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fix #14 when(value) with blows and whistles. Collection now is container (has Contains). greatly improved container properties of builtin classes.

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This commit is contained in:
Sergey Chernov 2025-06-13 17:25:56 +04:00
parent 7cc80e2433
commit be4f2c7f45
9 changed files with 389 additions and 31 deletions
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83
docs/tutorial.md
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@ -552,6 +552,89 @@ Or, more neat:
>>> just 3
>>> void
## When
It is very much like the kotlin's:
fun type(x) {
when(x) {
in 'a'..'z', in 'A'..'Z' -> "letter"
in '0'..'9' -> "digit"
'$' -> "dollar"
"EUR" -> "crap"
in ['@', '#', '^'] -> "punctuation1"
in "*&.," -> "punctuation2"
else -> "unknown"
}
}
assertEquals("digit", type('3'))
assertEquals("dollar", type('$'))
assertEquals("crap", type("EUR"))
>>> void
Notice, several conditions can be grouped with a comma.
Also, you can check the type too:
fun type(x) {
when(x) {
"42", 42 -> "answer to the great question"
is Real, is Int -> "number"
is String -> {
for( d in x ) {
if( d !in '0'..'9' )
break "unknown"
}
else "number"
}
}
}
assertEquals("number", type(5))
assertEquals("number", type("153"))
assertEquals("number", type(π/2))
assertEquals("unknown", type("12%"))
assertEquals("answer to the great question", type(42))
assertEquals("answer to the great question", type("42"))
>>> void
### supported when conditions:
#### Contains:
You can thest that _when expression_ is _contained_, or not contained, in some object using `in container` and `!in container`. The container is any object that provides `contains` method, otherwise the runtime exception will be thrown.
Typical builtin types that are containers (e.g. support `conain`):
| class | notes |
|------------|--------------------------------------------|
| Collection | contains an element (1) |
| Array | faster maybe that Collection's |
| List | faster than Array's |
| String | character in string or substring in string |
| Range | object is included in the range (2) |
(1)
: Iterable is not the container as it can be infinite
(2)
: Depending on the inclusivity and open/closed range parameters. BE careful here: String range is allowed, but it is usually not what you expect of it:
assert( "more" in "a".."z") // string range ok
assert( 'x' !in "a".."z") // char in string range: probably error
assert( 'x' in 'a'..'z') // character range: ok
assert( "x" !in 'a'..'z') // string in character range: could be error
>>> void
So we recommend not to mix characters and string ranges; use `ch in str` that works
as expected:
"foo" in "foobar"
>>> true
and also character inclusion:
'o' in "foobar"
>>> true
## while
Regular pre-condition while loop, as expression, loop returns the last expression as everything else:

2
library/build.gradle.kts
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@ -5,7 +5,7 @@ import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl
import org.jetbrains.kotlin.gradle.dsl.JvmTarget
group = "net.sergeych"
version = "0.5.2-SNAPSHOT"
version = "0.6.0-SNAPSHOT"
buildscript {
repositories {

