From 54adfe2c77d5a85d1575a5384eac0100abe38b8d Mon Sep 17 00:00:00 2001
From: "Michael D. Lowis" <mike@mdlowis.com>
Date: Tue, 10 Jul 2012 02:04:08 -0400
Subject: [PATCH] Added testes for exponent recognition

---
 source/lexer.scm     |  7 ++++---
 tests/test_lexer.scm | 45 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+), 3 deletions(-)

diff --git a/source/lexer.scm b/source/lexer.scm
index cfea702..9bda857 100644
--- a/source/lexer.scm
+++ b/source/lexer.scm
@@ -79,9 +79,10 @@
 (define (dlang/exponent in)
   (string-append
     ;(string (char-match-one-of in '(#\e #\E)))
-    (if (char=? (buf-lookahead! in 1) #\e)
-      (match in #\e) (match in #\E))
-    (dlang/integer in "")))
+    (string
+      (if (char=? (buf-lookahead! in 1) #\e)
+        (char-match in #\e) (char-match in #\E)))
+    (dlang/integer in)))
 
 (define (dlang/character in)
   (token 'character
diff --git a/tests/test_lexer.scm b/tests/test_lexer.scm
index 460f0dc..8b2be37 100644
--- a/tests/test_lexer.scm
+++ b/tests/test_lexer.scm
@@ -96,6 +96,51 @@
 
 ; dlang/exponent
 ;------------------------------------------------------------------------------
+(def-test "dlang/exponent should recognize an exponent of length one"
+  (call-with-input-string "e0"
+    (lambda (input)
+      (define buffer (buf input read-char))
+      (define result (dlang/exponent buffer))
+      (and (string? result)
+           (equal? "e0" result)))))
+
+(def-test "dlang/exponent should recognize an exponent of length two"
+  (call-with-input-string "e01"
+    (lambda (input)
+      (define buffer (buf input read-char))
+      (define result (dlang/exponent buffer))
+      (and (string? result)
+           (equal? "e01" result)))))
+
+(def-test "dlang/exponent should recognize an exponent of length three"
+  (call-with-input-string "e012"
+    (lambda (input)
+      (define buffer (buf input read-char))
+      (define result (dlang/exponent buffer))
+      (and (string? result)
+           (equal? "e012" result)))))
+
+(def-test "dlang/exponent should recognize an exponent with uppercase E"
+  (call-with-input-string "E012"
+    (lambda (input)
+      (define buffer (buf input read-char))
+      (define result (dlang/exponent buffer))
+      (and (string? result)
+           (equal? "E012" result)))))
+
+(def-test "dlang/exponent should error when no integer portion in input"
+  (call-with-input-string "e "
+    (lambda (input)
+      (define buffer (buf input read-char))
+      (check-error "Expected an integer"
+        (dlang/exponent buffer)))))
+
+(def-test "dlang/exponent should error when EOF"
+  (call-with-input-string ""
+    (lambda (input)
+      (define buffer (buf input read-char))
+      (check-error "Expected 'E', received EOF instead"
+        (dlang/exponent buffer)))))
 
 ; dlang/character
 ;------------------------------------------------------------------------------
-- 
2.52.0