diff --git a/.github/dependabot.yml b/.github/dependabot.yml
new file mode 100644
index 0000000..da0407c
--- /dev/null
+++ b/.github/dependabot.yml
@@ -0,0 +1,7 @@
+
+version: 2
+updates:
+  - package-ecosystem: "gomod" # See documentation for possible values
+    directory: "/" # Location of package manifests
+    schedule:
+      interval: "weekly"
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..8ddfece
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,27 @@
+
+name: CI
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        go: [ '1.21' ]
+    steps:
+      - uses: actions/checkout@v3
+
+      - name: Setup Go
+        uses: actions/setup-go@v3
+        with:
+          go-version: ${{ matrix.go }}
+
+      - name: Run CI
+        env:
+          COVERALLS_TOKEN: ${{ secrets.COVERALLS_TOKEN }}
+        run: make ci
diff --git a/.github/workflows/codeql.yml b/.github/workflows/codeql.yml
new file mode 100644
index 0000000..ddee4f0
--- /dev/null
+++ b/.github/workflows/codeql.yml
@@ -0,0 +1,38 @@
+
+name: "CodeQL"
+
+on:
+  push:
+    branches: [ "master" ]
+  pull_request:
+    branches: [ "master" ]
+  schedule:
+    - cron: '16 8 * * 1'
+
+jobs:
+  analyze:
+    name: Analyze
+    runs-on: ubuntu-latest
+    permissions:
+      actions: read
+      contents: read
+      security-events: write
+
+    strategy:
+      fail-fast: false
+      matrix:
+        language: [ 'go' ]
+
+    steps:
+    - name: Checkout repository
+      uses: actions/checkout@v3
+
+    - name: Initialize CodeQL
+      uses: github/codeql-action/init@v2
+      with:
+        languages: ${{ matrix.language }}
+
+    - name: Perform CodeQL Analysis
+      uses: github/codeql-action/analyze@v2
+      with:
+        category: "/language:${{matrix.language}}"
diff --git a/.gitignore b/.gitignore
index 6f72f89..1fe9898 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,25 +1,21 @@
-# If you prefer the allow list template instead of the deny list, see community template:
-# https://github.com/github/gitignore/blob/main/community/Golang/Go.AllowList.gitignore
-#
-# Binaries for programs and plugins
 *.exe
 *.exe~
 *.dll
 *.so
 *.dylib
-
-# Test binary, built with `go test -c`
+*.db
+*.db-journal
+*.mmdb
 *.test
-
-# Output of the go coverage tool, specifically when used with LiteIDE
 *.out
 
-# Dependency directories (remove the comment below to include it)
-# vendor/
+.idea/
+.vscode/
+.tools/
 
-# Go workspace file
-go.work
-go.work.sum
+coverage.txt
+coverage.out
 
-# env file
-.env
+bin/
+vendor/
+build/
\ No newline at end of file
diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..f56a2a5
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,350 @@
+
+# options for analysis running
+run:
+  go: "1.21"
+  concurrency: 4
+  timeout: 5m
+  tests: false
+  issues-exit-code: 1
+  modules-download-mode: readonly
+
+issues:
+  exclude-use-default: false
+  exclude-files:
+    - ".+_test.go"
+  exclude-dirs:
+    - "vendor/*"
+
+output:
+  formats:
+    - format: line-number
+  sort-results: true
+
+linters-settings:
+  govet:
+    enable:
+      # report mismatches between assembly files and Go declarations
+      - asmdecl
+      # check for useless assignments
+      - assign
+      # check for common mistakes using the sync/atomic package
+      - atomic
+      # check for non-64-bits-aligned arguments to sync/atomic functions
+      - atomicalign
+      # check for common mistakes involving boolean operators
+      - bools
+      # check that +build tags are well-formed and correctly located
+      - buildtag
+      # detect some violations of the cgo pointer passing rules
+      - cgocall
+      # check for unkeyed composite literals
+      - composites
+      # check for locks erroneously passed by value
+      - copylocks
+      # check for calls of reflect.DeepEqual on error values
+      - deepequalerrors
+      # report passing non-pointer or non-error values to errors.As
+      - errorsas
+      # find calls to a particular function
+      - findcall
+      # report assembly that clobbers the frame pointer before saving it
+      - framepointer
+      # check for mistakes using HTTP responses
+      - httpresponse
+      # detect impossible interface-to-interface type assertions
+      - ifaceassert
+      # check references to loop variables from within nested functions
+      - loopclosure
+      # check cancel func returned by context.WithCancel is called
+      - lostcancel
+      # check for useless comparisons between functions and nil
+      - nilfunc
+      # check for redundant or impossible nil comparisons
+      - nilness
+      # check consistency of Printf format strings and arguments
+      - printf
+      # check for comparing reflect.Value values with == or reflect.DeepEqual
+      - reflectvaluecompare
+      # check for possible unintended shadowing of variables
+      - shadow
+      # check for shifts that equal or exceed the width of the integer
+      - shift
+      # check for unbuffered channel of os.Signal
+      - sigchanyzer
+      # check the argument type of sort.Slice
+      - sortslice
+      # check signature of methods of well-known interfaces
+      - stdmethods
+      # check for string(int) conversions
+      - stringintconv
+      # check that struct field tags conform to reflect.StructTag.Get
+      - structtag
+      # report calls to (*testing.T).Fatal from goroutines started by a test.
+      - testinggoroutine
+      # check for common mistaken usages of tests and examples
+      - tests
+      # report passing non-pointer or non-interface values to unmarshal
+      - unmarshal
+      # check for unreachable code
+      - unreachable
+      # check for invalid conversions of uintptr to unsafe.Pointer
+      - unsafeptr
+      # check for unused results of calls to some functions
+      - unusedresult
+      # checks for unused writes
+      - unusedwrite
+    disable:
+      # find structs that would use less memory if their fields were sorted
+      - fieldalignment
+  gofmt:
+    # simplify code: gofmt with '-s' option, true by default
+    simplify: true
+  errcheck:
+    # report about not checking of errors in type assetions: 'a := b.(MyStruct)';
+    # default is false: such cases aren't reported by default.
+    check-type-assertions: true
+    # report about assignment of errors to blank identifier: 'num, _ := strconv.Atoi(numStr)';
+    # default is false: such cases aren't reported by default.
+    check-blank: true
+  gocyclo:
+    # minimal code complexity to report, 30 by default (but we recommend 10-20)
+    min-complexity: 15
+  misspell:
+    # Correct spellings using locale preferences for US or UK.
+    # Default is to use a neutral variety of English.
+    # Setting locale to US will correct the British spelling of 'colour' to 'color'.
+    locale: US
+  prealloc:
+    # XXX: we don't recommend using this linter before doing performance profiling.
+    # For most programs usage of prealloc will be a premature optimization.
+    # Report preallocation suggestions only on simple loops that have no returns/breaks/continues/gotos in them.
+    # True by default.
+    simple: true
+    range-loops: true # Report preallocation suggestions on range loops, true by default
+    for-loops: true # Report preallocation suggestions on for loops, false by default
+  unparam:
+    # Inspect exported functions, default is false. Set to true if no external program/library imports your code.
+    # XXX: if you enable this setting, unparam will report a lot of false-positives in text editors:
+    # if it's called for subdir of a project it can't find external interfaces. All text editor integrations
+    # with golangci-lint call it on a directory with the changed file.
+    check-exported: false
+  gci:
+    # Section configuration to compare against.
+    # Section names are case-insensitive and may contain parameters in ().
+    # The default order of sections is 'standard > default > custom > blank > dot',
+    # If 'custom-order' is 'true', it follows the order of 'sections' option.
+    # Default: ["standard", "default"]
+    #sections:
+      #- standard # Standard section: captures all standard packages.
+      #- default # Default section: contains all imports that could not be matched to another section type.
+      #- blank # Blank section: contains all blank imports. This section is not present unless explicitly enabled.
+      #- dot # Dot section: contains all dot imports. This section is not present unless explicitly enabled.
+    # Skip generated files.
+    # Default: true
+    skip-generated: true
+    # Enable custom order of sections.
+    # If 'true', make the section order the same as the order of 'sections'.
+    # Default: false
+    custom-order: false
+  gosec:
+    # To select a subset of rules to run.
+    # Available rules: https://github.com/securego/gosec#available-rules
+    # Default: [] - means include all rules
+    includes:
+      - G101 # Look for hard coded credentials
+      - G102 # Bind to all interfaces
+      - G103 # Audit the use of unsafe block
+      - G104 # Audit errors not checked
+      - G106 # Audit the use of ssh.InsecureIgnoreHostKey
+      - G107 # Url provided to HTTP request as taint input
+      - G108 # Profiling endpoint automatically exposed on /debug/pprof
+      - G109 # Potential Integer overflow made by strconv.Atoi result conversion to int16/32
+      - G110 # Potential DoS vulnerability via decompression bomb
+      - G111 # Potential directory traversal
+      - G112 # Potential slowloris attack
+      - G113 # Usage of Rat.SetString in math/big with an overflow (CVE-2022-23772)
+      - G114 # Use of net/http serve function that has no support for setting timeouts
+      - G201 # SQL query construction using format string
+      - G202 # SQL query construction using string concatenation
+      - G203 # Use of unescaped data in HTML templates
+      - G204 # Audit use of command execution
+      - G301 # Poor file permissions used when creating a directory
+      - G302 # Poor file permissions used with chmod
+      - G303 # Creating tempfile using a predictable path
+      - G304 # File path provided as taint input
+      - G305 # File traversal when extracting zip/tar archive
+      - G306 # Poor file permissions used when writing to a new file
+      - G307 # Deferring a method which returns an error
+      - G401 # Detect the usage of DES, RC4, MD5 or SHA1
+      - G402 # Look for bad TLS connection settings
+      - G403 # Ensure minimum RSA key length of 2048 bits
+      - G404 # Insecure random number source (rand)
+      - G501 # Import blocklist: crypto/md5
+      - G502 # Import blocklist: crypto/des
+      - G503 # Import blocklist: crypto/rc4
+      - G504 # Import blocklist: net/http/cgi
+      - G505 # Import blocklist: crypto/sha1
+      - G601 # Implicit memory aliasing of items from a range statement
+    # To specify a set of rules to explicitly exclude.
