for in range, range size and indexing

docs/Range.md

@@ -45,17 +45,57 @@ are equal or within another, taking into account the end-inclusiveness:
     assert( (1..<3) in (1..3) )
     >>> void
 
+## Range size and indexed access
+
+This might be confusing, but the range size and limits are used with for loops
+so their meaning is special.
+
+For open ranges, size throws and exception.
+
+For Int ranges, the `size` is `end` - `start` possibly + 1 for ind-inclusive ranges, and indexing getter returns all values from start to end, probably, inclusive:
+
+    val r = 1..3
+    assert( r.size == 3 )
+    assert( r[0] == 1 )
+    assert( r[1] == 2 )
+    assert( r[2] == 3 )
+    >>> void
+
+And for end-exclusive range:
+
+    val r = 1..<3
+    assert(r.size == 2)
+    assert( r[0] == 1 )
+    assert( r[1] == 2 )
+    >>> void
+
+In spite of this you can use ranges in for loops:
+
+    for( i in 1..3 ) 
+        println(i)
+    >>> 1
+    >>> 2
+    >>> 3
+    >>> void
+
+but
+
+    for( i in 1..<3 ) 
+        println(i)
+    >>> 1
+    >>> 2
+    >>> void
 
 # Instance members
 
-| member          | description                | args          |
+| member          | description                  | args          |
-|-----------------|----------------------------|---------------|
+|-----------------|------------------------------|---------------|
-| contains(other) | used in `in`               | Range, or Any |
+| contains(other) | used in `in`                 | Range, or Any |
-| inclusiveEnd    | true for '..'              | Bool          |
+| isEndInclusive  | true for '..'                | Bool          |
-| isOpen          | at any end                 | Bool          |
+| isOpen          | at any end                   | Bool          |
-| isIntRange      | both start and end are Int | Bool          |
+| isIntRange      | both start and end are Int   | Bool          |
-| start           |                            | Bool          |
+| start           |                              | Bool          |
-| end             |                            | Bool          |
+| end             |                              | Bool          |
-|                 |                            |               |
+| size            | for finite ranges, see above | Long          |
-|                 |                            |               |
+| []              | see above                    |               |
-|                 |                            |               |
+|                 |                              |               |

library/src/commonMain/kotlin/net/sergeych/ling/Compiler.kt

@@ -303,14 +303,14 @@ class Compiler(
 
                 Token.Type.DOTDOT, Token.Type.DOTDOTLT -> {
                     // closed-range operator
-                    val inclusiveEnd = t.type == Token.Type.DOTDOT
+                    val isEndInclusive = t.type == Token.Type.DOTDOT
                     val left = operand
                     val right = parseStatement(cc)
                     operand = Accessor {
                         ObjRange(
                             left?.getter?.invoke(it)?.value ?: ObjNull,
                             right?.execute(it) ?: ObjNull,
-                            inclusiveEnd = inclusiveEnd
+                            isEndInclusive = isEndInclusive
                         ).asReadonly
                     }
                 }

library/src/commonMain/kotlin/net/sergeych/ling/Context.kt

@@ -16,7 +16,10 @@ class Context(
 
     @Suppress("unused")
     fun raiseNPE(): Nothing = raiseError(ObjNullPointerError(this))
-
+    fun raiseIndexOutOfBounds(message: String = "Index out of bounds"): Nothing =
+        raiseError(ObjIndexOutOfBoundsError(this, message))
+    fun raiseArgumentError(message: String = "Illegal argument error"): Nothing =
+        raiseError(ObjIllegalArgumentError(this, message))
     fun raiseClassCastError(msg: String): Nothing = raiseError(ObjClassCastError(this, msg))
 
     fun raiseError(message: String): Nothing {

library/src/commonMain/kotlin/net/sergeych/ling/Obj.kt

@@ -52,9 +52,10 @@ sealed class Obj {
         getInstanceMemberOrNull(name)
             ?: throw ScriptError(atPos, "symbol doesn't exist: $name")
 
