)"
-    }
-}
-
-# Assert $left >= $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert greater or equal 2 1 # passes
-# > assert greater or equal 2 2 # passes
-# > assert greater or equal 1 2 # fails
-export def "assert greater or equal" [left: any, right: any, message?: string] {
-    assert ($left >= $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"Left: ($left), Right: ($right)"
-    }
-}
-
-# Assert length of $left is $right
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert length [0, 0] 2 # passes
-# > assert length [0] 3 # fails
-export def "assert length" [left: list, right: int, message?: string] {
-    assert (($left | length) == $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"Length of ($left) is ($left | length), not ($right)"
-    }
-}
-
-# Assert that ($left | str contains $right)
-#
-# For more documentation see the assert command
-#
-# # Examples
-#
-# > assert str contains "arst" "rs" # passes
-# > assert str contains "arst" "k" # fails
-export def "assert str contains" [left: string, right: string, message?: string] {
-    assert ($left | str contains $right) $message --error-label {
-        start: (metadata $left).span.start
-        end: (metadata $right).span.end
-        text: $"'($left)' does not contain '($right)'."
-    }
-}
-
-# Add the given paths to the PATH.
-#
-# # Example
-# - adding some dummy paths to an empty PATH
-# ```nushell
-# >_ with-env [PATH []] {
-#     std path add "foo"
-#     std path add "bar" "baz"
-#     std path add "fooo" --append
-#
-#     assert equal $env.PATH ["bar" "baz" "foo" "fooo"]
-#
-#     print (std path add "returned" --ret)
-# }
-# ╭───┬──────────╮
-# │ 0 │ returned │
-# │ 1 │ bar      │
-# │ 2 │ baz      │
-# │ 3 │ foo      │
-# │ 4 │ fooo     │
-# ╰───┴──────────╯
-# ```
-export def-env "path add" [
-    --ret (-r)  # return $env.PATH, useful in pipelines to avoid scoping.
-    --append (-a)  # append to $env.PATH instead of prepending to.
-    ...paths  # the paths to add to $env.PATH.
-] {
-    let-env PATH = (
-        $env.PATH
-        | if $append { append $paths }
-        else { prepend $paths }
-    )
-
-    if $ret {
-        $env.PATH
-    }
-}
-
-# Maintain a list of working directories and navigates them
-
-# the directory stack
-export-env {
-    let-env DIRS_POSITION = 0
-    let-env DIRS_LIST = [($env.PWD | path expand)]
-}
-
-# Add one or more directories to the list.
-# PWD becomes first of the newly added directories.
-export def-env "dirs add" [
-    ...paths: string    # directory or directories to add to working list
-    ] {
-        mut abspaths = []
-        for p in $paths {
-            let exp = ($p | path expand)
-            if ($exp | path type) != 'dir' {
-                let span = (metadata $p).span
-                error make {msg: "not a directory", label: {text: "not a directory", start: $span.start, end: $span.end } }
-            }
-        $abspaths = ($abspaths | append $exp)
-
-        }
-        let-env DIRS_LIST = ($env.DIRS_LIST | insert ($env.DIRS_POSITION + 1) $abspaths | flatten)
-        let-env DIRS_POSITION = $env.DIRS_POSITION + 1
-
-    _fetch 0
-}
-
-# Advance to the next directory in the list or wrap to beginning.
-export def-env "dirs next" [
-    N:int = 1   # number of positions to move.
-] {
-    _fetch $N    
-}
-
-# Back up to the previous directory or wrap to the end.
-export def-env "dirs prev" [
-    N:int = 1   # number of positions to move.
-] {
-    _fetch (-1 * $N)    
-}
-
-# Drop the current directory from the list, if it's not the only one.
-# PWD becomes the next working directory
-export def-env "dirs drop" [] {
-    if ($env.DIRS_LIST | length) > 1 {
-        let-env DIRS_LIST = (
-            ($env.DIRS_LIST | take $env.DIRS_POSITION) 
-            | append ($env.DIRS_LIST | skip ($env.DIRS_POSITION + 1))
-        )
-    }
-
-    _fetch 0
-}
-
-# Display current working directories.
-export def-env "dirs show" [] {
-    mut out = []
-    for $p in ($env.DIRS_LIST | enumerate) {
-        $out = ($out | append [
-            [active, path]; 
-            [($p.index == $env.DIRS_POSITION), $p.item]
-        ])
-    }
-
-    $out
-}
-
-# fetch item helper
-def-env  _fetch [
-    offset: int,    # signed change to position
-] {
-    # nushell 'mod' operator is really 'remainder', can return negative values.
