class constants added and class instances for integral types

docs/OOP.md

@@ -40,14 +40,28 @@ Class is the object, naturally, with class:
 
 Classes can be compared:
 
-    println(1.21::class == Math.PI::class)
-    println(3.14::class == 1::class)
-    println(π::class)
-    >>> true
-    >>> false
+    assert(1.21::class == Math.PI::class)
+    assert(3.14::class != 1::class)
+    assert(π::class == Real)
+    π::class
     >>> Real
+
+Note `Real` class: it is global variable for Real class; there are such class instances for all built-in types:
+
+    assert("Hello"::class == String)
+    assert(1970::class == Int)
+    assert(true::class == Bool)
     >>> void
 
+More complex is singleton classes, because you don't need to compare their class
+instances and generally don't need them at all, these are normally just Obj:
+
+    null::class
+    >>> Obj
+
+At this time, `Obj` can't be accessed as a class.
+
+
 ### Methods in-depth
 
 Regular methods are called on instances as usual `instance.method()`. The method resolution order is

docs/Real.md

@@ -0,0 +1,25 @@
+# Real built-in class
+
+Class that supports double-precision math. Woks much like double in other languages. We honor no floats, so it is '
+Real'.
+
+It's class in Ling is `Real`:
+
+    (π/2)::class
+    >>> Real
+
+you can use it's class to ensure type:
+
+    1.71::class == Real
+    >>> true
+
+## Member functions
+
+| name         | meaning                            | type |
+|--------------|------------------------------------|------|
+| `roundToInt` | round to nearest int like round(x) | Int  |
+|              |                                    |      |
+|              |                                    |      |
+|              |                                    |      |
+|              |                                    |      |
+|              |                                    |      |

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

@@ -13,6 +13,12 @@ data class Arguments(val list: List<Info>): Iterable<Obj> {
         return list.first().value
     }
 
+    inline fun <reified T: Obj>required(index: Int, context: Context): T {
+        if( list.size <= index ) context.raiseError("Expected at least ${index+1} argument, got ${list.size}")
+        return (list[index].value as? T)
+            ?: context.raiseError("Expected type ${T::class.simpleName}, got ${list[index].value::class.simpleName}")
+    }
+
     companion object {
         val EMPTY = Arguments(emptyList())
     }

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

@@ -67,7 +67,7 @@ class Context(
         }
     }
 
-    inline fun <reified T> addConst(value: T, vararg names: String) {
+    inline fun <reified T> addConstWithAliases(value: T, vararg names: String) {
         val obj = Obj.from(value)
         for (name in names) {
             addItem(
@@ -78,6 +78,8 @@ class Context(
         }
     }
 
+    fun addConst(name: String,value: Obj) = addItem(name, false, value)
+
     suspend fun eval(code: String): Obj =
         Compiler().compile(code.toSource()).execute(this)
 

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

@@ -190,6 +190,13 @@ data class ObjString(val value: String) : Obj() {
     }
 
     override fun toString(): String = value
+
+    override val objClass: ObjClass
+        get() = type
+
+    companion object {
+        val type = ObjClass("String")
+    }
 }
 
 interface Numeric {
@@ -273,10 +280,14 @@ data class ObjInt(var value: Long) : Obj(), Numeric {
     }
 
     override fun toString(): String = value.toString()
+
+    override val objClass: ObjClass = type
+
+    companion object {
+        val type = ObjClass("Int")
+    }
 }
 
-@Serializable
-@SerialName("bool")
 data class ObjBool(val value: Boolean) : Obj() {
     override val asStr by lazy { ObjString(value.toString()) }
 
@@ -286,6 +297,12 @@ data class ObjBool(val value: Boolean) : Obj() {
     }
 
     override fun toString(): String = value.toString()
+
+    override val objClass: ObjClass = type
+
+    companion object {
+        val type = ObjClass("Bool")
+    }
 }
 
 data class ObjNamespace(val name: String) : Obj() {
@@ -300,3 +317,4 @@ open class ObjError(val context: Context, val message: String) : Obj() {
 
 class ObjNullPointerError(context: Context) : ObjError(context, "object is null")
 
+class ObjAssertionError(context: Context, message: String) : ObjError(context, message)

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

@@ -21,8 +21,8 @@ class Script(
         val defaultContext: Context = Context().apply {
             addFn("println") {
                 print("yn: ")
-                for( (i,a) in args.withIndex() ) {
-                    if( i > 0 ) print(' ' + a.asStr.value)
+                for ((i, a) in args.withIndex()) {
+                    if (i > 0) print(' ' + a.asStr.value)
                     else print(a.asStr.value)
                 }
                 println()
@@ -30,28 +30,39 @@ class Script(
             }
             addFn("floor") {
                 val x = args.firstAndOnly()
-                if( x is ObjInt ) x
+                if (x is ObjInt) x
                 else ObjReal(floor(x.toDouble()))
             }
             addFn("ceil") {
                 val x = args.firstAndOnly()
-                if( x is ObjInt ) x
+                if (x is ObjInt) x
                 else ObjReal(ceil(x.toDouble()))
             }
             addFn("round") {
                 val x = args.firstAndOnly()
-                if( x is ObjInt ) x
+                if (x is ObjInt) x
                 else ObjReal(round(x.toDouble()))
             }
             addFn("sin") {
                 sin(args.firstAndOnly().toDouble())
             }
+
+            addFn("assert") {
+                val cond = args.required<ObjBool>(0, this)
+                if( !cond.value == true )
+                    raiseError(ObjAssertionError(this,"Assertion failed"))
+            }
+
+            addConst("Real", ObjReal.type)
+            addConst("String", ObjString.type)
+            addConst("Int", ObjInt.type)
+            addConst("Bool", ObjBool.type)
             val pi = ObjReal(PI)
             val z = pi.objClass
             println("PI class $z")
-            addConst(pi, "π")
+            addConst("π", pi)
             getOrCreateNamespace("Math").apply {
-                addConst( "PI", pi)
+                addConst("PI", pi)
             }
         }
     }

library/src/jvmTest/kotlin/BookTest.kt

@@ -189,7 +189,13 @@ class BookTest {
     }
 
     @Test
-    fun testsFromOOPrinciples() = runTest {
+    fun testsFromOOP() = runTest {
         runDocTests("../docs/OOP.md")
     }
+
+    @Test
+    fun testFromReal() = runTest {
+        runDocTests("../docs/real.md")
+    }
+
 }