+    # Available rules: https://github.com/securego/gosec#available-rules
+    # Default: []
+    excludes:
+      - G101 # Look for hard coded credentials
+      - G102 # Bind to all interfaces
+      - G103 # Audit the use of unsafe block
+      - G104 # Audit errors not checked
+      - G106 # Audit the use of ssh.InsecureIgnoreHostKey
+      - G107 # Url provided to HTTP request as taint input
+      - G108 # Profiling endpoint automatically exposed on /debug/pprof
+      - G109 # Potential Integer overflow made by strconv.Atoi result conversion to int16/32
+      - G110 # Potential DoS vulnerability via decompression bomb
+      - G111 # Potential directory traversal
+      - G112 # Potential slowloris attack
+      - G113 # Usage of Rat.SetString in math/big with an overflow (CVE-2022-23772)
+      - G114 # Use of net/http serve function that has no support for setting timeouts
+      - G201 # SQL query construction using format string
+      - G202 # SQL query construction using string concatenation
+      - G203 # Use of unescaped data in HTML templates
+      - G204 # Audit use of command execution
+      - G301 # Poor file permissions used when creating a directory
+      - G302 # Poor file permissions used with chmod
+      - G303 # Creating tempfile using a predictable path
+      - G304 # File path provided as taint input
+      - G305 # File traversal when extracting zip/tar archive
+      - G306 # Poor file permissions used when writing to a new file
+      - G307 # Deferring a method which returns an error
+      - G401 # Detect the usage of DES, RC4, MD5 or SHA1
+      - G402 # Look for bad TLS connection settings
+      - G403 # Ensure minimum RSA key length of 2048 bits
+      - G404 # Insecure random number source (rand)
+      - G501 # Import blocklist: crypto/md5
+      - G502 # Import blocklist: crypto/des
+      - G503 # Import blocklist: crypto/rc4
+      - G504 # Import blocklist: net/http/cgi
+      - G505 # Import blocklist: crypto/sha1
+      - G601 # Implicit memory aliasing of items from a range statement
+    # Exclude generated files
+    # Default: false
+    exclude-generated: true
+    # Filter out the issues with a lower severity than the given value.
+    # Valid options are: low, medium, high.
+    # Default: low
+    severity: medium
+    # Filter out the issues with a lower confidence than the given value.
+    # Valid options are: low, medium, high.
+    # Default: low
+    confidence: medium
+    # Concurrency value.
+    # Default: the number of logical CPUs usable by the current process.
+    concurrency: 12
+    # To specify the configuration of rules.
+    config:
+      # Globals are applicable to all rules.
+      global:
+        # If true, ignore #nosec in comments (and an alternative as well).
+        # Default: false
+        nosec: true
+        # Add an alternative comment prefix to #nosec (both will work at the same time).
+        # Default: ""
+        "#nosec": "#my-custom-nosec"
+        # Define whether nosec issues are counted as finding or not.
+        # Default: false
+        show-ignored: true
+        # Audit mode enables addition checks that for normal code analysis might be too nosy.
+        # Default: false
+        audit: true
+      G101:
+        # Regexp pattern for variables and constants to find.
+        # Default: "(?i)passwd|pass|password|pwd|secret|token|pw|apiKey|bearer|cred"
+        pattern: "(?i)example"
+        # If true, complain about all cases (even with low entropy).
+        # Default: false
+        ignore_entropy: false
+        # Maximum allowed entropy of the string.
+        # Default: "80.0"
+        entropy_threshold: "80.0"
+        # Maximum allowed value of entropy/string length.
+        # Is taken into account if entropy >= entropy_threshold/2.
+        # Default: "3.0"
+        per_char_threshold: "3.0"
+        # Calculate entropy for first N chars of the string.
+        # Default: "16"
+        truncate: "32"
+      # Additional functions to ignore while checking unhandled errors.
+      # Following functions always ignored:
+      #   bytes.Buffer:
+      #     - Write
+      #     - WriteByte
+      #     - WriteRune
+      #     - WriteString
+      #   fmt:
+      #     - Print
+      #     - Printf
+      #     - Println
+      #     - Fprint
+      #     - Fprintf
+      #     - Fprintln
+      #   strings.Builder:
+      #     - Write
+      #     - WriteByte
+      #     - WriteRune
+      #     - WriteString
+      #   io.PipeWriter:
+      #     - CloseWithError
+      #   hash.Hash:
+      #     - Write
+      #   os:
+      #     - Unsetenv
+      # Default: {}
+      G104:
+        fmt:
+          - Fscanf
+      G111:
+        # Regexp pattern to find potential directory traversal.
+        # Default: "http\\.Dir\\(\"\\/\"\\)|http\\.Dir\\('\\/'\\)"
+        pattern: "custom\\.Dir\\(\\)"
+      # Maximum allowed permissions mode for os.Mkdir and os.MkdirAll
+      # Default: "0750"
+      G301: "0750"
+      # Maximum allowed permissions mode for os.OpenFile and os.Chmod
+      # Default: "0600"
+      G302: "0600"
+      # Maximum allowed permissions mode for os.WriteFile and ioutil.WriteFile
+      # Default: "0600"
+      G306: "0600"
+
+  lll:
+    # Max line length, lines longer will be reported.
+    # '\t' is counted as 1 character by default, and can be changed with the tab-width option.
+    # Default: 120.
+    line-length: 120
+    # Tab width in spaces.
+    # Default: 1
+    tab-width: 1
+
+linters:
+  disable-all: true
+  enable:
+    - govet
+    - gofmt
+    - errcheck
+    - misspell
+    - gocyclo
+    - ineffassign
+    - goimports
+    - nakedret
+    - unparam
+    - unused
+    - prealloc
+    - durationcheck
+    - nolintlint
+    - staticcheck
+    - makezero
+    - nilerr
+    - errorlint
+    - bodyclose
+    - exportloopref
+    - gci
+    - gosec
+    - lll
+  fast: false
diff --git a/.lic.yaml b/.lic.yaml
new file mode 100644
index 0000000..737072f
--- /dev/null
+++ b/.lic.yaml
@@ -0,0 +1,3 @@
+author: Mikhail Knyazhev <markus621@yandex.com>
+lic_short: "BSD 3-Clause"
+lic_file: LICENSE
diff --git a/LICENSE b/LICENSE
index f288702..1fd5dac 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,674 +1,28 @@
-                    GNU GENERAL PUBLIC LICENSE
-                       Version 3, 29 June 2007
-
- Copyright (C) 2007 Free Software Foundation, Inc. <https://fsf.org/>
- Everyone is permitted to copy and distribute verbatim copies
- of this license document, but changing it is not allowed.
-
-                            Preamble
-
-  The GNU General Public License is a free, copyleft license for
-software and other kinds of works.
-
-  The licenses for most software and other practical works are designed
-to take away your freedom to share and change the works.  By contrast,
-the GNU General Public License is intended to guarantee your freedom to
-share and change all versions of a program--to make sure it remains free
-software for all its users.  We, the Free Software Foundation, use the
-GNU General Public License for most of our software; it applies also to
-any other work released this way by its authors.  You can apply it to
-your programs, too.
-
-  When we speak of free software, we are referring to freedom, not
-price.  Our General Public Licenses are designed to make sure that you
-have the freedom to distribute copies of free software (and charge for
-them if you wish), that you receive source code or can get it if you
-want it, that you can change the software or use pieces of it in new
-free programs, and that you know you can do these things.
-
-  To protect your rights, we need to prevent others from denying you
-these rights or asking you to surrender the rights.  Therefore, you have
-certain responsibilities if you distribute copies of the software, or if
-you modify it: responsibilities to respect the freedom of others.
-
-  For example, if you distribute copies of such a program, whether
-gratis or for a fee, you must pass on to the recipients the same
-freedoms that you received.  You must make sure that they, too, receive
-or can get the source code.  And you must show them these terms so they
-know their rights.
-
-  Developers that use the GNU GPL protect your rights with two steps:
-(1) assert copyright on the software, and (2) offer you this License
-giving you legal permission to copy, distribute and/or modify it.
-
-  For the developers' and authors' protection, the GPL clearly explains
-that there is no warranty for this free software.  For both users' and
-authors' sake, the GPL requires that modified versions be marked as
-changed, so that their problems will not be attributed erroneously to
-authors of previous versions.
-
-  Some devices are designed to deny users access to install or run
-modified versions of the software inside them, although the manufacturer
-can do so.  This is fundamentally incompatible with the aim of
-protecting users' freedom to change the software.  The systematic
-pattern of such abuse occurs in the area of products for individuals to
-use, which is precisely where it is most unacceptable.  Therefore, we
-have designed this version of the GPL to prohibit the practice for those
-products.  If such problems arise substantially in other domains, we
-stand ready to extend this provision to those domains in future versions
-of the GPL, as needed to protect the freedom of users.