-    # see: https://stackoverflow.com/questions/13683563/whats-the-difference-between-mod-and-remainder    
-    let pos = ($env.DIRS_POSITION 
-                + $offset 
-                + ($env.DIRS_LIST | length)
-            ) mod ($env.DIRS_LIST | length)
-    let-env DIRS_POSITION = $pos
-
-    cd ($env.DIRS_LIST | get $pos )
-}
-
-def CRITICAL_LEVEL [] { 50 }
-def ERROR_LEVEL    [] { 40 }
-def WARNING_LEVEL  [] { 30 }
-def INFO_LEVEL     [] { 20 }
-def DEBUG_LEVEL    [] { 10 }
-
-def parse-string-level [level: string] {
-    (
-        if $level == "CRITICAL" { (CRITICAL_LEVEL)}
-        else if $level == "CRIT" { (CRITICAL_LEVEL)}
-        else if $level == "ERROR" { (ERROR_LEVEL) }
-        else if $level == "WARNING" { (WARNING_LEVEL) }
-        else if $level == "WARN" { (WARNING_LEVEL) }
-        else if $level == "INFO" { (INFO_LEVEL) }
-        else if $level == "DEBUG" { (DEBUG_LEVEL) }
-        else { (INFO_LEVEL) }
-    )
-}
-
-def current-log-level [] {
-    let env_level = ($env | get -i NU_LOG_LEVEL | default (INFO_LEVEL))
-
-    try {
-        ($env_level | into int)
-    } catch {
-        parse-string-level $env_level
-    }
-}
-
-def now [] {
-    date now | date format "%Y-%m-%dT%H:%M:%S%.3f"
-}
-
-# Log critical message
-export def "log critical" [message: string] {
-    if (current-log-level) > (CRITICAL_LEVEL) { return }
-
-    print --stderr $"(ansi red_bold)CRT|(now)|($message)(ansi reset)"
-}
-# Log error message
-export def "log error" [message: string] {
-    if (current-log-level) > (ERROR_LEVEL) { return }
-
-    print --stderr $"(ansi red)ERR|(now)|($message)(ansi reset)"
-}
-# Log warning message
-export def "log warning" [message: string] {
-    if (current-log-level) > (WARNING_LEVEL) { return }
-
-    print --stderr $"(ansi yellow)WRN|(now)|($message)(ansi reset)"
-}
-# Log info message
-export def "log info" [message: string] {
-    if (current-log-level) > (INFO_LEVEL) { return }
-
-    print --stderr $"(ansi default)INF|(now)|($message)(ansi reset)"
-}
-# Log debug message
-export def "log debug" [message: string] {
-    if (current-log-level) > (DEBUG_LEVEL) { return }
-
-    print --stderr $"(ansi default_dimmed)DBG|(now)|($message)(ansi reset)"
-}
-
-# Utility functions to read, change and create XML data in format supported
-# by `to xml` and `from xml` commands
-
-# Get all xml entries matching simple xpath-inspired query
-export def xaccess [
-    path: list # List of steps. Each step can be a
-               # 1. String with tag name. Finds all children with specified name. Equivalent to `child::A` in xpath
-               # 2. `*` string. Get all children without any filter. Equivalent to `descendant` in xpath
-               # 3. Int. Select n-th among nodes selected by previous path. Equivalent to `(...)[1]` in xpath, but is indexed from 0.
-               # 4. Closure. Predicate accepting entry. Selects all entries among nodes selected by previous path for which predicate returns true. 
-] {
-    let input = $in
-    if ($path | is-empty) {
-        let path_span = (metadata $path).span
-        error make {msg: 'Empty path provided'
-                    label: {text: 'Use a non-empty  list of path steps'
-                            start: $path_span.start end: $path_span.end}}
-    }
-    # In xpath first element in path is applied to root element
-    # this way it is possible to apply first step to root element
-    # of nu xml without unrolling one step of loop
-    mut values = ()
-    $values = {content: [ { content: $input } ] }
-    for $step in ($path) {
-        match ($step | describe) {
-            'string' => {
-                if $step == '*' {
-                    $values = ($values.content | flatten)
-                } else {
-                    $values = ($values.content | flatten | where tag == $step)
-                }
-            },
-            'int' => {
-                $values = [ ($values | get $step) ]
-            },
-            'closure' => {
-                $values = ($values | where {|x| do $step $x})
-            },
-            $type => {
-                let step_span = (metadata $step).span
-                error make {msg: $'Incorrect path step type ($type)'
-                        label: {text: 'Use a string or int as a step'
-                                start: $step_span.start end: $step_span.end}}
-            }
-        }
-
-        if ($values | is-empty) {
-            return []
-        }
-    }
-    $values
-}
-
-def xupdate-string-step [ step: string rest: list updater: closure ] {
-    let input = $in
-
-    # Get a list of elements to be updated and their indices
-    let to_update = ($input.content | enumerate | filter {|it|
-        let item = $it.item
-        $step == '*' or $item.tag == $step
-    })
-
-    if ($to_update | is-empty) {
-        return $input
-    }
-
-    let new_values = ($to_update.item | xupdate-internal $rest $updater)
-
-    mut reenumerated_new_values = ($to_update.index | zip $new_values | each {|x| {index: $x.0 item: $x.1}})
-
-    mut new_content = []
-    for it in ($input.content | enumerate) {
-        let item = $it.item
-        let idx = $it.index
-
-        let next = (if (not ($reenumerated_new_values | is-empty)) and $idx == $reenumerated_new_values.0.index {
-            let tmp = $reenumerated_new_values.0
-            $reenumerated_new_values = ($reenumerated_new_values | skip 1)
-            $tmp.item
-        } else {
-            $item
-        })
-
-        $new_content = ($new_content | append $next)
-    }
