Clap — ESUG 2018

Clap is a command-line argument parser for Pharo

Github: https://github.com/cdlm/clap-st
Demo video: https://www.youtube.com/watch?v=VjnVZR4FMcQ

Transcript

1. CLAP
   

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3. Damien
   sept. 2018
   PHARO
   esug clap N+1
   tool
   demo
   4
   command-
   args
   line
   ommand
   ine

   rgument
   arser
   ommand
   ine

   rgument
   arser
   ommand
   ine

   rgument
   arser
   Command
   Line

   Argument
   Parser
   C
   L

   A
   P
   C
   L

   A
   P
   C
   L

   A
   P
   C
   L

   A
   P
   

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4. demo
   5
   

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5. 6
   github.com/cdlm/clap-st
   hello! I'm Damien Pollet
   RMOD team @ Inria Lille, France
   …and I teach Java… !
   Use the command line?

   please talk to me!
   besides Clap:
   ·Coral (a looong time ago)
   ·LaTeX typography for the Pharo books
   ·fari.sh (image builder/runner)
   

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6. what
   7
   

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7. 8
   hello
   command
   

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8. 9
   'foo'
   hello
   positional
   

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9. 10
   'foo'
   --shout
   hello
   positional
   flag
   command
   

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10. 11
    'foo'
    --shout
    hello
    positional
    flag
    --repeat 42
    flag
    command
    pos.
    

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11. 12
    2nd pos.
    1st pos.
    sub-cmd
    sub-command
    command
    git -C dir remote add foo git@gith
    pos
    flag
    

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12. flow
    13
    feedback

    to user
    application

    domain
    Queries, meanings

    +

    validations
    specification
    (= grammar)
    activation
    (= syntax tree)
    command line

    (= words)
    specification
    (= grammar)
    activation
    (= syntax tree)
    command
    flag
    positional
    command line

    (= words)
    hello --shout foo
    context
    match
    mismatch
    implicit
    Queries, meanings

    +

    validations
    feedback

    to user
    application

    domain
    !
    "
    

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13. how
    14
    

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14. specify
    15
    Positional
    Flag
    Command
    aliases
    Parameterized
    name
    description
    meaning
    defaultMeaning
    validations
    Parameter
    

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15. 16
    cmd := (ClapCommand withName: 'hello')
    description: 'Says hello';
    add: param;
    add: (ClapFlag withName: 'shout');
    meaning: [ :args | "# ]
    param := (ClapPositional withName: 'who')
    description: 'Recipient of greeting';
    defaultMeaning: [ 'world' ].
    

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16. activate
    args
    parent
    spec
    SubExpression
    Implicit
    word
    Explicit
    Parameter
    Expression
    ···Match
    Context
    

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17. 18
    parent
    match
    atName:'shout'
    Context
    #(hello esug)
    Command
    hello
    Positional
    esug
    atName:'who'
    Implicit
    context
    parent
    

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18. 19
    context := (ClapContext specification: cmd)
    arguments: #('hello' 'esug').
    "same + immediate evaluation:"
    cmd activateWith: #('hello' 'esug').
    

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19. context match.
    20
    context match atName: 'shout'.
    context match at: param.
    context match atName: 'who'.
    "a ClapPositionalMatch(esug)"
    "a ClapCommandMatch(hello esug)"
    "a ClapImplicit"
    

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20. give meaning
    21
    cmd meaning: [ :args | ].
    "#
    42
    "42"
    context match value.
    (context match atName: 'who') value. "esug"
    (context match atName: 'shout') value. "false"
    

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21. 22
    cmd meaning: [ :args |
    | recipient |
    recipient := args atName: 'who'.
    args context stdout
    << 'hello ' , recipient value;
    lf
    ]
    match of CMD
    spec
    match of positional
    meaning of positional
    (implicit matches give
    default meaning)
    

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22. ClapCommandLineExamples class >> hello
    
    ^
    install
    23
    (ClapCommand withName: 'hello')
    description: 'Says hello';
    add: (ClapPositional withName: 'who')
    description: 'Recipient of greeting'
    defaultMeaning: [ 'world' ].
    hello esug
    › ./pharo Pharo.image clap
    

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23. more
    24
    

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24. exit
    25
    context exitSuccess.
    Exit success signal.
    context exitFailure.
    context exit: 1.
    Exit failure signal.
    $
    %
    "OK for interactive use (catches Exit)"
    cmd activateWith: #('hello' 'esug').
    

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25. help
    26
    ClapCommand forHelp.
    ClapFlag forHelp. git commit --help
    git help commit
    documents specified sibling, or parent
    runs automatically
    meaning: [ :args |
    args atName: 'help' ifFound: [ :help |
    help value; exitSuccess ].
    documents parent
    requires explicit check
    

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26. validate
    27
    git -C dir remote add foo git@gith
    valid repo valid
    name
    valid URL
    ↺ work in progress…
    

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27. hack
    28
    

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28. 29
    github.com/cdlm/clap-st
    ✓ basic architecture
    ✓ workspace & commandline
    ✓ pharo commands
    version & evaluate → more to port
    ↺ validations
    error handling & feedback
    → common meanings
    → Coral-like DSL
    → port fari.sh
    → shell completions…
    

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29. fin
    30
    

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30. IBM Plex
    fonts
    Clapping
    Music
    Pharo
    postcard
    Coral
    slides
    Clap demo
    (YouTube)
    

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