-
-  Finally, every program is threatened constantly by software patents.
-States should not allow patents to restrict development and use of
-software on general-purpose computers, but in those that do, we wish to
-avoid the special danger that patents applied to a free program could
-make it effectively proprietary.  To prevent this, the GPL assures that
-patents cannot be used to render the program non-free.
-
-  The precise terms and conditions for copying, distribution and
-modification follow.
-
-                       TERMS AND CONDITIONS
-
-  0. Definitions.
-
-  "This License" refers to version 3 of the GNU General Public License.
-
-  "Copyright" also means copyright-like laws that apply to other kinds of
-works, such as semiconductor masks.
-
-  "The Program" refers to any copyrightable work licensed under this
-License.  Each licensee is addressed as "you".  "Licensees" and
-"recipients" may be individuals or organizations.
-
-  To "modify" a work means to copy from or adapt all or part of the work
-in a fashion requiring copyright permission, other than the making of an
-exact copy.  The resulting work is called a "modified version" of the
-earlier work or a work "based on" the earlier work.
-
-  A "covered work" means either the unmodified Program or a work based
-on the Program.
-
-  To "propagate" a work means to do anything with it that, without
-permission, would make you directly or secondarily liable for
-infringement under applicable copyright law, except executing it on a
-computer or modifying a private copy.  Propagation includes copying,
-distribution (with or without modification), making available to the
-public, and in some countries other activities as well.
-
-  To "convey" a work means any kind of propagation that enables other
-parties to make or receive copies.  Mere interaction with a user through
-a computer network, with no transfer of a copy, is not conveying.
-
-  An interactive user interface displays "Appropriate Legal Notices"
-to the extent that it includes a convenient and prominently visible
-feature that (1) displays an appropriate copyright notice, and (2)
-tells the user that there is no warranty for the work (except to the
-extent that warranties are provided), that licensees may convey the
-work under this License, and how to view a copy of this License.  If
-the interface presents a list of user commands or options, such as a
-menu, a prominent item in the list meets this criterion.
-
-  1. Source Code.
-
-  The "source code" for a work means the preferred form of the work
-for making modifications to it.  "Object code" means any non-source
-form of a work.
-
-  A "Standard Interface" means an interface that either is an official
-standard defined by a recognized standards body, or, in the case of
-interfaces specified for a particular programming language, one that
-is widely used among developers working in that language.
-
-  The "System Libraries" of an executable work include anything, other
-than the work as a whole, that (a) is included in the normal form of
-packaging a Major Component, but which is not part of that Major
-Component, and (b) serves only to enable use of the work with that
-Major Component, or to implement a Standard Interface for which an
-implementation is available to the public in source code form.  A
-"Major Component", in this context, means a major essential component
-(kernel, window system, and so on) of the specific operating system
-(if any) on which the executable work runs, or a compiler used to
-produce the work, or an object code interpreter used to run it.
-
-  The "Corresponding Source" for a work in object code form means all
-the source code needed to generate, install, and (for an executable
-work) run the object code and to modify the work, including scripts to
-control those activities.  However, it does not include the work's
-System Libraries, or general-purpose tools or generally available free
-programs which are used unmodified in performing those activities but
-which are not part of the work.  For example, Corresponding Source
-includes interface definition files associated with source files for
-the work, and the source code for shared libraries and dynamically
-linked subprograms that the work is specifically designed to require,
-such as by intimate data communication or control flow between those
-subprograms and other parts of the work.
-
-  The Corresponding Source need not include anything that users
-can regenerate automatically from other parts of the Corresponding
-Source.
-
-  The Corresponding Source for a work in source code form is that
-same work.
-
-  2. Basic Permissions.
-
-  All rights granted under this License are granted for the term of
-copyright on the Program, and are irrevocable provided the stated
-conditions are met.  This License explicitly affirms your unlimited
-permission to run the unmodified Program.  The output from running a
-covered work is covered by this License only if the output, given its
-content, constitutes a covered work.  This License acknowledges your
-rights of fair use or other equivalent, as provided by copyright law.
-
-  You may make, run and propagate covered works that you do not
-convey, without conditions so long as your license otherwise remains
-in force.  You may convey covered works to others for the sole purpose
-of having them make modifications exclusively for you, or provide you
-with facilities for running those works, provided that you comply with
-the terms of this License in conveying all material for which you do
-not control copyright.  Those thus making or running the covered works
-for you must do so exclusively on your behalf, under your direction
-and control, on terms that prohibit them from making any copies of
-your copyrighted material outside their relationship with you.
-
-  Conveying under any other circumstances is permitted solely under
-the conditions stated below.  Sublicensing is not allowed; section 10
-makes it unnecessary.
-
-  3. Protecting Users' Legal Rights From Anti-Circumvention Law.
-
-  No covered work shall be deemed part of an effective technological
-measure under any applicable law fulfilling obligations under article
-11 of the WIPO copyright treaty adopted on 20 December 1996, or
-similar laws prohibiting or restricting circumvention of such
-measures.
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-users, your or third parties' legal rights to forbid circumvention of
-technological measures.
-
-  4. Conveying Verbatim Copies.
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-  You may convey verbatim copies of the Program's source code as you
-receive it, in any medium, provided that you conspicuously and
-appropriately publish on each copy an appropriate copyright notice;
-keep intact all notices stating that this License and any
-non-permissive terms added in accord with section 7 apply to the code;
-keep intact all notices of the absence of any warranty; and give all
-recipients a copy of this License along with the Program.
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-and you may offer support or warranty protection for a fee.
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-  5. Conveying Modified Source Versions.
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-    "keep intact all notices".
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-    c) You must license the entire work, as a whole, under this
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-used to limit the access or legal rights of the compilation's users
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-
-  7. Additional Terms.
-
-  "Additional permissions" are terms that supplement the terms of this
-License by making exceptions from one or more of its conditions.
-Additional permissions that are applicable to the entire Program shall
-be treated as though they were included in this License, to the extent
-that they are valid under applicable law.  If additional permissions
-apply only to part of the Program, that part may be used separately
-under those permissions, but the entire Program remains governed by
-this License without regard to the additional permissions.
-
-  When you convey a copy of a covered work, you may at your option
-remove any additional permissions from that copy, or from any part of
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-additional permissions on material, added by you to a covered work,
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-  All other non-permissive additional terms are considered "further
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-a further restriction but permits relicensing or conveying under this
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-of that license document, provided that the further restriction does
-not survive such relicensing or conveying.
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-where to find the applicable terms.
-
-  Additional terms, permissive or non-permissive, may be stated in the
-form of a separately written license, or stated as exceptions;
-the above requirements apply either way.
-
-  8. Termination.
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-  You may not propagate or modify a covered work except as expressly
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-this License (including any patent licenses granted under the third
-paragraph of section 11).
-
-  However, if you cease all violation of this License, then your
-license from a particular copyright holder is reinstated (a)
-provisionally, unless and until the copyright holder explicitly and
-finally terminates your license, and (b) permanently, if the copyright
-holder fails to notify you of the violation by some reasonable means
-prior to 60 days after the cessation.
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-copyright holder, and you cure the violation prior to 30 days after
-your receipt of the notice.
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-  Termination of your rights under this section does not terminate the
-licenses of parties who have received copies or rights from you under
-this License.  If your rights have been terminated and not permanently
-reinstated, you do not qualify to receive new licenses for the same
-material under section 10.
-
-  9. Acceptance Not Required for Having Copies.
-
-  You are not required to accept this License in order to receive or
-run a copy of the Program.  Ancillary propagation of a covered work
-occurring solely as a consequence of using peer-to-peer transmission
-to receive a copy likewise does not require acceptance.  However,
-nothing other than this License grants you permission to propagate or
-modify any covered work.  These actions infringe copyright if you do
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-covered work, you indicate your acceptance of this License to do so.
-
-  10. Automatic Licensing of Downstream Recipients.
-
-  Each time you convey a covered work, the recipient automatically
-receives a license from the original licensors, to run, modify and
-propagate that work, subject to this License.  You are not responsible
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-
-  An "entity transaction" is a transaction transferring control of an
-organization, or substantially all assets of one, or subdividing an
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-  You may not impose any further restrictions on the exercise of the
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-(including a cross-claim or counterclaim in a lawsuit) alleging that
-any patent claim is infringed by making, using, selling, offering for
-sale, or importing the Program or any portion of it.
-
-  11. Patents.
-
-  A "contributor" is a copyright holder who authorizes use under this
-License of the Program or a work on which the Program is based.  The
-work thus licensed is called the contributor's "contributor version".
-
-  A contributor's "essential patent claims" are all patent claims
-owned or controlled by the contributor, whether already acquired or
-hereafter acquired, that would be infringed by some manner, permitted
-by this License, of making, using, or selling its contributor version,
-but do not include claims that would be infringed only as a
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-purposes of this definition, "control" includes the right to grant
-patent sublicenses in a manner consistent with the requirements of
-this License.
-
-  Each contributor grants you a non-exclusive, worldwide, royalty-free
-patent license under the contributor's essential patent claims, to
-make, use, sell, offer for sale, import and otherwise run, modify and
-propagate the contents of its contributor version.
-
-  In the following three paragraphs, a "patent license" is any express
-agreement or commitment, however denominated, not to enforce a patent
-(such as an express permission to practice a patent or covenant not to
-sue for patent infringement).  To "grant" such a patent license to a
-party means to make such an agreement or commitment not to enforce a
-patent against the party.