-
-    {tag: $input.tag attributes: $input.attributes content: $new_content}
-}
-
-def xupdate-int-step [ step: int rest: list updater: closure ] {
-    $in | enumerate | each {|it|
-        let item = $it.item
-        let idx = $it.index
-
-        if $idx == $step {
-            [ $item ] | xupdate-internal $rest $updater | get 0
-        } else {
-            $item
-        }
-    }
-}
-
-def xupdate-closure-step [ step: closure rest: list updater: closure ] {
-    $in | each {|it|
-        if (do $step $it) {
-            [ $it ] | xupdate-internal $rest $updater | get 0
-        } else {
-            $it
-        }
-    }
-}
-
-def xupdate-internal [ path: list updater: closure ] {
-    let input = $in
-
-    if ($path | is-empty) {
-        $input | each $updater
-    } else {
-        let step = $path.0
-        let rest = ($path | skip 1)
-
-        match ($step | describe) {
-            'string' => {
-                $input | each {|x| $x | xupdate-string-step $step $rest $updater}
-            },
-            'int' => {
-                $input | xupdate-int-step $step $rest $updater
-            },
-            'closure' => {
-                $input | xupdate-closure-step $step $rest $updater
-            },
-            $type => {
-                let step_span = (metadata $step).span
-                error make {msg: $'Incorrect path step type ($type)'
-                        label: {text: 'Use a string or int as a step'
-                                start: $step_span.start end: $step_span.end}}
-            }
-        }
-    }
-
-}
-
-# Update xml data entries matching simple xpath-inspired query
-export def xupdate [
-    path: list  # List of steps. Each step can be a
-                # 1. String with tag name. Finds all children with specified name. Equivalent to `child::A` in xpath
-                # 2. `*` string. Get all children without any filter. Equivalent to `descendant` in xpath
-                # 3. Int. Select n-th among nodes selected by previous path. Equivalent to `(...)[1]` in xpath, but is indexed from 0.
-                # 4. Closure. Predicate accepting entry. Selects all entries among nodes selected by previous path for which predicate returns true. 
-    updater: closure # A closure used to transform entries matching path.
-] {
-    {tag:? attributes:? content: [$in]} | xupdate-internal $path $updater | get content.0
-}
-
-# Get type of an xml entry
-#
-# Possible types are 'tag', 'text', 'pi' and 'comment'
-export def xtype [] {
-    let input = $in
-    if (($input | describe) == 'string' or 
-        ($input.tag? == null and $input.attributes? == null and ($input.content? | describe) == 'string')) {
-        'text'
-    } else if $input.tag? == '!' {
-        'comment'
-    } else if $input.tag? != null and ($input.tag? | str starts-with '?') {
-        'pi'
-    } else if $input.tag? != null {
-        'tag'
-    } else {
-        error make {msg: 'Not an xml emtry. Check valid types of xml entries via `help to xml`'}
-    }
-}
-
-# Insert new entry to elements matching simple xpath-inspired query
-export def xinsert [
-    path: list  # List of steps. Each step can be a
-                # 1. String with tag name. Finds all children with specified name. Equivalent to `child::A` in xpath
-                # 2. `*` string. Get all children without any filter. Equivalent to `descendant` in xpath
-                # 3. Int. Select n-th among nodes selected by previous path. Equivalent to `(...)[1]` in xpath, but is indexed from 0.
-                # 4. Closure. Predicate accepting entry. Selects all entries among nodes selected by previous path for which predicate returns true. 
-    new_entry: record # A new entry to insert into `content` field of record at specified position
-    position?: int  # Position to insert `new_entry` into. If specified inserts entry at given position (or end if
-                    # position is greater than number of elements) in content of all entries of input matched by 
-                    # path. If not specified inserts at the end.
-] {
-    $in | xupdate $path {|entry|
-        match ($entry | xtype) {
-            'tag' => {
-                let new_content = if $position == null {
-                    $entry.content | append $new_entry
-                } else {
-                    let position = if $position > ($entry.content | length) {
-                        $entry.content | length
-                    } else {
-                        $position
-                    }
-                    $entry.content | insert $position $new_entry
-                }
-
-                
-                {tag: $entry.tag attributes: $entry.attributes content: $new_content}
-            },
-            _ => (error make {msg: 'Can insert entry only into content of a tag node'})
-        }
-    }
-}
-                            
-# print a command name as dimmed and italic
-def pretty-command [] {
-    let command = $in
-    return $"(ansi default_dimmed)(ansi default_italic)($command)(ansi reset)"
-}
-
-# give a hint error when the clip command is not available on the system
-def check-clipboard [
-    clipboard: string  # the clipboard command name
-    --system: string  # some information about the system running, for better error
-] {
-    if (which $clipboard | is-empty) {
-        error make --unspanned {
-            msg: $"(ansi red)clipboard_not_found(ansi reset):
-    you are running ($system)
-    but
-    the ($clipboard | pretty-command) clipboard command was not found on your system."