112
library/src/commonMain/kotlin/net/sergeych/lyng/Compiler.kt
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@ -454,7 +454,7 @@ class Compiler(
Token.Type.ID -> {
// visibility
val visibility = if( isClassDeclaration && t.value == "private" ) {
val visibility = if (isClassDeclaration && t.value == "private") {
t = cc.next()
Visibility.Private
} else Visibility.Public
@ -650,7 +650,7 @@ class Compiler(
"void" -> Accessor { ObjVoid.asReadonly }
"null" -> Accessor { ObjNull.asReadonly }
"true" -> Accessor { ObjBool(true).asReadonly }
"false" -> Accessor { ObjBool(false).asReadonly }
"false" -> Accessor { ObjFalse.asReadonly }
else -> {
Accessor({
it.pos = t.pos
@ -709,6 +709,7 @@ class Compiler(
"class" -> parseClassDeclaration(cc, false)
"try" -> parseTryStatement(cc)
"throw" -> parseThrowStatement(cc)
"when" -> parseWhenStatement(cc)
else -> {
// triples
cc.previous()
@ -729,6 +730,113 @@ class Compiler(
}
}
data class WhenCase(val condition: Statement, val block: Statement)
private fun parseWhenStatement(cc: CompilerContext): Statement {
// has a value, when(value) ?
var t = cc.skipWsTokens()
return if (t.type == Token.Type.LPAREN) {
// when(value)
val value = parseStatement(cc) ?: throw ScriptError(cc.currentPos(), "when(value) expected")
cc.skipTokenOfType(Token.Type.RPAREN)
t = cc.next()
if (t.type != Token.Type.LBRACE) throw ScriptError(t.pos, "when { ... } expected")
val cases = mutableListOf<WhenCase>()
var elseCase: Statement? = null
lateinit var whenValue: Obj
// there could be 0+ then clauses
// condition could be a value, in and is clauses:
// parse several conditions for one then clause
// loop cases
outer@ while (true) {
var skipParseBody = false
val currentCondition = mutableListOf<Statement>()
// loop conditions
while (true) {
t = cc.skipWsTokens()
when (t.type) {
Token.Type.IN,
Token.Type.NOTIN -> {
// we need a copy in the closure:
val isIn = t.type == Token.Type.IN
val container = parseExpression(cc) ?: throw ScriptError(cc.currentPos(), "type expected")
currentCondition += statement {
val r = container.execute(this).contains(this, whenValue)
ObjBool(if (isIn) r else !r)
}
}
Token.Type.IS, Token.Type.NOTIS -> {
// we need a copy in the closure:
val isIn = t.type == Token.Type.IS
val caseType = parseExpression(cc) ?: throw ScriptError(cc.currentPos(), "type expected")
currentCondition += statement {
val r = whenValue.isInstanceOf(caseType.execute(this))
ObjBool(if (isIn) r else !r)
}
}
Token.Type.COMMA ->
continue
Token.Type.ARROW ->
break
Token.Type.RBRACE ->
break@outer
else -> {
if (t.value == "else") {
cc.skipTokens(Token.Type.ARROW)
if (elseCase != null) throw ScriptError(
cc.currentPos(),
"when else block already defined"
)
elseCase =
parseStatement(cc) ?: throw ScriptError(cc.currentPos(), "when else block expected")
skipParseBody = true
} else {
cc.previous()
val x = parseExpression(cc)
?: throw ScriptError(cc.currentPos(), "when case condition expected")
currentCondition += statement {
ObjBool(x.execute(this).compareTo(this, whenValue) == 0)
}
}
}
}
}
// parsed conditions?
if (!skipParseBody) {
val block = parseStatement(cc) ?: throw ScriptError(cc.currentPos(), "when case block expected")
for (c in currentCondition) cases += WhenCase(c, block)
}
}
statement {
var result: Obj = ObjVoid
// in / is and like uses whenValue from closure:
whenValue = value.execute(this)
var found = false
for (c in cases)
if (c.condition.execute(this).toBool()) {
result = c.block.execute(this)
found = true
break
}
if (!found && elseCase != null) result = elseCase.execute(this)
result
}
} else {
// when { cond -> ... }
TODO("when without object is not yet implemented")
}
}
private fun parseThrowStatement(cc: CompilerContext): Statement {
val throwStatement = parseStatement(cc) ?: throw ScriptError(cc.currentPos(), "throw object expected")
return statement {

35
library/src/commonMain/kotlin/net/sergeych/lyng/CompilerContext.kt
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@ -21,7 +21,11 @@ internal class CompilerContext(val tokens: List<Token>) {
fun hasNext() = currentIndex < tokens.size
fun hasPrevious() = currentIndex > 0
fun next() = tokens.getOrElse(currentIndex) { throw IllegalStateException("No next token") }.also { currentIndex++ }
fun next() =
if( currentIndex < tokens.size ) tokens[currentIndex++]
else Token("", tokens.last().pos, Token.Type.EOF)
// throw IllegalStateException("No more tokens")
fun previous() = if (!hasPrevious()) throw IllegalStateException("No previous token") else tokens[--currentIndex]
fun savePos() = currentIndex
@ -47,9 +51,7 @@ internal class CompilerContext(val tokens: List<Token>) {
throw ScriptError(at, message)
}
fun currentPos() =
if (hasNext()) next().pos.also { previous() }
else previous().pos.also { next() }
fun currentPos(): Pos = tokens[currentIndex].pos
/**
* Skips next token if its type is `tokenType`, returns `true` if so.
@ -145,19 +147,16 @@ internal class CompilerContext(val tokens: List<Token>) {
}
}
// fun expectKeyword(vararg keyword: String): String {
// val t = next()
// if (t.type != Token.Type.ID && t.value !in keyword) {
// throw ScriptError(t.pos, "expected one of ${keyword.joinToString()}")
//
// }
// data class ReturnScope(val needCatch: Boolean = false)
// private val
// fun startReturnScope(): ReturnScope {
// return ReturnScope()
// }
/**
* Skip newlines and comments. Returns (and reads) first non-whitespace token.
* Note that [Token.Type.EOF] is not considered a whitespace token.
*/
fun skipWsTokens(): Token {
while( current().type in wstokens ) next()
return next()
}
companion object {
val wstokens = setOf(Token.Type.NEWLINE, Token.Type.MULTILINE_COMMENT, Token.Type.SINLGE_LINE_COMMENT)
}
}

