feat(stdlib): isNaN and isFinite utility functions for Number

compiler/test/stdlib/number.test.gr

@@ -51,3 +51,33 @@ assert Number.abs(-1/2) == 1/2
 assert Number.neg(-25.5) == -25.5
 assert Number.neg(25.5) == -25.5
 assert Number.neg(1/2) == -1/2
+
+// isFinite
+assert Number.isFinite(0.0/0.0) == false // NaN
+assert Number.isFinite(1.0/0.0) == false // infinity
+assert Number.isFinite(-1.0/0.0) == false // -infinity
+assert Number.isFinite(1)
+assert Number.isFinite(1.0)
+assert Number.isFinite(0)
+assert Number.isFinite(0.0)
+assert Number.isFinite(-1)
+assert Number.isFinite(-1.0)
+assert Number.isFinite(25.76)
+assert Number.isFinite(-25.00)
+assert Number.isFinite(1/2)
+assert Number.isFinite(-1/2)
+
+// isNaN
+assert Number.isNaN(0.0/0.0)
+assert Number.isNaN(1) == false
+assert Number.isNaN(1.0) == false
+assert Number.isNaN(0) == false
+assert Number.isNaN(0.0) == false
+assert Number.isNaN(-1) == false
+assert Number.isNaN(-1.0) == false
+assert Number.isNaN(25.76) == false
+assert Number.isNaN(-25.00) == false
+assert Number.isNaN(1/2) == false
+assert Number.isNaN(-1/2) == false
+assert Number.isNaN(1.0/0.0) == false // infinity
+assert Number.isNaN(-1.0/0.0) == false // -infinity

stdlib/number.gr

@@ -1,13 +1,15 @@
 import WasmI32 from "runtime/unsafe/wasmi32"
 import WasmI64 from "runtime/unsafe/wasmi64"
+import WasmF32 from "runtime/unsafe/wasmf32"
 import WasmF64 from "runtime/unsafe/wasmf64"
 import {
   coerceNumberToWasmF64,
   reducedInteger,
-  isFloat
+  isFloat,
+  isBoxedNumber
 } from "runtime/numbers"
 import { newFloat64, newInt64 } from "runtime/dataStructures"
-
+import Tags from "runtime/unsafe/tags"
 
 /**
  * Computes the sum of its operands.
@@ -135,3 +137,61 @@ export let abs = (x: Number) => if (0 > x) x * -1 else x
  * @returns Number
  */
 export let neg = (x: Number) => if (x > 0) x * -1 else x
+
+/**
+ * Checks if a number is finite.
+ * All values are finite exept for floating point NaN, infinity or negative infinity.
+ * @param x: Number - The number to check
+ * @returns Bool
+ */
+@disableGC
+export let isFinite = (x: Number) => {
+	let asPtr = WasmI32.fromGrain(x)
+	if (isBoxedNumber(asPtr)) {
+		// Boxed numbers can have multiple subtypes, Of which float32 and float64 can be infinite,
+		let tag = WasmI32.load(asPtr, 4n)
+		if (WasmI32.eq(tag, Tags._GRAIN_FLOAT64_BOXED_NUM_TAG)) {
+			let wf64 = WasmF64.load(asPtr, 8n)
+			WasmF64.eq(WasmF64.sub(wf64, wf64), 0.W)
+		} else if (WasmI32.eq(tag, Tags._GRAIN_FLOAT32_BOXED_NUM_TAG)) {
+			let wf32 = WasmF32.load(asPtr, 8n)
+			WasmF32.eq(WasmF32.sub(wf32, wf32), 0.w)
+		} else {
+   		// Neither rational numbers nor boxed integers can be infinite or NaN.
+  		// Grain doesn't allow creating a rational with denominator of zero either.
+			true
+		}
+	} else {
+		// Simple numbers are integers and cannot be infinite.
+		true
+	}
+}
+
+/**
+ * Checks if a number contains the NaN value (Not A Number).
+ * Only boxed floating point numbers can contain NaN.
+ * @param x: Number - The number to check
+ * @returns Bool
+ */
+@disableGC
+export let isNaN = (n: Number) => {
+	let x = WasmI32.fromGrain(n)
+	if (isBoxedNumber(x)) {
+		// Boxed numbers can have multiple subtypes. Of which float32 and float64 can be NaN,
+		let tag = WasmI32.load(x, 4n)
+		if (WasmI32.eq(tag, Tags._GRAIN_FLOAT64_BOXED_NUM_TAG)) {
+			let wf64 = WasmF64.load(x, 8n)
+			WasmF64.ne(wf64, wf64)
+		} else if (WasmI32.eq(tag, Tags._GRAIN_FLOAT32_BOXED_NUM_TAG)) {
+			let wf32 = WasmF32.load(x, 8n)
+			WasmF32.ne(wf32, wf32)
+		} else {
+   		// Neither rational numbers nor boxed integers can be infinite or NaN.
+  		// Grain doesn't allow creating a rational with denominator of zero either.
+			false
+		}
+	} else {
+		// Simple numbers are integers and cannot be NaN.
+		false
+	}
+}

stdlib/runtime/numbers.gr

@@ -49,7 +49,7 @@ let isSimpleNumber = (x) => {
   WasmI32.eq(WasmI32.and(x, Tags._GRAIN_NUMBER_TAG_MASK), Tags._GRAIN_NUMBER_TAG_TYPE)
 }
 
-let isBoxedNumber = (x) => {
+export let isBoxedNumber = (x) => {
   if (WasmI32.eq(WasmI32.and(x, Tags._GRAIN_GENERIC_TAG_MASK), Tags._GRAIN_GENERIC_HEAP_TAG_TYPE)) {
     WasmI32.eq(WasmI32.load(x, 0n), Tags._GRAIN_BOXED_NUM_HEAP_TAG)
   } else {