-        }
-    }
-}
-
-# put the end of a pipe into the system clipboard.
-#
-# Dependencies:
-#   - xclip on linux x11
-#   - wl-copy on linux wayland
-#   - clip.exe on windows
-#
-# Examples:
-#     put a simple string to the clipboard, will be stripped to remove ANSI sequences
-#     >_ "my wonderful string" | clip
-#     my wonderful string
-#     saved to clipboard (stripped)
-#
-#     put a whole table to the clipboard
-#     >_ ls *.toml | clip
-#     ╭───┬─────────────────────┬──────┬────────┬───────────────╮
-#     │ # │        name         │ type │  size  │   modified    │
-#     ├───┼─────────────────────┼──────┼────────┼───────────────┤
-#     │ 0 │ Cargo.toml          │ file │ 5.0 KB │ 3 minutes ago │
-#     │ 1 │ Cross.toml          │ file │  363 B │ 2 weeks ago   │
-#     │ 2 │ rust-toolchain.toml │ file │ 1.1 KB │ 2 weeks ago   │
-#     ╰───┴─────────────────────┴──────┴────────┴───────────────╯
-#
-#     saved to clipboard
-#
-#     put huge structured data in the clipboard, but silently
-#     >_ open Cargo.toml --raw | from toml | clip --silent
-#
-#     when the clipboard system command is not installed
-#     >_ "mm this is fishy..." | clip
-#     Error:
-#       × clipboard_not_found:
-#       │     you are using xorg on linux
-#       │     but
-#       │     the xclip clipboard command was not found on your system.
-export def clip [
-    --silent: bool  # do not print the content of the clipboard to the standard output
-    --no-notify: bool  # do not throw a notification (only on linux)
-] {
-    let input = $in
-    let input = if ($input | describe) == "string" {
-        $input | ansi strip
-    } else { $input }
-
-    match $nu.os-info.name {
-        "linux" => {
-            if ($env.WAYLAND_DISPLAY? | is-empty) {
-                check-clipboard xclip --system $"('xorg' | pretty-command) on linux"
-                $input | xclip -sel clip
-            } else {
-                check-clipboard wl-copy --system $"('wayland' | pretty-command) on linux"
-                $input | wl-copy
-            }
-        },
-        "windows" => {
-            chcp 65001  # see https://discord.com/channels/601130461678272522/601130461678272524/1085535756237426778
-            check-clipboard clip.exe --system $"('xorg' | pretty-command) on linux"
-            $input | clip.exe
-        },
-        "macos" => {
-            check-clipboard pbcopy --system macOS
-            $input | pbcopy
-        },
-        _ => {
-            error make --unspanned {
-                msg: $"(ansi red)unknown_operating_system(ansi reset):
-    '($nu.os-info.name)' is not supported by the ('clip' | pretty-command) command.
-
-    please open a feature request in the [issue tracker](char lparen)https://github.com/nushell/nushell/issues/new/choose(char rparen) to add your operating system to the standard library."
-            }
-        },
-    }
-
-    if not $silent {
-        print $input
-
-        print --no-newline $"(ansi white_italic)(ansi white_dimmed)saved to clipboard"
-        if ($input | describe) == "string" {
-            print " (stripped)"
-        }
-        print --no-newline $"(ansi reset)"
-    }
-
-    if (not $no_notify) and ($nu.os-info.name == linux) {
-        notify-send "std clip" "saved to clipboard"
-    }
-}
-
 def error-fmt [] {
     $"(ansi red)($in)(ansi reset)"
 }
@@ -1387,7 +674,7 @@ def pretty-cmd [] {
 #
 #   search for string in command names, usage and search terms
 #   > help --find char
-export def help [
+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
 ] {
diff --git a/crates/nu-std/lib/log.nu b/crates/nu-std/lib/log.nu
new file mode 100644
index 0000000000..59c1204173
--- /dev/null
+++ b/crates/nu-std/lib/log.nu
@@ -0,0 +1,63 @@
+def CRITICAL_LEVEL [] { 50 }
+def ERROR_LEVEL    [] { 40 }
+def WARNING_LEVEL  [] { 30 }
+def INFO_LEVEL     [] { 20 }
+def DEBUG_LEVEL    [] { 10 }
+
+def parse-string-level [level: string] {
+    (
+        if $level == "CRITICAL" { (CRITICAL_LEVEL)}
+        else if $level == "CRIT" { (CRITICAL_LEVEL)}
+        else if $level == "ERROR" { (ERROR_LEVEL) }
+        else if $level == "WARNING" { (WARNING_LEVEL) }
+        else if $level == "WARN" { (WARNING_LEVEL) }
+        else if $level == "INFO" { (INFO_LEVEL) }
+        else if $level == "DEBUG" { (DEBUG_LEVEL) }
+        else { (INFO_LEVEL) }
+    )
+}
+
+def current-log-level [] {
+    let env_level = ($env | get -i NU_LOG_LEVEL | default (INFO_LEVEL))
