From 16030f4b6fb5c3708849fb0f824317db4c9bcc1d Mon Sep 17 00:00:00 2001
From: Robert Krimen <robertkrimen@gmail.com>
Date: Mon, 29 Apr 2013 17:29:08 +0200
Subject: [PATCH] Make parseInt behavior correspond to the 15.1.2.3 algorithm

---
 builtin.go     | 24 +++++++++++++++++++++---
 global.go      |  2 +-
 global_test.go | 24 +++++++++++++++++-------
 3 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/builtin.go b/builtin.go
index 9fdbf73..775ad52 100644
--- a/builtin.go
+++ b/builtin.go
@@ -123,13 +123,31 @@ func builtinGlobal_parseInt(call FunctionCall) Value {
 	return toValue(value)
 }
 
+var parseFloat_matchBadSpecial = regexp.MustCompile(`[\+\-]?(?:[Ii]nf$|infinity)`)
+var parseFloat_matchValid = regexp.MustCompile(`[0-9eE\+\-\.]|Infinity`)
+
 func builtinGlobal_parseFloat(call FunctionCall) Value {
 	// Caveat emptor: This implementation does NOT match the specification
-	string_ := strings.TrimSpace(toString(call.Argument(0)))
-	value, err := strconv.ParseFloat(string_, 64)
-	if err != nil {
+	input := strings.TrimSpace(toString(call.Argument(0)))
+	if parseFloat_matchBadSpecial.MatchString(input) {
 		return NaNValue()
 	}
+	value, err := strconv.ParseFloat(input, 64)
+	if err != nil {
+		for end := len(input); end > 0; end -= 1 {
+			input := input[0:end]
+			if !parseFloat_matchValid.MatchString(input) {
+				return NaNValue()
+			}
+			value, err = strconv.ParseFloat(input, 64)
+			if err == nil {
+				break
+			}
+		}
+		if err != nil {
+			return NaNValue()
+		}
+	}
 	return toValue(value)
 }
 
diff --git a/global.go b/global.go
index 1212337..995ec35 100644
--- a/global.go
+++ b/global.go
@@ -703,7 +703,7 @@ func newContext() *_runtime {
 		"Infinity", positiveInfinityValue(),
 		"eval", -1, builtinGlobal_eval,
 		"parseInt", -2, builtinGlobal_parseInt,
-		"parseFloat", builtinGlobal_parseFloat,
+		"parseFloat", -1, builtinGlobal_parseFloat,
 		"isNaN", builtinGlobal_isNaN,
 		"isFinite", builtinGlobal_isFinite,
 		"decodeURI", builtinGlobal_decodeURI_decodeURIComponent,
diff --git a/global_test.go b/global_test.go
index 6cee9eb..b01c251 100644
--- a/global_test.go
+++ b/global_test.go
@@ -118,7 +118,9 @@ func Test_parseInt(t *testing.T) {
 	test(`parseInt(" 11 ")`, "11")
 	test(`parseInt(" 11\n")`, "11")
 	test(`parseInt(" 11\n", 16)`, "17")
+
 	test(`parseInt("Xyzzy")`, "NaN")
+
 	test(`parseInt(" 0x11\n", 16)`, "17")
 	test(`parseInt("0x0aXyzzy", 16)`, "10")
 	test(`parseInt("0x1", 0)`, "1")
@@ -126,6 +128,7 @@ func Test_parseInt(t *testing.T) {
 		// TODO
 		test(`parseInt("0x10000000000000000000", 16)`, "75557863725914323419136")
 	}
+
 	test(`parseInt.length === 2`, "true")
 	test(`parseInt.prototype === undefined`, "true")
 }
@@ -141,14 +144,21 @@ func Test_parseFloat(t *testing.T) {
 	test(`parseFloat(" 11 ")`, "11")
 	test(`parseFloat(" 11\n")`, "11")
 	test(`parseFloat(" 11\n", 16)`, "11")
-	test(`parseFloat("Xyzzy")`, "NaN")
-	test(`parseFloat("0x0a")`, "NaN")
 	test(`parseFloat("11.1")`, "11.1")
-	if false {
-		test(`parseFloat(" 0x11\n", 16)`, "17")
-		// TODO parseFloat should return 10 in this scenario
-		test(`parseFloat("0x0aXyzzy")`, "10")
-	}
+
+	test(`parseFloat("Xyzzy")`, "NaN")
+
+	test(`parseFloat(" 0x11\n", 16)`, "0")
+	test(`parseFloat("0x0a")`, "0")
+	test(`parseFloat("0x0aXyzzy")`, "0")
+	test(`parseFloat("Infinity")`, "Infinity")
+	test(`parseFloat("infinity")`, "NaN")
+	test(`parseFloat("0x")`, "0")
+	test(`parseFloat("11x")`, "11")
+	test(`parseFloat("Infinity1")`, "Infinity")
+
+	test(`parseFloat.length === 1`, "true")
+	test(`parseFloat.prototype === undefined`, "true")
 }
 
 func Test_encodeURI(t *testing.T) {