-    suspend fun callInstanceMethod(context: Context,
+    suspend fun callInstanceMethod(
-                                   name: String,
+        context: Context,
-                                   args: Arguments = Arguments.EMPTY
+        name: String,
+        args: Arguments = Arguments.EMPTY
     ): Obj =
         // note that getInstanceMember traverses the hierarchy
         objClass.getInstanceMember(context.pos, name).value.invoke(context, this, args)
@@ -193,7 +194,7 @@ sealed class Obj {
         members[name] = WithAccess(initialValue, isMutable)
     }
 
-    fun addFn(name: String, isOpen: Boolean = false, code: suspend Context.()->Obj) {
+    fun addFn(name: String, isOpen: Boolean = false, code: suspend Context.() -> Obj) {
         createField(name, statement { code() }, isOpen)
     }
 
@@ -210,7 +211,6 @@ sealed class Obj {
         callOn(context.copy(atPos, args = args, newThisObj = thisObj))
 
 
-
     val asReadonly: WithAccess<Obj> by lazy { WithAccess(this, false) }
     val asMutable: WithAccess<Obj> by lazy { WithAccess(this, true) }
 
@@ -287,36 +287,40 @@ fun Obj.toBool(): Boolean =
     (this as? ObjBool)?.value ?: throw IllegalArgumentException("cannot convert to boolean $this")
 
 
-class ObjRange(val start: Obj?, val end: Obj?,val inclusiveEnd: Boolean) : Obj() {
+class ObjRange(val start: Obj?, val end: Obj?, val isEndInclusive: Boolean) : Obj() {
 
     override val objClass: ObjClass = type
 
     override fun toString(): String {
         val result = StringBuilder()
         result.append("${start ?: '∞'} ..")
-        if( !inclusiveEnd) result.append('<')
+        if (!isEndInclusive) result.append('<')
         result.append(" ${end ?: '∞'}")
         return result.toString()
     }
 
     suspend fun containsRange(context: Context, other: ObjRange): Boolean {
-        if( start != null ) {
+        if (start != null) {
             // our start is not -∞ so other start should be GTE or is not contained:
-            if( other.start != null && start.compareTo(context, other.start) > 0) return false
+            if (other.start != null && start.compareTo(context, other.start) > 0) return false
         }
-        if( end != null ) {
+        if (end != null) {
             // same with the end: if it is open, it can't be contained in ours:
-            if( other.end == null ) return false
+            if (other.end == null) return false
             // both exists, now there could be 4 cases:
             return when {
-                other.inclusiveEnd && inclusiveEnd ->
+                other.isEndInclusive && isEndInclusive ->
                     end.compareTo(context, other.end) >= 0
-                !other.inclusiveEnd && !inclusiveEnd ->
+
+                !other.isEndInclusive && !isEndInclusive ->
                     end.compareTo(context, other.end) >= 0
-                other.inclusiveEnd && !inclusiveEnd ->
+
+                other.isEndInclusive && !isEndInclusive ->
                     end.compareTo(context, other.end) > 0
-                !other.inclusiveEnd && inclusiveEnd ->
+
+                !other.isEndInclusive && isEndInclusive ->
                     end.compareTo(context, other.end) >= 0
+
                 else -> throw IllegalStateException("unknown comparison")
             }
         }
@@ -325,7 +329,7 @@ class ObjRange(val start: Obj?, val end: Obj?,val inclusiveEnd: Boolean) : Obj()
 
     override suspend fun contains(context: Context, other: Obj): Boolean {
 
-        if( other is ObjRange)
+        if (other is ObjRange)
             return containsRange(context, other)
 
         if (start == null && end == null) return true
@@ -334,18 +338,36 @@ class ObjRange(val start: Obj?, val end: Obj?,val inclusiveEnd: Boolean) : Obj()
         }
         if (end != null) {
             val cmp = end.compareTo(context, other)
-            if (inclusiveEnd && cmp < 0 || !inclusiveEnd && cmp <= 0) return false
+            if (isEndInclusive && cmp < 0 || !isEndInclusive && cmp <= 0) return false
         }
         return true
     }
 
