From 34758ebd78d39075dc58f88d33a28c700612121c Mon Sep 17 00:00:00 2001
From: Oskari Timperi <oskari.timperi@iki.fi>
Date: Tue, 8 Dec 2015 22:45:16 +0200
Subject: handle multiple +/- operations at the beginning of expression

---
 calc1.pas       | 26 +++++++++++++++++++++-----
 tests/calc1.txt |  6 ++++++
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/calc1.pas b/calc1.pas
index c77b427..541ae15 100644
--- a/calc1.pas
+++ b/calc1.pas
@@ -187,11 +187,27 @@ begin
 
     Op := Current;
 
-    if Op.TokenType = TT_Plus then
-        Eat(TT_Plus)
-    else if Op.TokenType = TT_Minus then
-        Eat(TT_Minus)
-    else if Op.TokenType = TT_Asterisk then
+    while (Op.TokenType = TT_Plus) or (Op.TokenType = TT_Minus) do
+    begin
+        Eat(Op.TokenType);
+
+        Right := Current;
+        Eat(TT_Integer);
+
+        if Op.TokenType = TT_Plus then
+            Result := TokenInteger(Left).Val + TokenInteger(Right).Val
+        else
+            Result := TokenInteger(Left).Val - TokenInteger(Right).Val;
+
+        TokenInteger(Left).Val := Result;
+
+        Op := Current;
+
+        if Op.TokenType = TT_Eof then
+            Exit;
+    end;
+
+    if Op.TokenType = TT_Asterisk then
         Eat(TT_Asterisk)
     else
         Eat(TT_Slash);
diff --git a/tests/calc1.txt b/tests/calc1.txt
index ad30e6e..127a498 100644
--- a/tests/calc1.txt
+++ b/tests/calc1.txt
@@ -31,3 +31,9 @@ Simple calculations
 
     10/2  5
     3*4  12
+
+Multiple Runs Of Plus And Minus
+    [Template]  The result of ${calculations} should be ${expected}
+    1+1+1  3
+    1-1-1  -1
+    5+1-2  4
-- 
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