+
+    try {
+        ($env_level | into int)
+    } catch {
+        parse-string-level $env_level
+    }
+}
+
+def now [] {
+    date now | date format "%Y-%m-%dT%H:%M:%S%.3f"
+}
+
+# Log critical message
+export def "log critical" [message: string] {
+    if (current-log-level) > (CRITICAL_LEVEL) { return }
+
+    print --stderr $"(ansi red_bold)CRT|(now)|($message)(ansi reset)"
+}
+# Log error message
+export def "log error" [message: string] {
+    if (current-log-level) > (ERROR_LEVEL) { return }
+
+    print --stderr $"(ansi red)ERR|(now)|($message)(ansi reset)"
+}
+# Log warning message
+export def "log warning" [message: string] {
+    if (current-log-level) > (WARNING_LEVEL) { return }
+
+    print --stderr $"(ansi yellow)WRN|(now)|($message)(ansi reset)"
+}
+# Log info message
+export def "log info" [message: string] {
+    if (current-log-level) > (INFO_LEVEL) { return }
+
+    print --stderr $"(ansi default)INF|(now)|($message)(ansi reset)"
+}
+# Log debug message
+export def "log debug" [message: string] {
+    if (current-log-level) > (DEBUG_LEVEL) { return }
+
+    print --stderr $"(ansi default_dimmed)DBG|(now)|($message)(ansi reset)"
+}
diff --git a/crates/nu-std/lib/mod.nu b/crates/nu-std/lib/mod.nu
new file mode 100644
index 0000000000..a3721ee0c6
--- /dev/null
+++ b/crates/nu-std/lib/mod.nu
@@ -0,0 +1,157 @@
+# std.nu, `used` to load all standard library components
+
+export use assert *
+export use dirs *
+export-env {
+    use dirs *
+}
+export use help *
+export use log *
+export use xml *
+
+# Add the given paths to the PATH.
+#
+# # Example
+# - adding some dummy paths to an empty PATH
+# ```nushell
+# >_ with-env [PATH []] {
+#     std path add "foo"
+#     std path add "bar" "baz"
+#     std path add "fooo" --append
+#
+#     assert equal $env.PATH ["bar" "baz" "foo" "fooo"]
+#
+#     print (std path add "returned" --ret)
+# }
+# ╭───┬──────────╮
+# │ 0 │ returned │
+# │ 1 │ bar      │
+# │ 2 │ baz      │
+# │ 3 │ foo      │
+# │ 4 │ fooo     │
+# ╰───┴──────────╯
+# ```
+export def-env "path add" [
+    --ret (-r)  # return $env.PATH, useful in pipelines to avoid scoping.
+    --append (-a)  # append to $env.PATH instead of prepending to.
+    ...paths  # the paths to add to $env.PATH.
+] {
+    let-env PATH = (
+        $env.PATH
+        | if $append { append $paths }
+        else { prepend $paths }
+    )
+
+    if $ret {
+        $env.PATH
+    }
+}
+
+# print a command name as dimmed and italic
+def pretty-command [] {
+    let command = $in
+    return $"(ansi default_dimmed)(ansi default_italic)($command)(ansi reset)"
+}
+
+# give a hint error when the clip command is not available on the system
+def check-clipboard [
+    clipboard: string  # the clipboard command name
+    --system: string  # some information about the system running, for better error
+] {
+    if (which $clipboard | is-empty) {
+        error make --unspanned {
+            msg: $"(ansi red)clipboard_not_found(ansi reset):
+    you are running ($system)
+    but
+    the ($clipboard | pretty-command) clipboard command was not found on your system."
+        }
+    }
+}
+
+# put the end of a pipe into the system clipboard.
+#
+# Dependencies:
+#   - xclip on linux x11
+#   - wl-copy on linux wayland
+#   - clip.exe on windows
+#
+# Examples:
+#     put a simple string to the clipboard, will be stripped to remove ANSI sequences
+#     >_ "my wonderful string" | clip
+#     my wonderful string
+#     saved to clipboard (stripped)
+#
+#     put a whole table to the clipboard
+#     >_ ls *.toml | clip
+#     ╭───┬─────────────────────┬──────┬────────┬───────────────╮
+#     │ # │        name         │ type │  size  │   modified    │
+#     ├───┼─────────────────────┼──────┼────────┼───────────────┤
+#     │ 0 │ Cargo.toml          │ file │ 5.0 KB │ 3 minutes ago │
+#     │ 1 │ Cross.toml          │ file │  363 B │ 2 weeks ago   │
+#     │ 2 │ rust-toolchain.toml │ file │ 1.1 KB │ 2 weeks ago   │
+#     ╰───┴─────────────────────┴──────┴────────┴───────────────╯
+#
+#     saved to clipboard
+#
+#     put huge structured data in the clipboard, but silently
+#     >_ open Cargo.toml --raw | from toml | clip --silent
+#
+#     when the clipboard system command is not installed
+#     >_ "mm this is fishy..." | clip
+#     Error:
+#       × clipboard_not_found:
+#       │     you are using xorg on linux
+#       │     but
+#       │     the xclip clipboard command was not found on your system.
