From 6d483c0a56cc25ff677eef48e8e6250f00f0f315 Mon Sep 17 00:00:00 2001
From: hazohelet <48541090+hazohelet@users.noreply.github.com>
Date: Mon, 30 Sep 2019 00:27:53 +0900
Subject: [PATCH] parser: float1 == float2 uses machine epsilon by default

---
 compiler/parser.v       |  9 ++++++++-
 vlib/builtin/int.v      |  9 +++++++++
 vlib/builtin/int_test.v | 14 ++++++++++++++
 vlib/math/math_test.v   |  8 ++++----
 4 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/compiler/parser.v b/compiler/parser.v
index c481bc7fd3..923afef94f 100644
--- a/compiler/parser.v
+++ b/compiler/parser.v
@@ -1597,11 +1597,14 @@ fn (p mut Parser) bterm() string {
 	p.expected_type = typ
 	is_str := typ=='string'  &&   !p.is_sql
 	is_ustr := typ=='ustring'
+	is_float := typ=='f64' || typ=='f32'
+	expr_type := typ
+
 	tok := p.tok
 	// if tok in [ .eq, .gt, .lt, .le, .ge, .ne] {
 	if tok == .eq || tok == .gt || tok == .lt || tok == .le || tok == .ge || tok == .ne {
 		p.fgen(' ${p.tok.str()} ')
-		if (is_str || is_ustr) && !p.is_js {
+		if ((is_float && tok == .eq) || (is_str || is_ustr)) && !p.is_js {
 			p.gen(',')
 		}
 		else if p.is_sql && tok == .eq {
@@ -1655,6 +1658,10 @@ fn (p mut Parser) bterm() string {
 			case Token.lt: p.cgen.set_placeholder(ph, 'ustring_lt(')
 			}
 		}
+		if is_float && tok == .eq {
+			p.gen(')')
+			p.cgen.set_placeholder(ph, '${expr_type}_eq(')
+		}
 	}
 	return typ
 }
diff --git a/vlib/builtin/int.v b/vlib/builtin/int.v
index 5543d9475d..5ec3726539 100644
--- a/vlib/builtin/int.v
+++ b/vlib/builtin/int.v
@@ -29,6 +29,15 @@ pub fn ptr_str(ptr voidptr) string {
 pub fn (a f64) eq(b f64) bool {
 	return C.fabs(a - b) <= C.DBL_EPSILON	
 }
+pub fn (a f32) eq(b f32) bool {
+	return C.fabsf(a - b) <= C.FLT_EPSILON	
+}
+pub fn (a f64) eqbit(b f64) bool {
+	return C.DEFAULT_EQUAL(a, b)
+}
+pub fn (a f32) eqbit(b f32) bool {
+	return C.DEFAULT_EQUAL(a, b)
+}
 
 // fn (nn i32) str() string {
 // return i
diff --git a/vlib/builtin/int_test.v b/vlib/builtin/int_test.v
index eae41cce39..0a2389c1e6 100644
--- a/vlib/builtin/int_test.v
+++ b/vlib/builtin/int_test.v
@@ -11,6 +11,20 @@ fn test_const() {
 	assert u == 1 // make sure this works without the cast
 }
 
+fn test_float_equal_operator() {
+	mut a := f32(1)
+	a += 0.000001
+	a -= 0.000001
+	assert a == 1
+	assert !a.eqbit(1)
+
+	a = f64(1)
+	a += 0.000001
+	a -= 0.000001
+	assert a == 1
+	assert !a.eqbit(1)
+}
+
 fn test_str_methods() {
 	assert i8(1).str() == '1'
 	assert i8(-1).str() == '-1'
diff --git a/vlib/math/math_test.v b/vlib/math/math_test.v
index c52300b7db..202556489c 100644
--- a/vlib/math/math_test.v
+++ b/vlib/math/math_test.v
@@ -37,14 +37,14 @@ fn test_factorial() {
 
 fn test_erf() {
 	assert math.erf(0) == 0
-	assert (math.erf(1.5) + math.erf(-1.5)).eq(0)
+	assert math.erf(1.5) + math.erf(-1.5) == 0
 	assert math.erfc(0) == 1
-	assert (math.erf(2.5) + math.erfc(2.5)).eq(1)
-	assert (math.erfc(3.6) + math.erfc(-3.6)).eq(2)
+	assert math.erf(2.5) + math.erfc(2.5) == 1
+	assert math.erfc(3.6) + math.erfc(-3.6) == 2
 }
 
 fn test_gamma() {
 	assert math.gamma(1) == 1
 	assert math.gamma(5) == 24
-	assert math.log_gamma(4.5).eq(math.log(math.gamma(4.5)))
+	assert math.log_gamma(4.5) == math.log(math.gamma(4.5))
 }