-
-  If you convey a covered work, knowingly relying on a patent license,
-and the Corresponding Source of the work is not available for anyone
-to copy, free of charge and under the terms of this License, through a
-publicly available network server or other readily accessible means,
-then you must either (1) cause the Corresponding Source to be so
-available, or (2) arrange to deprive yourself of the benefit of the
-patent license for this particular work, or (3) arrange, in a manner
-consistent with the requirements of this License, to extend the patent
-license to downstream recipients.  "Knowingly relying" means you have
-actual knowledge that, but for the patent license, your conveying the
-covered work in a country, or your recipient's use of the covered work
-in a country, would infringe one or more identifiable patents in that
-country that you have reason to believe are valid.
-
-  If, pursuant to or in connection with a single transaction or
-arrangement, you convey, or propagate by procuring conveyance of, a
-covered work, and grant a patent license to some of the parties
-receiving the covered work authorizing them to use, propagate, modify
-or convey a specific copy of the covered work, then the patent license
-you grant is automatically extended to all recipients of the covered
-work and works based on it.
-
-  A patent license is "discriminatory" if it does not include within
-the scope of its coverage, prohibits the exercise of, or is
-conditioned on the non-exercise of one or more of the rights that are
-specifically granted under this License.  You may not convey a covered
-work if you are a party to an arrangement with a third party that is
-in the business of distributing software, under which you make payment
-to the third party based on the extent of your activity of conveying
-the work, and under which the third party grants, to any of the
-parties who would receive the covered work from you, a discriminatory
-patent license (a) in connection with copies of the covered work
-conveyed by you (or copies made from those copies), or (b) primarily
-for and in connection with specific products or compilations that
-contain the covered work, unless you entered into that arrangement,
-or that patent license was granted, prior to 28 March 2007.
-
-  Nothing in this License shall be construed as excluding or limiting
-any implied license or other defenses to infringement that may
-otherwise be available to you under applicable patent law.
-
-  12. No Surrender of Others' Freedom.
-
-  If conditions are imposed on you (whether by court order, agreement or
-otherwise) that contradict the conditions of this License, they do not
-excuse you from the conditions of this License.  If you cannot convey a
-covered work so as to satisfy simultaneously your obligations under this
-License and any other pertinent obligations, then as a consequence you may
-not convey it at all.  For example, if you agree to terms that obligate you
-to collect a royalty for further conveying from those to whom you convey
-the Program, the only way you could satisfy both those terms and this
-License would be to refrain entirely from conveying the Program.
-
-  13. Use with the GNU Affero General Public License.
-
-  Notwithstanding any other provision of this License, you have
-permission to link or combine any covered work with a work licensed
-under version 3 of the GNU Affero General Public License into a single
-combined work, and to convey the resulting work.  The terms of this
-License will continue to apply to the part which is the covered work,
-but the special requirements of the GNU Affero General Public License,
-section 13, concerning interaction through a network will apply to the
-combination as such.
-
-  14. Revised Versions of this License.
-
-  The Free Software Foundation may publish revised and/or new versions of
-the GNU General Public License from time to time.  Such new versions will
-be similar in spirit to the present version, but may differ in detail to
-address new problems or concerns.
-
-  Each version is given a distinguishing version number.  If the
-Program specifies that a certain numbered version of the GNU General
-Public License "or any later version" applies to it, you have the
-option of following the terms and conditions either of that numbered
-version or of any later version published by the Free Software
-Foundation.  If the Program does not specify a version number of the
-GNU General Public License, you may choose any version ever published
-by the Free Software Foundation.
-
-  If the Program specifies that a proxy can decide which future
-versions of the GNU General Public License can be used, that proxy's
-public statement of acceptance of a version permanently authorizes you
-to choose that version for the Program.
-
-  Later license versions may give you additional or different
-permissions.  However, no additional obligations are imposed on any
-author or copyright holder as a result of your choosing to follow a
-later version.
-
-  15. Disclaimer of Warranty.
-
-  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
-APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
-HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
-OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
-THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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-IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
-ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
-
-  16. Limitation of Liability.
-
-  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
-WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
-THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
-GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
-USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
-DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
-PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
-EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
-SUCH DAMAGES.
-
-  17. Interpretation of Sections 15 and 16.
-
-  If the disclaimer of warranty and limitation of liability provided
-above cannot be given local legal effect according to their terms,
-reviewing courts shall apply local law that most closely approximates
-an absolute waiver of all civil liability in connection with the
-Program, unless a warranty or assumption of liability accompanies a
-copy of the Program in return for a fee.
-
-                     END OF TERMS AND CONDITIONS
-
-            How to Apply These Terms to Your New Programs
-
-  If you develop a new program, and you want it to be of the greatest
-possible use to the public, the best way to achieve this is to make it
-free software which everyone can redistribute and change under these terms.
-
-  To do so, attach the following notices to the program.  It is safest
-to attach them to the start of each source file to most effectively
-state the exclusion of warranty; and each file should have at least
-the "copyright" line and a pointer to where the full notice is found.
-
-    <one line to give the program's name and a brief idea of what it does.>
-    Copyright (C) <year>  <name of author>
-
-    This program is free software: you can redistribute it and/or modify
-    it under the terms of the GNU General Public License as published by
-    the Free Software Foundation, either version 3 of the License, or
-    (at your option) any later version.
-
-    This program is distributed in the hope that it will be useful,
-    but WITHOUT ANY WARRANTY; without even the implied warranty of
-    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-    GNU General Public License for more details.
-
-    You should have received a copy of the GNU General Public License
-    along with this program.  If not, see <https://www.gnu.org/licenses/>.
-
-Also add information on how to contact you by electronic and paper mail.
-
-  If the program does terminal interaction, make it output a short
-notice like this when it starts in an interactive mode:
-
-    <program>  Copyright (C) <year>  <name of author>
-    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
-    This is free software, and you are welcome to redistribute it
-    under certain conditions; type `show c' for details.
-
-The hypothetical commands `show w' and `show c' should show the appropriate
-parts of the General Public License.  Of course, your program's commands
-might be different; for a GUI interface, you would use an "about box".
-
-  You should also get your employer (if you work as a programmer) or school,
-if any, to sign a "copyright disclaimer" for the program, if necessary.
-For more information on this, and how to apply and follow the GNU GPL, see
-<https://www.gnu.org/licenses/>.
-
-  The GNU General Public License does not permit incorporating your program
-into proprietary programs.  If your program is a subroutine library, you
-may consider it more useful to permit linking proprietary applications with
-the library.  If this is what you want to do, use the GNU Lesser General
-Public License instead of this License.  But first, please read
-<https://www.gnu.org/licenses/why-not-lgpl.html>.
