Yuri

A type-safe URI builder for Kotlin. Work in progress.

tree

All usage examples are based on the following hypothetical file tree:

localhost
├── bin
│   ├── sh
│   └── sh.distrib
|       └── sh
├── etc
│   ├── vim
|   └── script.sh
└── usr
    ├── bin
    │   └── vim
    └── local
        └── bin
            └── sh

import

To work properly, Yuri needs a wildcard import:

import Y.*

usage

Yuri provides compile-time URI validation with a URI-like syntax.

listOf(
    // Compiles!
    Y.uri(localhost),
    Y.uri(localhost /bin),
    Y.uri(localhost /bin/sh),
    Y.uri(localhost /bin/sh.distrib),
    Y.uri(localhost /bin/sh.distrib/sh),
    Y.uri(localhost /etc),
    Y.uri(localhost /etc/vim),
    Y.uri(localhost /etc/script.sh),
    Y.uri(localhost /usr),
    Y.uri(localhost /usr/bin/vim),
    Y.uri(localhost /usr/local),
    Y.uri(localhost /usr/local/bin),
    Y.uri(localhost /usr/local/bin/sh),

    Y.uri(projectDir),
    Y.uri(projectDir /gradle),
    Y.uri(projectDir /gradlew),
    Y.uri(projectDir /settings_dot_gradle),
    Y.uri(projectDir /src/main),
    Y.uri(projectDir /src/main/kotlin)

    // Does not compile!
    // ,Y.uri(localhost /local)
    // ,Y.uri(localhost /bin/vim)
    // ,Y.uri(localhost /sh)
    // ,Y.uri(localhost /bin/local)
    // ,Y.uri(localhost /etc/local)
    // ,Y.uri(localhost /etc/sh)
    // ,Y.uri(localhost /etc/script)
    // ,Y.uri(localhost /usr/local/sh)
    // ,Y.uri(localhost /usr/local/bin/sh.distrib)
    // ,Y.uri(projectDir /test)
    // ,Y.uri(projectDir /compileKotlin)
    // ,Y.uri(projectDir /kotlin)
    // ,Y.uri(projectDir /production/classes/main)
).forEach { println("$it") }

search

You can perform Kleene-star prefix searches using Kotlin's spread-operator:

listOf(
    // Compiles!
    *bin,
    *sh,
    *vim,
    *bin/sh,
    *bin/sh.distrib,
    *etc/vim,
    *usr/bin,
    *sh.distrib,
    *sh.distrib/sh,
    *script.sh,
    *etc/script.sh
    
    // Does not compile!
    // , *etc/bin
    // , *etc/sh
    // , *local/usr
    // , *sh/distrib
    // , *sh/sh
).forEach { path -> println("*$path -> ${Y.uris(path)}") }

batch

Yuri provides an extension function for batch ops over multiple files:

Y.uris(*sh) { println(it) }
Y.uris(*sh) { it.createNewFile() }
Y.uris(*sh) { it.appendText("Hello Yuri") }
Y.uris(*sh) { it.setReadOnly() }

examples

To reproduce the example code above, run the following command from the project directory:

./gradlew run

generate

To generate the file tree, run the following command from the consumer directory:

../gradlew genSources [-Path=<absolute path to perform file tree scan>]

Unless -Path is specified, Yuri will scan the project directory. Code generation is provided by Kotlin Poet.

how?

See:

• Y.kt, for DSL and type checking
• Yuri.kt, for code generation

why?

• Because Strings are error prone (FileNotFoundException, NoSuchFileException...)

• Many filesystems can be scanned quickly and do not change

• To stress test Kotlin's type checker

• Real time automatic code generation is getting better

• Abusing operator overloading is fun! Learn how a DSL works

• Might come in handy for scripting and build automation

• Static resource discovery, e.g. webpage crawling, IP address scanning

• Projects freqently need to reference absolute or project-local resources