feat: Floating point arithmetic

tests/prolog/builtins/ArithmeticOperatorsTests.kt

@@ -4,8 +4,8 @@ import org.junit.jupiter.api.Assertions.*
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.api.assertThrows
 import prolog.Substitutions
-import prolog.ast.terms.Integer
-import prolog.ast.terms.Term
+import prolog.ast.arithmetic.Float
+import prolog.ast.arithmetic.Integer
 import prolog.ast.terms.Variable
 import prolog.logic.equivalent
 
@@ -285,6 +285,111 @@ class ArithmeticOperatorsTests {
         assertEquals(0, result.size, "X should not be equal to Y")
     }
 
+    @Test
+    fun `var is mul`() {
+        val op = Is(
+            Variable("X"),
+            Multiply(Integer(2), Integer(3))
+        )
+
+        val result = op.satisfy(emptyMap()).toList()
+
+        assertEquals(1, result.size, "X should be equal to 6")
+        assertTrue(result[0].isSuccess, "X should be equal to 6")
+        val subs = result[0].getOrNull()!!
+        assertEquals(1, subs.size, "X should be rebound")
+        assertTrue(
+            equivalent(Integer(6), subs[Variable("X")]!!, emptyMap()),
+            "X should be equal to 6"
+        )
+    }
+
+    @Test
+    fun `bound-var is mul`() {
+        val t1 = Variable("X")
+
+        val op = Is(
+            t1,
+            Multiply(Integer(2), Integer(3))
+        )
+        val map: Substitutions = mapOf(t1 to Integer(6))
+
+        val result = op.satisfy(map).toList()
+
+        assertEquals(1, result.size, "X should be equal to 6")
+        assertTrue(result[0].isSuccess, "X should be equal to 6")
+        val subs = result[0].getOrNull()!!
+        assertTrue(subs.isEmpty(), "X should not be rebound")
+    }
+
+    @Test
+    fun `var is bound-to-mul`() {
+        val t1 = Variable("X")
+        val t2 = Variable("Y")
+
+        val op = Is(t1, t2)
+        val map: Substitutions = mapOf(t1 to Integer(6), t2 to Multiply(Integer(2), Integer(3)))
+
+        val result = op.satisfy(map).toList()
+
+        assertEquals(1, result.size, "X should be equal to Y")
+        assertTrue(result[0].isSuccess, "X should be equal to Y")
+        val subs = result[0].getOrNull()!!
+        assertTrue(subs.isEmpty(), "X should not be rebound")
+    }
+
+    @Test
+    fun `2 is 4 div 2`() {
+        val op = Is(
+            Integer(2),
+            Divide(Integer(4), Integer(2))
+        )
+
+        val result = op.satisfy(emptyMap()).toList()
+
+        assertEquals(1, result.size, "2 should be equal to 4 / 2")
+        assertTrue(result[0].isSuccess, "2 should be equal to 4 / 2")
+        val subs = result[0].getOrNull()!!
+        assertTrue(subs.isEmpty(), "2 should not be rebound")
+    }
+
+    @Test
+    fun `4 div 2 is var`() {
+        val op = Is(
+            Variable("X"),
+            Divide(Integer(4), Integer(2))
+        )
+
+        val result = op.satisfy(emptyMap()).toList()
+
+        assertEquals(1, result.size, "X should be equal to 2")
+        assertTrue(result[0].isSuccess, "X should be equal to 2")
+        val subs = result[0].getOrNull()!!
+        assertEquals(1, subs.size, "X should be rebound")
+        assertTrue(
+            equivalent(Integer(2), subs[Variable("X")]!!, emptyMap()),
+            "X should be equal to 2"
+        )
+    }
+
+    @Test
+    fun `bound-var is 4 div 2`() {
+        val t1 = Variable("X")
+
+        val op = Is(
+            t1,
+            Divide(Integer(4), Integer(2))
+        )
+        val map: Substitutions = mapOf(t1 to Integer(2))
+
+        val result = op.satisfy(map).toList()
+
+        assertEquals(1, result.size, "X should be equal to 2")
+        assertTrue(result[0].isSuccess, "X should be equal to 2")
+        val subs = result[0].getOrNull()!!
+        assertTrue(subs.isEmpty(), "X should not be rebound")
+    }
+
     /**
      * ?- between(1, 2, X), Y is 1 + X.
      * X = 1, Y = 2 ;
@@ -441,4 +546,44 @@ class ArithmeticOperatorsTests {
 
         assertEquals(Integer(6), result.to, "2 * 3 should be equal to 6")
     }
+
+    @Test
+    fun `Divide 1 and 1 to get 1`() {
+        val t1 = Integer(1)
+        val t2 = Integer(1)
+
+        val result = Divide(t1, t2).simplify(emptyMap())
+
+        assertEquals(Integer(1), result.to, "1 / 1 should be equal to 1")
+    }
+
+    @Test
+    fun `Divide 2 and 2 to get 1`() {
+        val t1 = Integer(2)
+        val t2 = Integer(2)
+
+        val result = Divide(t1, t2).simplify(emptyMap())
+
+        assertEquals(Integer(1), result.to, "2 / 2 should be equal to 1")
+    }
+
+    @Test
+    fun `Divide 12 and 3 to get 4`() {
+        val t1 = Integer(12)
+        val t2 = Integer(3)
+
+        val result = Divide(t1, t2).simplify(emptyMap())
+
+        assertEquals(Integer(4), result.to, "12 / 3 should be equal to 4")
+    }
+
+    @Test
+    fun `Divide 1 and 2 to get float`() {
+        val t1 = Integer(1)
+        val t2 = Integer(2)
+
+        val result = Divide(t1, t2).simplify(emptyMap())
+
+        assertTrue(equivalent(result.to, Float(0.5f), emptyMap()), "1 / 2 should be equal to 0.5")
+    }
 }