+BSD 3-Clause License
+
+Copyright (c) 2024, Mikhail Knyazhev <markus621@yandex.com>
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its
+   contributors may be used to endorse or promote products derived from
+   this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..dc0de2c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,27 @@
+
+.PHONY: install
+install:
+	go install github.com/osspkg/devtool@latest
+
+.PHONY: setup
+setup:
+	devtool setup-lib
+
+.PHONY: lint
+lint:
+	devtool lint
+
+.PHONY: license
+license:
+	devtool license
+
+.PHONY: tests
+tests:
+	devtool test
+
+.PHONY: pre-commit
+pre-commit: setup license lint tests
+
+.PHONY: ci
+ci: install setup lint tests
+
diff --git a/common.go b/common.go
new file mode 100644
index 0000000..78aab04
--- /dev/null
+++ b/common.go
@@ -0,0 +1,19 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+type Summable interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64 |
+		~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 |
+		~float32 | ~float64
+}
+
+type Comparable interface {
+	~int | ~int8 | ~int16 | ~int32 | ~int64 |
+		~uint | ~uint8 | ~uint16 | ~uint32 | ~uint64 | ~uintptr |
+		~float32 | ~float64 |
+		~string
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..446066a
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,5 @@
+module go.osspkg.com/do
+
+go 1.21
+
+require go.osspkg.com/casecheck v0.3.0
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..178b450
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,2 @@
+go.osspkg.com/casecheck v0.3.0 h1:x15blEszElbrHrEH5H02JIIhGIg/lGZzIt1kQlD3pwM=
+go.osspkg.com/casecheck v0.3.0/go.mod h1:TRFXDMFJEOtnlp3ET2Hix3osbxwPWhvaiT/HfD3+gBA=
diff --git a/if.go b/if.go
new file mode 100644
index 0000000..efdd9d8
--- /dev/null
+++ b/if.go
@@ -0,0 +1,84 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+type _doIf[T any] struct {
+	value T
+	done  bool
+}
+
+type DoIf[T any] interface {
+	ElseIf(compare bool, value T) DoIf[T]
+	Else(value T) T
+	ElseIfFunc(compare bool, value func() T) DoIf[T]
+	ElseFunc(value func() T) T
+}
+
+func If[T any](compare bool, value T) DoIf[T] {
+	result := &_doIf[T]{}
+
+	if compare {
+		result.done = true
+		result.value = value
+	}
+
+	return result
+}
+
+func IfFunc[T any](compare bool, value func() T) DoIf[T] {
+	result := &_doIf[T]{}
+
+	if compare {
+		result.done = true
+		result.value = value()
+	}
+
+	return result
+}
+
+func (v *_doIf[T]) ElseIf(compare bool, value T) DoIf[T] {
+	if !v.done && compare {
+		v.done = true
+		v.value = value
+	}
+	return v
+}
+
+func (v *_doIf[T]) ElseIfFunc(compare bool, value func() T) DoIf[T] {
+	if !v.done && compare {
+		v.done = true
+		v.value = value()
+	}
+	return v
+}
+
+func (v *_doIf[T]) Else(value T) T {
+	if v.done {
+		return v.value
+	}
+	return value
+}
+
+func (v *_doIf[T]) ElseFunc(value func() T) T {
+	if v.done {
+		return v.value
+	}
+	return value()
+}
+
+func IfElse[T any](compare bool, thenV, elseV T) T {
+	if compare {
+		return thenV
+	}
+	return elseV
+}
+
+func IfElseFunc[T any](compare bool, thenV, elseV func() T) T {
+	if compare {
+		return thenV()
+	}
+	return elseV()
+}
diff --git a/if_test.go b/if_test.go
new file mode 100644
index 0000000..ebae1ca
--- /dev/null
+++ b/if_test.go
@@ -0,0 +1,105 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"reflect"
+	"testing"
+
+	"go.osspkg.com/do"
+)
+
+func TestUnit_If(t *testing.T) {
+	tests := []struct {
+		name   string
+		result any
+		want   any
+	}{
+		{
+			name:   "Case1",
+			result: do.If[int](true, 1).Else(0),
+			want:   1,
+		},
+		{
+			name:   "Case2",
+			result: do.If[int](false, 1).Else(0),
+			want:   0,
+		},
+		{
+			name:   "Case3",
+			result: do.If[int](false, 1).ElseIf(true, 2).Else(0),
+			want:   2,
+		},
+		{
+			name:   "Case4",
+			result: do.If[int](false, 1).ElseIf(false, 2).Else(0),
+			want:   0,
+		},
+		{
+			name:   "Case5",
+			result: do.IfElse[int](false, 1, 0),
+			want:   0,
+		},
+		{
+			name:   "Case5",
+			result: do.IfElse[int](true, 1, 0),
+			want:   1,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if !reflect.DeepEqual(tt.result, tt.want) {
+				t.Errorf("If() = %v, want %v", tt.result, tt.want)
+			}
+		})
+	}
+}
+
+func TestUnit_IfFunc(t *testing.T) {
+	tests := []struct {
+		name   string
+		result any
+		want   any
+	}{
+		{
+			name:   "Case1",
+			result: do.IfFunc[int](true, func() int { return 1 }).ElseFunc(func() int { return 0 }),
+			want:   1,
+		},
+		{
+			name:   "Case2",
+			result: do.IfFunc[int](false, func() int { return 1 }).ElseFunc(func() int { return 0 }),
+			want:   0,
+		},
+		{
+			name:   "Case3",
+			result: do.IfFunc[int](false, func() int { return 1 }).ElseIfFunc(true, func() int { return 2 }).ElseFunc(func() int { return 0 }),
+			want:   2,
+		},
+		{
+			name:   "Case4",
+			result: do.IfFunc[int](false, func() int { return 1 }).ElseIfFunc(false, func() int { return 2 }).ElseFunc(func() int { return 0 }),
+			want:   0,
+		},
+		{
+			name:   "Case5",
+			result: do.IfElseFunc[int](false, func() int { return 1 }, func() int { return 0 }),
+			want:   0,
+		},
+		{
+			name:   "Case5",
+			result: do.IfElseFunc[int](true, func() int { return 1 }, func() int { return 0 }),
+			want:   1,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if !reflect.DeepEqual(tt.result, tt.want) {
+				t.Errorf("If() = %v, want %v", tt.result, tt.want)
+			}
+		})
+	}
+}
diff --git a/map.go b/map.go
new file mode 100644
index 0000000..e7ae2e9
--- /dev/null
+++ b/map.go
@@ -0,0 +1,96 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+import (
+	"slices"
+)
+
+func EachMap[K Comparable, V any](in map[K]V, call func(key K, value V)) {
+	for _, k := range Keys[K, V](in) {
+		call(k, in[k])
+	}
+}
+
+func FilterMap[K comparable, V any](in map[K]V, filter func(key K, value V) bool) (out map[K]V) {
+	out = make(map[K]V, len(in))
+	for k, v := range in {
+		if !filter(k, v) {
+			continue
+		}
+		out[k] = v
+	}
+	return
+}
+
+func Keys[K Comparable, V any](in map[K]V) (out []K) {
+	out = make([]K, 0, len(in))
+	for k := range in {
+		out = append(out, k)
+	}
+	slices.Sort(out)
+	return
+}
+
+func Values[K Comparable, V any](in map[K]V) (out []V) {
+	out = make([]V, 0, len(in))
+	for _, k := range Keys[K, V](in) {
+		out = append(out, in[k])
+	}
+	return
+}
+
+func JoinMap[K comparable, V any](in ...map[K]V) (out map[K]V) {
+	size := 0
+	for _, m := range in {
+		size += len(m)
+	}
+	out = make(map[K]V, size)
+	for _, m := range in {
+		for k, v := range m {
+			out[k] = v
+		}
+	}
+	return
+}
+
+func FlipMap[K, V comparable](in map[K]V) (out map[V]K) {
+	out = make(map[V]K, len(in))
+	for k, v := range in {
+		out[v] = k
+	}
+	return
+}
+
+func DivideMap[K Comparable, V any](in map[K]V) (keys []K, values []V) {
+	keys = Keys[K, V](in)
+	values = make([]V, 0, len(in))
+	for _, k := range keys {
+		values = append(values, in[k])
+	}
+	return
+}
+
+func CombineMap[K comparable, V any](keys []K, values []V) (out map[K]V) {
+	out = make(map[K]V, len(keys))
+	lenValues := len(values) - 1
+	for i, k := range keys {
+		var zero V
+		if i > lenValues {
+			out[k] = zero
+			continue
+		}
+		out[k] = values[i]
+	}
+	return
+}
+
+func ReduceMap[K Comparable, V any](in map[K]V, call func(result, value V, key K) V) (out V) {
+	for _, k := range Keys[K, V](in) {
+		out = call(out, in[k], k)
+	}
+	return
+}
diff --git a/map_test.go b/map_test.go
new file mode 100644
index 0000000..107adc6
--- /dev/null
+++ b/map_test.go
@@ -0,0 +1,70 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"fmt"
+	"testing"
+
+	"go.osspkg.com/casecheck"
+	"go.osspkg.com/do"
+)
+
+func TestUnit_CombineMap(t *testing.T) {
+	out := do.CombineMap[int, string]([]int{1, 2, 3}, []string{"1", "2", "3", "4"})
+	casecheck.Equal(t, map[int]string{1: "1", 2: "2", 3: "3"}, out)
+
+	out = do.CombineMap[int, string]([]int{1, 2, 3}, []string{"1", "2"})
+	casecheck.Equal(t, map[int]string{1: "1", 2: "2", 3: ""}, out)
+}
+
+func TestUnit_EachMap(t *testing.T) {
+	result := "|"
+	do.EachMap[string, int](map[string]int{"1": 1, "2": 2}, func(key string, value int) {
+		result += fmt.Sprintf("%s:%d|", key, value)
+	})
+	casecheck.Equal(t, `|1:1|2:2|`, result)
+}
+
+func TestUnit_FilterMap(t *testing.T) {
+	out := do.FilterMap[int, string](map[int]string{1: "1", 2: "2", 3: "3"}, func(key int, _ string) bool {
+		return key%2 == 0
+	})
+	casecheck.Equal(t, map[int]string{2: "2"}, out)
+}
+
+func TestUnit_Keys(t *testing.T) {
+	out := do.Keys[int, string](map[int]string{1: "1", 2: "2", 3: "3"})
+	casecheck.Equal(t, []int{1, 2, 3}, out)
+}
+
+func TestUnit_Values(t *testing.T) {
