software.amazon.smithy.kotlin.codegen.utils.CaseUtils.kt Maven / Gradle / Ivy

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/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 * SPDX-License-Identifier: Apache-2.0.
 */
package software.amazon.smithy.kotlin.codegen.utils

/**
 * Split a string on word boundaries
 */
fun String.splitOnWordBoundaries(): List {
    // adapted from Java v2 SDK CodegenNamingUtils.splitOnWordBoundaries
    var result = this

    // all non-alphanumeric characters: "acm-success"-> "acm success"
    result = result.replace(Regex("[^A-Za-z0-9+]"), " ")

    // if a number has a standalone v in front of it, separate it out
    result = result.replace(Regex("([^a-z]{2,})v([0-9]+)"), "$1 v$2 ") // TESTv4 -> "TEST v4 "
        .replace(Regex("([^A-Z]{2,})V([0-9]+)"), "$1 V$2 ") // TestV4 -> "Test V4 "

    // add a space between camelCased words
    result = result.split(Regex("(?<=[a-z])(?=[A-Z]([a-zA-Z]|[0-9]))")).joinToString(separator = " ") // AcmSuccess -> // "Acm Success"

    // add a space after acronyms
    result = result.replace(Regex("([A-Z]+)([A-Z][a-z])"), "$1 $2") // "ACMSuccess" -> "ACM Success"

    // add space after a number in the middle of a word
    result = result.replace(Regex("([0-9])([a-zA-Z])"), "$1 $2") // "s3ec2" -> "s3 ec2"

    // remove extra spaces - multiple consecutive ones or those and the beginning/end of words
    result = result.replace(Regex("\\s+"), " ") // "Foo  Bar" -> "Foo Bar"
        .trim() // " Foo " -> "Foo"

    return result.split(" ")
}

/**
 * Convert a string to `PascalCase` (uppercase start with upper case word boundaries)
 */
fun String.toPascalCase(): String = splitOnWordBoundaries().joinToString(separator = "") { it.lowercase().replaceFirstChar { c -> c.uppercaseChar() } }

/**
 * Convert a string to `camelCase` (lowercase start with upper case word boundaries)
 */
fun String.toCamelCase(): String = toPascalCase().replaceFirstChar { c -> c.lowercaseChar() }

/**
 * Inverts the case of a character. For example:
 * * 'a' → 'A'
 * * 'A' → 'a'
 * * '!' → '!'
 */
fun Char.toggleCase(): Char = if (isUpperCase()) lowercaseChar() else uppercaseChar()

/**
 * Toggles the case of the first character in the string. For example:
 * * "apple" → "Apple"
 * * "Apple" → "apple"
 * * "!apple" → "!apple"
 */
fun String.toggleFirstCharacterCase(): String = when {
    isEmpty() -> this
    else -> first().toggleCase() + substring(1)
}