+export def clip [
+    --silent: bool  # do not print the content of the clipboard to the standard output
+    --no-notify: bool  # do not throw a notification (only on linux)
+] {
+    let input = $in
+    let input = if ($input | describe) == "string" {
+        $input | ansi strip
+    } else { $input }
+
+    match $nu.os-info.name {
+        "linux" => {
+            if ($env.WAYLAND_DISPLAY? | is-empty) {
+                check-clipboard xclip --system $"('xorg' | pretty-command) on linux"
+                $input | xclip -sel clip
+            } else {
+                check-clipboard wl-copy --system $"('wayland' | pretty-command) on linux"
+                $input | wl-copy
+            }
+        },
+        "windows" => {
+            chcp 65001  # see https://discord.com/channels/601130461678272522/601130461678272524/1085535756237426778
+            check-clipboard clip.exe --system $"('xorg' | pretty-command) on linux"
+            $input | clip.exe
+        },
+        "macos" => {
+            check-clipboard pbcopy --system macOS
+            $input | pbcopy
+        },
+        _ => {
+            error make --unspanned {
+                msg: $"(ansi red)unknown_operating_system(ansi reset):
+    '($nu.os-info.name)' is not supported by the ('clip' | pretty-command) command.
+
+    please open a feature request in the [issue tracker](char lparen)https://github.com/nushell/nushell/issues/new/choose(char rparen) to add your operating system to the standard library."
+            }
+        },
+    }
+
+    if not $silent {
+        print $input
+
+        print --no-newline $"(ansi white_italic)(ansi white_dimmed)saved to clipboard"
+        if ($input | describe) == "string" {
+            print " (stripped)"
+        }
+        print --no-newline $"(ansi reset)"
+    }
+
+    if (not $no_notify) and ($nu.os-info.name == linux) {
+        notify-send "std clip" "saved to clipboard"
+    }
+}
diff --git a/crates/nu-std/lib/xml.nu b/crates/nu-std/lib/xml.nu
new file mode 100644
index 0000000000..83ad08e2dd
--- /dev/null
+++ b/crates/nu-std/lib/xml.nu
@@ -0,0 +1,206 @@
+# Utility functions to read, change and create XML data in format supported
+# by `to xml` and `from xml` commands
+
+# Get all xml entries matching simple xpath-inspired query
+export def xaccess [
+    path: list # List of steps. Each step can be a
+               # 1. String with tag name. Finds all children with specified name. Equivalent to `child::A` in xpath
+               # 2. `*` string. Get all children without any filter. Equivalent to `descendant` in xpath
+               # 3. Int. Select n-th among nodes selected by previous path. Equivalent to `(...)[1]` in xpath, but is indexed from 0.
+               # 4. Closure. Predicate accepting entry. Selects all entries among nodes selected by previous path for which predicate returns true. 
+] {
+    let input = $in
+    if ($path | is-empty) {
+        let path_span = (metadata $path).span
+        error make {msg: 'Empty path provided'
+                    label: {text: 'Use a non-empty  list of path steps'
+                            start: $path_span.start end: $path_span.end}}
+    }
+    # In xpath first element in path is applied to root element
+    # this way it is possible to apply first step to root element
+    # of nu xml without unrolling one step of loop
+    mut values = ()
+    $values = {content: [ { content: $input } ] }
+    for $step in ($path) {
+        match ($step | describe) {
+            'string' => {
+                if $step == '*' {
+                    $values = ($values.content | flatten)
+                } else {
+                    $values = ($values.content | flatten | where tag == $step)
+                }
+            },
+            'int' => {
+                $values = [ ($values | get $step) ]
+            },
+            'closure' => {
+                $values = ($values | where {|x| do $step $x})
+            },
+            $type => {
+                let step_span = (metadata $step).span
+                error make {msg: $'Incorrect path step type ($type)'
+                        label: {text: 'Use a string or int as a step'
+                                start: $step_span.start end: $step_span.end}}
+            }
+        }
+
+        if ($values | is-empty) {
+            return []
+        }
+    }
+    $values
+}
+
+def xupdate-string-step [ step: string rest: list updater: closure ] {
+    let input = $in
+
+    # Get a list of elements to be updated and their indices
+    let to_update = ($input.content | enumerate | filter {|it|
+        let item = $it.item
+        $step == '*' or $item.tag == $step
+    })
+
+    if ($to_update | is-empty) {
+        return $input
+    }
+