+    override suspend fun getAt(context: Context, index: Int): Obj {
+        if( !isIntRange ) {
+            return when (index) {
+                0 -> start ?: ObjNull
+                1 -> end ?: ObjNull
+                else -> context.raiseIndexOutOfBounds("index out of range: $index for max of 2 for non-int ranges")
+            }
+        }
+        // int range, should be finite
+        val r0 = start?.toInt() ?: context.raiseArgumentError("start is not integer")
+        var r1 = end?.toInt() ?: context.raiseArgumentError("end is not integer")
+        if( isEndInclusive ) r1++
+        val i = index + r0
+        if( i >= r1 ) context.raiseIndexOutOfBounds("index $index is not in range (${r1-r0})")
+        return ObjInt(i.toLong())
+    }
+
+
     val isIntRange: Boolean by lazy {
         start is ObjInt && end is ObjInt
     }
 
     companion object {
         val type = ObjClass("Range").apply {
-            addFn("start" ) {
+            addFn("start") {
                 thisAs<ObjRange>().start ?: ObjNull
             }
             addFn("end") {
@@ -357,8 +379,21 @@ class ObjRange(val start: Obj?, val end: Obj?,val inclusiveEnd: Boolean) : Obj()
             addFn("isIntRange") {
                 thisAs<ObjRange>().isIntRange.toObj()
             }
-            addFn("inclusiveEnd") {
+            addFn("isEndInclusive") {
-                thisAs<ObjRange>().inclusiveEnd.toObj()
+                thisAs<ObjRange>().isEndInclusive.toObj()
+            }
+            addFn("size") {
+                val self = thisAs<ObjRange>()
+                if (self.start == null || self.end == null)
+                    raiseError("size is only available for finite ranges")
+                if (self.isIntRange) {
+                    if (self.isEndInclusive)
+                        ObjInt(self.end.toLong() - self.start.toLong() + 1)
+                    else
+                        ObjInt(self.end.toLong() - self.start.toLong())
+                } else {
+                    ObjInt(2)
+                }
             }
         }
     }
@@ -378,3 +413,5 @@ class ObjNullPointerError(context: Context) : ObjError(context, "object is null"
 
 class ObjAssertionError(context: Context, message: String) : ObjError(context, message)
 class ObjClassCastError(context: Context, message: String) : ObjError(context, message)
+class ObjIndexOutOfBoundsError(context: Context,message: String="index out of bounds") : ObjError(context,message)
+class ObjIllegalArgumentError(context: Context,message: String="illegal argument") : ObjError(context,message)

library/src/commonMain/kotlin/net/sergeych/ling/ObjList.kt

@@ -6,9 +6,9 @@ class ObjList(val list: MutableList<Obj>) : Obj() {
         list.joinToString(separator = ", ") { it.inspect() }
     }]"
 
-    fun normalize(context: Context, index: Int, allowInclusiveEnd: Boolean = false): Int {
+    fun normalize(context: Context, index: Int, allowisEndInclusive: Boolean = false): Int {
         val i = if (index < 0) list.size + index else index
-        if (allowInclusiveEnd && i == list.size) return i
+        if (allowisEndInclusive && i == list.size) return i
         if (i !in list.indices) context.raiseError("index $index out of bounds for size ${list.size}")
         return i
     }
@@ -75,7 +75,7 @@ class ObjList(val list: MutableList<Obj>) : Obj() {
                     val l = thisAs<ObjList>()
                     var index = l.normalize(
                         this, requiredArg<ObjInt>(0).value.toInt(),
-                        allowInclusiveEnd = true
+                        allowisEndInclusive = true
                     )
                     for (i in 1..<args.size) l.list.add(index++, args[i])
                     ObjVoid

library/src/commonTest/kotlin/ScriptTest.kt

@@ -904,7 +904,7 @@ class ScriptTest {
             assert(r.isOpen == false)
             assert(r.start == 10)
             assert(r.end == 20)
-            assert(r.inclusiveEnd == true)
+            assert(r.isEndInclusive == true)
             assert(r.isIntRange)
             
             assert(12 in r)
@@ -938,7 +938,7 @@ class ScriptTest {
             assert(r.isOpen == false)
             assert(r.start == 10)
             assert(r.end == 20)
-            assert(r.inclusiveEnd == false)
+            assert(r.isEndInclusive == false)
             assert(r.isIntRange)
             
             assert(12 in r)