+	out := do.Values[int, string](map[int]string{1: "1", 2: "2", 3: "3"})
+	casecheck.Equal(t, []string{"1", "2", "3"}, out)
+}
+
+func TestUnit_JoinMap(t *testing.T) {
+	out := do.JoinMap[int, string](map[int]string{1: "1", 2: "2", 3: "3"}, map[int]string{1: "1", 2: "22", 4: "4"})
+	casecheck.Equal(t, map[int]string{1: "1", 2: "22", 3: "3", 4: "4"}, out)
+}
+
+func TestUnit_FlipMap(t *testing.T) {
+	out := do.FlipMap[int, string](map[int]string{1: "01", 2: "02", 3: "03"})
+	casecheck.Equal(t, map[string]int{"01": 1, "02": 2, "03": 3}, out)
+}
+
+func TestUnit_DivideMap(t *testing.T) {
+	keys, values := do.DivideMap[int, string](map[int]string{2: "02", 3: "03", 1: "01"})
+	casecheck.Equal(t, []int{1, 2, 3}, keys)
+	casecheck.Equal(t, []string{"01", "02", "03"}, values)
+}
+
+func TestUnit_ReduceMap(t *testing.T) {
+	out := do.ReduceMap[int, string](map[int]string{2: "02", 1: "01", 3: "03"}, func(result, value string, key int) string {
+		return result + value
+	})
+	casecheck.Equal(t, "010203", out)
+}
diff --git a/math.go b/math.go
new file mode 100644
index 0000000..9a5cac6
--- /dev/null
+++ b/math.go
@@ -0,0 +1,51 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+import "time"
+
+func MinMax[T Comparable](value, minimum, maximum T) T {
+	if minimum > value {
+		return minimum
+	}
+	if maximum < value {
+		return maximum
+	}
+	return value
+}
+
+func MinMaxTime(value, minimum, maximum time.Time) time.Time {
+	if value.Before(minimum) {
+		return minimum
+	}
+	if value.After(maximum) {
+		return maximum
+	}
+	return value
+}
+
+func Range[T Summable](from, to, step T) (out []T) {
+	out = make([]T, 0, 2)
+	for i := from; i <= to; i += step {
+		out = append(out, i)
+	}
+	return
+}
+
+func Sum[T Comparable](elements ...T) (out T) {
+	for _, element := range elements {
+		out += element
+	}
+	return
+}
+
+func Average[T Summable](elements ...T) (out T) {
+	for _, element := range elements {
+		out += element
+	}
+	out = out / T(len(elements))
+	return
+}
diff --git a/math_test.go b/math_test.go
new file mode 100644
index 0000000..96f4355
--- /dev/null
+++ b/math_test.go
@@ -0,0 +1,49 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"testing"
+	"time"
+
+	"go.osspkg.com/casecheck"
+	"go.osspkg.com/do"
+)
+
+func TestUnit_MinMax(t *testing.T) {
+	casecheck.Equal(t, 5, do.MinMax[int](5, 0, 10))
+	casecheck.Equal(t, 0, do.MinMax[int](-5, 0, 10))
+	casecheck.Equal(t, 10, do.MinMax[int](20, 0, 10))
+}
+
+func TestUnit_Sum(t *testing.T) {
+	casecheck.Equal(t, 15, do.Sum[int](5, 0, 10))
+	casecheck.Equal(t, 11.5, do.Sum[float64](1.5, 0, 10))
+	casecheck.Equal(t, "aabbcc", do.Sum[string]("aa", "bb", "cc"))
+}
+
+func TestUnit_Average(t *testing.T) {
+	casecheck.Equal(t, 5, do.Average[int](5, 0, 10))
+	casecheck.Equal(t, 3.75, do.Average[float64](1.5, 2.5, 1, 10))
+}
+
+func TestUnit_Range(t *testing.T) {
+	casecheck.Equal(t, []float64{1, 1.5, 2, 2.5, 3}, do.Range[float64](1, 3, 0.5))
+	casecheck.Equal(t, []int64{1, 2, 3}, do.Range[int64](1, 3, 1))
+	casecheck.Equal(t, []byte{'a', 'b', 'c'}, do.Range[byte]('a', 'c', 1))
+}
+
+func TestUnit_MinMaxTime(t *testing.T) {
+	mi := time.Now()
+	ma := time.Now().Add(1 * time.Hour)
+
+	v := mi.Add(-10 * time.Second)
+	casecheck.Equal(t, mi, do.MinMaxTime(v, mi, ma))
+	v = mi.Add(10 * time.Second)
+	casecheck.Equal(t, v, do.MinMaxTime(v, mi, ma))
+	v = ma.Add(10 * time.Second)
+	casecheck.Equal(t, ma, do.MinMaxTime(v, mi, ma))
+}
diff --git a/recovery.go b/recovery.go
new file mode 100644
index 0000000..7174214
--- /dev/null
+++ b/recovery.go
@@ -0,0 +1,83 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+	"sync"
+)
+
+func Recovery(call func()) (err error) {
+	defer func() {
+		if val := recover(); val != nil {
+			err = fmt.Errorf(
+				"panic=%w trace=%s",
+				fmt.Errorf("%+v", val),
+				Trace(
+					4,
+					1,
+					"go.osspkg.com/do.Recovery",
+				),
+			)
+		}
+	}()
+
+	call()
+	return
+}
+
+var bufPool = sync.Pool{New: func() any { return bytes.NewBuffer(make([]byte, 0, 1024)) }}
+
+func Trace(skipLines, countLines int, skipFunc ...string) string {
+	list := make([]uintptr, countLines+1)
+
+	//nolint:errcheck
+	execFile, _ := os.Executable()
+	execDir := filepath.Dir(execFile)
+	//nolint:errcheck
+	workDir, _ := os.Getwd()
+	goDir := runtime.GOROOT()
+
+	n := runtime.Callers(skipLines, list)
+	frame := runtime.CallersFrames(list[:n])
+
+	//nolint:errcheck
+	buf := bufPool.Get().(*bytes.Buffer)
+	defer func() {
+		buf.Reset()
+		bufPool.Put(buf)
+	}()
+
+	var line int
+	for {
+		v, ok := frame.Next()
+		if !ok {
+			break
+		}
+
+		doWrite := true
+		for _, s := range skipFunc {
+			if strings.Contains(v.Function, s) {
+				doWrite = false
+			}
+		}
+
+		if doWrite {
+			line++
+			filePath := strings.TrimPrefix(v.File, workDir)
+			filePath = strings.TrimPrefix(filePath, execDir)
+			filePath = strings.TrimPrefix(filePath, goDir)
+			fmt.Fprintf(buf, "%s.%s:%d %v", IfElse(line == 1, "", "\n"), filePath, v.Line, v.Function)
+		}
+
+	}
+	return buf.String()
+}
diff --git a/recovery_test.go b/recovery_test.go
new file mode 100644
index 0000000..22ba4f2
--- /dev/null
+++ b/recovery_test.go
@@ -0,0 +1,25 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"errors"
+	"testing"
+
+	"go.osspkg.com/casecheck"
+	"go.osspkg.com/do"
+)
+
+func TestUnit_Recovery(t *testing.T) {
+	err := do.Recovery(func() {
+		func() {
+			panic(1)
+		}()
+	})
+	casecheck.Error(t, err)
+	casecheck.Contains(t, err.Error(), "panic=1 trace=./recovery_test.go:19 go.osspkg.com/do_test.TestUnit_Recovery.func1.1")
+	casecheck.Equal(t, "1", errors.Unwrap(err).Error())
+}
diff --git a/slice.go b/slice.go
new file mode 100644
index 0000000..8ad696e
--- /dev/null
+++ b/slice.go
@@ -0,0 +1,198 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+func Each[T any](in []T, call func(value T, index int)) {
+	for i, v := range in {
+		call(v, i)
+	}
+}
+
+func Join[T any](in ...[]T) (out []T) {
+	size := 0
+	for _, m := range in {
+		size += len(m)
+	}
+	out = make([]T, 0, size)
+	for _, s := range in {
+		out = append(out, s...)
+	}
+	return
+}
+
+func Chunk[T any](in []T, count int) (out [][]T) {
+	count = MinMax(count, 1, len(in))
+	out = make([][]T, 0, len(in)/count+IfElse(len(in)%count == 0, 0, 1))
+
+	chunk := make([]T, 0, 2)
+	for i, v := range in {
+		if i%count == 0 {
+			if len(chunk) != 0 {
+				out = append(out, chunk)
+			}
+			chunk = make([]T, 0, count)
+		}
+		chunk = append(chunk, v)
+	}
+	out = append(out, chunk)
+	return
+}
+
+func ToMap[T comparable](in []T) (out map[T]struct{}) {
+	out = make(map[T]struct{}, len(in))
+	for _, v := range in {
+		out[v] = struct{}{}
+	}
+	return
+}
+
+func Reduce[T any](in []T, call func(result, value T, index int) T) (out T) {
+	for i, v := range in {
+		out = call(out, v, i)
+	}
+	return
+}
+
+func LastIndexOf[T comparable](in []T, element T) (index int, ok bool) {
+	for i, v := range in {
+		if v == element {
+			index = i
+			ok = true
+		}
+	}
+	return
+}
+
+func IndexOf[T comparable](in []T, element T) (index int, ok bool) {
+	for i, v := range in {
+		if v == element {
+			return i, true
+		}
+	}
+	return 0, false
+}
+
+func Include[T comparable](in []T, element T) (ok bool) {
+	_, ok = IndexOf[T](in, element)
+	return
+}
+
+func Exclude[T comparable](in []T, elements ...T) (out []T) {
+	out = make([]T, 0, len(in))
+	elMap := ToMap[T](elements)
+	for _, t := range in {
+		if _, ok := elMap[t]; ok {
+			continue
+		}
+		out = append(out, t)
+	}
+	return
+}
+
+func Pop[T any](in *[]T) (out T, ok bool) {
+	if len(*in) == 0 {
+		return
+	}
+
+	i := len(*in) - 1
+	out, ok = (*in)[i], true
+	*in = (*in)[:i]
+	return
+}
+
+func Push[T any](in *[]T, elements ...T) {
+	*in = append(*in, elements...)
+}
+
+func Shift[T any](in *[]T) (out T, ok bool) {
+	if len(*in) == 0 {
+		return
+	}
+
+	li := len(*in) - 1
+	out, ok = (*in)[0], true
+	if li == 0 {
+		*in = (*in)[:0]
+	} else {
+		*in = (*in)[1:]
+	}
+	return
+}
+
+func Unshift[T any](in *[]T, elements ...T) {
+	Splice[T](in, 0, 0, elements...)
+}
+
+func Reverse[T any](in []T) {
+	j := len(in) - 1
+	for i := 0; i < len(in)/2; i++ {
+		in[i], in[j] = in[j], in[i]
+		j--
+	}
+}
+
+// Copy - start, end - element index (inclusive)
+func Copy[T any](in []T, start, end int) (out []T) {
+	start = MinMax(start, 0, len(in))
+	end = MinMax(end+1, start+1, len(in))
+	out = make([]T, end-start)
+	copy(out[0:], in[start:end])
+	return
+}
+
+func Splice[T any](in *[]T, start, deleteCount int, elements ...T) {
+	lastPos := len(*in)
+	start = MinMax(start, 0, lastPos)
+	deleteCount = MinMax(deleteCount, 0, lastPos)
+	deletePos := MinMax(deleteCount+start, 0, lastPos)
+
+	*in = append((*in)[:start], (*in)[deletePos:]...)