+    let new_values = ($to_update.item | xupdate-internal $rest $updater)
+
+    mut reenumerated_new_values = ($to_update.index | zip $new_values | each {|x| {index: $x.0 item: $x.1}})
+
+    mut new_content = []
+    for it in ($input.content | enumerate) {
+        let item = $it.item
+        let idx = $it.index
+
+        let next = (if (not ($reenumerated_new_values | is-empty)) and $idx == $reenumerated_new_values.0.index {
+            let tmp = $reenumerated_new_values.0
+            $reenumerated_new_values = ($reenumerated_new_values | skip 1)
+            $tmp.item
+        } else {
+            $item
+        })
+
+        $new_content = ($new_content | append $next)
+    }
+
+    {tag: $input.tag attributes: $input.attributes content: $new_content}
+}
+
+def xupdate-int-step [ step: int rest: list updater: closure ] {
+    $in | enumerate | each {|it|
+        let item = $it.item
+        let idx = $it.index
+
+        if $idx == $step {
+            [ $item ] | xupdate-internal $rest $updater | get 0
+        } else {
+            $item
+        }
+    }
+}
+
+def xupdate-closure-step [ step: closure rest: list updater: closure ] {
+    $in | each {|it|
+        if (do $step $it) {
+            [ $it ] | xupdate-internal $rest $updater | get 0
+        } else {
+            $it
+        }
+    }
+}
+
+def xupdate-internal [ path: list updater: closure ] {
+    let input = $in
+
+    if ($path | is-empty) {
+        $input | each $updater
+    } else {
+        let step = $path.0
+        let rest = ($path | skip 1)
+
+        match ($step | describe) {
+            'string' => {
+                $input | each {|x| $x | xupdate-string-step $step $rest $updater}
+            },
+            'int' => {
+                $input | xupdate-int-step $step $rest $updater
+            },
+            'closure' => {
+                $input | xupdate-closure-step $step $rest $updater
+            },
+            $type => {
+                let step_span = (metadata $step).span
+                error make {msg: $'Incorrect path step type ($type)'
+                        label: {text: 'Use a string or int as a step'
+                                start: $step_span.start end: $step_span.end}}
+            }
+        }
+    }
+
+}
+
+# Update xml data entries matching simple xpath-inspired query
+export def xupdate [
+    path: list  # List of steps. Each step can be a
+                # 1. String with tag name. Finds all children with specified name. Equivalent to `child::A` in xpath
+                # 2. `*` string. Get all children without any filter. Equivalent to `descendant` in xpath
+                # 3. Int. Select n-th among nodes selected by previous path. Equivalent to `(...)[1]` in xpath, but is indexed from 0.
+                # 4. Closure. Predicate accepting entry. Selects all entries among nodes selected by previous path for which predicate returns true. 
+    updater: closure # A closure used to transform entries matching path.
+] {
+    {tag:? attributes:? content: [$in]} | xupdate-internal $path $updater | get content.0
+}
+
+# Get type of an xml entry
+#
+# Possible types are 'tag', 'text', 'pi' and 'comment'
+export def xtype [] {
+    let input = $in
+    if (($input | describe) == 'string' or 
+        ($input.tag? == null and $input.attributes? == null and ($input.content? | describe) == 'string')) {
+        'text'
+    } else if $input.tag? == '!' {
+        'comment'
+    } else if $input.tag? != null and ($input.tag? | str starts-with '?') {
+        'pi'
+    } else if $input.tag? != null {
+        'tag'
+    } else {
+        error make {msg: 'Not an xml emtry. Check valid types of xml entries via `help to xml`'}
+    }
+}
+
+# Insert new entry to elements matching simple xpath-inspired query
+export def xinsert [
+    path: list  # List of steps. Each step can be a
+                # 1. String with tag name. Finds all children with specified name. Equivalent to `child::A` in xpath
+                # 2. `*` string. Get all children without any filter. Equivalent to `descendant` in xpath
+                # 3. Int. Select n-th among nodes selected by previous path. Equivalent to `(...)[1]` in xpath, but is indexed from 0.
+                # 4. Closure. Predicate accepting entry. Selects all entries among nodes selected by previous path for which predicate returns true. 
+    new_entry: record # A new entry to insert into `content` field of record at specified position
+    position?: int  # Position to insert `new_entry` into. If specified inserts entry at given position (or end if
+                    # position is greater than number of elements) in content of all entries of input matched by 
+                    # path. If not specified inserts at the end.
