Implement the _TALLY system variable for the COUNT command

src/Common/FoxProCmd.xh

@@ -162,6 +162,42 @@
 #command DIR               => __VfpDir( "" )
 #command DIRECTORY         => __VfpDir( "" )
 
+// COUNT — the VO rule in dbcmd.xh requires the TO clause (it expands to
+// "<xvar> := 0", which leaves a dangling ":=" when TO is omitted) and never
+// updates _TALLY. VFP accepts the TO clause both right after COUNT and at the
+// end, so both orders need their own rule: an optional clause cannot be matched
+// across a mandatory one.
+#command COUNT                                                          ;
+         [ALL]                                                          ;
+         [<REST:REST>]                                                  ;
+         [NEXT <nnext>]                                                 ;
+         [RECORD <rec>]                                                 ;
+         [FOR <lfor>]                                                   ;
+         [WHILE <lwhile>]                                               ;
+         [<noopt: NOOPTIMIZE>]                                          ;
+      => __VfpCount( <{lfor}>, <{lwhile}>, <nnext>, <rec>, <.rest.>, <.noopt.> )
+
+#command COUNT TO <xvar>                                                ;
+         [ALL]                                                          ;
+         [<REST:REST>]                                                  ;
+         [NEXT <nnext>]                                                 ;
+         [RECORD <rec>]                                                 ;
+         [FOR <lfor>]                                                   ;
+         [WHILE <lwhile>]                                               ;
+         [<noopt: NOOPTIMIZE>]                                          ;
+      => <xvar> := __VfpCount( <{lfor}>, <{lwhile}>, <nnext>, <rec>, <.rest.>, <.noopt.> )
+
+#command COUNT                                                          ;
+         [ALL]                                                          ;
+         [<REST:REST>]                                                  ;
+         [NEXT <nnext>]                                                 ;
+         [RECORD <rec>]                                                 ;
+         [FOR <lfor>]                                                   ;
+         [WHILE <lwhile>]                                               ;
+         TO <xvar>                                                      ;
+         [<noopt: NOOPTIMIZE>]                                          ;
+      => <xvar> := __VfpCount( <{lfor}>, <{lwhile}>, <nnext>, <rec>, <.rest.>, <.noopt.> )
+
 // WAIT
 #xcommand WAIT <msg> [<win:WINDOW> [AT <nRow>, <nCol>]] [<now:NOWAIT>] [<nclr:NOCLEAR>] [TIMEOUT <secs>] ;
     => __VfpWait(<msg>, <.win.>, <!nRow!>, <!nCol!>, <.now.>, <.nclr.>, <!secs!>)

src/Runtime/XSharp.VFP.Tests/TallyTests.prg

@@ -0,0 +1,135 @@
+//
+// Copyright (c) XSharp B.V.  All Rights Reserved.
+// Licensed under the Apache License, Version 2.0.
+// See License.txt in the project root for license information.
+//
+
+USING System
+USING XUnit
+
+BEGIN NAMESPACE XSharp.VFP.Tests
+    CLASS TallyTests
+
+        STATIC CONSTRUCTOR
+            XSharp.RuntimeState.Dialect := XSharpDialect.FoxPro
+        END CONSTRUCTOR
+
+        PRIVATE METHOD CreateTestCursor() AS VOID
+            CREATE CURSOR curtally (f I)
+            INSERT INTO curtally VALUES (1)
+            INSERT INTO curtally VALUES (2)
+            INSERT INTO curtally VALUES (3)
+            INSERT INTO curtally VALUES (4)
+            INSERT INTO curtally VALUES (5)
+            GO TOP
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountWithoutToClauseSetsTally AS VOID
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT
+                Assert.Equal(5, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountWithForSetsTally AS VOID
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT FOR curtally->f > 2
+                Assert.Equal(3, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountToVariableSetsBothTheVariableAndTally AS VOID
+            LOCAL n AS USUAL
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT TO n
+                Assert.Equal(5, (INT) n)
+                Assert.Equal(5, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountAcceptsToBeforeFor AS VOID
+            LOCAL n AS USUAL
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT TO n FOR curtally->f > 3
+                Assert.Equal(2, (INT) n)
+                Assert.Equal(2, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountAcceptsToAfterFor AS VOID
+            LOCAL n AS USUAL
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT FOR curtally->f > 3 TO n
+                Assert.Equal(2, (INT) n)
+                Assert.Equal(2, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountAcceptsScopeBeforeFor AS VOID
+            LOCAL n AS USUAL
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT ALL FOR curtally->f > 2 TO n NOOPTIMIZE
+                Assert.Equal(3, (INT) n)
+                Assert.Equal(3, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD CountNextLimitsTheScope AS VOID
+            LOCAL n AS USUAL
+            TRY
+                SELF:CreateTestCursor()
+                _TALLY := -1
+                COUNT NEXT 3 TO n
+                Assert.Equal(3, (INT) n)
+                Assert.Equal(3, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+        [Fact, Trait("Category", "Tally")];
+        METHOD NavigationDoesNotChangeTally AS VOID
+            TRY
+                SELF:CreateTestCursor()
+                COUNT
+                _TALLY := 99
+                GO TOP
+                Assert.Equal(99, (INT) _TALLY)
+            FINALLY
+                USE
+            END TRY
+        END METHOD
+
+    END CLASS
+END NAMESPACE

src/Runtime/XSharp.VFP.Tests/XSharp.VFP.Tests.xsproj

@@ -108,6 +108,7 @@
     <Compile Include="SetDateCommandTests.prg" />
     <Compile Include="SQLStatementTests.prg" />
     <Compile Include="StrConvTests.prg" />
+    <Compile Include="TallyTests.prg" />
     <Compile Include="TypeTests.prg" />
     <Compile Include="EmptyTests.prg" />
     <Compile Include="FoxArraytests.prg" />

src/Runtime/XSharp.VFP/Commands.prg

@@ -224,3 +224,10 @@ FUNCTION __VfpWaitForKey(uTimeout AS USUAL) AS STRING
 
 function __VfpWaitClear() as void
     return
+
+/// <exclude/>
+FUNCTION __VfpCount(cbFor, cbWhile, nNext, nRecord, lRest, lNoOpt) AS LONG CLIPPER
+    LOCAL nCount := 0 AS LONG
+    DbEval({|| nCount += 1}, cbFor, cbWhile, nNext, nRecord, lRest, lNoOpt)
+    _TALLY := nCount
+    RETURN nCount