+	lastPos = len(*in)
+
+	*in = append(*in, elements...)
+	copy((*in)[start+len(elements):], (*in)[start:lastPos])
+	copy((*in)[start:], elements[:])
+}
+
+func Filter[T any](in []T, filter func(value T, index int) bool) (out []T) {
+	out = make([]T, 0, len(in))
+	for i, v := range in {
+		if filter(v, i) {
+			out = append(out, v)
+		}
+	}
+	return
+}
+
+func Diff[T comparable](arr1 []T, arr2 []T) (out []T) {
+	out = make([]T, 0, len(arr1)+len(arr2))
+	arr2Map := ToMap[T](arr2)
+	for _, v := range arr1 {
+		if _, ok := arr2Map[v]; ok {
+			delete(arr2Map, v)
+			continue
+		}
+		out = append(out, v)
+	}
+	for _, v := range arr2 {
+		if _, ok := arr2Map[v]; ok {
+			out = append(out, v)
+		}
+	}
+	return
+}
+
+func Unique[T comparable](in []T) (out []T) {
+	inMap := ToMap[T](in)
+	out = make([]T, 0, len(inMap))
+	for _, v := range in {
+		if _, ok := inMap[v]; ok {
+			out = append(out, v)
+			delete(inMap, v)
+		}
+	}
+	return
+}
diff --git a/slice_test.go b/slice_test.go
new file mode 100644
index 0000000..a28fb6b
--- /dev/null
+++ b/slice_test.go
@@ -0,0 +1,191 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"fmt"
+	"testing"
+
+	"go.osspkg.com/casecheck"
+	"go.osspkg.com/do"
+)
+
+func TestUnit_Each(t *testing.T) {
+	result := "|"
+	do.Each[string]([]string{"1", "2"}, func(key string, index int) {
+		result += fmt.Sprintf("(%d)%s|", index, key)
+	})
+	casecheck.Equal(t, `|(0)1|(1)2|`, result)
+}
+
+func TestUnit_Join(t *testing.T) {
+	out := do.Join[string]([]string{"1", "2"}, []string{"5", "6"}, []string{"0", "2"})
+	casecheck.Equal(t, []string{"1", "2", "5", "6", "0", "2"}, out)
+}
+
+func TestUnit_Chunk(t *testing.T) {
+	out := do.Chunk[int]([]int{1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 1}, 3)
+	casecheck.Equal(t, [][]int{{1, 2, 3}, {4, 5, 6}, {7, 8, 9}, {0, 1}}, out)
+
+	out = do.Chunk[int]([]int{1, 2, 3}, 3)
+	casecheck.Equal(t, [][]int{{1, 2, 3}}, out)
+
+	out = do.Chunk[int]([]int{1, 2, 3}, 0)
+	casecheck.Equal(t, [][]int{{1}, {2}, {3}}, out)
+}
+
+func TestUnit_ToMap(t *testing.T) {
+	out := do.ToMap[string]([]string{"1", "2"})
+	casecheck.Equal(t, map[string]struct{}{"1": {}, "2": {}}, out)
+}
+
+func TestUnit_Reduce(t *testing.T) {
+	out := do.Reduce[string]([]string{"1", "2"}, func(result, value string, index int) string {
+		return result + value
+	})
+	casecheck.Equal(t, "12", out)
+}
+
+func TestUnit_LastIndexOf(t *testing.T) {
+	out, ok := do.LastIndexOf[int]([]int{1, 2, 3, 3, 4}, 3)
+	casecheck.True(t, ok)
+	casecheck.Equal(t, 3, out)
+}
+
+func TestUnit_IndexOf(t *testing.T) {
+	out, ok := do.IndexOf[int]([]int{1, 2, 3, 3, 4}, 3)
+	casecheck.True(t, ok)
+	casecheck.Equal(t, 2, out)
+
+	out, ok = do.IndexOf[int]([]int{1, 2, 3, 3, 4}, 10)
+	casecheck.False(t, ok)
+}
+
+func TestUnit_Include(t *testing.T) {
+	ok := do.Include[int]([]int{1, 2, 3, 3, 4}, 3)
+	casecheck.True(t, ok)
+
+	ok = do.Include[int]([]int{1, 2, 3, 3, 4}, 10)
+	casecheck.False(t, ok)
+}
+
+func TestUnit_Exclude(t *testing.T) {
+	out := do.Exclude[int]([]int{1, 2, 3, 3, 4}, 3)
+	casecheck.Equal(t, []int{1, 2, 4}, out)
+}
+
+func TestUnit_Pop(t *testing.T) {
+	data := []int{1, 2}
+
+	out, ok := do.Pop[int](&data)
+	casecheck.True(t, ok)
+	casecheck.Equal(t, 2, out)
+
+	out, ok = do.Pop[int](&data)
+	casecheck.True(t, ok)
+	casecheck.Equal(t, 1, out)
+
+	out, ok = do.Pop[int](&data)
+	casecheck.False(t, ok)
+}
+
+func TestUnit_Push(t *testing.T) {
+	data := []int{1, 2}
+
+	do.Push[int](&data, 5, 6, 7)
+	casecheck.Equal(t, []int{1, 2, 5, 6, 7}, data)
+}
+
+func TestUnit_Shift(t *testing.T) {
+	data := []int{1, 2}
+
+	out, ok := do.Shift[int](&data)
+	casecheck.True(t, ok)
+	casecheck.Equal(t, 1, out)
+
+	out, ok = do.Shift[int](&data)
+	casecheck.True(t, ok)
+	casecheck.Equal(t, 2, out)
+
+	out, ok = do.Shift[int](&data)
+	casecheck.False(t, ok)
+	casecheck.Equal(t, []int{}, data)
+}
+
+func TestUnit_Unshift(t *testing.T) {
+	data := []int{1, 2}
+	do.Unshift[int](&data, 10, 12, 11)
+	casecheck.Equal(t, []int{10, 12, 11, 1, 2}, data)
+}
+
+func TestUnit_Reverse(t *testing.T) {
+	data := []int{1, 2, 10, 12, 11}
+	do.Reverse(data)
+	casecheck.Equal(t, []int{11, 12, 10, 2, 1}, data)
+}
+
+func TestUnit_Splice(t *testing.T) {
+	data := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	do.Splice[int](&data, 2, 3, 111, 112, 113)
+	casecheck.Equal(t, []int{0, 1, 111, 112, 113, 5, 6, 7, 8, 9}, data)
+
+	data = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	do.Splice[int](&data, 2, 10, 111, 112, 113)
+	casecheck.Equal(t, []int{0, 1, 111, 112, 113}, data)
+
+	data = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	do.Splice[int](&data, 100, 10, 111, 112, 113)
+	casecheck.Equal(t, []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 111, 112, 113}, data)
+
+	data = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	do.Splice[int](&data, 0, 10, 111, 112, 113)
+	casecheck.Equal(t, []int{111, 112, 113}, data)
+
+	data = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	do.Splice[int](&data, 0, 0, 111, 112, 113)
+	casecheck.Equal(t, []int{111, 112, 113, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, data)
+
+	data = []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+	do.Splice[int](&data, -1, -1, 111, 112, 113)
+	casecheck.Equal(t, []int{111, 112, 113, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, data)
+}
+
+func TestUnit_Copy(t *testing.T) {
+	data := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+
+	out := do.Copy[int](data, 2, 5)
+	casecheck.Equal(t, []int{2, 3, 4, 5}, out)
+
+	out = do.Copy[int](data, 2, 10)
+	casecheck.Equal(t, []int{2, 3, 4, 5, 6, 7, 8, 9}, out)
+
+	out = do.Copy[int](data, 2, 0)
+	casecheck.Equal(t, []int{2}, out)
+}
+
+func TestUnit_Filter(t *testing.T) {
+	data := []int{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+
+	out := do.Filter[int](data, func(value int, _ int) bool {
+		return value%2 == 0
+	})
+	casecheck.Equal(t, []int{0, 2, 4, 6, 8}, out)
+}
+
+func TestUnit_Diff(t *testing.T) {
+	data1 := []int{0, 1, 2, 3, 4}
+	data2 := []int{3, 4, 5, 6, 7, 8, 9}
+
+	out := do.Diff[int](data1, data2)
+	casecheck.Equal(t, []int{0, 1, 2, 5, 6, 7, 8, 9}, out)
+}
+
+func TestUnit_Uniq(t *testing.T) {
+	data := []int{0, 1, 5, 2, 1, 5, 2, 8, 0, 2}
+
+	out := do.Unique[int](data)
+	casecheck.Equal(t, []int{0, 1, 5, 2, 8}, out)
+}
diff --git a/strings_words.go b/strings_words.go
new file mode 100644
index 0000000..d1e1c65
--- /dev/null
+++ b/strings_words.go
@@ -0,0 +1,175 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+	"strings"
+	"unicode"
+	"unicode/utf8"
+)
+
+type Words interface {
+	Strings() []string
+	Bytes() [][]byte
+	UseDefaultBlock()
+	SetBlock(detectors ...func(r rune) bool)
+	UseDefaultDigital()
+	SetDigital(detectors ...func(r rune) bool)
+	UseDefaultSymbol()
+	SetSymbol(detectors ...func(r rune) bool)
+}
+
+type _words struct {
+	reader io.ReadSeeker
+	block  []func(r rune) bool