+] {
+    $in | xupdate $path {|entry|
+        match ($entry | xtype) {
+            'tag' => {
+                let new_content = if $position == null {
+                    $entry.content | append $new_entry
+                } else {
+                    let position = if $position > ($entry.content | length) {
+                        $entry.content | length
+                    } else {
+                        $position
+                    }
+                    $entry.content | insert $position $new_entry
+                }
+
+                
+                {tag: $entry.tag attributes: $entry.attributes content: $new_content}
+            },
+            _ => (error make {msg: 'Can insert entry only into content of a tag node'})
+        }
+    }
+}
diff --git a/crates/nu-std/src/lib.rs b/crates/nu-std/src/lib.rs
index 627c42d72f..674805b155 100644
--- a/crates/nu-std/src/lib.rs
+++ b/crates/nu-std/src/lib.rs
@@ -2,8 +2,29 @@ use nu_parser::{parse, parse_module_block};
 use nu_protocol::report_error;
 use nu_protocol::{engine::StateWorkingSet, Module, ShellError, Span};
 
-fn get_standard_library() -> &'static str {
-    include_str!("../std.nu")
+fn add_file(
+    working_set: &mut StateWorkingSet,
+    name: &String,
+    content: &[u8],
+) -> (Module, Vec<Span>) {
+    let start = working_set.next_span_start();
+    working_set.add_file(name.clone(), content);
+    let end = working_set.next_span_start();
+
+    let (_, module, comments) =
+        parse_module_block(working_set, Span::new(start, end), name.as_bytes());
+
+    if let Some(err) = working_set.parse_errors.first() {
+        report_error(working_set, err);
+    }
+
+    parse(working_set, Some(name), content, true);
+
+    if let Some(err) = working_set.parse_errors.first() {
+        report_error(working_set, err);
+    }
+
+    (module, comments)
 }
 
 fn load_prelude(working_set: &mut StateWorkingSet, prelude: Vec<(&str, &str)>, module: &Module) {
@@ -45,26 +66,15 @@ pub fn load_standard_library(
 ) -> Result<(), miette::ErrReport> {
     let delta = {
         let name = "std".to_string();
-        let content = get_standard_library().as_bytes();
+        let content = include_str!("../lib/mod.nu");
 
-        let mut working_set = StateWorkingSet::new(engine_state);
-
-        let start = working_set.next_span_start();
-        working_set.add_file(name.clone(), content);
-        let end = working_set.next_span_start();
-
-        let (_, module, comments) =
-            parse_module_block(&mut working_set, Span::new(start, end), name.as_bytes());
-
-        if let Some(err) = working_set.parse_errors.first() {
-            report_error(&working_set, err);
-        }
-
-        parse(&mut working_set, Some(&name), content, true);
-
-        if let Some(err) = working_set.parse_errors.first() {
-            report_error(&working_set, err);
-        }
+        let submodules = vec![
+            ("assert", include_str!("../lib/assert.nu")),
+            ("dirs", include_str!("../lib/dirs.nu")),
+            ("help", include_str!("../lib/help.nu")),
+            ("log", include_str!("../lib/log.nu")),
+            ("xml", include_str!("../lib/xml.nu")),
+        ];
 
         let prelude = vec![
             ("std help", "help"),
@@ -75,8 +85,16 @@ pub fn load_standard_library(
             ("std help operators", "help operators"),
         ];
 
-        load_prelude(&mut working_set, prelude, &module);
+        let mut working_set = StateWorkingSet::new(engine_state);
 
+        for (name, content) in submodules {
+            let (module, comments) =
+                add_file(&mut working_set, &name.to_string(), content.as_bytes());
+            working_set.add_module(name, module, comments);
+        }
+
+        let (module, comments) = add_file(&mut working_set, &name, content.as_bytes());
+        load_prelude(&mut working_set, prelude, &module);
         working_set.add_module(&name, module, comments);
 
         working_set.render()
diff --git a/crates/nu-std/tests.nu b/crates/nu-std/tests/run.nu
similarity index 100%
rename from crates/nu-std/tests.nu
rename to crates/nu-std/tests/run.nu
diff --git a/crates/nu-std/test_asserts.nu b/crates/nu-std/tests/test_asserts.nu
similarity index 100%
rename from crates/nu-std/test_asserts.nu
rename to crates/nu-std/tests/test_asserts.nu
diff --git a/crates/nu-std/test_dirs.nu b/crates/nu-std/tests/test_dirs.nu
similarity index 100%
rename from crates/nu-std/test_dirs.nu
rename to crates/nu-std/tests/test_dirs.nu
diff --git a/crates/nu-std/test_logger.nu b/crates/nu-std/tests/test_logger.nu
similarity index 83%
rename from crates/nu-std/test_logger.nu
rename to crates/nu-std/tests/test_logger.nu
index be935df81d..5272789231 100644
--- a/crates/nu-std/test_logger.nu
+++ b/crates/nu-std/tests/test_logger.nu
@@ -37,10 +37,3 @@ export def test_debug [] {
     assert no message INFO debug 
     assert message DEBUG debug DBG
 }
-export def example [] {
-    log debug "Debug message"
-    log info "Info message"
-    log warning "Warning message"
-    log error "Error message"
-    log critical "Critical message"
-}
diff --git a/crates/nu-std/test_std.nu b/crates/nu-std/tests/test_std.nu
similarity index 100%
rename from crates/nu-std/test_std.nu
rename to crates/nu-std/tests/test_std.nu
diff --git a/crates/nu-std/test_xml.nu b/crates/nu-std/tests/test_xml.nu
similarity index 100%
rename from crates/nu-std/test_xml.nu
rename to crates/nu-std/tests/test_xml.nu
diff --git a/toolkit.nu b/toolkit.nu
index 8ba0f138fa..aa2ebc1860 100644
--- a/toolkit.nu
+++ b/toolkit.nu
@@ -37,7 +37,7 @@ export def test [
 
 # run the tests for the standard library
 export def "test stdlib" [] {
-    cargo run -- crates/nu-std/tests.nu
+    cargo run -- crates/nu-std/tests/run.nu
 }
 
 # print the pipe input inside backticks, dimmed and italic, as a pretty command