2
library/src/commonMain/kotlin/net/sergeych/lyng/Obj.kt
View File

@ -89,7 +89,7 @@ open class Obj {
}
open suspend fun contains(context: Context, other: Obj): Boolean {
context.raiseNotImplemented()
return invokeInstanceMethod(context, "contains", other).toBool()
}
open val asStr: ObjString by lazy {

26
library/src/commonMain/kotlin/net/sergeych/lyng/ObjClass.kt
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@ -42,7 +42,8 @@ open class ObjClass(
visibility: Visibility = Visibility.Public,
pos: Pos = Pos.builtIn
) {
if (name in members || allParentsSet.any { name in it.members })
val existing = members[name] ?: allParentsSet.firstNotNullOfOrNull { it.members[name] }
if( existing?.isMutable == false)
throw ScriptError(pos, "$name is already defined in $objClass or one of its supertypes")
members[name] = ObjRecord(initialValue, isMutable, visibility)
}
@ -97,7 +98,19 @@ val ObjIterable by lazy {
*/
val ObjCollection by lazy {
val i: ObjClass = ObjIterable
ObjClass("Collection", i)
ObjClass("Collection", i).apply {
// it is not effective, but it is open:
addFn("contains", isOpen = true) {
val obj = args.firstAndOnly()
val it = thisObj.invokeInstanceMethod(this, "iterator")
while (it.invokeInstanceMethod(this, "hasNext").toBool()) {
if( obj.compareTo(this, it.invokeInstanceMethod(this, "next")) == 0 )
return@addFn ObjTrue
}
ObjFalse
}
}
}
val ObjIterator by lazy { ObjClass("Iterator") }
@ -145,6 +158,15 @@ val ObjArray by lazy {
addFn("iterator") {
ObjArrayIterator(thisObj).also { it.init(this) }
}
addFn("contains", isOpen = true) {
val obj = args.firstAndOnly()
for( i in 0..< thisObj.invokeInstanceMethod(this, "size").toInt()) {
if( thisObj.getAt(this, i).compareTo(this, obj) == 0 ) return@addFn ObjTrue
}
ObjFalse
}
addFn("isample") { "ok".toObj() }
}
}

4
library/src/commonMain/kotlin/net/sergeych/lyng/ObjList.kt
View File

@ -75,6 +75,10 @@ class ObjList(val list: MutableList<Obj> = mutableListOf()) : Obj() {
return this
}
override suspend fun contains(context: Context, other: Obj): Boolean {
return list.contains(other)
}
override val objClass: ObjClass
get() = type

8
library/src/commonMain/kotlin/net/sergeych/lyng/ObjString.kt
View File

@ -31,6 +31,14 @@ data class ObjString(val value: String) : Obj() {
return ObjChar(value[index])
}
override suspend fun contains(context: Context, other: Obj): Boolean {
return if (other is ObjString)
value.contains(other.value)
else if (other is ObjChar)
value.contains(other.value)
else context.raiseArgumentError("String.contains can't take $other")
}
companion object {
val type = ObjClass("String").apply {
addConst("startsWith",

