Add main-kts demo scripts

Author: ligee

jvm/main-kts/MainKts.md

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+
+# Kotlin Scripting Examples: `kotlin-main-kts` usages
+
+Scripts demonstrating the usage of the `kotlin-main-kts` script definition jar, distributied with the Kotlin compiler
+and IntelliJ plugin.
+
+*See also [simplified implementation in this repository](../simple-main-kts/SimpleMainKts.md)*
+
+## Description
+ 
+The purpose of the `main-kts` is to allow writing simple but extendable  utility scripts for the usage in the command 
+line, replacing the simple Kotlin programs with `main` function (hence the `main` in its name).
+
+### Usage
+
+For example a script (note that the file should have an extension corresponding to the script definition, in this case 
+`.smain.kts`):
+
+```kotlin
+println("Hello, ${args[0]}")
+```
+
+could be executed with the command
+
+```
+kotlinc -cp <path/to/kotlin-main-kts.jar> script.main.kts
+```
+
+and starting from Kotlin version 1.3.70 it could even be used without explicit `kotlin-main-kts.jar` in the classpath,
+provided that the compiler could find the required jars. In addition starting from 1.3.70 `kotlin` runner supports 
+scripts the same way as `kotlinc -script` combination:
+
+```
+kotlin script.main.kts
+```
+
+or even as simple as 
+
+```
+./script.main.kts
+```
+
+provided that the shebang line is added to the script and works in the given OS shell. *(See examples below.)*
+
+### Caching
+
+The compiled scripts are cashed to the directory defined by an environmen variable `KOTLIN_MAIN_KTS_COMPILED_SCRIPTS_CACHE_DIR` 
+*(`$TEMP/main.kts.compiled.cache` by default)*, and if the script is not changed, the compiled one is executed from the cache.
+
+### IntelliJ support
+
+Starting from the Kotlin IntelliJ plugin version 1.3.70, the `.main.kts` scripts are supported automatically in the 
+IntelliJ IDEA, provided that they are placed outside of the regular source folders. E.g. if this project is imported into 
+the IntelliJ, the demo scripts in the [`scripts`](scripts) folders should be properly highlighted and support navigation,
+including navigation into imported libraries. 
+
+## Demo Scripts
+
+- [`kotlinx-html.main.kts`](scripts/kotlinx-html.main.kts) demonstrates usage of the 
+[`kotlinx-html` library](https://github.com/Kotlin/kotlinx.html) by JetBrains, to generate HTML output 
+- [`kotlin-shell.main.kts`](scripts/kotlin-shell.main.kts) demonstrates usage of the 
+[`kotlin-shell` library](https://github.com/jakubriegel/kotlin-shell) by Jakub Riegel, to execute OS shell commands
+with easy interaction with Kotlin code

jvm/main-kts/scripts/kotlin-shell.main.kts

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+#!/usr/bin/env kotlin
+
+@file:Repository("https://dl.bintray.com/jakubriegel/kotlin-shell")
+@file:DependsOn("eu.jrie.jetbrains:kotlin-shell-core:0.2.1")
+@file:DependsOn("org.slf4j:slf4j-simple:1.7.28")
+@file:CompilerOptions("-Xopt-in=kotlin.RequiresOptIn")
+@file:OptIn(kotlinx.coroutines.ExperimentalCoroutinesApi::class)
+
+import eu.jrie.jetbrains.kotlinshell.shell.*
+
+shell {
+    if (args.isEmpty()) {
+        "ls -l"()
+    } else {
+        var lines = 0
+        var words = 0
+        var chars = 0
+
+        var wasSpace = false
+
+        pipeline {
+            "cat ${args[0]}".process() pipe
+                    streamLambda { strm, _, _ ->
+                        while (true) {
+                            val byte = strm.read()
+                            if (byte < 0) break
+                            val ch = byte.toChar()
+                            chars++
+                            if (ch == '\n') lines++
+                            val isSpace = ch == '\n' || ch == '\t' || ch == ' '
+                            if (!wasSpace && isSpace) {
+                                wasSpace = true
+                            } else if (wasSpace && !isSpace) {
+                                words++
+                                wasSpace = false
+                            }
+                        }
+                    }
+        }
+
+        println("My wc:")
+        println("$lines $words $chars")
+        println("System wc:")
+        "wc ${args[0]}"()
+    }
+}

jvm/main-kts/scripts/kotlinx-html.main.kts

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+#!/usr/bin/env kotlin
+
+@file:Repository("https://jcenter.bintray.com")
+@file:DependsOn("org.jetbrains.kotlinx:kotlinx-html-jvm:0.6.11")
+
+import kotlinx.html.*; import kotlinx.html.stream.*; import kotlinx.html.attributes.*
+
+val addressee = args.firstOrNull() ?: "World"
+
+print(createHTML().html {
+    body {
+        h1 { +"Hello, $addressee!" }
+    }
+})
+