+	symbol []func(r rune) bool
+	digit  []func(r rune) bool
+}
+
+func NewStringWords(s string) Words {
+	w := &_words{
+		reader: strings.NewReader(s),
+	}
+	w.UseDefaultBlock()
+	w.UseDefaultDigital()
+	w.UseDefaultSymbol()
+	return w
+}
+
+func NewBytesWords(b []byte) Words {
+	w := &_words{
+		reader: bytes.NewReader(b),
+	}
+	w.UseDefaultBlock()
+	w.UseDefaultDigital()
+	w.UseDefaultSymbol()
+	return w
+}
+
+func (v *_words) Strings() (out []string) {
+	//nolint:errcheck
+	v.reader.Seek(0, 0)
+	scanner := bufio.NewScanner(v.reader)
+	scanner.Split(v.scannerFunc)
+	for scanner.Scan() {
+		out = append(out, scanner.Text())
+	}
+	return
+}
+
+func (v *_words) Bytes() (out [][]byte) {
+	//nolint:errcheck
+	v.reader.Seek(0, 0)
+	scanner := bufio.NewScanner(v.reader)
+	scanner.Split(v.scannerFunc)
+	for scanner.Scan() {
+		out = append(out, scanner.Bytes())
+	}
+	return
+}
+
+func (v *_words) UseDefaultBlock() {
+	v.SetBlock(unicode.IsDigit, unicode.IsLetter)
+}
+
+func (v *_words) SetBlock(detectors ...func(r rune) bool) {
+	v.block = detectors
+}
+
+func (v *_words) isBlock(r rune) bool {
+	for _, fn := range v.block {
+		if fn(r) {
+			return true
+		}
+	}
+	return false
+}
+
+func (v *_words) UseDefaultDigital() {
+	v.SetDigital(unicode.IsDigit)
+}
+
+func (v *_words) SetDigital(detectors ...func(r rune) bool) {
+	v.digit = detectors
+}
+
+func (v *_words) isDigital(r rune) bool {
+	for _, fn := range v.digit {
+		if fn(r) {
+			return true
+		}
+	}
+	return false
+}
+
+func (v *_words) UseDefaultSymbol() {
+	v.SetSymbol(unicode.IsPunct, unicode.IsSymbol)
+}
+
+func (v *_words) SetSymbol(detectors ...func(r rune) bool) {
+	v.symbol = detectors
+}
+
+func (v *_words) isSymbol(r rune) bool {
+	for _, fn := range v.symbol {
+		if fn(r) {
+			return true
+		}
+	}
+	return false
+}
+
+func (v *_words) scannerFunc(data []byte, atEOF bool) (int, []byte, error) {
+	var (
+		start int
+	)
+
+	for index := 0; index < len(data); {
+		cR, cW := utf8.DecodeRune(data[index:])
+		nR, _ := utf8.DecodeRune(data[index+cW:])
+		index += cW
+
+		switch true {
+		case v.isBlock(cR):
+			if !v.isBlock(nR) {
+				return index, data[start:index], nil
+			}
+		case v.isDigital(cR):
+			if !v.isDigital(nR) {
+				return index, data[start:index], nil
+			}
+		case v.isSymbol(cR):
+			if !v.isSymbol(nR) {
+				return index, data[start:index], nil
+			}
+		default:
+			start = index
+		}
+	}
+
+	if atEOF && len(data) > start {
+		return len(data), data[start:], nil
+	}
+
+	return start, nil, nil
+}
+
+func WordStrings(s string) []string {
+	w := NewStringWords(s)
+	w.UseDefaultBlock()
+	w.UseDefaultSymbol()
+	return w.Strings()
+}
+
+func WordBytes(b []byte) [][]byte {
+	w := NewBytesWords(b)
+	w.UseDefaultBlock()
+	w.UseDefaultSymbol()
+	return w.Bytes()
+}
diff --git a/strings_words_test.go b/strings_words_test.go
new file mode 100644
index 0000000..3c7d9e1
--- /dev/null
+++ b/strings_words_test.go
@@ -0,0 +1,70 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"testing"
+	"unicode"
+
+	"go.osspkg.com/casecheck"
+	"go.osspkg.com/do"
+)
+
+func TestUnit_WordStrings(t *testing.T) {
+	data := `
+a11
+Привет!
+Hello World {user name }
+123 * 123 =111
+`
+	out := do.WordStrings(data)
+	casecheck.Equal(t, []string{
+		"a11", "Привет", "!", "Hello", "World", "{", "user", "name",
+		"}", "123", "*", "123", "=", "111",
+	}, out)
+}
+
+func TestUnit_WordCustom(t *testing.T) {
+	data := `
+a11
+Привет!
+Hello World {user name }
+123 * 123 =111
+`
+	w := do.NewStringWords(data)
+	w.SetBlock(unicode.IsLetter)
+	out := w.Strings()
+	casecheck.Equal(t, []string{
+		"a", "11", "Привет", "!", "Hello", "World", "{", "user", "name",
+		"}", "123", "*", "123", "=", "111",
+	}, out)
+}
+
+func TestUnit_WordBytes(t *testing.T) {
+	data := `
+a11
+Привет!
+Hello World {user name }
+123 * 123 =111
+`
+	out := do.WordBytes([]byte(data))
+	casecheck.Equal(t, [][]byte{
+		[]byte("a11"),
+		[]byte("Привет"),
+		[]byte("!"),
+		[]byte("Hello"),
+		[]byte("World"),
+		[]byte("{"),
+		[]byte("user"),
+		[]byte("name"),
+		[]byte("}"),
+		[]byte("123"),
+		[]byte("*"),
+		[]byte("123"),
+		[]byte("="),
+		[]byte("111"),
+	}, out)
+}
diff --git a/try.go b/try.go
new file mode 100644
index 0000000..3875286
--- /dev/null
+++ b/try.go
@@ -0,0 +1,59 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do
+
+import "fmt"
+
+func Try(try func(), catch func(err error), finally func()) {
+	if try != nil {
+		err := Recovery(try)
+		if err != nil && catch != nil {
+			//nolint:errcheck
+			_ = Recovery(func() {
+				catch(err)
+			})
+		}
+	}
+
+	if finally != nil {
+		//nolint:errcheck
+		_ = Recovery(finally)
+	}
+}
+
+type (
+	StepByStep[V any] struct {
+		steps []func(V) (V, error)
+	}
+)
+
+func NewStepByStep[V any]() *StepByStep[V] {
+	return &StepByStep[V]{
+		steps: make([]func(V) (V, error), 0),
+	}
+}
+
+func (v *StepByStep[V]) Add(fn func(V) (V, error)) {
+	v.steps = append(v.steps, fn)
+}
+
+func (v *StepByStep[V]) Exec(value V) (val V, err error) {
+	val = value
+	for i, step := range v.steps {
+		e := Recovery(func() {
+			val, err = step(val)
+		})
+		if e != nil {
+			err = fmt.Errorf("panic on step #%d: %w", i+1, e)
+			return
+		}
+		if err != nil {
+			err = fmt.Errorf("fail on step #%d: %w", i+1, err)
+			return
+		}
+	}
+	return
+}
diff --git a/try_test.go b/try_test.go
new file mode 100644
index 0000000..0730529
--- /dev/null
+++ b/try_test.go
@@ -0,0 +1,66 @@
+/*
+ *  Copyright (c) 2024 Mikhail Knyazhev <markus621@yandex.com>. All rights reserved.
+ *  Use of this source code is governed by a BSD 3-Clause license that can be found in the LICENSE file.
+ */
+
+package do_test
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	"go.osspkg.com/casecheck"
+	"go.osspkg.com/do"
+)
+
+func TestUnit_Try(t *testing.T) {
+	var errs error
+	do.Try(nil, func(err error) {
+		errs = err
+	}, nil)
+	casecheck.NoError(t, errs)
+
+	errs = nil
+	do.Try(func() {
+		panic(1)
+	}, func(err error) {
+		errs = fmt.Errorf("%w+catch", errors.Unwrap(err))
+	}, func() {
+		errs = fmt.Errorf("%w+finally", errs)
+	})
+	casecheck.Equal(t, `1+catch+finally`, errs.Error())
+}
+
+func TestUnit_StepByStep(t *testing.T) {
+	sbs := do.NewStepByStep[string]()
+	sbs.Add(func(s string) (string, error) {
+		return s + "a", nil
+	})
+	sbs.Add(func(s string) (string, error) {
+		return s + "b", nil
+	})
+
+	v, err := sbs.Exec("123")
+	casecheck.NoError(t, err)
+	casecheck.Equal(t, "123ab", v)
+
+	sbs.Add(func(s string) (string, error) {
+		switch s {
+		case "000ab":
+			return s, fmt.Errorf("1")
+		case "111ab":
+			panic("0")
+		default:
+			return s, nil
+		}
+	})
+
+	_, err = sbs.Exec("000")
+	casecheck.Error(t, err)
+	casecheck.Equal(t, "fail on step #3: 1", err.Error())
+
+	_, err = sbs.Exec("111")
+	casecheck.Error(t, err)
+	casecheck.Equal(t, "panic on step #3: panic=0 trace=./try_test.go:53 go.osspkg.com/do_test.TestUnit_StepByStep.func3", err.Error())
+}