148
library/src/commonTest/kotlin/ScriptTest.kt
View File

@ -298,9 +298,9 @@ class ScriptTest {
@Test
fun eqNeqTest() = runTest {
assertEquals(ObjBool(true), eval("val x = 2; x == 2"))
assertEquals(ObjBool(false), eval("val x = 3; x == 2"))
assertEquals(ObjFalse, eval("val x = 3; x == 2"))
assertEquals(ObjBool(true), eval("val x = 3; x != 2"))
assertEquals(ObjBool(false), eval("val x = 3; x != 3"))
assertEquals(ObjFalse, eval("val x = 3; x != 3"))
assertTrue { eval("1 == 1").toBool() }
assertTrue { eval("true == true").toBool() }
@ -313,17 +313,17 @@ class ScriptTest {
@Test
fun logicTest() = runTest {
assertEquals(ObjBool(false), eval("true && false"))
assertEquals(ObjBool(false), eval("false && false"))
assertEquals(ObjBool(false), eval("false && true"))
assertEquals(ObjFalse, eval("true && false"))
assertEquals(ObjFalse, eval("false && false"))
assertEquals(ObjFalse, eval("false && true"))
assertEquals(ObjBool(true), eval("true && true"))
assertEquals(ObjBool(true), eval("true || false"))
assertEquals(ObjBool(false), eval("false || false"))
assertEquals(ObjFalse, eval("false || false"))
assertEquals(ObjBool(true), eval("false || true"))
assertEquals(ObjBool(true), eval("true || true"))
assertEquals(ObjBool(false), eval("!true"))
assertEquals(ObjFalse, eval("!true"))
assertEquals(ObjBool(true), eval("!false"))
}
@ -1979,4 +1979,138 @@ class ScriptTest {
""".trimIndent()
)
}
@Test
fun testSimpleWhen() = runTest {
eval(
"""
var result = when("a") {
"a" -> "ok"
else -> "fail"
}
assertEquals(result, "ok")
result = when(5) {
3 -> "fail1"
4 -> "fail2"
else -> "ok2"
}
assert(result == "ok2")
result = when(5) {
3 -> "fail"
4 -> "fail2"
}
assert(result == void)
""".trimIndent()
)
}
@Test
fun testWhenIs() = runTest {
eval(
"""
var result = when("a") {
is Int -> "fail2"
is String -> "ok"
else -> "fail"
}
assertEquals(result, "ok")
result = when(5) {
3 -> "fail1"
4 -> "fail2"
else -> "ok2"
}
assert(result == "ok2")
result = when(5) {
3 -> "fail"
4 -> "fail2"
}
assert(result == void)
result = when(5) {
!is String -> "ok"
4 -> "fail2"
}
assert(result == "ok")
""".trimIndent()
)
}
@Test
fun testWhenIn() = runTest {
eval(
"""
var result = when('e') {
in 'a'..'c' -> "fail2"
in 'a'..'z' -> "ok"
else -> "fail"
}
// assertEquals(result, "ok")
result = when(5) {
in [1,2,3,4,6] -> "fail1"
in [7, 0, 9] -> "fail2"
else -> "ok2"
}
assert(result == "ok2")
result = when(5) {
in [1,2,3,4,6] -> "fail1"
in [7, 0, 9] -> "fail2"
in [-1, 5, 11] -> "ok3"
else -> "fail3"
}
assert(result == "ok3")
result = when(5) {
!in [1,2,3,4,6, 5] -> "fail1"
!in [7, 0, 9, 5] -> "fail2"
!in [-1, 15, 11] -> "ok4"
else -> "fail3"
}
assert(result == "ok4")
result = when(5) {
in [1,3] -> "fail"
in 2..4 -> "fail2"
}
assert(result == void)
""".trimIndent()
)
}
@Test
fun testWhenSample1() = runTest {
eval(
"""
fun type(x) {
when(x) {
in 'a'..'z', in 'A'..'Z' -> "letter"
in '0'..'9' -> "digit"
in "$%&" -> "hate char"
else -> "unknown"
}
}
assertEquals("digit", type('3'))
assertEquals("letter", type('E'))
assertEquals("hate char", type('%'))
""".trimIndent()
)
}
@Test
fun testWhenSample2() = runTest {
eval(
"""
fun type(x) {
when(x) {
"42", 42 -> "answer to the great question"
is Real, is Int -> "number"
is String -> {
for( d in x ) {
if( d !in '0'..'9' )
break "unknown"
}
else "number"
}
}
}
assertEquals("number", type(5))
""".trimIndent()
)
}
}