From 80861f2219705b4101293c4ccb0aa033d090d4a1 Mon Sep 17 00:00:00 2001
From: penguindark <57967770+penguindark@users.noreply.github.com>
Date: Mon, 17 Feb 2020 02:35:01 +0100
Subject: [PATCH] scanner: exponent without sign

---
 vlib/compiler/scanner.v       | 9 +++++++--
 vlib/v/scanner/scanner.v      | 9 +++++++--
 vlib/v/scanner/scanner_test.v | 9 +++++++++
 3 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/vlib/compiler/scanner.v b/vlib/compiler/scanner.v
index 855c1c1e3c..f1c2d23750 100644
--- a/vlib/compiler/scanner.v
+++ b/vlib/compiler/scanner.v
@@ -213,8 +213,13 @@ fn (s mut Scanner) ident_dec_number() string {
 	}
 	// scan exponential part
 	mut has_exponential_part := false
-	if s.expect('e+', s.pos) || s.expect('e-', s.pos) {
-		exp_start_pos := s.pos += 2
+	if s.expect('e', s.pos) || s.expect('E', s.pos) {
+		exp_start_pos := (s.pos++)
+
+		if s.text[s.pos] in [`-`, `+`] {
+			s.pos++
+		}
+
 		for s.pos < s.text.len && s.text[s.pos].is_digit() {
 			s.pos++
 		}
diff --git a/vlib/v/scanner/scanner.v b/vlib/v/scanner/scanner.v
index dfca75dddc..331aac7efb 100644
--- a/vlib/v/scanner/scanner.v
+++ b/vlib/v/scanner/scanner.v
@@ -208,8 +208,13 @@ fn (s mut Scanner) ident_dec_number() string {
 	}
 	// scan exponential part
 	mut has_exponential_part := false
-	if s.expect('e+', s.pos) || s.expect('e-', s.pos) {
-		exp_start_pos := s.pos += 2
+	if s.expect('e', s.pos) || s.expect('E', s.pos) {
+		exp_start_pos := (s.pos++)
+
+		if s.text[s.pos] in [`-`, `+`] {
+			s.pos++
+		}
+
 		for s.pos < s.text.len && s.text[s.pos].is_digit() {
 			s.pos++
 		}
diff --git a/vlib/v/scanner/scanner_test.v b/vlib/v/scanner/scanner_test.v
index 7c7553c563..6c3f3c0b28 100644
--- a/vlib/v/scanner/scanner_test.v
+++ b/vlib/v/scanner/scanner_test.v
@@ -33,7 +33,16 @@ fn test_scan() {
 	assert c == 9
 	c = 1_000_000
 	assert c == 1000000
+	
+	// test float conversion and reading
 	d := f64(23_000_000e-3)
 	assert int(d) == 23000 
+	mut e := f64(1.2E3) * f64(-1e-1)
+	assert e == -120.0
+	e = f64(1.2E3) * f64(1e-1)
+	assert e == 120.0
+	assert 1.23e+10 == 1.23e10
+	assert 1.23e+10 == 1.23e0010
+	assert -1.23e+10 == 1.23e0010*-1.0
 }